Agilent Technologies 11980A Operation And Service Manual page 43

Fiber optic interferometer

Table of Contents

Procedure

1 Connect the system as shown in

2 Set Agilent 71400C reference level and attenuator to appropriate values.

3 Set the Agilent 71400C controls as follows:

4 Sweep the modulation frequency of the modulation source between 12 MHz

Operation Verification

Start Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 MHz

Stop Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 MHz

Reference level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 dBm

Optical Attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 dB

Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 dB/div

Resolution Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 kHz

Video Bandwidth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 kHz

Trace A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MAX HOLD

and 20 MHz. The Agilent 71400C should have a display similar to that shown in

Figure

5-3.

Reference level and attenuator values can be adjusted to position the trace for

the particular laser output power that is being used. The nulls represent can-

cellation effects due to the separate paths available to the optical energy, and

indicate continuity in both optical paths of the interferometer. If the displayed

trace does not indicate any nulls, then the test has failed.

5-6

Figure

5-2.

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