Laser module allowing simultaneous wavelength and power control

摘要

An apparatus for simultaneously stabilising the output power and wavelength of a semiconductor laser is disclosed. A wavelength discriminating scheme is used to provide a wavelength error signal and an output power detection scheme is used to provide an output power level signal. The wavelength error signal is used to adjust the behaviour of a temperature sensor such that an automatic temperature control (ATC) module configured to maintain a pre-determined output from the temperature sensor, adjusts the actual laser temperature to minimize said signal. The output power level signal is directly delivered to an automatic power control (APC) module, which adjusts the drive current fed into the laser to minimize said signal using known control circuitry means. Adjusting the properties of the temperature sensor makes it possible for the apparatus to manipulate laser temperature and current to achieve simultaneous power, wavelength and temperature control, using the constant-temperature and constant-power external control modules used by semiconductor lasers that do not stabilize wavelength.