A unique method and apparatus for locking on an absolute wavelength of laser
light
output by a laser package by actively compensating for a change in the temperature
of an etalon optical filter is disclosed. Changes in etalon response characteristics
due to temperature changes are compensated for by the addition (or subtraction)
of an output voltage offset to the voltage control signal sent to the Thermo-Electric
Cooler (TEC) from a controller within the laser package. The voltage offset is
calculated by monitoring the etalon temperature. The voltage offset value provides
for active compensation of changes in the etalon temperature and effectively "readjusts"
the output of the laser as if the etalon temperature itself had been readjusted.
