How To Disable Modulation; How To Use The Internal Modulation; How To Set The Frequency Of A Modulated Signal; How To Set The Modulation Mode - Agilent Technologies 8163A User Manual

Laser Sources How to Use Laser Source Modules

How to Disable Modulation

If <Off> is displayed as the Modulation Source parameter, [Mod Src], the laser
source outputs an unmodulated continuous-wave signal.
To disable modulation:
1 Move to the Laser Source channel and press [Details] softkey.
2 Move to the modulation source parameter, [Mod Src], and press Enter.
3 Move to <Off>, by using the cursor key, and press Enter.

How to Use the Internal Modulation

The internal modulation is a square wave with a 50% duty cycle. You can set both
the amplitude and the frequency of this signal. The amplitude is set by the power
parameter. This is the maximum output power of the output signal; at the
minimum output power, no power is output.
Output
Power
t
Figure 63 The Modulated Signal

How to Set the Frequency of a Modulated Signal

To set the frequency of the modulation to 6.500 kHz:
1 Move to the frequency parameter, [Mod Frq], press Enter.
2 Enter 6.500 press Enter.

How to Set the Modulation Mode

3 Move to the modulation source parameter, [Mod Src], and press Enter.
4 Move to <Internal>, by using the cursor key, and press Enter. The text Int
appears in the Laser Source channel.

How to Increase Linewidth

You can use coherence control to increase the linewidth of the optical signal
output from your Agilent 8163A Series Laser Source module.
Enabling the coherence control increases the linewidth 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.
To enable coherence control:
1 Move to the Laser Source channel and press [Details].
96
Agilent 8163A Lightwave Multimeter, Agilent 8164A Lightwave Measurement
System, & Agilent 8166A Lightwave Multichannel System, Fourth Edition