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MOGlabs MWM Manual

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MWM wavemeter
mogwave 1.4.15
Revision 3.19
Firmware 0.6.9

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Summary of Contents for MOGlabs MWM

  • Page 1 MWM wavemeter mogwave 1.4.15 Revision 3.19 Firmware 0.6.9...
  • Page 2 MOGL Contact For further information, please contact: MOG Laboratories P/L MOGLabs USA LLC 49 University St 419 14th St Carlton VIC 3053 Huntingdon PA 16652 AUSTRALIA +61 3 9939 0677 +1 814 251 4363 info@moglabs.com...
  • Page 3 We hope that you find the useful, and please let us know if you have any suggestions for improvement of the or this document, so that we can make life in the lab better for all. abs, Melbourne, Australia MOGL www.moglabs.com...

  • Page 5: Table Of Contents

    Contents Preface 1 Introduction 1.1 Basic setup ......1.2 Software installation ..... . . 2 Standalone operation 2.1 On-device measurements .
  • Page 6 Contents 5 Signal out and PID laser controller ....MOGL 5.2 PID parameters ......5.3 Integrator windup .
  • Page 7 Contents G Ugrading firmware References...
  • Page 8 Contents...

  • Page 9: Introduction

    1. Introduction optical instrument is a high resolution diffraction grat- MOGL ing spectrometer in Littrow configuration. Optical interference creates an image of a singlemode fibre core at a wavelength-dependent position on a semiconductor imaging sensor. The image is digitised at high spatial reso- lution and with high dynamic range and speed.
  • Page 10 Chapter 1. Introduction Figure 1.2: Web interface homepage. power on/off via the OK pushbutton. To power on or off, hold the OK button down for 2 to 3 seconds. 3. If possible, use a network connection for improved response times and faster data acquisition.

  • Page 11: Software Installation

    When you connect the , your computer should automatically find and install drivers from the Windows update service. If not, in the c:\Program Files\MOGLabs install directory (typically ) you should find the USB_VCPdriver folder which will contain setup programs for 32-bit and 64- bit systems.
  • Page 12 Chapter 1. Introduction 3. Once installation is completed, restart your computer. 4. When your computer is finished booting, disconnect the USB cable from your wavemeter, and then reconnect.

  • Page 13: Standalone Operation

    2. Standalone operation should be used with the mogwave For full functionality, the MOGL Windows -based application package provided (see chapter 4), but it can also be operated as a standalone instrument using the pushbuttons and on-screen menu system. The also offers a web interface (see chapter 3) for operation with a web browser, for example on a smartphone.

  • Page 14: Measuring

    Chapter 2. Standalone operation 2.2.1 Pushbuttons There are four pushbuttons to the right of the display, to select the measurement mode or to step through the menus. ← Stop measuring, if device-based measurement is active. Activate firmware upgrade if held down during startup. ↑...

  • Page 15: Device Menus

    2.4 Device menus The right-hand image shows the third mode of operation, where the dis- played number is the setpoint rather than the actual measured wavelength. That allows slightly faster operation (1250 measurements per second). 2.4 Device menus 2.4.1 Home screen The default screen on power-up, showing firmware version number, device serial number, wavelength range, temperature, pressure, exposure time and connection.
  • Page 16 Chapter 2. Standalone operation 2.4.4 Units measures wavelength in ambient conditions, but uses measured temperature and pressure to estimate the wavelength in vacuum, in air at standard temperature and pressure, or as a frequency or wavenumber. Column returns the sensor pixel number corresponding to the spectral peak, for diagnostic purposes.
  • Page 17 2.4 Device menus 2.4.6 Ethernet The ethernet sub-menu shows the current address, and stored (static default) values for static address, netmask, gateway DHCP TCP/IP port. To save and activate the new values, move down the menu to either Save to eeprom or Save and restart and press .
  • Page 18 Chapter 2. Standalone operation 2.4.9 About Provides information including serial number and firmware version.

