HP 86037B, Instruction Manual

Page: 54 / 204

2-36
Operation
Checking Test Fiber Stability
Checking Test Fiber Stability
Changes in environmental temperature can affect the length of the fiber-optic
cables that you are testing. Because changes in length degrade measurement
results, use this procedure to determine if the fiber-optic cable has stabilized
and is ready to test. For information on the theory behind this test, refer to the
sidebar
“Measurement theory” on page 2-38 .
1 Connect a patch cord “through” cable between the
SOURCE OUTPUT
and
RECEIVER
INPUT
.
2 Click
Modulator Bias
and then click
OK
.
3 When the modulator bias adjustment is complete, remove the thru fiber and
connect the fiber to be tested between the test ports.
4 On the front panel of the HP 8168 tunable laser source, press the
LOCAL
key.
When you complete this procedure and return to using the mouse or key-
board, control of the instruments return to the HP 86037B. The network ana-
lyzer and tunable laser source are automatically initialized for all of the system
measurements.
5 Verify the laser output power is set to at least –4 dBm at a wavelength in the
passband of the fiber-optic cable that you are testing.
6 On the front panel of the HP 8753 network analyzer, press the
LOCAL
key.
7 Enter the CW frequency by pressing:
MENU, CW FREQ,
and
1 G/n.
8 Enter the number of points by pressing:
MENU, NUMBER of POINTS,
and then
401
X1.
9 Enter a convenient sweep time, such as 60 seconds, by pressing:
MENU, SWEEP
TIME,
and then
60 X1.
10 Press
MENU, TRIGGER MENU,
and
CONTINUOUS.
11 Press
MENU
and then
MEASURE RESTART.
12 Wait until the first sweep is complete, and then press:
SCALE/REF
and then
AUTOSCALE.