Patent ID: 6289028
Filing Date: 2001-09-11
Classification: G02B,H01S

Abstract:
A laser apparatus, comprising:a laser for producing a beam of laser radiation having a selected wavelength;means for splitting first and second laser light beams from said beam of laser radiation;a first optical filter disposed for receiving at least a portion of said first split beam, said first filter producing a first filtered beam in accordance with a first spectral filter function;a photodetector for receiving at least a portion of said first filtered beam and for producing a first detector signal;a second optical filter disposed for receiving at least a portion of said second split beam and for producing a second filtered beam in accordance with a second spectral filter function;a second photodetector for receiving at least a portion of said second split beam and for producing a second detected signal;said first filter including a substrate having a filter layer, said filter layer including at least one film layer having a dielectric constant differing from that of said substrate,an error signal circuit in electrical communication with said first and second photodetectors for generating an error signal responsive to said first and second detected signals and representative of the deviation of the wavelength of the laser radiation from a set-point wavelength;a laser wavelength control element in electrical communication with said error circuit for adjusting the operating temperature of said laser in response to said error signal so as to tend toward said set-point wavelength; and whereinsaid first split beam is incident on a surface of one of said substrate and said filter layer at a non-zero angle of incidence.