Photodiode Current (Pdi) Measurement - ILX Lightwave LDX-36000 Series User Manual

6
C H A P T E R

Photodiode Current (PDI) Measurement

To perform an accurate photodiode calibration, large resistor values are
recommended.
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10 Send the photodiode measurement calibration to the 36000 using the following command:
11 Set the current on the current source to 50% of full scale ( 5 mA)
12 Retrieve the 36000's photodiode current measurement with the following command:
13 Verify that the photodiode current measurement is within the accuracy specifications of
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 LDX-36000 Series
C A L I B R A T I O N A N D T R O U B L E S H O O T I N G
Photodiode Current (PDI) Measurement
Set the 36000 display to Power Photodiode by sending the following command:
LAS:DIS:PPD
Set the PD Bias to 0 Volts by sending the following command: LASER:PDBIAS 0
Set the user photodiode calibration to 0 by sending the following command:
LAS:CALPD 0
Set the factory photodiode calibration to default values by sending the following
command: LAS:CAL:MDI 1,0
Connect a current source to the photodiode input pins in the DB9 connector on the back
of the 36000. Set the current source to 20% of full scale (2 mA)
Record the 36000's photodiode current measurement with the following command:
LAS:PPD?
Set the current source current to 80% of full scale (8 mA)
Record the 36000's photodiode current measurement with the following command:
LAS:PPD?
Calculate the slope and offset of the photodiode current measurement with the following
equations:
slope = (80% Setpoint Current Value - 20% Setpoint Current Value) / (36000 80%
measurement - 36000 20% measurement)
offset = 80% Setpoint Current Value - (slope * 36000 80% measurement)
LAS:CAL:MDI slope,offset
LAS:PPD?
the instrument