A control apparatus for stabilizing optical wavelength output by a laser module
in which a laser element, temperature sensor and cooling/heating element are installed,
comprises a temperature deviation detecting circuit comprising a temperature monitor
for detecting a laser temperature, and a first comparator for outputting a first
control signal indicating a difference between the laser temperature and a control
target value, a wavelength deviation detecting circuit comprising a wavelength
monitor for detecting light output from the laser element, and a second comparator
for outputting a second control signal indicating a difference between the wavelength
of the detected output light and a control target value, a selector circuit for
selecting either of the detecting circuits according to the external conditions
of the laser element, and a current controller for controlling the current supplied
to the cooling/heating element based on the output signal from the selected detecting circuit.
