Laser features
28
temperature of the laser cavity itself also changes such that the laser wavelength
changes in response to both thermo-optic and physical changes in the optical
path length. See
“Tuning the wavelength” on page 80
Fast wavelength
modulation
As an option, the laser includes the capability to use an external signal to
modulate the emission wavelength using a Piezo. Laser modules with this option
can be modulated using an external electrical signal.
Input circuits
“Fast wavelength modulation” on page 37
provides examples of fast
wavelength modulation circuits and performance.
Wav/- Signal
To modulate the wavelength, apply an external differential signal to Pins A10 and
C10 of the main electrical interface. See
“Main electrical interface” on page 113
for the connector’s pin assignment.
As this signal varies and increases its positive potential, the wavelength
increases.
shows the
frequency response when the fast wavelength
modulation feature is utilized. The graph shows the response for both standard
and wide thermal tuning substrates.
Figure 4
Frequency response using wavelength modulation
The response shown in
is for a laser with a wavelength at 1550 nm. The
response is scaled linearly with the wavelength of the laser. Further,
the Narrow
Thermal Tuning module which has less vibration sensitivity, shows resonances
that are higher in frequency. These modules are therefore more suitable for
applications where modulations between 30 and 45 kHz are required.
Note:
The frequency response is relatively flat up to 20 kHz, but resonances are
seen at frequencies at and above the first resonance occurring at approximately
30 kHz. Wavelength modulation can be used for frequencies above 20 kHz, but
it is recommended to avoid modulating the laser at the resonance frequencies.
Summary of Contents for Koheras BASIK
Page 6: ...6 ...
Page 14: ...14 ...
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Page 36: ...Module labels 36 ...
Page 46: ...External cavity stabilization BASIK X15 46 ...
Page 48: ...48 ...
Page 54: ...Connecting the SDK GUI to the laser 54 ...
Page 58: ...Controlling the laser emissions 58 ...
Page 90: ...Graphing 90 Figure 61 Graphing tab Y axis settings X axis ...
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Page 104: ...Connecting the optical output 104 ...
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Page 120: ...Installing CONTROL 120 ...
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Page 126: ...Item 800 601 01 Customer Revision 1 5 NKTP Revision 2 0 Release Date 2022 03 ...