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Quick Reference Guide
11
Typical test connections
Figure 7
shows typical connections to the laser diode, the back photodiode detector, and
the front photodiode detector in a laser diode test setup (interlock connections are not
shown; see
Figure 6
). Connections are as follows:
•
The center conductors of the CURRENT OUTPUT and VOLTAGE SENSE HI and
LO terminals connect to the laser diode under test. Current is applied to the laser
diode through the CURRENT OUTPUT HI and LO terminals, and voltage across
the DUT is measured through the VOLTAGE SENSE HI and LO terminals.
•
DETECTOR 1 connects to the back photodiode detector. The CURRENT INPUT
(center conductor) is connected to one photodiode terminal while the BIAS termi-
nal (inner shield) is connected to the other photodiode terminal.
•
DETECTOR 2 connects to the forward photodiode detector. The CURRENT
INPUT (center conductor) is connected to one photodiode terminal while the BIAS
terminal (inner shield) is connected to the other photodiode terminal.
Connection considerations
When making connections to the laser diode, observe the following considerations to
avoid pulse degradation due to distributed inductance and other effects:
•
Use only the supplied 15
Ω
coaxial cables or equivalent.
•
Maximum recommended length for the sum of both cables is 40 cm.
•
Connect the four cable shields together at the DUT.
•
Carry cable shields as close to the DUT as possible. Minimize the length of
exposed (unshielded) signal lines.
•
Dress the VOLTAGE SENSE cables as far away from the CURRENT OUTPUT
cables to avoid magnetic coupling. Twist the SENSE cables together to further
reduce magnetic coupling.
•
Connect the VOLTAGE SENSE leads as close to the body of the DUT as possible.
See the specifications in Appendix A and information in Appendix F of the Model 2520
User’s Manual for more information.