US4893313A — Semiconductor laser device which has a double-het…

Claim 1

Independent Claim 158 words

A semiconductor laser device for emitting a laser beam having a wavelength λ, comprising: a double-hetero structure including: an active layer made of In(Ga 1-y Alpgd y)P and having a thickness d and a refractive index n a , and first and second surfaces; a first cladding layer of a first conductivity type formed on the first surface of the active layer having a refractive index n c , made of In(Ga 1-x Al x )P, where x and y satisfy the inequality of 0≦y<x ≦1; and a second cladding layer of a second conductivity type formed on the second surface of the active layer, having a refractive index nc 2 , and made of In(Ga 1-z Al z )P, where y and z satisfy the inequality of 0≦y<z≦1, wherein said double-hetero structure satisfies the following ineguality: 0.015Δ.sup.-1/2 <d/λ<0.028Δ.sup.-1/2 where is specific refractive index difference defined as: Δ=(Δ.sub.l +Δ.sub.2)/2 Δ.sub.1 =(na.sup.2-n c.sub.2)/(2n.sub.a 2) and Δ.sub.2 =(na.sup.2-n c2.sup.2)/(2n.sub.a 2)

Claim 2

Dependent Claim 158 words

A semiconductor laser device for emitting a laser beam having a wavelength λ, comprising: a double-hetero structure including: an active layer made of In(Ga 1-y Alpgd y)P and having a thickness d and a refractive index n a , and first and second surfaces; a first cladding layer of a first conductivity type formed on the first surface of the active layer having a refractive index n c , made of In(Ga 1-x Al x )P, where x and y satisfy the inequality of 0≦y<x ≦1; and a second cladding layer of a second conductivity type formed on the second surface of the active layer, having a refractive index nc 2 , and made of In(Ga 1-z Al z )P, where y and z satisfy the inequality of 0≦y<z≦1, wherein said double-hetero structure satisfies the following ineguality: 0.015Δ.sup.-1/2 <d/λ<0.028Δ.sup.-1/2 where is specific refractive index difference defined as: Δ=(Δ.sub.l +Δ.sub.2)/2 Δ.sub.1 =(na.sup.2-n c.sub.2)/(2n.sub.a 2) and Δ.sub.2 =(na.sup.2-n c2.sup.2)/(2n.sub.a 2)

Claim 3

Dependent Claim 21 words

The semiconductor laser device according to claim 1, wherein the thickness d of said active layer satisfies the following formula: d/λ≈0.022Δ.sup.-1/2

Claim 4

Dependent Claim 48 words

The semiconductor laser device according to claim 1, wherein said first and second cladding layers have a thickness H 1 and a thickness H 2 , respectively, which satisfies the following inequality; 0.08(Δ.sub.1 d/λ).sup.-1/2 <H.sub.1 /λ<0.l2(Δ.sub.1 d/λ).sup.-1/2 and 0.08(A 2 d/λ) -1/2 <H 2 /λ<0.l2(Δ 2 d/λ) -1/2

Claim 5

Dependent Claim 60 words

The semiconductor laser device according to claim 1, wherein said active layer is made of In 0 .5 (Ga 1-y Al y ) 0 .5 P, and said first and second cladding layers are made of In 0 .5 (Ga 1-x Al x ) 0 .5 P and In 0 .5 (Ga 1-z Al z ) 0 .5 P, respectively.

Claim 6

Dependent Claim 37 words

The semiconductor laser device according to claim 1, wherein the thickness d of the active layer satisfies the following equality: 0.03 μm ≦d ≦0.1 μm and the x and z satisfies the following quality: 0.65 ≦x,z ≦0.8

Claim 7

Dependent Claim 83 words

The semiconductor laser device according to claim 1, further comprising: a first contact layer formed on said first cladding layer at an opposite side of said active layer, and a second contact layer formed on said second cladding layer at an opposite side of said active layer and said double-hetero structure having a thickness H 1 and a thickness H 2 , respectively, which satisfies the following inequality: 0.08({ 1d/ λ) -1/2 <H 1 /λ<0.l2(Δ 1 d/λ) -1/2 and 0.08(Δ.sub.2 d/λ).sup.-1/2<H.sub.2 λ/λ<0.l2(Δ.sub.2 d/λ).sup.-1/2

Claim 8

Dependent Claim 27 words

The semiconductor laser device according to claim 3, wherein the thicknesses H 1 and H 2 satisfy the following inequality: H.sub.1 /λ≈0.1(Δ.sub.1 d/λ).sub.-1/2 and H.sub.2 /λ≈0.1(Δ.sub.2 d/λ).sup.-1/2

Claim 9

Dependent Claim 210 words

The semiconductor laser device for emitting a beam having a wavelength Δ, comprising: a semiconductor substrate of a first conductivity type; an active layer made of In1 -v (Ga 1 -y Al y ) v P and having a thickness d, and having first and second surfaces, which satisfies the inequality of 0.03 μm ≦d ≦0.1 μm; a first cladding layer of the first conductivity type formed between the substrate and the first surface of said active layer and made of In 1-v (Ga 1-x Al x ) v P, where v is a composition ratio satisfy the ineguality of 0 ≦v ≦1; a cladding structure including a second cladding layer of a second conductivity type formed on the second surface of the active layer having a refractive index n c , made of In 1-v (Ga 1-z Al z ) v P, and having a flat section an a stripe-shaped ridge section projecting from the flat section, where composition ratio x, y and z satisfying the inequality of 0≦y <x, z≦1, the aluminum ratio x and z of the second cladding layers being satisfy the inequality of 0.65≦x, z ≦0.8; and a confining layer formed on the flat section of the second cladding layer for confining the laser beam.

