Datasheet

Chapter 5: Starter Kit Operation
vi. connect the red/black banana cables
vii. switch on the external power supply
b) setup the TPG pulse parameters following the guidelines of section 5.2
c) connect the TPG back to the Starter Kit and turn it on
CAUTION:
Make sure the laser temperature is below specifications before
turning on the external power supply. Overheating the laser chip
may result in permanent damage.
6. increase the voltage slowly and monitor the current according to the QCL IV
curve included in the ALPES LASERS datasheet (see section 4.4):
• the current should start increasing at the threshold voltage, at a value close
to the one indicated in the ALPES LASERS datasheet
• for pulsed mode: at maximum voltage, the current supplied by the exter-
nal power supply (eps) should correspond to the maximum peak current
(see section 4.4.1) of the datasheet multiplied by the duty cycle with some
overhead:
I
eps
= I
peak
× duty cycle + overhead
CAUTION:
Do not exceed maximum voltage or current specified in ALPES
LASERS datasheet. Permanent damage to the laser chip may occur.
• if no current is flowing, a misconnection might be the cause, repeat step 8
of the installation procedure described in section 3.2
• if a current above 100 mA is read, a ground loop might be the cause, review
all connections according to section 3.3
7. monitor the laser power using a powermeter:
a) make sure that the range suits the power range of the laser (see datasheet)
b) reset it to 0
c) align the laser beam with the powermeter
The power should start rising around the threshold of the ALPES LASERS datasheet
IV curve (see section 4.4).
Note: exact power measurement of an IR beam is very difficult as it depends
on ambient temperature and powermeter characteristics. Therefore the exact
values shown in the datasheet might not be reproduced in a different setup as
the one used by ALPES LASERS for routine tests.
66 QCL user’s manual v3.0