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Page 2 User’s Guide Agilent 86121A WDM Channel Analyzer...
Page 3 Reproduction, adaptation, marked on prod- Warranty. No other warranty is or translation without ucts which have a This Agilent Technologies expressed or implied. Agi- prior written permission is laser output. instrument product is war- lent Technologies specifi- prohibited, except as...
Page 4: General Safety Considerations
General Safety Considerations General Safety Considerations This product has been designed and tested in accor- dance with IEC Publication 1010, Safety Requirements for Electronic Measuring Apparatus, and has been sup- plied in a safe condition. The instruction documentation contains information and warnings which must be fol- lowed by the user to ensure safe operation and to main- tain the product in a safe condition.
Page 5 General Safety Considerations There is no output laser aperture The Agilent 86121A does not have an output laser aperture. However, light less than 1 nw escapes out of the front-panel OPTICAL INPUT connector. Operator maintenance or precau- tions are not necessary to maintain safety. No controls, adjust- ments, or performance of procedures result in hazardous radiation exposure.
Page 6 General Safety Considerations C A U T I O N This product has autoranging line voltage input. Be sure the supply voltage is within the specified range. C A U T I O N Ventilation Requirements. When installing the product in a cabinet, the convection into and out of the product must not be restricted.
Page 8: Table Of Contents
Getting Started Setting Up the WDM Channel Analyzer 1-2 Chapter 2 A Quick Tour A Quick Tour 2-2 Agilent 86121A Front and Rear Panels 2-3 WDM Channel Analyzer Display 2-5 Front-Panel Keys 2-7 The Softkeys 2-9 Changing the Printer Paper 2-14...
Page 9 Regulatory Information 7-13 Chapter 8 Reference Options and Accessories 8-2 Error Messages 8-3 Front-Panel Fiber-Optic Adapters 8-9 Power Cords 8-10 Cleaning Connections for Accurate Measurements 8-11 Printer Head Cleaning Procedure 8-22 Returning the Instrument for Service 8-25 Agilent Technologies Service Offices 8-28...
Page 10: Getting Started
Chapter 1 Getting Started...
Page 11: Setting Up The Wdm Channel Analyzer
Setting Up the WDM Channel Analyzer Setting Up the WDM Channel Analyzer This chapter shows you how to set up your WDM chan- nel analyzer, and connect the power and accessories. Refer to Chapter 8, “Reference” for the following addi- tional information: •...
Page 12 Setting Up the WDM Channel Analyzer Package contents for the 86121A WDM Channel Analyzer ❒ Inspect the shipping container for damage. ❒ Inspect the instrument. ❒ Verify you received the options and accessories you or- dered. Keep the shipping container and cushioning material...
Page 13 Setting Up the WDM Channel Analyzer 1 Locate the line-input connector on the rear panel of the instrument. 2 Disconnect the line-power cable if it is connected. 3 Use a small flat-blade screwdriver to open the pull-out fuse drawer. 4 Verify that the value of the line-voltage fuse in the pull- out drawer is correct.
Page 14 Setting Up the WDM Channel Analyzer You can connect a PCL-language printer to the Parallel connector on the rear panel of the instrument. Use a parallel Centronics printer cable, such as the C2950A (2 m) or C2951A (3 m).
Page 15 Setting Up the WDM Channel Analyzer The WDM channel analyzer automatically adjusts for line input voltages in the range of 100 to 240 VAC. There is no manual selection switch. The line cord is matched to the country of origin of the order. Refer to “Power Cords”...
Page 16 Setting Up the WDM Channel Analyzer Press the power switch at the lower-left corner of the front panel. After a short initialization period, the display will look similar to the figure shown below. If the WDM channel analyzer fails to turn on properly, consider the following possibilities: •...
Page 17 Setting Up the WDM Channel Analyzer In order for the WDM channel analyzer to accurately measure wavelengths and meet its published specifica- tions, you must enter the elevation where you will be performing your measurements. 1 Press the Setup key. 2 Press the MORE softkey.
Page 18 Setting Up the WDM Channel Analyzer The Preset key on the instrument sets the entire WDM channel analyzer wavelength range of 1270–1650 nm. If a user-defined wavelength range limit was set using WL LIM, the following procedure will ensure that responses across the full wavelength range are mea- sured.
Page 19 1-10 Setting Up the WDM Channel Analyzer C A U T I O N Fiber-optic connectors are easily damaged when connected to dirty or damaged cables and accessories. The front-panel INPUT connector of the WDM channel analyzer is no exception. When you use improper cleaning and handling techniques, you risk expensive instrument repairs, damaged cables, and compromised measurements.
Page 20 Setting Up the WDM Channel Analyzer 1-11 To learn more about this or any Agilent Technologies product, visit our web site at http://www.agilent.com. To learn more about Fiber Optic Test Equipment, go to the Agilent Technologies home page listed above, and follow this path: 1 Click Products.
Page 22: A Quick Tour
Chapter 2 A Quick Tour Agilent 86121A Front and Rear Panels 2-3 WDM Channel Analyzer Display 2-5 Front-Panel Keys 2-7 The Softkeys 2-9 The Startup menu 2-9 The Signal-to-Noise measurement menu 2-9 The Drift measurement menu 2-10 The Delta measurement menu 2-10...
Page 23 Agilent 86121A simultaneously measures multiple laser lines, you can characterize wavelength-division-multi- plexed (WDM) systems. Characterize laser lines easily With the Agilent 86121A you can quickly and easily measure any of the following parameters: • Measure up to 200 laser lines simultaneously • Wavelengths and powers •...
Page 24: Agilent 86121A Front And Rear Panels
Agilent 86121A Front and Rear Panels Agilent 86121A Front and Rear Panels...
Page 25 Agilent 86121A Front and Rear Panels...
Page 26: Wdm Channel Analyzer Display
WDM Channel Analyzer Display WDM Channel Analyzer Display Display after the front-panel Run key is pressed Delta Annotation Selected Line The Delta display The Drift display...
Page 27 WDM Channel Analyzer Display The S/N with Averaging display...
Page 28: Front-Panel Keys
Front-Panel Keys Front-Panel Keys The WDM channel analyzer has front-panel keys that perform a function when pressed. The analyzer continuously measures the input spec- trum at the front-panel OPTICAL INPUT connector. When- ever measurements are being acquired, an asterisk (*) is displayed in the display’s upper-right corner.
Page 29 Front-Panel Keys Sets the WDM channel analyzer to a known state. Preset Conditions Settings after Preset Settings after Power is Item Key is Pressed Turned On Wavelength range limiting last state Start wavelength 1270 nm last state Stop wavelength 1650 nm last state Graphical display Measurement acquisition...
Page 30: The Softkeys
The Softkeys The Softkeys The softkeys can be accessed using the front-panel keys. This section includes brief descriptions of the menus. Chapter 3, “Making Measurements” for additional information on each of the WDM channel analyzer func- tions. The Startup menu These are the softkeys visible on instrument startup.
Page 31 2-10 The Softkeys The Drift measurement menu The Drift measurement softkeys are accessed by press- ing the front-panel Drift key. The Delta measurement menu The Delta measurement softkeys are accessed by press- ing the front-panel Delta key.
Page 32 The Softkeys 2-11 The Setup menu...
Page 33 2-12 The Softkeys The Disk menu The Printer menu...
Page 34 8-11. C A U T I O N The input circuitry of the Agilent 86121A can be damaged when the total input power level, the sum of all lines input, exceeds +18 dBm. To prevent input damage,...
Page 35: Changing The Printer Paper
2-14 Changing the Printer Paper Changing the Printer Paper...
Page 36 Avoid dropping the coin or screwdriver, used to open the printer door, into the printer assembly. C A U T I O N Always use Agilent Technologies brand paper to ensure quality printing and long printer life. Order paper as Agilent part number 9270-1370.
Page 38 Chapter 3 Making Measurements Measuring Wavelength and Power 3-3 Limiting the wavelength measurement range 3-3 Measuring broadband devices and chirped lasers 3-4 Graphical display of optical power spectrum 3-5 Instrument states 3-6 Power bar 3-6 Changing the Units and Measurement Rate 3-7 Displayed units 3-7 Measurement rate 3-7 Defining Laser-Line Peaks 3-9...
Page 39: Making Measurements
C A U T I O N Do not exceed +18 dBm input power. The Agilent 86121A’s input circuitry can be damaged when total input power exceeds 18 dBm. You can measure power levels that are greater by adding attenuation and entering a power offset as described in “To measure total...
Page 40: Measuring Wavelength And Power
Measuring Wavelength and Power Measuring Wavelength and Power Limiting the wavelength measurement range 3-3 Measuring broadband devices and chirped lasers 3-4 Graphical display of optical power spectrum 3-5 Instrument states 3-6 Power bar 3-6 Note If the measured amplitudes are low, clean the front-panel OPTI- CAL INPUT connector.
Page 41 Measuring Wavelength and Power value and then press RETURN when you are done. Measuring broadband devices and chirped lasers When first turned on, or when the green Preset key is pressed, the WDM channel analyzer is configured to measure narrowband devices such as DFB lasers and modes of FP lasers.
Page 42 Measuring Wavelength and Power Graphical display of optical power spectrum A graphical display of optical power versus wavelength is shown from the start wavelength value to the stop wavelength value. The start wavelength value is shown in the upper-left corner of the graphical display, and the stop wavelength value is shown in the upper-right cor- ner of the graphical display.