Claim 10

Dependent Claim 210 words

The semiconductor laser device for emitting a beam having a wavelength Δ, comprising: a semiconductor substrate of a first conductivity type; an active layer made of In1 -v (Ga 1 -y Al y ) v P and having a thickness d, and having first and second surfaces, which satisfies the inequality of 0.03 μm ≦d ≦0.1 μm; a first cladding layer of the first conductivity type formed between the substrate and the first surface of said active layer and made of In 1-v (Ga 1-x Al x ) v P, where v is a composition ratio satisfy the ineguality of 0 ≦v ≦1; a cladding structure including a second cladding layer of a second conductivity type formed on the second surface of the active layer having a refractive index n c , made of In 1-v (Ga 1-z Al z ) v P, and having a flat section an a stripe-shaped ridge section projecting from the flat section, where composition ratio x, y and z satisfying the inequality of 0≦y <x, z≦1, the aluminum ratio x and z of the second cladding layers being satisfy the inequality of 0.65≦x, z ≦0.8; and a confining layer formed on the flat section of the second cladding layer for confining the laser beam.

Claim 11

Dependent Claim 23 words

The semiconductor laser device according to claim 8, wherein said beam confining layer is made of Ga 1-r Al r As, where 0<r<1.

Claim 12

Dependent Claim 21 words

The semiconductor laser device according to claim 8, wherein said semiconductor substrate and said laser beam-confining layer are made of GaAs.

Claim 13

Dependent Claim 67 words

The semiconductor laser device according to I5 claim 8, wherein the flat portion of said cladding structure has a thickness ho which satisfies the following inequality: h.sub.o /λ≦0.l3(Δd.sub.2 d/λ).sup.-1/2 where d is the thickness of said active layer, λ is the wavelength of the beam, and Δd 2 (=z-y) is the difference between the aluminum ratio of said second cladding layer and that of said active layer.

Claim 14

Dependent Claim 67 words

The semiconductor laser device according to claim 8, wherein said ridge section, which contacts said flat section, has a width W which satisfies the following inequality: W/λ≦20[h.sub.o /λ)(Δx.sub.2 d/λ).sup.1/2].sup.1/3 where d is the thickness of said active layer, λ is the wavelength of the beam, and Δx 2 (=z-y) is the difference between the aluminum ratio of said second cladding layer and that of said active layer.

Claim 15

Dependent Claim 100 words

The semiconductor laser device according to claim 8, wherein said first cladding layer has a thickness H 1 , and said second cladding layer at the striped shaped ridge section has a thickness H 2 , said thicknesses H 1 and H 2 satisfying the following inequalities, respectively: 0.25(Δx.sub.1 d/λ).sup.-1/2≦H.sub.1 /λ≦0.38(Δx.sub.1 d/λ).sup.-1/2 0.25(Δx.sub.2 d/λ).sup.-1/2≦H.sub.2 /λ≦0.38(Δx.sub.2 d/λ).sup.-1/2 where Δx 1 (=z-y) is the difference between the aluminum ratio of said first cladding layer and that of said active layer, and Δx 2 (=z-y) is the difference between the aluminum ratio of said second cladding layer and that of said active layer.

Claim 16

Dependent Claim 56 words

The semiconductor laser device according to claim 8, wherein the ridge section of said cladding structure includes a third cladding layer formed on said second cladding layer and made of In 1-v (Ga 1-s Al s ) v P, and a fourth cladding layer formed on the third cladding layer and made of Inl-c(Gal-uAlu)vP, where 0≦u<s.

Claim 17

Dependent Claim 26 words

The semiconductor laser device according to claim 14, wherein said third cladding layer has a thickness t which satisfies the following inequality: 45 Å≦t ≦200 Å.

Claim 18

Dependent Claim 30 words

The semiconductor laser device according to claim 8, wherein the aluminum ratio X of the first cladding layer, and the aluminum ratio y of the second cladding layer are 0.7.

Claim 19

Dependent Claim 44 words

The semiconductor laser device according to claim 15, wherein said laser beam-confining layer is made of Ga l-w Al w As of the first conductivity type, where 0≦w<1, and has a carrier concentration D which satisfies the following inequality: 1.0×10.sup.18 cm.sup.-3 ≦D ≦5×10.sup.19 cm.sup.-3

Claim 20

Dependent Claim 21 words

The semiconductor laser device according to claim 15, wherein said semiconductor substrate and said beam-confining layer are made of n-type GaAs.

Claim 21

Dependent Claim 20 words

The semiconductor laser device according to claim 16, wherein Si is doped, as an impurity, in said laser beam-confining layer.

Claim 22

Dependent Claim 30 words

The semiconductor laser device according to claim 15, wherein said beam-confining layer has a carrier concentration D given as follows: 2.5×10 18 cm -3 ≦D ≦1×10 19 cm -3 .

Claim 23

Dependent Claim 28 words

The semiconductor laser device according to claim 20, wherein said beam-confining layer has an impurity concentration ranging from 1×10 18 cm -2 to 3×10 18 cm -3 .

Claim 24

Dependent Claim 50 words

The semiconductor laser device according to claim 13, further comprising at least one second capping layer of the second conductivity type, interposed between said second contact layer and said cladding structure, and having a band gap greater than that of said substrate and less than that of said cladding structure.

Claim 25

Dependent Claim 39 words

The semiconductor laser device according to claim 8, wherein said laser beam-confining layer has a thickness of at least 0.7 μm, and a height not greater than 1.5 μm which is measured from the ridge of said cladding structure.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-01-08	1993-07-10	1994-01-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-01-08	1997-07-10	1998-01-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-01-08	2001-07-10	2002-01-09	$7700.00	Window Closed / Lapsed

Semiconductor laser device which has a double-hetero structure having an optimal layer thickness

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