Apparatus and method for calibrating a wavelength stabilized laser

A wavelength stabilized laser system, comprising:

• a laser that produces a laser light having an amplitude and a wavelength that varies as a function of a temperature of the laser;
• a temperature control device that controls the temperature of the laser;
• a beam splitter that deflects a portion of the laser light;
• a first detector that receives the portion of the laser light from the beam splitter and provides a first signal representing the amplitude of the laser light;
• a filter having a gain that is a function of the wavelength of the laser light, the filter receiving the laser light and outputting a filtered light having an amplitude that varies with the wavelength of the laser light;
• a second detector that provides a second signal representing the amplitude of the filtered light;
• a sealed housing containing the laser, the first and second detectors and the filter, the housing having a window;
• an electromagnetic radiation source outside of the housing that transmits a calibration beam through the window and through the filter, onto the second detector;
• means for controlling the temperature control device based on the first and second signals, and for monitoring a light transmitting characteristic of the filter based on the second signal.

A method for calibrating a laser, comprising the steps of:

• monitoring an amplitude of a laser light output by the laser;
• filtering the laser light in a filter, to form a filtered light having an amplitude that varies with the wavelength of the laser light;
• monitoring the amplitude of the filtered light;
• transmitting a calibration beam from outside a housing of the laser through a window of the housing and through the filter;
• and
• monitoring the filtered calibration beam.