Page 43 Measuring Wavelength and Power Instrument states Four different instrument states can be saved and recalled at a later time. The actual instrument condi- tions that are saved are identical to those saved from the previous state after power is turned on. These con- ditions are shown in the table on page 2-8.
Page 44: Changing The Units And Measurement Rate
86121A can be set to update approximately two times per second. This reduces both wavelength resolution and accuracy but can be benefi- cial in some applications.
Page 45 Changing the Units and Measurement Rate NOTE When measuring laser lines carrying data at 10 Gb/s in NOR- MAL update mode, the instrument resolution is less than the modulation bandwidth of the laser lines. In this case, the dis- played power of the laser lines will be less than the actual power by approximately 1 dB.
Page 46: Defining Laser-Line Peaks
Defining Laser-Line Peaks Defining Laser-Line Peaks The Agilent 86121 WDM Channel Analyzer uses two rules to identify valid laser-line peaks. Understanding these rules is essential to getting the most from your measurements. For example, these rules allow you to “hide” AM modulation sidebands or locate laser lines with small amplitudes.
Page 47 3-10 Defining Laser-Line Peaks Peak excursion The peak excursion defines the rise and fall in ampli- tude that must take place in order for a laser line to be recognized. The rise and fall can be out of the noise, or in the case of two closely spaced signals, out of the filter skirts of the adjacent signal.
Page 48 Defining Laser-Line Peaks 3-11 To define laser-line peaks 1 Press the Setup key. 2 Press the THRSHLD softkey. 3 Press PX EXC, and enter the peak excursion value. Use softkey to select the digit that requires editing. Use the softkeys to change the value. The peak excursion value can range from 1 to 30 dB.
Page 49: Measuring Laser Separation
3-12 Measuring Laser Separation Measuring Laser Separation To measure channel separation 3-13 You can use relative power measurements to measure flatness (pre-emphasis) in a WDM system. Simply select one carrier as the reference and measure the remaining carriers relative to the reference level. The power difference represents the system flatness.
Page 50 Measuring Laser Separation 3-13 The WDM channel analyzer displays separation on this spectrum as shown in the following figure. Notice that the 1541.747 nm laser line is selected as the reference. It is shown in absolute units. The wavelengths and pow- ers of the remaining responses are shown relative to this reference.
Page 51 3-14 Measuring Laser Separation Press RESET to turn off the delta calculations so that all responses are shown in absolute wavelength and pow- ers. To measure flatness 1 Press the front-panel Delta key. 2 Select ∆ PWR. 3 Use the softkeys to select the laser line with the greatest power level.
Page 52: Measuring Laser Drift
Measuring Laser Drift 3-15 Measuring Laser Drift In this section, you’ll learn how the WDM channel ana- lyzer can be used to monitor drift (changes to the wave- length and amplitude of a laser over time). Drift is measured simultaneously for every laser line. The WDM channel analyzer keeps track of the initial, current, min- imum, and maximum values of each laser line and dis- plays their differences relative to itself.
Page 53 3-16 Measuring Laser Drift If measurement updating stops or the values become blanked If, in the middle of a measurement, the number of laser lines present changes, the measurement stops until the original number of lines returns. You’ll notice that a CLEAR softkey appears and one of the following messages is displayed: E46 NUM LINES <...
Page 54 Measuring Laser Drift 3-17 Display shows absolute minimum values since the drift measurement was started. This measurement gives the shortest wavelength and smallest power measured. The laser line of interest may have since drifted to a greater value. Note that the minimum wavelength and mini- mum power may not have occurred simultaneously.
Page 55: Measuring Signal-To-Noise Ratios With Averaging
3-18 Measuring Signal-to-Noise Ratios with Averaging Measuring Signal-to-Noise Ratios with Averaging Signal-to-noise measurements provide a direct indica- tion of system performance. Signal-to-noise measure- ments are especially important in WDM systems because there is a direct relation between signal-to- noise and bit error rate. The WDM channel analyzer dis- plays signal-to-noise measurements in the third column.
Page 56 Measuring Signal-to-Noise Ratios with Averaging 3-19 Location of noise measurements. To determine the noise power, the WDM channel ana- lyzer first determines the proximity of any adjacent sig- nal. If the next closest signal is ≤200 GHz (approximately 1.6 nm at 1550 nm) away from the sig- nal of interest, then the noise power is measured half way between the two channels and an equal distance to the other side of the signal of interest.
Page 57 3-20 Measuring Signal-to-Noise Ratios with Averaging Averaging When the lasers being measured are modulated, espe- cially with repetitive data formats such as SONET or PRBS, the noise floor is raised. Averaging reduces the noise floor and allows an improvement of greater than 10 dB in a signal-to-noise measurement.
Page 58 Measuring Signal-to-Noise Ratios with Averaging 3-21 4 When the measurement is complete, the instrument will stop. 5 To make a new measurement, press the Run key. 6 To exit, press the EXIT softkey, then press the Run key to return to continuous measurement.
Page 59: Measuring Modulated Lasers
3-22 Measuring Modulated Lasers Measuring Modulated Lasers A laser that is amplitude modulated at low frequencies (for example, modulated in the audio frequency range) can cause spurious wavelengths to be displayed below and above the correct wavelength. The power of these spurious wavelengths is below that of the correct wave- length.
Page 60 Measuring Modulated Lasers 3-23 A laser modulated at high frequency (in the RF or microwave range) can also cause spurious wavelengths to be displayed, especially when the modulation is of a repetitive nature such as that of PRBS or SONET digital formats.
Page 61: Measuring Total Power Greater Than 10 Dbm
OPTICAL INPUT connector and the fiber-optic cable. The attenuator must reduce the total input power to the 86121A so that it is below +10 dBm. 2 Press Setup, MORE, CAL, and then PWR OFS. Notice that the PWR OFS annotation appears on the screen to indicate an offset is applied.
Page 62: Calibrating Measurements
Calibrating Measurements 3-25 Calibrating Measurements The wavelength of light changes depending on the material that the light is passing through. To display meaningful wavelength measurements, the Agilent 86121 performs two steps, measuring the wave- length in air and converting the wavelength to show val- ues in a vacuum.
Page 63 3-26 Calibrating Measurements 6 Press RETURN to complete the entry. Converting feet to meters If you know your elevation in feet, you can convert this value to meters by using the following equation: -------------- - 3.281...
Page 64: Setting The Date And Time
Setting the Date and Time 3-27 Setting the Date and Time The Agilent 86121A uses an internal clock to stamp files and printouts with the time and date. To make sure files are dated correctly, use the following steps to set the date and time.
Page 65: Saving The Measurement Results
3-28 Saving the Measurement Results Saving the Measurement Results You can save measurement results from the WDM chan- nel analyzer on the built-in 3.5” disk drive. The data is saved in a comma-separated-variable (CSV) format. It can be read by many common spreadsheet programs by indicating that the data file is a .csv file.
Page 66: Printing Measurement Results
Printing Measurement Results 3-29 Printing Measurement Results The Agilent 86121A includes an internal thermal printer. Measurement results can be sent directly to the internal printer or to an external printer. To create a hardcopy on the internal printer To print using the internal printer, make sure that the printer contains paper.
Page 67 3-30 Printing Measurement Results To create a hardcopy on an external printer To print using an external printer, connect a compatible Centronics printer to the rear-panel PARALLEL PRINTER PORT connector. The output is ASCII text. An example of a compatible printer is an HP LaserJet series printer.
Page 68: Programming
Chapter 4 Programming Addressing and Initializing the Instrument 4-3 To change the GPIB address 4-4 Making Measurements 4-5 Commands are grouped in subsystems 4-6 Measurement instructions give quick results 4-8 Measure delta, drift, and signal-to-noise 4-13 The format of returned data 4-13 Monitoring the Instrument 4-15 Status registers 4-15 Queues 4-20...
Page 69 IEEE Standard 488.2-1987, IEEE Standard Codes, Formats, Protocols and Common commands For Use with ANSI/IEEE Std 488.1-1987. New York, NY, 1987. Types of commands The Agilent 86121A responds to three types of com- mands: • Common commands • Measurement instructions • Subsystem commands...
Page 70: Addressing And Initializing The Instrument
Addressing and Initializing the Instrument Addressing and Initializing the Instrument The GPIB address of the Agilent 86121A is configured at the factory to a value of 20. You must set the output and input functions of your programming language to send the commands to this address.
Page 71 Addressing and Initializing the Instrument To change the GPIB address 1 Press the Setup key. 2 Press MORE twice, then REMOTE. 3 Press GPIB. 4 Use the softkeys to change the GPIB address. 5 Press RETURN.
Page 72: Making Measurements
The simplified block diagram of the Agilent 86121A shown here lists some of the available programming commands. Each command is placed next to the instrument section it configures or queries data from.
Page 73 Table 4-7, “Programming Commands,” on page 4-42 Table 4-8, “Keys Versus Commands,” on page 4-47 Commands are grouped in subsystems The Agilent 86121A commands are grouped in the fol- lowing subsystems. You’ll find a description of each command in Chapter 5, “Programming Commands”.
Page 74 Table 4-1 on page 4-7 shows the kinds of measurements that the Agilent 86121A can perform and the associated programming commands used to return that data. In some cases, there is more than one method that can be used to obtain the desired data.
