Arroyo Instruments LaserSource 4400 Series, Руководство пользователя

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Page 44 · 4400 Series LaserSource User’s Manual
Optimizing for Pulse Performance
The
LaserSource is a high-power instrument that requires an understanding of
proper setup when operating the unit in pulse mode, either via with a square
wave signal into the analog modulation input or in QCW mode.
Cables
The most critical aspect of your setup is the cable connecting the LaserSource
to your device. You should use the shortest possible wires, particularly in high
current applications, and avoid the use of connectors. Poor cables can result in
significant voltage spikes at the leading edge of the pulse which cause
significant overshoot and ringing of the current waveform as well as challenging
thermal management conditions for the
4400 .
To start, ensure you are working with a wire gauge that is adequate for the
application. Review the
Cable Wiring section above for recommend wire sizes.
In addition to wire guage, it is highly recommended to use twisted-pair wire, as
that can have an even bigger impact on pulse performance. Consider the two
pulses below. Pulse is voltage (1 volt per division), green is current (10 Amps
per division). Both use 12 AWG stranded wire, 24 inches [60cm] in length, but
the wires in the right pulse are twisted, approximately one twist every 2 inches
[5cm]). The current waveform is much cleaner and the voltage overshoot is far
less.
In addition to poor waveform performance, high peak voltages can also cause
one of two error conditions: excessive power loads inside the
LaserSource ,
resulting the driver turning itself off and generating an E-537 thermal error; or
insufficient compliance to meet the peak voltage, resulting in the E-540
headroom violation. In either case, the driver will shut down the output to
prevent damage to the driver or the laser.