Patent ID: 6967976

Claim:
A tunable laser comprising: (a) a laser pump; (b) a resonant optical cavity having a round trip light path, said optical cavity having an odd number of reflective surfaces and comprising: i) a gain medium responsive to pumping by said laser pump, one face of said gain medium forming a first reflective endface of the resonant optical cavity; and ii) a tuning etalon, positioned within the resonant optical cavity, said etalon comprising two spaced apart mirrors having a controllable mirror-to-mirror separation distance, and forming the other reflective endface of said optical cavity, so that light traveling on said round trip light path is reflected from the etalon, and whereby the emission wavelength of the gain medium is determined by a selected separation distance of the etalon mirrors and is selected to have a value that differs from a wavelength of peak reflectivity of the etalon, and wherein said gain medium comprises an electrically pumped, single-mode, semiconductor optical waveguide.