Page 75 This is equiva- lent to using the NORMAL and FAST softkeys. :MEASure command MEASure configures the Agilent 86121A, captures new data, and queries the data all in one step. For example, to measure the longest wavelength, send the following...
Page 76 Making Measurements :READ command The READ command works like the MEASure com- mand except that it does not configure the settings of the instrument. You can use the CONFigure command to configure the instrument for a particular measure- ment without returning any data. The MEASure and READ commands are identical to combining the following commands: Command...
Page 77 4-10 Making Measurements FETCh does not reconfigure the display. For example, if the display is in the Peak WL mode, sending :FETCh:ARRay does not configure the display to the List by WL even though an array of data is returned to the computer.
Page 78 (A <size> parameter indicates the number of measurements to take.) However, the Agilent 86121A’s ARRay command refers to the measurements performed for one measurement sweep; this results in an array of measured signals. Because the <size>...
Page 79 4-12 Making Measurements For example, suppose that you wanted to set the eleva- tion correction value and then send an :INIT:IMM com- mand. The following programming fragment results in an error “–213 Init ignored”. This occurs because the :ELEVation command causes the recalculation of the data which is like sending the :INIT:IMM command.
Page 80 Making Measurements 4-13 Measure delta, drift, and signal-to-noise To select a measurement, use one of the following STATe commands: CALC3:DELT:POW:STAT (delta power) CALC3:DELT:WAV:STAT (delta wavelength) CALC3:DELT:WPOW:STAT (delta power and wavelength) CALC3:DRIF:STAT (drift) CALC3:ASNR:STAT (signal-to-noise ratio averaging) If you select a drift measurement, you can select one of the following additional states: CALC3:DRIF:DIFF:STAT (difference)
Page 81 4-14 Making Measurements OUTPUT 720;”:CALCulate1:POINts?” ENTER 720;Length OUTPUT 720;”:CALCulate1:DATA?” ENTER 720;Result$ Data can be corrected for elevation Normally, the WDM channel analyzer provides measure- ment values calculated for conditions in air at sea level. Use the :SENSe:CORRection:ELEVation command to compensate for air dispersion. Altitudes up to 5000 meters can be entered.
Page 82: Monitoring The Instrument
Monitoring the Instrument 4-15 Monitoring the Instrument Almost every program that you write will need to moni- tor the Agilent 86121A for its operating status. This includes querying execution or command errors and determining whether or not measurements have been completed.
Page 83 4-16 Monitoring the Instrument Status Byte register The Status Byte Register contains summary bits that monitor activity in the other status registers and queues. The Status Byte Register’s bits are set and cleared by the presence and absence of a summary bit from other registers or queues.
Page 84 Monitoring the Instrument 4-17 The Status Byte Register can be read using either the *STB? common command or the GPIB serial poll com- mand. Both commands return the decimal-weighted sum of all set bits in the register. The difference between the two methods is that the serial poll com- mand reads bit 6 as the Request Service (RQS) bit and clears the bit which clears the SRQ interrupt.
Page 85 4-18 Monitoring the Instrument Table 4-3. Bits in Operation Status Register Definition not used SETTling - indicating that the instrument is waiting for the motor to reach the proper position before beginning data acquisition. RANGing - indicating the instrument is currently gain ranging. not used MEASuring - indicating that the instrument is making a measurement.
Page 86 Monitoring the Instrument 4-19 Standard Event Status register The Standard Event Status Register monitors the fol- lowing instrument status events: • OPC - Operation Complete • RQC - Request Control • QYE - Query Error • DDE - Device Dependent Error •...
Page 87 4-20 Monitoring the Instrument these bits is 60. Therefore, you can enable any of these bits to generate the summary bit by sending the *ESE 60 command. Whenever an error occurs, it sets one of these bits in the Standard Event Status Register. Because the bits are all enabled, a summary bit is generated to set bit 5 in the Status Byte Register.
Page 88 Monitoring the Instrument 4-21 and the most recent error is discarded. The length of the error queue in the instrument is 30 (29 positions for the error messages, and 1 position for the “Queue over- flow” message). The error queue is read with the SYSTEM:ERROR? query.
Page 89: Reviewing Scpi Syntax Rules
4-22 Reviewing SCPI Syntax Rules Reviewing SCPI Syntax Rules SCPI command are grouped in subsystems In accordance with IEEE 488.2, the commands are grouped into “subsystems.” Commands in each sub- system perform similar tasks. The following subsystems are provided: Measurement Instructions Calculate1 Subsystem Calculate2 Subsystem Calculate3 Subsystem...
Page 90 Reviewing SCPI Syntax Rules 4-23 Programs written in long form are easily read and are almost self-documenting. Using short form commands conserves the amount of controller memory needed for program storage and reduces the amount of I/O activity. The rules for creating short forms from the long form is as follows: The mnemonic is the first four characters of the key- word unless the fourth character is a vowel, in which...
Page 91 4-24 Reviewing SCPI Syntax Rules Combine commands from different subsystems You can send commands and program queries from dif- ferent subsystems on the same line. Simply precede the new subsystem by a semicolon followed by a colon. In the following example, the colon and semicolon pair before DISP allows you to send a command from another subsystem.
Page 92 Reviewing SCPI Syntax Rules 4-25 instruction in a string. Several representations of a number are possible. For example, the following num- bers are all equal: 0.28E2 280E-1 28000m 0.028K 28E-3K If a measurement cannot be made, no response is given and an error is placed into the error queue.
Page 93 4-26 Reviewing SCPI Syntax Rules Program message terminator The string of instructions sent to the instrument are executed after the instruction terminator is received. The terminator may be either a new-line (NL) charac- ter, the End-Or-Identify (EOI) line asserted, or a combi- nation of the two.
Page 94 Reviewing SCPI Syntax Rules 4-27 You can send multiple queries to the instrument within a single program message, but you must also read them back within a single program message. This can be accomplished by either reading them back into a string variable or into multiple numeric variables.
Page 95: Example Programs
Example 6. Increase a source’s wavelength accuracy 4-40 These programs are provided to give you examples of using Agilent 86121A remote programming commands in typical applications. They are not meant to teach general programming techniques or provide ready-to- use solutions. They should allow you to see how mea- surements are performed and how to return data to the computer.
Page 96 4-11. Tempo subroutine This subroutine, which is only found in Example 3, pauses the program for a few seconds while the 86121A measures the drift on a laser. The argument in the example sets the pause for 10 seconds.
Page 97 4-30 Example Programs Example 1. Measure a DFB laser This program measures the power and wavelength of a DFB laser. It first sets the WDM channel analyzer in the single-acquisition measurement mode. Then, it triggers the WDM channel analyzer with the MEASure com- mand to capture measurement data of the input spec- trum.
Page 98 Example Programs 4-31 ENTER @Mwm;Opc_done OUTPUT @Mwm;"*IDN?" ENTER @Mwm;Identity$ RETURN Identity$ FNEND Example 2. Measure WDM channels This program measures the multiple laser lines of a WDM system. It measures both the power and wave- lengths of each line. First, the program sets the WDM channel analyzer in the single-acquisition measurement mode.
Page 99 4-32 Example Programs ENTER @Mwm;Cme OUTPUT @Mwm; ":SYST:ERR?" ENTER @Mwm;Err_msg$ PRINT Err_msg$ UNTIL NOT BIT(Cme,2) AND NOT BIT(Cme,4) AND NOT BIT(Cme,5) AND Err$,"+0") Subend:SUBEND Set_ese:SUB Set_ese COM /Instrument/ @Mwm OUTPUT @Mwm; "*ESE";IVAL("00110100",2) SUBEND Identity:DEF FNIdentity$; COM /Instrument/ @Mwm DIM Identity$[50] Identity$=""...
Page 100 Example Programs 4-33 Example 3. Measure WDM channel drift This program measures the drift of channels in a WDM system. It measures drift in both power and wavelength of each line. First, the program sets the WDM channel analyzer in the continuous-acquisition measurement mode.
Page 101 4-34 Example Programs ENTER @Mwm USING "#,K";Current_ref_pwr(*) ! Turn off drift reference state Cmd_opc(":CALC3:DRIF:REF:STAT OFF") Err_mngmt(":CALC3:DRIF:REF:STAT OFF") ! Turn on drift max min calculation Cmd_opc(":CALC3:DRIF:DIFF:STAT ON") Err_mngmt(":CALC3:DRIF:DIFF:STAT ON") Tempo(10) ALLOCATE Current_diff_wl(1:Nb_pt) ALLOCATE Current_diff_pw(1:Nb_pt) ! Query drift wavelengths and powers OUTPUT @Mwm;":CALC3:DATA? WAV" ENTER @Mwm USING "#,K";Current_diff_wl(*) OUTPUT @Mwm;":CALC3:DATA? POW"...
Page 102 Example Programs 4-35 SUBEND Identity:DEF FNIdentity$; COM /Instrument/ @Mwm DIM Identity$[50] Identity$="" OUTPUT @Mwm;"*RST" OUTPUT @Mwm;"*OPC?" ENTER @Mwm;Opc_done OUTPUT @Mwm;"*IDN?" ENTER @Mwm;Identity$ RETURN Identity$ FNEND Cmd_opc:SUB Cmd_opc(Set_cmd$) COM /Instrument/ @Mwm OUTPUT @Mwm;Set_cmd$ OUTPUT @Mwm;"*OPC?" ENTER @Mwm;Opc_done$ SUBEND Tempo:SUB Tempo(Temp) FOR I=Temp TO 0 STEP -1) DISP "Waiting for ";VAL$(I);"...
