Datasheet

1.3 Starter kit
1.3.2. Laser Diode Driver (LDD)
The Laser Diode Driver shown in figure 1.10 is a switching unit which creates cur-
rent pulses to drive the laser. The LDD is controlled by a TPG (see section 1.3.3)
and powered by an external power supply. It is equipped with a Bias-T for electrical
wavelength tuning (see section B.3 for details).
Figure 1.10.: Laser Diode Driver (LDD).
Voltage rating and operating temperature
The LDD is based on dedicated power MOSFETS with compliance with up to 30A
and 60V. During operation, the temperature of the case should not exceed 60
◦
C.
The LDD electronic card lies on a copper plate and no other means of active cooling
is provided. In normal conditions, those temperatures are not reached as the laser
operating voltage is of typically 2A, well above the LDD voltage rating.
Laser pulse parameters measurement
Estimated values of the laser pulse parameters (peak voltage, supply voltage, duty
cycle, frequency) can be measured through the BNC monitor connector with 20A/V
shown in figure 1.10. The data provided by the measuring unit is useful for monitoring
and surveillance, and to give a rough estimate of current parameters.
Note: the exact measurement of short strong pulses with diodes and averaging
circuitry is non-trivial, therefore accurate time and voltage measurements should be
performed directly on the LLH or HHL housing through the laser and base connec-
tors.
c
2012 SA 11