NKT Photonics Koheras ADJUSTIK HP, Product Manual

Page: 76 / 115

CONTROL settings
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coupling. Refer to “Wavelength modulation coupling” on page 42 for further
information.
Note: When using wavelength modulation with an X15 laser, and the Modulation
range parameter is set to Narrow , the modulation signal will be AC-coupled, and
the DC-component enters a software integrating function that tunes the wave -
length up or down when the DC-voltage varies either positive or negative re -
spectively. The speed of wavelength tuning is set with the Integrating update
interval.
Modulation Range
For X15 lasers, you can use the Modulation Range drop-down menu to set the
modulation range to either narrow or wide.
When set to Narrow , modulation depth is limited but the X15’s low phase noise is
maintained. To increase the modulation depth, change the range setting to Wide .
When the modulation range is set to Wide , phase noise increases.
Note: Refer to “Narrow vs. Wide modulation range” on page 42 for further infor -
mation on configuring the modulation range.
Signal output
You can output the internal generator signal (internal modulation) from the
wavelength modulation pins of the laser. To output the signal from the pins, set
the Modulation type to Internal and the Signal output selector to Enabled . To
disable the output signal, set the Signal output drop-down menu to Disabled .
When multiple lasers are used, one laser can be used as a master signal
generator with the other lasers configured as slaves.
1. For all the lasers, connect the Wav pins together and the
Wavelength- pins together.
2. Designate one laser as the master by setting it to operate in Internal
modulation mode with the Signal output setting Enabled .
3. All other lasers will operate in slave mode by setting them to operate in
External modulation mode.
Integrating update interval
You can set the update interval of the software integration function with this
setting. The setting is intended for use with X15 lasers when they are set to DC
coupling and Narrow modulation range.
Internal generator Frequency
When the modulation source is set to Internal , the frequency of the internal
generator signal can be adjusted to between 8 MHz (0.008 Hz) and 100 kHz
(100,000 Hz). To adjust the frequency, use either the slider or the direct input
field in the upper right corner of the slider.