Page 103 4-36 Example Programs Example 4. Measure WDM channel separation This program measures the line separations on a WDM system. It measures separation (delta) between power and wavelength of each line using commands from the CALCulate3 subsystem. Refer to the introduction to this section for a descrip- tion of each subroutine that is contained in this pro- gram.
Page 104 Example Programs 4-37 Delta Pwr to line ",I+1," is : ";(I=1)*(Delta_pwr(I+1))+(NOT I=1)*(Delta_pwr(I+1)-Delta_pwr(I));" dB" NEXT I PRINT USING "6A,2D,17A,M4D.3D,31A,S2D.2D,4A";"Line : ";I;" wavelength is : ";(Delta_wl(1)+Delta_wl(Nb_pt))/1.0E-9;" nm. Absolute line level is : ";Delta_pwr(1)+Delta_pwr(Nb_pt);" dBm" STOP Error_msg: ! PRINT "The program is aborted due to : ";ERRM$ Err_mngmt:SUB Err_mngmt(OPTIONAL Cmd_msg$) COM /Instrument/ @Mwmt DIM Err_msg$[255]...
Page 105 4-38 Example Programs Example 5. Measure signal-to-noise ratio of each WDM channel This program measures signal-to-noise ratios on a WDM system. It measures the ratio for each line using com- mands from the CALCulate3 subsystem. Refer to the introduction to this section for a descrip- tion of each subroutine that is contained in this pro- gram.
Page 106 Example Programs 4-39 PRINT "The program is aborted due to : ";ERRM$ Err_mngmt:SUB Err_mngmt(OPTIONAL Cmd_msg$) COM /Instrument/ @Mwmt DIM Err_msg$[255] INTEGER Cme CLEAR @Mwm REPEAT ! OUTPUT @Mwm;"*ESR?" ENTER @Mwm;Cme OUTPUT @Mwm;":SYST:ERR?" ENTER @Mwm;Err_msg$ IF NPAR>0 AND NOT POS(Err_msg$,"+0") THEN PRINT "This command ";Cmd_msg$;"...
Page 107 Agi- lent 8167B and the 8168D,E,F Tunable Laser Sources. Essentially, the accuracy of the Agilent 86121A is trans- ferred to the tunable laser source. The absolute accu- racy of the tunable laser source is increased from <±0.1 nm to <±0.003 nm which is the absolute accuracy...
Page 108 Example Programs 4-41 ENTER @Mwm;Identity$ PRINT "MWM IS A ";identity$ ! Ask user for desired wavelength INPUT "What wavelength (nm)do you wish to have",Target_wl Target_wl=Target_wl*1.OE-9 PRINT "the target wavelength is : ";Target_wl ! Set wavelength of tunable laser source OUTPUT @Tls; ":WAVE ";VAL$(Target_wl) OUTPUT @Tls;...
Page 109: Lists Of Commands
4-42 Lists of Commands Lists of Commands Table 4-7. Programming Commands (1 of 5) Command Description Code Codes: S indicates a standard SCPI command. I indicates an instrument specific command. Common Commands *CLS Clears all event registers and the error queue. *ESE Sets the bits in the standard-event status enable register.
Page 110 Lists of Commands 4-43 Table 4-7. Programming Commands (2 of 5) Command Description Code Codes: S indicates a standard SCPI command. I indicates an instrument specific command. CALCulate1 (CALC1) Subsystem :CALCulate1:DATA? Queries the uncorrected frequency-spectrum data of the input signal. :CALCulate1:TRANsform Sets and queries the number of points in the :FREQuency:POINts?
Page 111 4-44 Lists of Commands Table 4-7. Programming Commands (3 of 5) Command Description Code Codes: S indicates a standard SCPI command. I indicates an instrument specific command. :CALCulate3:DELTa:REFerence Selects the signal to be used as the reference :FREQuency for the DELTa calculations. :CALCulate3:DELTa:REFerence Queries the power level of the reference sig- :POWer?
Page 112 Lists of Commands 4-45 Table 4-7. Programming Commands (4 of 5) Command Description Code Codes: S indicates a standard SCPI command. I indicates an instrument specific command. :DISPlay:MARKer:MAXimum:NEXT Moves the marker to the signal with the clos- est power level just below the power level of the signal at the current marker position.
Page 113 SYSTem Subsystem :SYSTem:DATE Sets the clock date. :SYSTem:ERRor? Queries an error from the error queue. :SYSTem:HELP:HEADers? Queries an ASCII listing of all Agilent 86121A remote commands. :SYSTem:PRESet Performs the equivalent of a front-panel PRE- SET key press. :SYSTem:TIME Sets the clock time.
Page 114 Lists of Commands 4-47 Table 4-8. Keys Versus Commands (1 of 2) Equivalent Command ∆ :CALCulate3:DELTa:POWer[:STATe] ∆ :CALCulate3:DELTa:WAVelength[:STATe] ∆ :CALCulate3:DELTa:WPOWer[:STATe] WL/PWR BAR OFF :DISPlay[:WINDow]:GRAPhics:STATe BAR ON :DISPlay[:WINDow]:GRAPhics:STATe BROAD :SENSe:CORRection:DEVice BROad See ELEV and PWR OFS :UNIT:POWer DEVICE :SENSe:CORRection:DEVice DRIFT :CALCulate3:DRIFt[:STATe] ELEV :SENSe:CORRection:ELEVation EXIT...
Page 115 4-48 Lists of Commands Table 4-8. Keys Versus Commands (2 of 2) Equivalent Command :INITiate:CONTinuous ON S/N AVG :CALCulate3:ASNR:STATe SELECT :CONFigure:POWer Setup See CAL and UPDATE START WL :CALCulate2:WLIMit:STARt STOP WL :CALCulate2:WLIMit:STOP Stop :INITiate:CONTinuous OFF THRSHLD See PK EXC and PK THLD :MEASure:ARRay:POWer:FREQuency UPDATE Measurement Instructions and :CALCulate1:TRANsform:FRE-...
Page 116 Chapter 5 Programming Commands Common Commands 5-3 Measurement Instructions 5-11 CALCulate1 Subsystem 5-17 CALCulate2 Subsystem 5-21 CALCulate3 Subsystem 5-29 CONFigure Measurement Instruction 5-40 DISPlay Subsystem 5-41 FETCh Measurement Instruction 5-44 HCOPy Subsystem 5-45 MEASure Measurement Instruction 5-46 MMEMory Subsystem 5-47 READ Measurement Instruction 5-48 SENSe Subsystem 5-49 STATus Subsystem 5-53...
Page 117 Programming Commands Programming Commands This chapter is the reference for all Agilent 86121A pro- gramming commands. Commands are organized by sub- system. Convention Description < > Angle brackets indicate values entered by the programmer. ”Or” indicates a choice of one element from a list.
Page 118: Common Commands
Common Commands Common Commands Common commands are defined by the IEEE 488.2 standard. They control generic device functions which could be common among many different types of instru- ments. Common commands can be received and pro- cessed by the instrument whether they are sent over the GPIB as separate program messages or within other program messages.
Page 119 Common Commands Bit Weight Enables PON – Power On Not Used CME – Command Error EXE – Execution Error DDE – Device Dependent Error QYE – Query Error Not Used OPC – Operation Complete a. High enables the event status register bit. <integer>...
Page 120 The following identification string is returned. The third Query Response entry is the serial number of the instrument. The last entry in the string is the firmware version number; this value may vary between instruments. AGILENT, 86121A, USaaaabbbb, 1.000 DIM Id$[50] Example OUTPUT 720;”*IDN?” ENTER 720;Id$...
Page 121 The computer can poll the event status register to check when the Agilent 86121A has completed the operation. Use the *OPC? query to ensure all operations have completed before continuing the program. By following a com- mand with an *OPC? query and an ENTER statement, the program will pause until the response (ASCII “1”) is...
Page 122 Common Commands results in error number –230, “Data corrupt or stale”. You must initiate a new sweep with :INIT:IMM before you can use the :FETCh command. Item Setting Start wavelength 1270 nm Stop wavelength 1650 nm Graphical display Measurement acquisition single Elevation correction value 0 meters...
Page 123 Common Commands The following constitutes an instrument state: single/ Description continuous measurement mode, power bar on/off, nor- mal/fast update, frequency units, elevation, peak excur- sion, peak threshold, power offset, wavelength limit on/ off, wavelength limit start, wavelength limit stop, and signal-to-noise average count.
Page 124 Common Commands In this example, the command enables ESB (event sum- mary) bit 5 in the status byte register to generate a ser- vice request. *STB? The *STB (status byte) query returns the current value of the status byte of the instrument. The master summary status (MSS) bit 6 indicates Description whether or not the device has at least one reason for...
Page 125 5-10 Common Commands The following example starts the data acquisition Example according to the current settings. OUTPUT 720;”*TRG” *TST? The *TST (test) query starts a self-test on the instru- ment. The result of the test is placed in the output queue. A Description zero indicates the test passed and a non-zero value indi- cates the test failed.
Page 126: Measurement Instructions
Measurement Instructions 5-11 Measurement Instructions Use the measurement instructions documented in this section to perform measurements and return the desired results to the computer. Four basic measure- ment instructions are used: CONFigure, FETCh, READ, and MEASure. Because the command trees for each of these four basic measurement instructions are identi- cal, only the MEASure tree is documented.