  • Page 19: Web Interface

    3. Web interface With the connected to your network, the device web server (see figure below) provides real-time wavelength readings to any web browser including mobile phones, desktop and laptop computers. Simply enter the display (e.g. 10.1.1.128) into device IP address, as shown on the your web browser and you should see a webpage similar to that below, provided your computer/phone is on the same subnet as the device.

  • Page 20: Home Page

    Chapter 3. Web interface • The abs logo can be clicked to access the abs website. MOGL MOGL • The menu bar provides access to several key Functions, the device Home page, and to a Help page which provides a link to this user- manual via the abs website.

  • Page 21: Live View

    3.2 Live view 3.2 Live view Live view is very similar to the home page, but the wavelength and other Static readings change in real time. The button switches back to the static home page. Figure 3.2: Live view, showing the wavelength, exposure time, device temperature, status in real time.

  • Page 22: Live

    Chapter 3. Web interface 3.3 Live+ Live+ shows just the real-time value of the wavelength, in the largest font that will allow the number to fit within the current window. Change the browser window size to enlarge or reduce the display. Use your browser back-button to return to the previous web page.
  • Page 23 3.4 Device setup Figure 3.4: Device setup page. most situations, a maximum exposure time of 100 ms is more than sufficient and ensures good responsiveness from the device. Camera gain Drop-down list of analogue gain on the imaging sensor. The default is 1, but higher values can be used to reduce exposure times and thereby...

  • Page 24: Software

    Chapter 3. Web interface increase measurement rate, particularly for frequency locking with the servo. 3.4.2 PID settings The internal parameters can be adjusted, though in general it is prob- ably easier to use mogwave; see section 4.3.4. Vout shows the current value of the output voltage.

  • Page 25: Mogwave

    4. MOGWAVE The host software mogwave provides a graphical user interface that allows measurement and calibration functions. See appendix E for information on starting mogwave and configuring default parameters. 4.1 Device discovery By default, a device discoverer (Figure 4.1) is initiated when mogwave is started.

  • Page 26: Main Display

    Chapter 4. MOGWAVE slow, and the application does not find your device, you can either edit the shortcut link which was created during the install process, to pro- vide command-line parameters that specify the device address, or edit the default.cfg file. Further details are provided in the mogwave chapter 4, or in appendix E.
  • Page 27 4.2 Main display erage of a set number of spectra (see below). The display can be zoomed into an area around the highest peak using 10x and 25x zoom functions, and the spectrum can be shown in linear or log form. 2d image inset The inset shows a 2d image of the area around the highest spectral peak, which should be approximately Gaussian and symmetric.

  • Page 28: Menu

    Chapter 4. MOGWAVE 4.3 Menu 4.3.1 Device Device network settings To configure the wavemeter network connection settings address, mask, gateway and port). Particularly useful for configuring the network settings via Device command This opens a new dialog for interactive command access to the telnet device, similar to but this approach will work via...
  • Page 29 4.3 Menu LCD Screen Opens a window showing the current image on the device (see below). Right-click in the image to close the window, or left-click to save the image to a file. .PNG 4.3.2 Spectrum Save spectrum The current spectrum can be saved to a tab-separated .dat file using the File menu at the top of the window.
  • Page 30 Chapter 4. MOGWAVE background noise can be determined. Bgnd Acquire new background measurements. Save Save current HDR spectrum. Saves all separate exposure time spectra and background measurements, with calculated HDR spectrum and a smoothed spectrum. Go/Stop To generate HDR spectra in real time. The main application must be actively collecting spectra (if not, press the Start/Stop button in the main application).
  • Page 31 4.3 Menu use higher power to keep exposure times below 1 ms at 1x gain. Acquire full image Captures a full image from the sensor. Due to limited memory on the device, the image is captured in bands. Acquisition will take about 2 minutes using and five or six seconds on fast (100 Mb/s) ethernet.
  • Page 32 Chapter 4. MOGWAVE mogwave controller to the device controller (arrow points from MOGWave ) or vice versa (arrow points from Device Device MOGWave Output (V) feedback signal V ( ). Can be edited to set a fixed Shows the output voltage, if is not enabled.

