Laser Diode Connections And Shielding - Newport 8000 User Manual

Chapter 3
3.4.1

Laser Diode Connections and Shielding

It is recommended that the connections to the module output be made using twisted
wire pairs with an earth-grounded shield available at pin 3, except MOPA modules,
that use the ground post on the mainframe. The output terminals of the module are
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Laser Diode Driver Module Operation
Before connecting the laser diode to the module, be sure
that the LASER ENABLE is in the OFF position. Before
turning on the laser output, be sure that the current limit
and voltage compliance limit have been correctly set.
The cable connections to the laser must be secure to avoid
an open circuit, should they be jostled or bumped. Should
an open circuit occur during laser operations, the laser
output will normally be turned off automatically.
Except for MOPA modules, special circuits in the laser
module are present for detecting intermittent contacts and
connections. These circuits detect the abrupt change in
current that occurs when the output circuit is opened.
Experience indicates that should an open circuit occur
during laser operation, the laser may be damaged.
Therefore, secure cabling is important.
Although the Intermittent Contact circuitry works well in
helping to protect the laser diode, there is still a danger in
having poor connections, as no circuit can protect
It is possible with some modes of modulation, especially
square-wave, to trigger the intermittent contact circuit and
cause a shut-down. If this is the case for you, the
intermittent contact feature may be disabled in the laser
set up menu, with reduced laser protection in the case of
poor connections.
CAUTION
NOTE
NOTE
completely.
NOTE
31