Page 127 5-12 Measurement Instructions MEASure{:ARRay | [:SCALar]}:POWer? [<expected_value>[,<resolution>]] Returns amplitude values. Used With <expected_value> <resolution> SCALar optional ignored ARRay ignored ignored When used with a :SCALar command, a single value is Description returned. The display is placed in the single-wavelength mode, and the marker is placed on the signal having a power level that is closest to the <expected_value>...
Page 128 Measurement Instructions 5-13 The following line is an example of a returned string Query Response when :MEAS:SCAL:POW? MAX is sent: -5.88346500E+000 If six laser lines are located and :MEAS:ARR:POW? is sent, the following string could be returned. Notice that the first returned number indicates the number of laser- line values returned in the query.
Page 129 5-14 Measurement Instructions CONFigure command When this function is used with the CONFigure command, the query question mark character “?” must not be included in the string. However, the FETCh, READ, and MEASure command are queries and require the question mark. Refer to the examples for this command.
Page 130 Measurement Instructions 5-15 MEASure{:ARRay | [:SCALar]} :POWer:WAVelength? [<expected_value>[,<resolution>]] Returns wavelength values. Used With <expected_value> <resolution> SCALar optional optional ARRay optional ignored a. Although ignored, this argument must be present if the resolution argument is specified. When used with a :SCALar command, a single value is Description returned.
Page 131 5-16 Measurement Instructions <resolution> Constants MAXimum 0.01 resolution (fast update) MINimum 0.001 resolution (normal) DEFault Current resolution :CONF:ARR:POW:WAV DEF, MAX Examples :FETC:ARR:POW:WAV? DEF, MIN :READ:ARR:POW:WAV? :MEAS:ARR:POW:WAV? :CONF:SCAL:POW:WAV 1300NM, MAX :FETC:SCAL:POW:WAV? 1300NM, MIN :READ:SCAL:POW:WAV? 1300NM :MEAS:SCAL:POW:WAV? 1300NM The following line is an example of a returned string Query Response when :MEAS:SCAL:POW:WAV? MAX is sent: +1.5529258E-006...
Page 132: Calculate1 Subsystem
Use the CALCulate1 commands to query uncorrected frequency-spectrum data. In NORMAL measurement update mode, 15,047 values are returned. If the Agilent 86121A is set for FAST measurement update mode (low resolution), 7,525 values are returned. The commands in this subsystem have the following...
Page 133 5-18 CALCulate1 Subsystem The following string is a typical example of the first few returned values: +4.02646500E+001,+6.78125100E+001,+6.17986600E+001,+4.26768200E +001,+4.80245300E+001,+3.10491300E+001,+1.13409400E+001,+5.07832 500E+001,+2.77746200E+001,+3.89150500E+001,+3.50217600E+001,+7.3 4649800E-001,+5.64983800E+000, Notice that only measurement values are returned to the computer. There is no first value that indicates the number of values contained in the string as there is, for example, with the FETCh, READ, and MEASure com- mands.
Page 134 1557.195 nm (in vacuum). If your program is aborted or interrupted after sending this query, the Agilent 86121A continues to process the data but does not place it in the output buffer. Because of the amount of data processed, the instrument will not respond to any new commands in its input buffer for up to 20 seconds.
Page 135 Always use an *OPC? query or a *WAI command to ensure that this command has the time to complete before sending any more commands to the instrument. Refer to “Always force the Agilent 86121A to wait for non-sequential commands” on page 4-11 for more information. For normal update:...
Page 136: Calculate2 Subsystem
CALCulate2 Subsystem 5-21 CALCulate2 Subsystem Use the CALCulate2 commands to query corrected val- ues frequency-spectrum data. The commands in this subsystem have the following command hierarchy: :CALCulate2 :DATA? :PEXCursion :POINts? :PTHReshold :WLIMit [:STATe] :STARt :FREQuency [:WAVelength] :STOP :FREQuency [:WAVelength] :CALCulate2:DATA? {FREQuency | POWer | WAVelength} Queries the corrected peak data of the input laser line.
Page 137 –200 dBm; the WAVelength query returns 100 nm (1.0E–7). :CALCulate2:PEXCursion{?| {<integer> | MINimum | MAXimum | DEFault}} Sets the peak excursion limit used by the Agilent 86121A to determine valid laser line peaks. <integer> represents logarithmic units in dB. Valid range is 1 to 30 dB. Constant...
Page 138 Always use an *OPC? query or a *WAI command to ensure that this command has the time to complete before sending any more commands to the instrument. Refer to “Always force the Agilent 86121A to wait for non-sequential commands” on page 4-11 for more information. :CALCulate2:POINts? Queries the number of points in the data set.
Page 139 Attribute Summary Preset State: on *RST State: on SCPI Compliance: instrument specific When this function is on, the Agilent 86121A has an Description input range from the WLIMit STARt to the WLIMit STOP. When this function is off, the instrument displays peaks over the full wavelength range.
Page 140 CALCulate2 Subsystem 5-25 Whenever the 86121A receives this command, it repro- cesses the data and performs a new peak search. Non-sequential command Always use an *OPC? query or a *WAI command to ensure that this command has the time to complete before sending any more commands to the instrument.
Page 141 Refer to “Always force the Agilent 86121A to wait for non-sequential commands” on page 4-11 for more information. :CALCulate2:WLIMit:STOP:FREQuency {?|{<real> | MINimum | MAXimum }} Sets the stopping frequency for the wavelength limit range.
Page 142 Refer to “Always force the Agilent 86121A to wait for non-sequential commands” on page 4-11 for more information. :CALCulate2:WLIMit:STOP[:WAVelength] {?|{<real> | MINimum | MAXimum }} Sets the stopping wavelength for the wavelength limit range.
Page 143 Always use an *OPC? query or a *WAI command to ensure that this command has the time to complete before sending any more commands to the instrument. Refer to “Always force the Agilent 86121A to wait for non-sequential commands” on page 4-11 for more information.
Page 144: Calculate3 Subsystem
CALCulate3 Subsystem 5-29 CALCulate3 Subsystem Use the CALCulate3 commands to perform delta, drift, signal-to-noise, and Fabry-Perot measurements. The commands in this subsystem have the following com- mand hierarchy: :CALCulate3 :ASNR :CLEar :COUNt [:STATe] :DATA? :DELTa :POWer [:STATe] :PRESet :REFerence :FREQuency :POWer? [:WAVelength] :WAVelength...
Page 145 5-30 CALCulate3 Subsystem :CALCulate3:ASNR:CLEar Clears the number of measurements used in the signal- to-noise calculation. Preset State: not affected Attribute Summary *RST State: not affected SCPI Compliance: instrument specific This command clears the number of measurements Description used in the signal-to-noise calculation. The current measurement is used as the new reference for the sig- nal-to-noise calculation.
Page 146 CALCulate3 Subsystem 5-31 This command turns the average signal-to-noise calcu- Description lation on or off. Only one of the CALCulate3 calcula- tions (ASNR, DELTa, DRIFt, or SNR) can be turned on at a time. Turning on the ASNR calculation while another calculation is on will generate a “Settings con- flict”...
Page 147 5-32 CALCulate3 Subsystem ited. The following string is a typical example of six val- ues returned when POWer is specified from a delta power measurement: -7.42833100E+000,-1.00087200E+000,-2.52121400E+000, -3.41918900E+000,-3.80437200E+000,-6.36282900E+000 Notice that only measurement values are returned to the computer. There is no first value that indicates the number of values contained in the string as there is, for example, with the FETCh, READ, and MEASure com- mands.
Page 148 CALCulate3 Subsystem 5-33 :CALCulate3:DELTa:PRESet Turns off all delta measurement states. Preset State: not affected Attribute Summary *RST State: not affected SCPI Compliance: instrument specific Command Only :CALCulate3:DELTa:REFerence:FREQuency{?| {<real> | MINimum | MAXimum}} Selects the reference laser line for DELTa calculations. <real>...
Page 149 5-34 CALCulate3 Subsystem Constant Description MINimum 1270 nm MAXimum 1650 nm Preset State: 1270 nm (236.0571 THz) Attribute Summary *RST State: 1270 nm (236.0571 THz) laser line SCPI Compliance: instrument specific The reference will be the laser line at the wavelength Description closest to the wavelength entered.
Page 150 CALCulate3 Subsystem 5-35 :CALCulate3:DELTa:WPOWer[:STATe]{?| {ON | OFF | 1 | 0}} Turns the delta wavelength and power measurement mode on and off. Preset State: off Attribute Summary *RST State: off SCPI Compliance: instrument specific When on, the wavelength of the reference laser line is Description subtracted from the wavelength values of all laser lines except the reference.
Page 151 5-36 CALCulate3 Subsystem Note Only one STATe command can be turned on at any one time. Attempting to turn more than one state on at a time results in a “–221 Settings Conflict” error. Refer to “Measure delta, drift, and signal-to-noise” on page 4-13 for additional information on selecting measurements.
Page 152 CALCulate3 Subsystem 5-37 Note Only one STATe command can be turned on at any one time. Attempting to turn more than one state on at a time results in a “–221 Settings Conflict” error. Refer to “Measure delta, drift, and signal-to-noise” on page 4-13 for additional information on selecting measurements.