  • Page 33: Acquisition

    4.4 Acquisition closed, but the device-based controller will remain running if it was enabled. mogwave must also be acquiring measurements for the mogwave controller to work, but the main display interval does not affect actual measurement speed and thus response. 4.3.5 Help Manual (online) Links to the latest user manual at the...

  • Page 34: Wavelength

    Chapter 4. MOGWAVE When selected, the current wavelength is saved as a reference. The refer- ence is subtracted from future measurements so the displayed wavelength shows the change relative to the reference value. 4.6 Wavelength Wavelength The primary wavelength measurement is shown in a variable size (stretchable) text window.

  • Page 35: Functions

    4.7 Functions If the toggle is on, the measured wavelength will be displayed on the device screen, in current units. This can be helpful for tuning a laser, if the is close to the laser and far from the host computer. On device Normally the displayed wavelength is calculated by mogwave.
  • Page 36 Chapter 4. MOGWAVE more rapid updates of the Time Series plot. Also reduces the rate of up- date of the main wavelength numeric display. Fast and Faster can both be selected for fastest possible Time Series update rate. Device-based measurements are less accurate than can be achieved with full mogwave analysis, particularly when the default in-device imaging row is different to the optimum row determined by mogwave.

  • Page 37: Status Bar

    4.8 Status bar 4.8 Status bar The status bar shows secondary information including the measured air device temperature and air pressure, the serial number, and the communi- cations channel including address and port number if communicating by , or the port number.
  • Page 38 Chapter 4. MOGWAVE The row can change, due to thermal drift or if the fibre is changed, in particular if changing from FC/PC to FC/APC or vice versa. The row is tracked automatically but the row must initially be close, to within about 10 pixels of the centre of the spectral peak.

  • Page 39: Signal Out And Pid

    5. Signal out and PID can output an analogue signal on the connector (V 5 to +5 V). That signal can be a fixed value, a signal proportional to measured laser wavelength, or a control signal that attempts to drive the wavelength of a laser towards a set wavelength.

  • Page 40: Mogl Abs Dlc Laser Controller

    MOGL output to the input and set on (external piezo MWM SMA DLC SWEEP DIP 9 stack control); see figure below. Set both the offset and windup parameters to 1.25 V. Use the knob as a master gain on the feedback.

  • Page 41: Integrator Windup

    5.3 Integrator windup Gain (V/unit) Defines the gain, G. The gain is in volts per unit, where the units are the currently active measurement units if operating using the standalone controller, or via the drop-down unit selector in the mogwave menu.

  • Page 42: Examples

    Chapter 5. Signal out and PID 5.4 Examples 5.4.1 Analogue output of wavelength With = 1 and = 0, the output voltage will be directly proportional to the measured wavelength relative to the setpoint. Fig- ure 5.2 shows an oscilloscope trace of V for an measuring the wavelength of a rapidly scanning laser, for example to optimise the laser...
  • Page 43 5.4 Examples control voltage is 0 to 2.5 V, corresponding to laser frequency change of around 20 GHz (0.04 nm). If the frequency change is positive for positive change in control voltage, a negative gain should be used for negative feedback control. It would then seem logical to use an overall gain of 2 5/0 04 = 62 5 V/nm, with each...
  • Page 44 Chapter 5. Signal out and PID (20 GHz), a higher Gain setting can be used with reduced gain via the control. The net feedback gain will be the same but more of the SPAN output range will be used.

  • Page 45: Calibration

    6. Calibration Recalibration of the can be required due to drift and metal creep, accidental mechanical shock, or to change the operating wavelength. Usu- ally it is a very simple process of measuring a known laser wavelength and clicking one button. Multi-point calibration across the operating wave- length range will improve the accuracy.
  • Page 46 Chapter 6. Calibration To calibrate, simply enter the known wavelength for your light source. Re- peat at as many different wavelengths as desired, across the measurement range of the device, typically every one or two nm. The sum of the resid- uals can provide an indication of whether the new calibration coefficients are more precise than the old.
  • Page 47 6.1 Existing wavelength range If more than four calibration points have been entered, then press the button to calculate the full cubic calibration function. If three or two points are entered, the calibration will be limited to a quadratic or linear function.

