US5608752A — Semiconductor laser device and method of designin…

Claim 1

Independent Claim 151 words

A method of designing a semiconductor laser device comprising the steps of: providing a device having a cladding layer of a first conductivity type, an active layer which is formed on said cladding layer of a first conductivity type and into which current confined to a width W is injected, a cladding layer of a second conductivity type formed on said active layer, and a saturable light absorbing layer provided in at least one of both cladding layers, and setting the value of the thickness d a of said active layer, the optical confinement factor Γ a of said active layer, the thickness d s of said saturable light absorbing layer, the optical confinement factor Γ s of said saturable light absorbing layer, said current confinement width W, and the light spot size S on a facet of said semiconductor laser device to obtain stable self-sustained pulsation of said laser device.

Claim 2

Independent Claim 151 words

A method of designing a semiconductor laser device comprising the steps of: providing a device having a cladding layer of a first conductivity type, an active layer which is formed on said cladding layer of a first conductivity type and into which current confined to a width W is injected, a cladding layer of a second conductivity type formed on said active layer, and a saturable light absorbing layer provided in at least one of both cladding layers, and setting the value of the thickness d a of said active layer, the optical confinement factor Γ a of said active layer, the thickness d s of said saturable light absorbing layer, the optical confinement factor Γ s of said saturable light absorbing layer, said current confinement width W, and the light spot size S on a facet of said semiconductor laser device to obtain stable self-sustained pulsation of said laser device.

Claim 3

Dependent Claim 111 words

The method according to claim 1, wherein said setting step includes setting the values of the thickness d a of said active layer, the optical confinement factor Γ a of said active layer, the thickness d s of said saturable light absorbing layer, the optical confinement factor Γ s of said saturable light absorbing layer, said current confinement width W, and said light spot size S in a range enclosed by lines defined by equations (A) to (D): y=-ax+b (A) y=-cx+d, (a>c, b>d) (B) y=e (C) x=f (D) where a, b, c, d, e and f are each positive constants and y=(S-W)/W, x=(Γ s /d s )/(Γ a /d a ).

Claim 4

Dependent Claim 96 words

The method according to claim 2, wherein said setting step includes setting the thickness d a of said active layer, the optical confinement factor Γ a of said active layer, the thickness d s of said saturable light absorbing layer, the optical confinement factor Γ s of said saturable light absorbing layer, said current confinement width W and said light spot size S in a range enclosed by lines defined by equations (1) to (4): y=-5x+1.3, (x≦0.25) (1) y=-(1/25)x+3/50, (0.25≦x≦1) (2) y=0.6 (3) x=1 (4) where y=(S-W)/W, x=(Γ s /d s )/(Γ a /d a ).

Claim 5

Dependent Claim 96 words

The method according to claim 3, wherein said setting step includes setting the thickness d a of said active layer, the optical confinement factor Γ a of said active layer, the thickness d s of said saturable light absorbing layer, the optical confinement factor Γ s of said saturable light absorbing layer, said current confinement width W, and said light spot size S in a range enclosed by lines defined by equations (5) to (8): y=-5x+1.35, (x≦0.25) (5) y=-(1/15)x+7/60, (0.25≦x≦1) (6) y=0.6 (7) x=1 (8) where y=(S-W)/W, x=(Γ s /d s )/(Γ a /d a ).

Claim 6

Dependent Claim 30 words

The method according to claim 1, wherein said setting step includes setting the width of said saturable light absorbing layer to be smaller than the width of said active layer.

Claim 7

Dependent Claim 24 words

The method according to claim 1, wherein said setting step includes setting the thickness of said active layer to not more than 0.1 μm.

Claim 8

Dependent Claim 30 words

The method according to claim 6, wherein said setting step includes setting the thickness of said active layer to not less than 0.035 μm and not more than 0.1 μm.

