20
Step 4: Select the Modulation Input Bandwidth
When only DC control of the output is necessary, the noise performance can be
maximized by applying a single pole filter to the setpoint signal (the sum of the Adjust
Potentiometer and Modulation Input). This filter is inserted when Switch 6 is ON.
OFF
ON
2 3
4 5 6 7
9
1
10
8
CONFIGURATION
OFF
ON
2 3
4 5 6 7
9
1
10
8
CONFIGURATION
High Bandwidth Mode
Low Bandwidth Mode
Step 5: Select the Photodiode Range
You must have a monitor photodiode to operate in constant power mode. For
maximum sensitivity, two ranges of sensing are provided. If your photodiode
maximum current exceeds 200
µ
A, use the wider range.
OFF
ON
2 3
4 5 6 7
9
1
10
8
OFF
ON
2 3
4 5 6 7
9
1
10
8
OFF
ON
2 3
4 5 6 7
9
1
10
8
Max PD current 2000
µ
A
Max PD current 200
µ
A Max PD current 20
µ
A
To increase the range to 20mA, set the switch for the 2000
µ
A range and place a 10
Ω
resistor across pins 5 & 6 of the Output Connector.
Step 6: Select the Modulation Sensitivity & Enable or Disable Modulation
The sensitivity selection is provided to maximize modulation performance. The
modulation signal can be passed through as a 1:1 signal or attenuated by a 10:1
factor. The following details the modulation transfer functions for constant power
mode.
Transfer Functions
PD Range
Switch 9
ON
Switch 9
OFF
2000
µµ
A Range
400
µµ
A / V
40
µµ
A / V
200
µµ
A Range
40
µµ
A / V
4
µµ
A / V
OFF
ON
2 3
4 5 6 7
9
1
10
8
CONFIGURATION
Switch 10 either enables or disables modulation. Modulation is disabled when Switch
10 is OFF. It is enabled when Switch 10 is ON.
1:1 modulation with
modulation enabled