  • Page 48: Calibrating With Mogl Abs Fzw Wavemeter

    Chapter 6. Calibration full range of the device, but may be less accurate within the calibration range. Both single and multipoint calibrations will save the new calibration co- efficients on the device. They also save all calibration points (measured and known wavelengths) to a .csv file. To avoid reprogramming the device with new calibration data, hit the Cancel button.

  • Page 49: New Wavelength Range

    C:\Program Files (x86)\ HighFinesse\Wavelength Meter WS6 1234\Com-Test\wlmData.dll C:\Program Files (x86)\MOGLabs\mogwave\mogwave Copy this to From time to time, HighFinesse change the way they store and load wlmData.dll, and the above may not work for your system. Contact abs if you are having difficulty.
  • Page 50 Chapter 6. Calibration W2). For Rev 2 devices, release the three locking screws holding the element in place at the bottom of the device, inside the optical chamber; for Rev 3 and later, release the two locking set screws on the end opposte the fibre port (one is inside the plastic cover).
  • Page 51 6.4 New wavelength range Di ractive optical element Release screws Figure 6.2: Rev 3, showing location of diffractive optical element and release screws.

  • Page 52: New Fibre

    Chapter 6. Calibration 3. Couple light into the , preferably with plenty of power (a few microwatts) exiting from the fibre endface (at the end). 4. Run the mogwave program, and rotate the diffractive optical element (see below) until a spectral peak is seen. On Rev 2 devices, the indicator line on the diffractive element holder should point towards the fibre such that the surface of the diffractive element is exposed to the light.
  • Page 53 6.5 New fibre mogwave Device Command option, execute the following command: set,row,mainY where mainY is the y location of the main spot. Reset the device, then calibrate as above for new wavelength range. See also section 4.8 for mogwave tools to aid with focus and adjusting the default row.
  • Page 54 Chapter 6. Calibration...

  • Page 55: A Specifications

    A. Specifications Specification Parameter Wavelength 350 nm – 1100 nm Wavelength 23 nm at 780 nm Range 1 pW at exit of singlemode fibre Min input power ±1 GHz (±0 001 nm) at 780 nm Accuracy (at time of calibration) 100 MHz (0.1 pm) at 780 nm Precision Electronics...
  • Page 56 Appendix A. Specifications Specification Parameter ◦ Resolution ±0 008 Temperature ◦ ◦ Range 10 to +40 Resolution ±1 Pa Pressure Range 260 hPa – 1260 hPa 0 to +5 V, 12-bit (1 mV) Aux ADC input Interface 10/100 TP RJ45 Ethernet USB1.1, plug type USB-B output, ±2 5 V...
  • Page 57 1050 1150 Wavelength (nm) Figure A.1: Typical detector spectral response.
  • Page 58 Appendix A. Specifications...

  • Page 59: B Communications

    B. Communications can be connected by or ethernet ( ). From the user and TCP/IP device perspective the two are equivalent, but if possible, use a network connection for improved response times and faster data acquisition. B.1 TCP/IP When ethernet is connected, the will attempt to obtain an address .
  • Page 60 Appendix B. Communications You can also access the device indirectly through a socket server estab- lished by mogwave on your host computer. The mogwave server provides fully calibrated wavelength measurement, allowing mogwave to act as an API for data acquisition systems, for example matlab or LabVIEW. See appendix F for more information.
  • Page 61 B.1 TCP/IP approach will work via . Type a command into the command line win- dow, and hit Enter to send that command to the device (see appendix D); the response will appear in the box below the command line window. Some commands are not permitted because they require complex data flow.

