11
Software Control
External Control
Digital
On/Off
modulation
Up to 100Hz
Analog
On/Off
modulation
Up to 1MHz
Continuous
waveform
Up to 20kHz
On/Off modulation
On/Off modulation is best when the operator wants fast and accurate modulation with
discrete signals. Digital modulation is possible with two options. Option one is over
the SW up to 100Hz. Option two over a 0-3.3V TTL input signal up to 1MHZ. For digital
modulation over SW, choose “Digital” from the “Modulation Mode” drop-down menu
on the main screen and set “Pulse Enable” to ON and set “On Time “ and “Off Time”.
The unit of On and Off Time is ms. For digital modulation over TTL input signal, choose
“Analog” from the “Modulation Mode” drop-down menu on the main screen and use
a function generator or a similar external signal source for the 0-3.3V TTL input Signal.
A function generator, or similar external signal source, is needed to drive the modula
-
tion.
Continuous waveform
To modulate the laser power choose “Analog” from the “Modulation Mode” drop-
down menu. The signal is calibrated from 0.33V to 3.3V. This corelates with 10% to
100% of laser power. Below 0.33V the laser power is not longer linear and below the
threshold current the laser is no longer in lasing mode. A function generator, or similar
external signal source, is needed to drive the modulation.
