US4677633A — Semiconductor laser with a two-striped channel

Claim 1

Independent Claim 168 words

In a semiconductor laser comprising: a substrate having a two step-striping channel; and a double heterostructure-laser-operating area having successively a first cladding layer, an active layer and a second cladding layer on said substrate, said two step-striped channel being composed of a first channel and a second channel having a width which is narrower than the width of said first channel and having a depth which is deeper than the depth of said first channel, and said second channel being positioned in the center portion of said first channel, thereby allowing current injected into said active layer to flow into the center portion of said two step-striped channel, the improvement wherein the difference Δn in complex refraction index between the inside and the outside of said second channel is at least 4×10 -3 with regard to the real number portion Re(Δn) thereof, and no more than 4×10 -3 with regard to the imaginary number portion Im(Δn) thereof, and the ratio of Re(Δn) to Im(Δn) is at least 1.5.

Claim 2

Dependent Claim 168 words

In a semiconductor laser comprising: a substrate having a two step-striping channel; and a double heterostructure-laser-operating area having successively a first cladding layer, an active layer and a second cladding layer on said substrate, said two step-striped channel being composed of a first channel and a second channel having a width which is narrower than the width of said first channel and having a depth which is deeper than the depth of said first channel, and said second channel being positioned in the center portion of said first channel, thereby allowing current injected into said active layer to flow into the center portion of said two step-striped channel, the improvement wherein the difference Δn in complex refraction index between the inside and the outside of said second channel is at least 4×10 -3 with regard to the real number portion Re(Δn) thereof, and no more than 4×10 -3 with regard to the imaginary number portion Im(Δn) thereof, and the ratio of Re(Δn) to Im(Δn) is at least 1.5.

Claim 3

Dependent Claim 30 words

A semiconductor laser according to claim 1, wherein said active layer is a crescent active layer having a downward curvature corresponding to the center portion of said two step-striped channel.

Claim 4

Dependent Claim 43 words

A semiconductor laser according to claim 1, wherein the thickness of said active layer corresponding to the center portion of said two step-striped channel is greater than that of said active layer corresponding to each of both sides of said two step-striped channel.

Claim 5

Dependent Claim 69 words

A semiconductor laser according to claim 1, wherein said first channel has a selected width to form window regions in the vicinity of the facets of the laser, said active layer is a plane-shape in each of said window regions in the vicinity of the facets of the laser and a crescent-shape in the other region in the inside of the laser, resulting in a window stripe semiconductor laser.

Claim 6

Dependent Claim 153 words

In a semiconductor laser comprising: a substrate; a two step-striped channel formed on said substrate and including a first channel and a second channel formed in said first channel, said second channel being narrower and deeper than said first channel; and a double heterostructure-laser-operating area formed over said substrate and including a first cladding layer disposed on a side of said area adjacent to said substrate, an active layer disposed on said first cladding layer, and a second cladding layer disposed on said active layer; the improvement wherein: said active layer and said first cladding layer have thicknesses selected so that the difference Δn in complex refraction index between the inside and the outside of said second channel has a real number portion Re(Δn) of at least 4×10 -3 and an imaginary number portion Im(Δn) of no more than 4×10 -3 , and the ratio of Re(Δn) to Im(Δn) is at least 1.5.

Claim 7

Dependent Claim 153 words

In a semiconductor laser comprising: a substrate; a two step-striped channel formed on said substrate and including a first channel and a second channel formed in said first channel, said second channel being narrower and deeper than said first channel; and a double heterostructure-laser-operating area formed over said substrate and including a first cladding layer disposed on a side of said area adjacent to said substrate, an active layer disposed on said first cladding layer, and a second cladding layer disposed on said active layer; the improvement wherein: said active layer and said first cladding layer have thicknesses selected so that the difference Δn in complex refraction index between the inside and the outside of said second channel has a real number portion Re(Δn) of at least 4×10 -3 and an imaginary number portion Im(Δn) of no more than 4×10 -3 , and the ratio of Re(Δn) to Im(Δn) is at least 1.5.

Claim 8

Dependent Claim 27 words

A semiconductor laser according to claim 5, wherein said active layer has a concave portion which bulges downwardly in the central region of said two step-striped channel.

Claim 9

Dependent Claim 68 words

A semiconductor laser according to claim 5, wherein said first channel has a selected width to form window regions in the vicinity of the facets of said laser, said active layer has a planar shape in each of said window regions in the vicinity of the facets of the laser and a concave shape at the inside region of the laser resulting in a window stripe semiconductor laser.

Claim 10

Dependent Claim 41 words

A semiconductor laser according to claim 5, wherein: said substrate comprises an n-GaAs substrate; said first cladding layer comprise an n-GaAlAs cladding layer; said active layer comprises an n-GaAlAs active layer; and said second cladding layer comprises a p-GaAlAs cladding layer.

Claim 11

Dependent Claim 19 words

A semiconductor according to claim 8, and further including an n-GaAs cap layer disposed on said second cladding layer.

Claim 12

Dependent Claim 48 words

A semiconductor laser according to claim 5, and further comprising a current blocking layer disposed on said substrate between said substrate and said first cladding layer, said two step-striped channel being formed in said current blocking layer, with said second channel extending into a portion of said substrate.

Claim 13

Dependent Claim 51 words

A semiconductor laser according to claim 10, wherein: said substrate comprises a p-GaAs substrate; said current blocking layer comprises an n-GaAs current blocking layer; said first cladding layer comprises a p-GaAlAs cladding layer; said active layer comprises a p-GaAlAs active layer; and said second cladding layer comprises an n-GaAlAs cladding layer.

Claim 14

Dependent Claim 20 words

A semiconductor laser according to claim 11, and further including an n-GaAs cap layer disposed on said second cladding layer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1990-06-29	1990-12-29	1991-06-30	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1994-06-29	1994-12-29	1995-06-30	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1998-06-29	1998-12-29	1999-06-30	$7700.00	Window Closed / Lapsed

Semiconductor laser with a two-striped channel

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