  • Page 62: Usb

    Appendix B. Communications 3. Telnet to the , for example address 10.1.1.180 and port 7802, and use the set command to reconfigure the network settings: telnet 10.1.1.180 7802 set,ipaddr,"192.168.1.100" set,ipgw,"192.168.1.1" reset After reset, the device will default to the new settings. If using PuTTY client, set the Host Name to 10.1.1.180, telnet (www.putty.org) as a...
  • Page 63 If you do not see a virtual COM port under “Ports” in the Device Manager then manually install the driver. The driver install package should be c:\Program Files (x86)\MOGLabs\USB_VCPdriver 1. Run the driver setup program. This will copy the drivers to your...
  • Page 64 1. Right-click on the mogwave desktop shortcut and select Properties. 2. Edit the Target to add -u -p xx at the end (see figure below). It should be something like C:\Program Files (x86)\MOGLabs\mogwave\mogwave\mogwave.exe -u -p 15 3. Select Apply to save the new shortcut.
  • Page 65 B.2 USB Figure B.1: mogwave shortcut properties, edited to add port number. Note that the Target has been abbreviated here.
  • Page 66 Appendix B. Communications...

  • Page 67: C Programming

    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - # MWM wavemeter python example # ( c ) MOGLabs 2020 # Using python driver from moglabs . com...
  • Page 68 Appendix C. Programming # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - from mogdevice import MOGDevice import sys import matplotlib .
  • Page 69 C.1 python example # convert to list for i in xrange (0 , bufsize /2) : word = ord ( bindata [2* i ]) +( ord ( bindata [2* i +1]) < <8) image . append ( word ) y = image [0: cols ] # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - # Plot spectrum # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -...
  • Page 70 Appendix C. Programming...

  • Page 71: D Command Language

    D. Command language is controlled via simple text commands of the form: wavelength,vacuum Each command begins with a text key. Only a few letters of the text key are required, just enough to uniquely identify the command against all other valid commands. Some commands will have a sub-command, and/or parameters including integers, hexadecimal integers (e.g.

  • Page 72: Pid Control

    floating-point number from 5 to +5. gain pid,gain,val Set the output gain in volts/unit. For example, if the is displaying in nm (vac) , driving a moglabs laser system with controller, a reasonable...

  • Page 73: General Functions

    D.3 General functions value would be 10 V/nm. Changing display units will not change this value. can and often should be negative. enable pid,enable Resets and then activates the controller. The output will initially be set to the offset (see above) and then vary according to the algorithm described in section 5.

  • Page 74: Display Functions

    Appendix D. Command language D.4 Display functions DISPLAY Commands to control the on-device display. line display,line,x,y,str Display string str at location x,y. 0 ≤ ≤ 16; 0 ≤ ≤ 7 bigline display,bigline,x,y,str Display string str at location x,y, using large font. 0 ≤...
  • Page 75 D.5 Auxilliary measurements implemented in current models. dac,v connector, ±2 5 V 12-bit. Set voltage on v can be an integer: 0 ≤ v ≤ 4095 corresponding to 2 5 + 2 5 V or a floating-point number 2 5 ≤ v ≤ +2 5 but in that case must include a dac,2 decimal point.

  • Page 76: Imaging

    Appendix D. Command language TBOOT tboot Temperature at last reset or power-on. D.6 Imaging SPECTRUM spectrum Acquire currently defined field of view using currently defined exposure time, sum first two rows and return sum in binary. Thus for typical 2592 columns, return 2592 16-bit integers (two bytes each, least significant byte first).
  • Page 77 D.6 Imaging wavelength used for wavelength determination with command. cam,fov,rowstart,colstart,nrows,ncols Define the field of view (i.e. the imaging area). 0 ≤ rowstart ≤ 1944 and must be even. 0 ≤ colstart ≤ 2592 and must be multiple of 4. 0 ≤ nrows ≤ 1943 and must be odd. 0 ≤...

  • Page 78: Configuration Settings

    Appendix D. Command language ncols number of columns -1 swu,swl exposure time binx,biny binning (0, 1 or 3 for 1x, 2x or 4x) gain gain D.7 Configuration settings SET, GET Set and report configuration values. Each command de- EEPROM scribed below has a corresponding command to report the relevant parameter.
  • Page 79 D.7 Configuration settings set,mac,"xx.xx.xx.xx.xx.xx" Set ethernet address. The device is factory configured with a address reserved by abs from the IEEE REgistration Authority. It MOGL should not be necessary to change the default MAC address. ipport set,ipport,u16 port number to unsigned 16-bit u16. The device will respond Set the TCP/IP to telnet queries on that port.
  • Page 80 Defines the user ID for firmware upload. Default value is “moglabs”. When uploading new firmware, you will be asked for a user ID and password. This command allows you to set the user ID to limit access to firmware changes.

