How To Set Modulation - Keysight N777-C Series User Manual

5 N777-C Instrument's Front Panel Display

How to set Modulation?

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To view the Modulation window, click on the Modulation tab. The
following window appears:
The following modulation modes are available:
• OFF - No modulation
• Coherence - You can use coherence control to increase the line width
of the optical signal output from your Tunable Laser instrument.
Enabling the coherence control increases the line width of the optical
output signal to between 50 and 500 MHz (typically). Coherence
control greatly reduces interference effects and therefore improves the
power stability in sensitive test setups.
The N777-C instruments also allow adjustment of the line width
broadening with the "Coherence Level" setting. A level of 100%
corresponds to minimal broadening. The default level is usually a good
setting.
• Wavelength Locking - You can choose wavelength locking as the
modulation source, so the change in output wavelength is roughly
proportional to the voltage you apply to the input BNC connector on
the front panel of your Tunable Laser instrument.This enables you to
fine tune the output wavelength within a limited wavelength range.
Keysight N777-C Series Tunable Laser Family User's Guide