Patent ID: 7339962

Claim:
A control process for locking a laser to any one of a plurality of desired wavelengths lying in respective wavelength channels, comprising: a. setting the laser to output within one of the wavelength channels; b. measuring a first power value indicative of the power being transmitted by a frequency selective element having a frequency response matched to the wavelength channels; c. measuring a second power value indicative of the total power being output by the laser; d. determining a first error value from the difference between the first power value and a desired first power value for the wavelength channel currently set; e. determining a second error value from the difference between the second power value and a desired second power value for the wavelength channel currently set; f. determining a laser control parameter from the difference between one of the first and second error values and a constant factor multiplied by the other of the first and second error values; and g. using the laser control parameter to lock the laser to the desired wavelength.