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OWNERS MANUAL | Cobolt 08-01 Series | D0141-K SEPTEMBER 2020
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140
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P
o
wer
(
m
W
)
Current (mA)
Power vs. Current for a typical 405 nm MLD laser
The user is given the choice of two impedance values for the laser’s analog modulation circuit: 1 k
and 50
. The
impedance value can be toggled either in the Cobolt Monitor
™
software or by software commands. The default
impedance is set to 1 k
, and for most cases it is recommended to use this value. When using a 50
signal generator,
the rising and falling edges of the output may suffer ringing due to the impedance mismatch, a problem which can be
solved by setting the impedance to 50
. Using the low impedance will cause more of the power to be dissipated in
the signal generator, so in order to modulate up to full power the user should monitor the voltage across the laser
device to ensure that it reaches 1 V.
Modulation mode combinations
In addition to the modulation types described above, the Cobolt 06-MLD can be operated with a combination of
modulation signals.
On/off + another mode
Any mode can be operated in combination with on/off modulation. When the laser is in modulation mode and a signal
is input to the on/off modulation socket, the laser operates in both modes simultaneously. When the on/off input state
is high, the laser behaves as if it were in digital or analog mode, and when it is low the laser switches off regardless of
the digital or analog state. This is a useful way to produce a train of pulses.
D Analog
The MLD can be used with hybrid d analog modulation signals. This can be accessed in the Cobolt Monitor
software under the Modulation Type option. In this mode, whenever the digital state is on, the laser runs at a power
determined by the analog voltage.