Page 153 5-38 CALCulate3 Subsystem Note Only one STATe command can be turned on at any one time. Attempting to turn more than one state on at a time results in a “–221 Settings Conflict” error. Refer to “Measure delta, drift, and signal-to-noise” on page 4-13 for additional information on selecting measurements.
Page 154 CALCulate3 Subsystem 5-39 :CALCulate3:POINts? Queries the number of points in the data set. Preset State: unaffected by Attribute Summary RST State: unaffected by SCPI Compliance: instrument specific Query Only The value returned is the number of points returned by Description the CALC3:DATA? query.
Page 155: Configure Measurement Instruction
5-40 CONFigure Measurement Instruction CONFigure Measurement Instruction For information on the CONFigure measurement instruction, refer to “Measurement Instructions” on page 5-11.
Page 156: Display Subsystem
DISPlay Subsystem 5-41 DISPlay Subsystem The commands in this subsystem have the following command hierarchy: :DISPlay :ERRor :CLEar :ALL :MARKer: :MAXimum :LEFT :NEXT :PREVious :RIGHt [:WINDow] :GRAPhics :STATe :DISPlay:ERRor:CLEar Clears the topmost error in the display’s error queue. Preset State: Unaffected by Attribute Summary *RST state: Unaffected by SCPI Compliance: Instrument specific...
Page 157 5-42 DISPlay Subsystem :DISPlay:MARKer:MAXimum:LEFT Moves the marker left to the next laser line. Preset State: marker set to maximum-power laser line Attribute Summary *RST State: marker set to maximum-power laser line SCPI Compliance: instrument specific Command Only Moves the marker from the current marker position to Description the next laser line having the following characteristic: •...
Page 158 DISPlay Subsystem 5-43 :DISPlay[:WINDow]:GRAPhics:STATe{?| {ON | OFF | 1 | 0}} Turns on and off the display of the power bars. Preset State: on Attribute Summary *RST State: on SCPI Compliance: standard Specifying on displays the power bars except in drift Description and signal-to-noise measurements.
Page 159: Fetch Measurement Instruction
5-44 FETCh Measurement Instruction FETCh Measurement Instruction For information on the FETCh measurement instruc- tion, refer to “Measurement Instructions” on page 5-11.
Page 160: Hcopy Subsystem
HCOPy Subsystem 5-45 HCOPy Subsystem Use the command in this subsystem to print the dis- played measurement results to a printer. This sub- system has the following command hierarchy: :HCOPy :DESTination [:IMMediate] :HCOPy:DESTination: {INTernal | CENTronics} Sets the destination printer for the instrument. Preset State: not affected Attribute Summary *RST State: internal...
Page 161: Measure Measurement Instruction
5-46 MEASure Measurement Instruction MEASure Measurement Instruction For information on the MEASure measurement instruc- tion, refer to “Measurement Instructions” on page 5-11.
Page 162: Mmemory Subsystem
MMEMory Subsystem 5-47 MMEMory Subsystem This subsystem has the following command hierarchy: :MMEMory :STORe :TABLe :MMEMory:STORe[:TABLe] Creates a new file and stores the present data on the internal disk drive of the instrument. The data will be stored in the root directory under an automatically gen- erated file name.
Page 163: Read Measurement Instruction
5-48 READ Measurement Instruction READ Measurement Instruction For information on the READ measurement instruction, refer to “Measurement Instructions” on page 5-11.
Page 164: Sense Subsystem
SENSe Subsystem 5-49 SENSe Subsystem Use the SENSe commands to correct measurement results for elevation above sea level. You can also enter an amplitude offset. The commands in this subsystem have the following command hierarchy: [:SENSe] :CORRection :DEVice :ELEVations :OFFSet [:MAGNitude] :DATA? :SENSe:CORRection:[DEVice]{?| {NARRow | BROad}}...
Page 165 Always use an *OPC? query or a *WAI command to ensure that this command has the time to complete before sending any more commands to the instrument. Refer to “Always force the Agilent 86121A to wait for non-sequential commands” on page 4-11 for more information. :SENSe:CORRection:OFFSet:MAGNitude{?| {<real> | MINimum | MAXimum}} Enters an offset for amplitude values.
Page 166 SENSe Subsystem 5-51 Constant Description − MINimum 40.0 dB MAXimum 40.0 dB Preset State: 0.0 Attribute Summary *RST State: 0.0 SCPI Compliance: standard The query form returns the current offset setting as Query Response shown in the following example: +5.00000000E+000 :SENSe:DATA? Queries the time domain samples of the input laser line.
Page 167 If your program is aborted or interrupted after sending this query, the Agilent 86121A continues to process the data but does not place it in the output buffer. Because of the amount of data processed, the instrument will not respond to any new commands in its input buffer for 30 or 40 seconds.
Page 168: Status Subsystem
STATus Subsystem 5-53 STATus Subsystem Use the commands in this subsystem to control the Agilent 86121A’s status-reporting structures. These structures provide registers that you can use to deter- mine if certain events have occurred. The commands in this subsystem have the following...
Page 169 5-54 STATus Subsystem :STATus:{OPERation | QUEStionable}:ENABle{?| <value>} Sets the enable mask for the questionable or operation event register. <integer> an integer from 0 to 65535. Preset State: none Attribute Summary *RST State: none SCPI Compliance: standard The enable mask selects which conditions in the event Description register cause the summary bit in the status byte to be set.
Page 170 STATus Subsystem 5-55 :STATus:OPERation:NTRansition{?| <integer>} Selects bits in the event register which can be set by negative transitions of the corresponding bits in the condition register. <integer> an integer from 0 to 65535. Preset State: none Attribute Summary *RST State: none SCPI Compliance: standard Changes in the state of a condition register bit causes Description...
Page 171 5-56 STATus Subsystem When queried, the largest value that can be returned is 32767. This is because the most-significant register bit cannot be set true. OUTPUT 720;”:STATUS:OPER:PTRansition 16” Example :STATus:PRESet Presets the enable registers and the PTRansition and NTRansition filters. Preset State: none Attribute Summary *RST State: none...
Page 172: System Subsystem
Attribute Summary *RST State: none SCPI Compliance: standard Query Only The Agilent 86121A has a 30 entry error queue. The Description queue is a first-in, first-out buffer. Repeatedly sending the query :SYSTEM:ERROR? returns the error numbers and descriptions in the order in which they occur until the queue is empty.
Page 173 5-58 SYSTem Subsystem ENTER 720;Error$ PRINT Error$ :SYSTem:HELP:HEADers? Queries a listing of all the remote programming com- mands available for the Agilent 86121A. Preset State: none Attribute Summary *RST State: none SCPI Compliance: instrument specific Query Only The returned ASCII string of commands is in the IEEE Description 488.2 arbitrary-block data format.
Page 174 SYSTem Subsystem 5-59 :SYSTem:PRESet Performs the equivalent of pressing the front-panel PRE- SET key. Preset State: none Attribute Summary *RST State: none SCPI Compliance: standard Command Only The instrument state is set according to the settings Description shown in the following table. Settings after Preset Key Settings after Power Item...
Page 175 Queries the version of SCPI that the WDM channel ana- lyzer complies with. Preset State: none Attribute Summary *RST State: none SCPI Compliance: standard Query Only The SCPI version used in the Agilent 86121A is 1995.0. Description SCPI Version Instrument Serial Prefix 1995.0 US3545 and above...
Page 176: Trigger Subsystem
TRIGger Subsystem 5-61 TRIGger Subsystem The SCPI definition defines the TRIGger subsystem to include ABORt, ARM, INITiate, and TRIGger com- mands. The Agilent 86121A has no ARM or TRIGger commands. The commands in this subsystem have the following command hierarchy:...
Page 177 Always use an *OPC? query or a *WAI command to ensure that this command has the time to complete before sending any more commands to the instrument. Refer to “Always force the Agilent 86121A to wait for non-sequential commands” on page 4-11 for more information. :INITiate:IMMediate Initiates a new measurement sequence.
Page 178 Chapter 6 Performance Tests Test 1. Absolute Wavelength Accuracy 6-4 Test 2. Sensitivity 6-5 Test 3. Polarization Dependence 6-7 Test 4. Optical Input Return Loss 6-8 Test 5. Amplitude Accuracy and Linearity 6-11...
Page 179: Performance Tests
Test 3. Polarization Dependence 6-7 Test 4. Optical Input Return Loss 6-8 Test 5. Amplitude Accuracy and Linearity 6-11 Allow the 86121A to warm up for 15 minutes before doing any of the performance tests. Calibration Cycle This instrument requires periodic verification of perfor- mance.
Page 180 Performance Tests Test Equipment Requirements • 1523.488 nm HeNe gas laser (196.7804 THz) • Optical power meter (Agilent 8153/81532A or equiva- lent) • Optical attenuator (Agilent 8156A or equivalent) • 1310 nm and 1550 nm DFB lasers (>0 dBm output pow- er, ±0.005 dB stability for 10 minutes) •...
Page 181: Test 1. Absolute Wavelength Accuracy
2 Turn on the HeNe and allow the laser to warm up for 15 minutes. 3 On the font panel of the Agilent 86121A press the Preset key. Press MORE, UNITS, WL, and then THZ. 4 Read the frequency measured on the Agilent 86121A,...