  • Page 81: Eeprom Access

    D.8 EEPROM access D.8 EEPROM access EEPROM Low-level commands to set and retrieve values. EEPROM read eeprom,read,addr16 Read single byte at address addr16. rword eeprom,rword,addr16 Read 16-bit word at address addr16. rlong eeprom,rlongaddr16 Read 32-bit long at address addr16. eeprom,seq,addr16,num16 Read num16 bytes starting at address addr16.
  • Page 82 Appendix D. Command language fset eeprom,fset Copy current configuration to factory default preservation area.

  • Page 83: E Mogwave Configuration

    Target 2. Edit the to add the appropriate command-line options, for example: C: Program Files MOGLabs mogwave mogwave.exe -u -p 15 to specify on port 15. 3. Press OK to save the shortcut changes. The shortcut should then start your software appropriately.
  • Page 84 Appendix E. mogwave configuration help configuration filename debug options address enable logging of errors maximum exposure time (ms) port or channel TCP/IP USBCOM sensor row simulation wavelength timeout multiplier enable FZW for calibration (y/n) HighFinesse for calibration (y/n) -c The configuration filename; see below. mogwave will first try to open the file within the current working directory (the directory where mogwave is located, or the “Start in”...

  • Page 85: Configuration File

    -f Enable MOGLabs FZW wavemeter reading for calibration (see sec- tion 6.2). Values are y, yes, n or no. -w Enable HighFinesse WLM wavemeter reading for calibration (see section 6.3).
  • Page 86 Appendix E. mogwave configuration...

  • Page 87: F Mogwave Server

    F. mogwave server mogwave provides a server that can be accessed via , providing an TCP/IP API so that wavelength measurements are accessible to other applications such as matlab or LabVIEW. To use the server, you should start mogwave and ensure that it is making sensible measurements. You can then stop mogwave and make single measurements on demand through the server, or leave mogwave running and access the most recent measurement from the server as needed.

  • Page 88: Mogwave Commands

    Appendix F. mogwave server command to mogwave, which will report help The above example sends the back something like: mogwave running wavemeter W2001101140930 Wavelength range 766.2 to 788.9nm, difference 22.7nm Valid commands: wave, last, close, start, stop, die, kill F.3 mogwave commands The mogwave server is controlled via simple text commands of the form wave The commands must match exactly, with no abbreviations or extensions.
  • Page 89 F.3 mogwave commands width are not necessarily associated with the same instantaneous spectral measurement. See above for optional units specification. UNCERT uncert[,units] Returns the statistical uncertainty for the most recent measurement if ac- quiring; initiates a single new measurement if not. Note that the values wave uncert returned by...
  • Page 90 Appendix F. mogwave server TWOD twod[,state] Switch between high accuracy 2d mode and faster 1d mode. See above for definition of state. CLOSE, EXIT close exit Close the socket (i.e. disconnects). TCP/IP KILL, DIE kill Terminate mogwave.
  • Page 91 5. Watch the device display until it shows the address, then open your web browser at that address. 6. At the prompt, enter your user ID and password. Initially these are moglabs wavemeter 7. Select Browse and then select the new MOG-WM.bin firmware file. Upload 8.
  • Page 93 Bibliography [1] J. D. White and R. E. Scholten. Compact diffraction grating laser waveme- ter with sub-picometer accuracy and picowatt sensitivity using a webcam imaging sensor. Rev. Sci. Inst., 83:113104 (2012). http://dx.doi.org/10. 1063/1.4765744 [2] P. J. Fox, R. E. Scholten, M. R. Walkiewicz and R. E. Drullinger. A reliable, compact and low-cost Michelson wavemeter for laser wavelength measure- ment.
  • Page 96 2014 – 2020 MOG Laboratories Pty Ltd 49 University St, Carlton VIC 3053, Australia Product specifications and descriptions in this docu- Tel: +61 3 9939 0677 info@moglabs.com ment are subject to change without notice.

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