Vescent Photonics D2-125, Manual

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2021/04/17 23:32 17/18 Reconfigurable Laser Servo
Product Manuals - https://www.vescent.com/manuals/
Tab. 1: D2-125 locking D2-100 or TOSA
D2-125 Stand-alone Test
It is possible to “lock the D2-125 to itself” as a self-test. Under the following conditions, the D2-125
should behave as described. Depending on your observations, contact
Vescent technical support and
discuss the performance.
Switch to Side Lock Mode 1.
Set Ramp to Servo (not Aux) 2.
Disconnect the 125 from all input and output 3.
Connect the Servo Output to the Error Input 4.
Set Gain to about the middle of the course range 5.
Set the Ramp Center to the middle of its range 6.
Set Ramp Amp to max 7.
Set DC Offset to center of its range 8.
What voltage do you see on the Servo Out Monitor (into 1 MΩ impedance) 9.
In Ramp mode? 1.
Should be a ±9-10V triangle wave at 500 Hz 1.
In Unlock mode? 2.
Should be 0 V (Could be offset by the Ramp Center) 1.
In Lock mode? 3.
Should be 0 V (Could be offset by either the Ramp Center or DC Offset) 1.
If D2-125 rails, return to Unlock mode, switch the Gain Sign from + to - (or vice versa) and retry 10.
In Lock mode, turn up gain. At some point, the Servo Out should oscillate at something close to 11.
10 MHz, depending on the specific corner settings of the PI
2
D loop
1)
quantity 2 when PL option ordered
2)
In Peak Lock mode, the 50 Ω to ground is AC-coupled. A measurement of the DC impedance will yield
a higher value.
3)
Referenced to 50Ω load
4)
Oscillation frequency when Laser Servo locked to itself in proportional mode.
5)
Gain referenced to Primary Servo Output.
6)
Into a 1 MΩ load
7)
It is not necessary to trigger the oscilloscope to a positive slope, however, switching the trigger slope
will change whether the servo locks to a positive slope (positive slope trigger on oscilloscope) or
negative slope (negative slope trigger on oscilloscope)