Semiconductor laser device
AssigneeMatsushita Electric Inductrial Co., Ltd.
InventorsToshihiro Fujita, Jun Ohya, Kenichi Matsuda, Hiroyuki Serizawa
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Abstract
A semiconductor laser device of a new monolithic structure has a long transparent optical waveguide used as a passive cavity directly coupled with an active cavity possessing a gain in the direction of the optical axis of the active cavity on a compound semiconductor substrate. The device is intended to satisfy all four characteristics, which are; (1) stable single longitudinal mode oscillation; (2) narrow spectral linewidth; (3) suppression of wavelength chirping due to current modulation; and (4) low noise and to be applied as a light source for optical fiber communication, optical information processing or the like.
Claims14
A semiconductor laser device comprising:
- a semiconductor substrate;
- an active cavity formed on said semiconductor substrate;
- and
- a passive cavity formed on said semiconductor substrate, said active and passive cavities being integrally formed on sa id semiconductor substrate with monolithic structure and coupled in the direction of optical axes of said cavities,
- said active cavity including,
- an active layer for emitting light therefrom,
- clad layers for confining said light into said active layer, and
- electrodes for injecting current into said active layer,
- said passive cavity including,
- a waveguide layer for transferring therethrough the light emitted in said active cavity, and
- clad layers for ocnfining said light to said waveguide layer,
- said active and passive cavities having rectangular waveguide structure to confine said light in a plane perpendicular to said direction of optical axes of said cavities,
- resonator means for laser oscillation of said semiconductor laser device,
- the ratio L.sub.0 /L.sub.1 of optical length L.sub.0 of said passive cavity to optical length L.sub.1 of said active cavity being set in a range of L.sub.0 /L.sub.1 .gtoreq.0.5,
- whereby the light emitted in said active cavity is transferred through said passive cavity and reflected and fed back to said active cavity.
Dependencies are inferred from the claim text.