Claim 9

Dependent Claim 265 words

The method according to claim 1, wherein said step of providing includes selecting an Al x Ga 1-x As cladding layer of a first conductivity type as said cladding layer of a first conductivity type, selecting an Al X Ga 1-X As first cladding layer of said second conductivity type formed on said active layer and an Al X Ga 1-X As second cladding layer of a second conductivity type constituting a stripe-shaped ridge portion formed on said first cladding layer as said cladding layer of a second conductivity type, and selecting a saturable light absorbing layer of a second conductivity type formed between said first cladding layer and said second cladding layer as said saturable light absorbing layer, and providing for a current blocking layer of a first conductivity type provided on a side surface of said ridge portion and on said saturable light absorbing layer, and said setting step includes setting the thickness d a of said active layer, the thickness d s of said saturable light absorbing layer, and the thickness t c of said first cladding layer in a range enclosed by lines defined by equations (9) to (13): t.sub.c =0.45 (9) d.sub.s /d.sub.a =0.8 (10) t.sub.c =-(3/5)×(d.sub.s /d.sub.a)+7/10, d.sub.s /d.sub.a ≦0.6(11) t.sub.c =-(1/10)×(d.sub.s /d.sub.a)+2/5, ≦0.6d.sub.s /d.sub.a ≦0.8 (12) t.sub.c =-(1/2)×(d.sub.s /d.sub.a)+3/4, 0.6≦d.sub.s /d.sub.a ≦0.8 (13) setting the thickness d a of said active layer in a range between about 0.04 μm and about 0.06 μm, and setting the composition ratio X in said cladding layer of a first conductivity type in a range of between about 0.4 and about 0.6.

Claim 10

Dependent Claim 230 words

A semiconductor laser device comprising: an Al X Ga 1-X As cladding layer of a first conductivity type; an active layer formed on said cladding layer of a first conductivity type; an Al X Ga 1-X As first cladding layer of a second conductivity type formed on said active layer; a saturable light absorbing layer of a second conductivity type formed on said first cladding layer; an Al X Ga 1-X As second cladding layer of a second conductivity type constituting a stripe-shaped ridge portion formed on said saturable light absorbing layer; and a current blocking layer of a first conductivity type provided on a side surface of said ridge portion and on said saturable light absorbing layer, the thickness d a of said active layer, the thickness d s of said saturable light absorbing layer, and the thickness t c of said first cladding layer satisfying conditions in a range enclosed by straight lines indicated by equations (9) to (13): t.sub.c =0.45 (9) d.sub.s /d.sub.a =0.9 (10) t.sub.c =-(3/5)×(d.sub.s /d.sub.a)+7/10, d.sub.s /d.sub.a ≦0.6(11) t.sub.c =-(1/10)×(d.sub.s /d.sub.a)+2/5, 0.6≦d.sub.s /d.sub.a ≦0.8 (12) t.sub.c =-(1/2)×(d.sub.s /d.sub.a)+3/4, 0.6≦d.sub.s /d.sub.a ≦0.8 (13) the thickness d a of said active layer being not less than 0.04 μm not more than 0.06 μm, and the composition ratio X in said cladding layer of a first conductivity type being not less than 0.4 not more than 0.6.

Claim 11

Dependent Claim 230 words

A semiconductor laser device comprising: an Al X Ga 1-X As cladding layer of a first conductivity type; an active layer formed on said cladding layer of a first conductivity type; an Al X Ga 1-X As first cladding layer of a second conductivity type formed on said active layer; a saturable light absorbing layer of a second conductivity type formed on said first cladding layer; an Al X Ga 1-X As second cladding layer of a second conductivity type constituting a stripe-shaped ridge portion formed on said saturable light absorbing layer; and a current blocking layer of a first conductivity type provided on a side surface of said ridge portion and on said saturable light absorbing layer, the thickness d a of said active layer, the thickness d s of said saturable light absorbing layer, and the thickness t c of said first cladding layer satisfying conditions in a range enclosed by straight lines indicated by equations (9) to (13): t.sub.c =0.45 (9) d.sub.s /d.sub.a =0.9 (10) t.sub.c =-(3/5)×(d.sub.s /d.sub.a)+7/10, d.sub.s /d.sub.a ≦0.6(11) t.sub.c =-(1/10)×(d.sub.s /d.sub.a)+2/5, 0.6≦d.sub.s /d.sub.a ≦0.8 (12) t.sub.c =-(1/2)×(d.sub.s /d.sub.a)+3/4, 0.6≦d.sub.s /d.sub.a ≦0.8 (13) the thickness d a of said active layer being not less than 0.04 μm not more than 0.06 μm, and the composition ratio X in said cladding layer of a first conductivity type being not less than 0.4 not more than 0.6.

