THORLABS LDM56, Operating Manual, Page: 8 / 24

Temperature-Controlled Laser Diode Mounts Chapter 4: Setup
Page 6 TTN121126-D02
Figure 2 Polarity Switch Settings
3. Most laser diodes are three pins with the case tied to one of the laser
pins and also to one of the photodiode pins. The other laser and
photodiode pin will be isolated from the case. The LDM56(/M) and
LDM90(/M) mounts were designed to operate the laser case at ground
potential, therefore this common pin will be inserted into either the 3
o’clock or the 9 o’clock position of the laser connector. Locate the
isolated laser pin and insert it in the 12 o’clock position. The isolated
photodiode should now be in the 6 o’clock position. Refer to the figure
below.
Figure 3 LD and PD Orientation
4. Install the laser mounting flange and the cover. Install both screws
through the mounting flange and loosely into the cold plate, then
carefully tighten each screw a little bit at a time until the flange is just
snug. Do not over tighten either screw – the flange will sit slightly above
the cold plate. If removed during installation reinstall the cover using the
four 2-56 cap head screws provided.
Note: The four sockets comprising the laser diode connector are 0.6" deep, laser
diode leads do not need to be cut unless they are longer than 0.6".
Note: The laser connector is located close enough to the front face of the copper
cold plate to allow easy installation of short leaded lasers. The clearance area
around the LD and PD sockets is sufficient to prevent the pins from contacting
the cold plate.