Patent ID: 6567433
Filing Date: 2003-05-20
Classification: H01S

Abstract:
A method for calibrating a laser with multiple tuning parameters using a first etalon, a second etalon, and a gas absorption cell containing a gas of known light absorption characteristics, with the second etalon providing more closely-spaced transmission peaks as a function of wavelength than the first etalon, the method comprising the steps of:routing an output beam from the laser through the first etalon while tuning the laser through a range of a first tuning parameter to produce a first relatively coarse etalon transmission spectrum, the first etalon spectrum being a function of the first laser tuning parameter; routing the output beam from the laser through the first etalon while tuning the laser through a range of a second tuning parameter to produce a second relatively coarse etalon transmission spectrum, the second etalon spectrum being a function of the second laser tuning parameter; deriving a relative wavelength map based on the first and second relatively coarse etalon transmission spectra; processing the relative wavelength map to determine a sequence of combinations of the first and second tuning parameters for use in varying the wavelength of the laser throughout a range of output wavelengths; routing the output beam from the laser through the second etalon and through the gas cell while tuning the laser through a range of relative wavelengths using the sequence of combinations of the first and second tuning parameters to produce a relatively fine etalon transmission spectrum as a function of the laser tuning parameters and a gas absorption spectrum as a function of the laser tuning parameters; and comparing the detected relatively fine etalon transmission spectrum with the detected gas absorption spectrum to determine the absolute transmission wavelength of the laser as a function of the laser tuning parameters.