- All use of a bias-T on a specific QC laser has to be accepted by
Alpes Lasers SA before; otherwise all warranty will be lost.
- The bias-T should never be used at the highest specified current or
output power, otherwise the risk of thermal roll-over failure is imminent.
- If optical output power can be monitored, this should be used during
set-up of the bias-T to make sure that thermal roll-over is not reached:
Temporary increasing of the pulse current must always result in increased
optical power output, otherwise the DC bias current is already too high.
- As a rule of thumb, the overall dissipated power (sum of DC bias current
dissipation and pulse current dissipation) must never be higher than
the average dissipated power given by the highest current / voltage /
temperature combination specified in the datasheet. Take into account that
the average dissipated power for a given pulse current I, pulse voltage
U, and duty cycle d is given by
, whereas the
dissipated power due to a bias current IB is given by
. (U is the voltage on the laser, but it is safe for this calculation
of bias current dissipation to use the voltage on the LDD pulser input.)