Lightwave Communications LDX-3232 manual Laser Forward Voltage Measurement Calibration

C H A P T E R 6

CALIBRATION AND TR OU BLESHOOTING

Remote Calibration of the LDX-3232 Current Source

Laser Forward Voltage Measurement Calibration

The following procedure is for calibrating the LASER voltage measurement.

Configure the current source in the following manner for the laser current source voltage calibration:

Function	State	GPIB Command
LASER MODE	I (constant current low bandwidth)	LAS:MODE:ILBW
RANGE	2000 mA	LAS:RANGE1
CURRENT LIMIT	Set to FS (full scale of range)	LAS:LIM:Ix
I SETPOINT	400 mA	LAS:LDI 400

a.With the LASER output off, connect a calibrated voltmeter, in parallel with a resistor (15 Ω, 5 W), to the LASER output (Laser Anode and Laser Cathode) on the rear panel of the Current Source.

b.The current source output must be on in order to enter the LDV calibration mode. Enter the LAS:OUT ON command to turn the current source output on.

c.Enter the LAS:CAL:LDV command to place the Current Source in its LASER Voltage Calibration mode.

d.Enter the measured voltage (in volts) via the LAS:LDV <nrf value> command. The measured value of the voltage should not be entered until the LDX-3232 Current Source is ready to receive it. The current source will be ready to receive the voltage value when, after a LAS:CAL:LDV? query is sent, the response from the Current Source is "1".

e.Once the actual voltage value is entered via the LAS:LDV <nrf value> command, the Current Source will set the current to approximately one-fourth (1/4) of the original value. It will then expect the second calibration voltage point.

f.Input the second actual (measured) LASER forward voltage (as an <nrf value>) as in Step d.

g.Once the second actual voltage value is entered via the LAS:LDV command, the Current Source will store the new calibration constants. The OPC? query may be used (after the LAS:LDV value is sent) to determine when the calibration is completed. Or, wait about two seconds before continuing with other GPIB commands.

98 LDX-3232