Claim 12

Dependent Claim 197 words

A semiconductor laser device comprising: a cladding layer of a first conductivity type; an active layer which is formed on said cladding layer of a first conductivity type and into which current confined to a width W is injected; a cladding layer of a second conductivity type comprising a flat portion formed on said active layer and a stripe-shaped ridge portion formed on a part of said flat portion; and a saturable light absorbing layer provided in said ridge portion or between said ridge portion and said flat portion and having a smaller width than that of said active layer, and wherein the thickness d a of said active layer, the optical confinement factor Γ a of said active layer, the thickness d s of said saturable light absorbing layer, the optical confinement factor Γ s of said saturable light absorbing layer, said current confinement width W, and the light spot size S on a facet of said semiconductor laser device satisfy conditions in a range enclosed by straight lines indicated by equations (1) to (4): y=-5x+1.3, (x≦0.25) (1) y=-(1/25)x+3/50, (0.25≦x≦1) (2) y=0.6 (3) x=1 (4) where y=(S-W)/W, x=(Γ s /d s )/(Γ a /d a ).

Claim 13

Dependent Claim 197 words

A semiconductor laser device comprising: a cladding layer of a first conductivity type; an active layer which is formed on said cladding layer of a first conductivity type and into which current confined to a width W is injected; a cladding layer of a second conductivity type comprising a flat portion formed on said active layer and a stripe-shaped ridge portion formed on a part of said flat portion; and a saturable light absorbing layer provided in said ridge portion or between said ridge portion and said flat portion and having a smaller width than that of said active layer, and wherein the thickness d a of said active layer, the optical confinement factor Γ a of said active layer, the thickness d s of said saturable light absorbing layer, the optical confinement factor Γ s of said saturable light absorbing layer, said current confinement width W, and the light spot size S on a facet of said semiconductor laser device satisfy conditions in a range enclosed by straight lines indicated by equations (1) to (4): y=-5x+1.3, (x≦0.25) (1) y=-(1/25)x+3/50, (0.25≦x≦1) (2) y=0.6 (3) x=1 (4) where y=(S-W)/W, x=(Γ s /d s )/(Γ a /d a ).

Claim 14

Dependent Claim 96 words

The semiconductor laser device according to claim 10, wherein the thickness d a of said active layer, the optical confinement factor Γ a of said active layer, the thickness d s of said saturable light absorbing layer, the optical confinement factor Γ s of said saturable light absorbing layer, said current confinement width W, and said light spot size S satisfy conditions in a range enclosed by straight lines indicated by equations (5) to 8): y=-5x+1.35, (x≦0.25) (5) y=-(1/15)x+7/60, (0.25≦x≦1) (6) y=0.6 (7) x=1 (8) where y=(S-W)/W, x=(Γ s /d s )/(Γ a /d a ).

Claim 15

Dependent Claim 54 words

The semiconductor laser device according to claim 10, wherein said cladding layer of a first conductivity type is composed of Al X Ga 1-X As, said cladding layer of a second conductivity type is composed of Al X Ga 1-X As, and said active layer is composed of Al Y Ga 1-Y As (0≦Y<X<1).

Claim 16

Dependent Claim 21 words

The semiconductor laser device according to claim 10, wherein the thickness of said active layer is not more than 0.1 μm.

Claim 17

Dependent Claim 26 words

The semiconductor laser device according to claim 13, wherein the thickness of said active layer is not less than 0.035 μm not more than 0.1 μm.

Claim 18

Dependent Claim 26 words

The semiconductor laser device according to claim 10, further comprising an etching stop layer of a second conductivity type formed on said saturable light absorbing layer.

Claim 19

Dependent Claim 50 words

The semiconductor laser device according to claim 10, further comprising a current blocking layer of a first conductivity type provided on a side surface of said ridge portion and on said flat portion and having a larger band gap than that of said cladding layer of a second conductivity type.

Claim 20

Dependent Claim 34 words

The semiconductor laser device according to claim 10, wherein the reflectivity of a facet on the side of light output of said semiconductor laser device is not less than 10% nor more than 20%.

Claim 21

Dependent Claim 146 words

A semiconductor laser device comprising: a cladding layer of a first conductivity type; an active layer formed on said cladding layer of a first conductivity type; a cladding layer of a second conductivity type comprising a flat portion formed on said active layer and a stripe-shaped ridge portion formed on a part of said flat portion; a saturable light absorbing layer provided in at least one of said cladding layer of a first conductivity type and said cladding layer of a second conductivity type, said saturable light absorbing layer being located at least in said ridge portion or in a region facing said ridge portion; and a current blocking layer of a first conductivity type provided on a side surface of said ridge portion and on said flat portion and having a larger band gap than that of said cladding layer of a second conductivity type.

