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US 4,794,618 AGranted
Distributed feedback laser diode
AssigneeNEC Corporation
InventorIkuo Mito
Life of this patent
Estimating the term…
Abstract
An improved distributed feedback laser diode comprises a diffraction grating in a resonator. The diffraction grating is formed to have a phase shift of .lambda./8 to 3.lambda./16 at a portion thereof so that the phase shift amount of approximately .lambda./4 is obtained in a case where a maximum rate of light output is produced thereby to result in a single axial mode oscillation.
Claims8
A distributed feedback laser diode comprising:
- a substrate;
- a planar waveguide structure including a first light confining layer, a second light confining layer and an active layer therebetween;
- a diffraction grating formed between said waveguide structure and said substrate;
- partially reflecting films formed on opposing ends of said waveguide structure;
- electrodes formed respectively below said substrate and above said waveguide structure;
- said diffraction grating having a phase shift at a portion thereof away from ends thereof producing thereby a phase shift amount of .lambda./8 to 3.lambda./16 between pitches of said diffraction grating on either side of said phase shift.
3 more elements
A distributed feedback laser diode comprising:
- a diffraction grating formed on a substrate, said diffraction grating having a phase shift at a portion thereof away from ends thereof producing thereby a phase shift amount of .lambda./8 to 3.lambda./16 between pitches of said diffraction grating on either side of said phase shift;
- a guided layer formed through said diffraction grating on said substrate;
- an active layer formed through said diffraction grating on said substrate;
- a cladding layer formed on said active layer;
- a current blocking layer formed on said cladding layer;
- a buried layer formed on said current confining layer;
- a cap layer formed on said buried layer;
- a pair of electrodes respectively provided on outer surfaces of said substrate and cap layer;
- and
- a pair of partially reflecting films respectively provided on both end planes of a layered structure thus fabricated on said substrate.
7 more elements
Dependencies are inferred from the claim text.