Page 182: Test 2. Sensitivity
• ±0.005 dB stability for 10 minutes) C A U T I O N Do not exceed +18 dBm source power. The input circuitry of the Agilent 86121A can be damaged when total input power exceeds 18 dBm. Procedure Perform the following procedure first using the 1310 nm laser and then repeat the steps using the 1550 nm laser.
Page 183 Test 2. Sensitivity 9 Read the power and wavelength measured on the Agilent 86121, and compare them to the specifications listed in Chapter 7, “Specifications and Regulatory Information”.
Page 184: Test 3. Polarization Dependence
• Agilent 11896A polarization controller C A U T I O N Do not exceed +18 dBm source power. The input circuitry of the Agilent 86121A can be damaged when total input power exceeds 18 dBm. Procedure Perform the following procedure first using the 1310 nm laser and then repeat the steps using the 1550 nm laser.
Page 185: Test 4. Optical Input Return Loss
5 mm diameter mandrel six times. 10 The return loss module measures the termination parameter. 11 Connect the HMS-10/HP/HRL to FC/PC patchcord to the front-panel OPTICAL INPUT connector of the Agilent 86121A. 12 The lightwave multimeter measures the return loss.
Page 186 11 The return loss module measures the termination parameter. 12 Connect the HMS-10/HP/HRL to FC/APC patchcord to the front-panel OPTICAL INPUT connector of the Agilent 86121A. 13 The lightwave multimeter measures the return loss. Compare this measurement with the specification listed Chapter 7, “Specifications and Regulatory...
Page 187 6-10 Test 4. Optical Input Return Loss FC/APC patchcord loss The effect of having loss in the FC/APC patchcord 1-to-2 con- nector pair is to under measure the return loss by twice the FC/ APC patchcord 1-to-2 loss. For example, if this connector pair loss is 0.5 dB, then the actual return loss caused by the 14.6 dB Fresnel reflection is 15.6 dB, but we enter 14.6 dB as an R value.
Page 188: Test 5. Amplitude Accuracy And Linearity
Test 5. Amplitude Accuracy and Linearity 6-11 Test 5. Amplitude Accuracy and Linearity Equipment Amplitude linearity is performed using the following devices: • 1550 nm DFB lasers (>0 dBm output power, ±0.005 dB stability for 10 minutes) • Optical attenuator (Agilent 8156A or equivalent) •...
Page 189 6-1. For each setting, record the power measured on the Agilent 86121A. After completing this step, the table’s column titled “Agilent 86121A Power Reading” should be completely filled in. 20 Calculate the “Linearity” value for each row in the table...
Page 190 Information”. The data may show multiple amplitude plateaus separated by small amplitude steps. This is not a problem as long as the amplitude steps are within the linearity specification. Table 6-1. Linearity Data Values Agilent 86121A Desired Attenuator Power Meter Power...
Page 192: Specifications And Regulatory Information
Chapter 7 Specifications and Regulatory Information Definition of Terms 7-3 Specifications—NORMAL Update Mode 7-6 Specifications—FAST Update Mode 7-9 Operating Specifications 7-12 Regulatory Information 7-13 Declaration of Conformity 7-14...
Page 193 Specifications and Regulatory Information Specifications and Regulatory Information This chapter lists specification and characteristics of the instrument. The distinction between these terms is described as follows: • Specifications describe warranted performance over the temperature range 0°C to +55°C and relative humidity <95% (unless otherwise noted).
Page 194: Definition Of Terms
Definition of Terms Definition of Terms Wavelength Range refers to the allowable wavelength range of the optical input signal. Absolute accuracy indicates the maximum wavelength error over the allowed environmental conditions. The wavelength accuracy is based on fundamental physical constants, which are absolute standards not requiring traceability to artifacts kept at national standards labo- ratories.
Page 195 Definition of Terms Flatness refers to the maximum amplitude error in a measurement between two lines that are separated in wavelength by no more than the specified amount. Linearity indicates the maximum power error in mea- suring the change in power of one laser line. Polarization Dependence indicates the maximum dis- played power variation as the polarization of the input signal is varied.
Page 196 Definition of Terms Measurement Measurement cycle time refers to the cycle time when Cycle Time measuring wavelength and power of laser lines. Specific advanced applications may require longer cycle times.
Page 197: Specifications-Normal Update Mode
Specifications—NORMAL Update Mode Specifications—NORMAL Update Mode Each laser line is assumed to have a linewidth (includ- ing modulation sidebands) of less than 5 GHz. All specifications apply when the instrument is in the following modes: • NORMAL update mode unless noted. Refer to “To change the measurement speed”...
Page 198 Specifications—NORMAL Update Mode Amplitude ± ± Calibration accuracy at calibration 0.5 dB (at 1310 and 1550 nm 30 nm) wavelengths ± Flatness, 30 nm from any wavelength ± 1250-1600 nm (characteristic) 0.2 dB ± 1250-1650 nm (characteristic) 0.5 dB ± Linearity, 1270 nm to 1600 nm, lines above 0.3 dB –30 dBm...
Page 199 Specifications—NORMAL Update Mode Input Return Loss With flat contacting connectors 35 dB With angled contacting connectors 50 dB (Option 022) Measurement Cycle Time Normal update mode (characteristic) 1.0 s (1 measurement-per-second) Measurement Applications Signal-to-Noise Ratio, modulated lasers (characteristic) ≥ >35 dB with 100 averages channel spacing 100 GHz ≥...
Page 200: Specifications-Fast Update Mode
Specifications—FAST Update Mode Specifications—FAST Update Mode Each laser line is assumed to have a linewidth (includ- ing modulation sidebands) of less than 10 GHz. All specifications apply when the instrument is in the following modes: • FAST update mode unless noted. Refer to “To change the measurement speed”...
Page 201 7-10 Specifications—FAST Update Mode Amplitude ± ± Calibration accuracy at calibration 0.5 dB (at 1310 and 1550 nm 30 nm) wavelengths ± Flatness, 30 nm from any wavelength ± 1250-1600 nm (characteristic) 0.2 dB ± 1250-1650 nm (characteristic) 0.5 dB ±...
Page 202 Specifications—FAST Update Mode 7-11 Input Return Loss With flat contacting connectors 35 dB With angled contacting connectors 50 dB (Option 022) Measurement Cycle Time Fast update mode (characteristic) 0.5 s (2 measurements-per-second) Measurement Applications Signal-to-Noise Ratio, modulated lasers (characteristic) ≥ >35 dB with 100 averages channel spacing 200 GHz...
Page 203: Operating Specifications
7-12 Operating Specifications Operating Specifications Operating Specifications indoor Power 115 VAC: 110 VA MAX. / 60 WATTS MAX. / 1.1 A MAX. 230 VAC: 150 VA MAX. / 70 WATTS MAX. / 0.6 A MAX. Voltage nominal: 115 VAC / 230 VAC range 115 VAC: 90–132 V range 230 VAC: 198–254 V Frequency...
Page 204: Regulatory Information
Regulatory Information 7-13 Regulatory Information • Laser Classification: This product contains an FDA Laser Class I (IEC Laser Class 1) laser. • This product complies with 21 CFR 1040.10 and 1040.11. Notice for Germany: Noise Declaration Acoustic Noise Emission Geraeuschemission LpA <...
Page 205 7-14 Regulatory Information Declaration of Conformity...
Page 206: Reference
Power Cords 8-10 Cleaning Connections for Accurate Measurements 8-11 Choosing the Right Connector 8-11 Inspecting Connectors 8-14 Cleaning Connectors 8-18 Printer Head Cleaning Procedure 8-22 Returning the Instrument for Service 8-25 Preparing the Instrument for Shipping 8-26 Agilent Technologies Service Offices 8-28...
Page 207: Options And Accessories
Options and Accessories Options and Accessories Table 8-1. Options and Accessories Available for the Agilent 86121A Item Description Quantity Part Number Option 010 Delete FC/PC connector — — Option 011 Diamond HMS-10 connector interface 08154-61701 Option 013 DIN 47256 connector interface...
Page 208: Error Messages
Error Messages Error Messages In this section, you’ll find all the error messages that the Agilent 86121A can display on its screen. Table 8-2 on page 8-3 lists all instrument-specific errors. Table 8-3 on page 8-6 lists general SCPI errors.
Page 209 Error Messages Table 8-2. Instrument Specific Error Messages (2 of 3) Error Error Message Description Number "Bad cal ROM data" bad mtr ctl sample const in ROM "Bad cal ROM data" bad mtr ctl phase const in ROM "Bad cal ROM data" bad mtr ctl misc const in ROM "Bad cal ROM data"...
Page 210 Error Messages Table 8-2. Instrument Specific Error Messages (3 of 3) Error Error Message Description Number "Change Not allowed in coh len" no low res mode in coherence len "Change Not allowed in S/N" no low res mode in sig noise "Unknown keypress"...
Page 211 Error Messages Table 8-3. General SCPI Error Messages (1 of 3) Error Number Description No errors –100 Command error (unknown command) –101 Invalid character –102 Syntax error –103 Invalid separator –104 Data type error –105 GET not allowed –108 Parameter not allowed –109 Missing parameter –112...
Page 212 Error Messages Table 8-3. General SCPI Error Messages (2 of 3) Error Number Description –200 Execution error –211 “Trigger in progress” Caused by sending the *TRG command when the instrument is already taking a measurement or when the instrument is in continuous measurement mode.
