9
OPERATING INSTRUCTIONS (STAND-ALONE)
WHAT’S IN THE BOX
• QCL Instrument
•
Power Cable, type appropriate for final location
• Red fuse tray
• Two 0.63 A fuses and two 1.25 A fuses for fuse box on the
back panel
• USB Flash Drive, includes all necessary software,
instrument documentation, and additional storage space
• Keys for the keyswitch
• Interlock Replacement Kit (interlocks for QCL D-SUB and
Active Interlock BNC)
THEORY OF OPERATION
The QCL Series low noise drivers are designed expressly to
drive quantum cascade lasers, and utilize patented
1
circuitry
to deliver ultra-low noise current and still maintain a wide
modulation bandwidth.
The QCL drivers are controlled current sources; they deliver
the current commanded by the setpoint. The current source
continually monitors the actual output current, compares it to
the setpoint, and adjusts the current if there is a difference
between the two signals.
As current is driven through the load, there is a voltage drop
across the load proportional to the load resistance and current.
As the current increases, the voltage drop may increase to
the point that it reaches the Compliance Voltage limit of the
current source. Once that occurs the current source is no
longer able to increase the current driven to the load even if
you increase the setpoint.
The QCL driver includes features that help protect your laser,
and also make the driver more versatile in a wide array of
applications. These features are explained in detail in the
Operating Instructions.
• The user-adjustable current limit prevents overdriving the
laser even if the external modulation signal is above the
maximum drive current for the laser.
• Over- and under-voltage protection circuits protect the
driver and QCL if the power supply voltages fall outside of
the acceptable operating range.
• Over-temperature protection circuits safely shut down
the output if the internal temperature of the QCL driver
rises to an unsafe level. The fan turns on to manage the
internal temperature.
• Output slow-start ramps the current to setpoint over
1.5 msec.
• A mechanical relay shorts the output connections when
the output is disabled, and when the QCL driver is
powered off.
1
Covered by U.S. Patents 6,696,887; 6,867,644 and
7,176,755. Licensed from Battelle Memorial Institute.
The External Modulation Input can be used for adding to
or subtracting from the internal setpoint on the QCL LAB
Instrument. Inputting positive voltages will result in adding
to the setpoint, while inputting negative voltages will result in
subtracting from the setpoint.
These instructions are for operating the QCL Laboratory
Series instrument. Fuses are provided but not installed. After
installing the fuses in the fuse box, be sure to install the fuse
box so the correct voltage for your country is showing. We
also recommend using a test load until you are familiar with
operation of the instrument.
REQUIRED AND OPTIONAL
EQUIPMENT
FOR SET UP
•
Small, narrow headed flathead screwdriver (required)
• Test load (optional)
• Wavelength Interlock Replacement Kit with interlock
overrides (optional)
COMPUTER REQUIREMENTS FOR
REMOTE OPERATION ONLY (OPTIONAL)
Operating System: Windows XP SP2 or later
Note
: See
ESD INFORMATION
Before proceeding, it is critical that you take precautions to
prevent electrostatic discharge (ESD) damage to the load.
ESD damage can result from improper handling of sensitive
electronics, and is easily preventable with simple precautions.
