LDM9T
Chapter 4: Setup
Page 8
15827-D02
4.6. Using a Third-Party Laser Controller
When using a third-party controller, a custom cable will have to be made to
properly interface to the laser mount. Please refer to the table below for laser
connections.
Figure 4 LD Controller DB9 Connection
Pin
Signal
Description
1
Interlock and
Status Pin
(LDC Specific)
This pin is the input to the LD Status indicator and interlock
circuits. When using Thorlabs’ LDC controllers, no external
circuitry is required.
2
Photodiode
Cathode
This pin is connected to the 12 o’clock pin on the laser
socket when the PD polarity switch is set to AG (anode
grounded). It is attached to ground and the 9 o’clock and 3
o’clock pins on the laser socket when the PD polarity switch
is set to CG (cathode grounded).
3
Laser Ground
(Case)
This pin is
connected to the 9 o’clock and 3 o’clock pins on
the laser socket and corresponds to the settings of the LD
and PD polarity switches. i.e., If the LD and PD switches are
set to AG, then this pin grounds the anode of the laser diode
and photodiode.
4
Photodiode
Anode
This pin is connected to the
12 o’clock pin on the laser
socket when the PD polarity switch is set to CG (cathode
grounded). It is attached to ground and the 9 o’clock and 3
o’clock pins on the laser socket when the PD polarity switch
is set to AG (anode grounded).
5
Interlock and
Status Return
This pin is the return side of the Status and Interlock
circuitry.
7
Laser Diode
Cathode
This pin is connected to the 6 o’clock pin on the laser socket
when the LD polarity switch is set to AG (anode ground).
Otherwise it is floating.
8
Laser Diode
Anode
This pin is connected to the 6 o’clock pin on the laser socket
when the LD polarity switch is set to CG (cathode ground).
Otherwise it is floating.
6, 9
NC
These pins are typically used to monitor LD voltage when
used with the Thorlabs LDC series controllers. This mount
does not support this feature.
