ILX Lightwave LDC-3700C Series, User Manual, Page: 33 / 176

O P E R A T I O N S
Connecting to the Laser Controller
04_09 LDC-3700C Series
17
C H A P T E R
2
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Connecting the Laser Current Source
The 9-pin connector marked CURRENT SOURCE on the back panel of your
Controller, is used to connect your laser diode to the controller. There are
connections provided for laser cathode and anode, photodiode cathode and
anode, chassis ground and interlock. The pinout diagram for this connector is
shown in Figure 2.2.
Make sure the laser current and voltage measurement connections are correct:
connect pin 4, Cathode Voltage Sense, and pin 5, Laser Cathode, to the laser
diode cathode; and connect pin 8, Anode Voltage Sense, and pin 9, Laser Anode,
to the laser diode anode.
Figure 2.2 Back Panel LD Connector
Interlock Connections
In order for the laser output to be enabled, a short must exist between the
Interlock pins (pins 1 and 2) of the connector. The short can be a direct short
across the pins or a switch to prevent laser operation until the switch is closed. If a
short does not exist between these two pins, the INTERLOCK LED illuminates on
the front panel and the laser output is disabled.
The interlock terminals on the LASER connector, pins 1 and 2, must be kept isolated
from all other connections including earth ground.
Photodiode Connections
Many laser diode modules contain an internal photodiode that monitors the back-
facet emission of the laser. Usually, this photodiode is internally connected to
either the laser anode or cathode.
The photodiode and laser connections to the LDC-3700C Series Laser Diode
Controller are electrically isolated from ground and each other. So, if a 4-pin