Page 213 Error Messages Table 8-3. General SCPI Error Messages (3 of 3) Error Number Description –410 Query INTERRUPTED –420 Query UNTERMINATED –430 Query DEADLOCKED –440 “Query UNTERMINATED after indef resp“ Query was unterminated after an indefinite response.
Page 214: Front-Panel Fiber-Optic Adapters
Front-Panel Fiber-Optic Adapters Front-Panel Fiber-Optic Adapters The FC/PC adapter is the standard adapter supplied with the instrument. Dust Covers Part Number FC connector 1005-0594 Diamond HMS-10 connector 1005-0593 DIN connector 1005-0595 ST connector 1005-0596 SC connector 1005-0597...
Page 215: Power Cords
8-10 Power Cords Power Cords Cable Part Length Plug Type Plug Description Color Country (in/cm) 250V 8120-1351 Straight *BS1363A 90/228 Gray United Kingdom, 8120-1703 90° 90/228 Mint Gray Cyprus, Nigeria, Zimbabwe, Singapore 250V 8120-1369 Straight *NZSS198/ 79/200 Gray Australia, New Zealand 8120-0696 90°...
Page 216: Cleaning Connections For Accurate Measurements
Cleaning Connections for Accurate Measurements 8-11 Cleaning Connections for Accurate Measurements Today, advances in measurement capabilities make con- nectors and connection techniques more important than ever. Damage to the connectors on calibration and verification devices, test ports, cables, and other devices can degrade measurement accuracy and dam- age instruments.
Page 217 8-12 Cleaning Connections for Accurate Measurements tainty into account? • Will a connector degrade the return loss too much, or will a fusion splice be required? For example, many DFB lasers cannot operate with reflections from connectors. Often as much as 90 dB isolation is needed. Figure 8-1.
Page 218 Cleaning Connections for Accurate Measurements 8-13 Figure 8-2. Universal adapters to Diamond HMS-10. The HMS-10 encases the fiber within a soft nickel silver (Cu/Ni/Zn) center which is surrounded by a tough tung- sten carbide casing, as shown in Figure 8-3. Figure 8-3.
Page 219 8-14 Cleaning Connections for Accurate Measurements The soft core, while allowing precise centering, is also the chief liability of the connector. The soft material is easily damaged. Care must be taken to minimize exces- sive scratching and wear. While minor wear is not a problem if the glass face is not affected, scratches or grit can cause the glass fiber to move out of alignment.
Page 220 Cleaning Connections for Accurate Measurements 8-15 The cure for these problems is disciplined connector care as described in the following list and in “Cleaning Connectors” on page 8-18. Use the following guidelines to achieve the best possible performance when making measurements on a fiber- optic system: •...
Page 221 8-16 Cleaning Connections for Accurate Measurements Figure 8-6. Damage from improper cleaning. While these often work well on first insertion, they are great dirt magnets. The oil or gel grabs and holds grit that is then ground into the end of the fiber. Also, some early gels were designed for use with the FC, non-con- tacting connectors, using small glass spheres.
Page 222 Cleaning Connections for Accurate Measurements 8-17 pressure. Also, if a piece of grit does happen to get by the cleaning procedure, the tighter connection is more likely to damage the glass. Tighten the connectors just until the two fibers touch. •...
Page 223 C A U T I O N Agilent Technologies strongly recommends that index matching compounds not be applied to their instruments and accessories. Some compounds, such as gels, may be difficult to remove and can contain damaging particulates.
Page 224 Cleaning Connections for Accurate Measurements 8-19 Table 8-4. Cleaning Accessories Item Agilent Part Number Isopropyl alcohol 8500-5344 Cotton swabs 8520-0023 Small foam swabs 9300-1223 Compressed dust remover (non-residue) 8500-5262 Table 8-5. Dust Caps Provided with Lightwave Instruments Item Agilent Part Number Laser shutter cap 08145-64521 FC/PC dust cap...
Page 225 8-20 Cleaning Connections for Accurate Measurements Do not scrub during this initial cleaning because grit can be caught in the swab and become a gouging ele- ment. 5 Immediately dry the fiber end with a clean, dry, lint-free cotton swab or lens paper. 6 Blow across the connector end face from a distance of 6 to 8 inches using filtered, dry, compressed air.
Page 226 Cleaning Connections for Accurate Measurements 8-21 Although foam swabs can leave filmy deposits, these de- posits are very thin, and the risk of other contamination buildup on the inside of adapters greatly outweighs the risk of contamination by foam swabs. 2 Clean the adapter with the foam swab.
Page 227: Printer Head Cleaning Procedure
8-22 Printer Head Cleaning Procedure Printer Head Cleaning Procedure Lint from normal use of the printer may eventually col- lect on the printer head and degrade print quality. Use the procedure provided in this section to clean the printer head. W A R N I N G This servicing procedure is for use by qualified personnel only.
Page 228 Printer Head Cleaning Procedure 8-23 Figure 8-8. Example of a static-safe workstation Procedure 1 Turn off the instrument and remove the line power cord. 2 Place the instrument at a static-safe work station as described in the introduction to this procedure. 3 Use a coin or screwdriver to open the printer door that is located on the top of the instrument.
Page 229 8-24 Printer Head Cleaning Procedure 5 Unscrew the retaining screw that secures the sheet- metal cover that protects the printer head from electrostatic discharge. Slide the sheet-metal cover towards the retaining screw and then lift it straight up to remove. 6 Lift the printer head lever to the vertical position.
Page 230: Returning The Instrument For Service
The instructions in this section show you how to prop- erly return the instrument for repair or calibration. Always call the Agilent Technologies Instrument Sup- port Center first to initiate service before returning your instrument to a service office. This ensures that...
Page 231 8-26 Returning the Instrument for Service Preparing the Instrument for Shipping 1 Write a complete description of the failure and attach it to the instrument. Include any specific performance details related to the problem. The following information should be returned with the instrument. •...
Page 232 Returning the Instrument for Service 8-27 charge. • For instruments weighing less than 54 kg (120 lb), use a double-walled, corrugated cardboard carton of 159 kg (350 lb) test strength. • The carton must be large enough to allow approxi- mately 7 cm (3 inches) on all sides of the instrument for packing material, and strong enough to accommo- date the weight of the instrument.
Page 233: Agilent Technologies Service Offices
8-28 Agilent Technologies Service Offices Agilent Technologies Service Offices Before returning an instrument for service, call the Agi- lent Technologies Instrument Support Center at (800) 403-0801, visit the Test and Measurement Web Sites by Country page at http://www.tm.agilent.com/tmo/coun- try/English/index.html, or call one of the numbers listed below.
Page 234 Index Numerics 1 nm annotation, 3-18 cabinet, cleaning, iv softkey, 1-8 CALCulate1 subsystem, 5-17 CALCulate2 subsystem, 5-21 ABORt programming command, 5-61 CALCulate3 subsystem, 4-13, 4-33, 4-36, accessories, 8-2 4-38, 5-29 static-safe, 8-22 calibration adapters, fiber optic, 8-9 accuracy, 7-3 adding parameters, 4-24 cycle, 6-2, 7-2 address.
Page 235 Index-2 *TST (test), 5-10 messages, 8-3 *WAI (wait), 5-10 queue, 4-20 definition, 4-22 ERRor programming command, 5-57 sending, 4-24 Error_msg subroutine, 4-28 compressed dust remover, 8-19 *ESE, 4-28, 5-3 computer control, 4-5 *ESR, 5-4 CONFigure measurement instruction, 5-11 EVENT programming command, 5-53–5-54 connector care, 8-11...
Page 236 Index-3 flatness, 3-14 GPIB, 4-5 *IDN?, 4-29, 5-5 instructions, 4-22, 5-11 IEC Publication 1010, iii laser drift, 3-15 IEEE 488.2 standard, 4-2 laser line separation, 3-12 IMMediate programming command, 5-45, modulated lasers, effects of, 3-22 5-62 monitoring performance over time, 3-15 init ignored, 8-7 of broadband...
Page 237 Index-4 wavelength, 2-2 RIGHT programming command, 5-42 Peak WL softkey, 3-16 *RST, 4-3, 4-29, 5-6 performance tests, 6-2 key, 3-16 PEXCursion programming command, 5-22 PK EXC softkey, 3-11 PK THLD softkey, 3-11 safety, iv POINts? programming command, 5-19, 5-23, symbols, 1-2, 2-2 5-39 sales and service offices, 8-28...
Page 238 Index-5 Tempo subroutine, 4-29 terahertz, 3-7 THRSHLD softkey, 3-11 softkey, 3-7 TIME programming command, 5-60 total power maximum measurable, 3-24 transient data, 4-9 *TRG, 5-9 trigger ignore, 8-7 TRIGger subsystem, 5-61 *TST, 5-10 UNITS softkey, 3-7 up-arrow softkey, 2-7 UPDATE softkey, 3-8 uppercase letters, 4-23...

Agilent Technologies 86121A User Manual

Chapter 1 Getting Started

Chapter 2 A Quick Tour

Chapter 3 Making Measurements

Chapter 4 Programming

Chapter 5 Programming Commands

Chapter 6 Performance Tests

Chapter 7 Specifications and Regulatory Information

Chapter 8 Reference

Quick Links

Related Manuals for Agilent Technologies 86121A

Summary of Contents for Agilent Technologies 86121A

Table of Contents