Patent ID: 6373872
Filing Date: 2002-04-16
Classification: G02B,G02F,H01S

Abstract:
A laser apparatus comprising:an amplifying waveguide segment capable of providing optical gain over a first optical frequency band, said amplifying waveguide segment characterized by a first temperature dependent effective refractive index with a positive refractive index change with increases of temperature; a passive intracavity waveguide segment optically coupled to said amplifying waveguide segment for providing a path for optical energy therein, said passive intracavity waveguide segment characterized by a second temperature-dependent effective refractive index with a negative refractive index change with increases of temperature; and a frequency selective feedback structure coupling optical energy of a selected second optical frequency band within said first optical frequency band back into said amplifying waveguide segment forming a resonant cavity, wherein said frequency selective feedback structure comprises a thermo-optical feedback waveguide segment, a grating formed in said feedback waveguide segment, and a thermal actuator for heating said feedback waveguide segment to produce a change in refractive index of said feedback waveguide segment for tuning said selected second optical frequency band, and wherein a round trip optical path traversed by said optical energy within said resonant cavity between successive couplings into said amplifying waveguide segment has a round trip optical length that is substantially independent of ambient temperature over a specified ambient temperature range.