Claim 22

Dependent Claim 146 words

A semiconductor laser device comprising: a cladding layer of a first conductivity type; an active layer formed on said cladding layer of a first conductivity type; a cladding layer of a second conductivity type comprising a flat portion formed on said active layer and a stripe-shaped ridge portion formed on a part of said flat portion; a saturable light absorbing layer provided in at least one of said cladding layer of a first conductivity type and said cladding layer of a second conductivity type, said saturable light absorbing layer being located at least in said ridge portion or in a region facing said ridge portion; and a current blocking layer of a first conductivity type provided on a side surface of said ridge portion and on said flat portion and having a larger band gap than that of said cladding layer of a second conductivity type.

Claim 23

Dependent Claim 51 words

The semiconductor laser device according to claim 18, wherein said cladding layer of a second conductivity type is composed of Al X Ga 1-X As, said active layer is composed of Al Y Ga 1-Y As, and said current blocking layer is composed of Al Z Ga 1-Z As, and 0≦Y<X<Z<1.

Claim 24

Dependent Claim 24 words

The semiconductor laser device according to claim 19, further comprising an anti-oxidation layer of a first conductivity type formed on said current blocking layer.

Claim 25

Dependent Claim 28 words

The semiconductor laser device according to claim 18, wherein the reflectivity of a facet on the light output side is not less than 10% nor more than 20%.

Claim 26

Dependent Claim 22 words

The semiconductor laser device according to claim 18, wherein said saturable light absorbing layer is located at least in said ridge portion.

Claim 27

Dependent Claim 38 words

The semiconductor laser device according to claim 18, wherein said saturable light absorbing layer is located at least in said ridge portion, said semiconductor laser device further comprising an etching stop layer on said saturable light absorbing layer.

Claim 28

Dependent Claim 41 words

The semiconductor laser device according to claim 18, wherein said saturable light absorbing layer is located in said cladding layer of a second conductivity type, said semiconductor laser device further comprising an etching stop layer on said saturable light absorbing layer.

Claim 29

Dependent Claim 87 words

A semiconductor laser device comprising: a cladding layer of a first conductivity type; an active layer formed on said cladding layer of a first conductivity type; a cladding layer of a second conductivity type formed on said active layer; and a saturable light absorbing layer provided in at least one of said cladding layer of a first conductivity type and said cladding layer of a second conductivity type, the reflectivity of a facet on the light output side being not less than 10% nor more than 20%.

Claim 30

Dependent Claim 87 words

A semiconductor laser device comprising: a cladding layer of a first conductivity type; an active layer formed on said cladding layer of a first conductivity type; a cladding layer of a second conductivity type formed on said active layer; and a saturable light absorbing layer provided in at least one of said cladding layer of a first conductivity type and said cladding layer of a second conductivity type, the reflectivity of a facet on the light output side being not less than 10% nor more than 20%.

Claim 31

Dependent Claim 41 words

The semiconductor laser device according to claim 25, wherein said saturable light absorbing layer is located in said cladding layer of a second conductivity type, said semiconductor laser device further comprising an etching stop layer on said saturable light absorbing layer.

Claim 32

Dependent Claim 146 words

A semiconductor laser device comprising: a cladding layer of a first conductivity type, an active layer on said cladding layer of a first conductivity type and into which current confined to a width W is injected, a cladding layer of a second conductivity type on said active layer, a saturable light absorbing layer in at least one of said cladding layers, and a current blocking layer of a first conductivity type for confining current to said width W, provided on said cladding layer of a second conductivity type and having a larger band gap than the band gap of said cladding layer of a second conductivity type, said saturable light absorbing layer being located in a portion in which said current confined to said width W flows or at least in a region facing a portion in which said current confined to said width W flows.

Claim 33

Dependent Claim 146 words

A semiconductor laser device comprising: a cladding layer of a first conductivity type, an active layer on said cladding layer of a first conductivity type and into which current confined to a width W is injected, a cladding layer of a second conductivity type on said active layer, a saturable light absorbing layer in at least one of said cladding layers, and a current blocking layer of a first conductivity type for confining current to said width W, provided on said cladding layer of a second conductivity type and having a larger band gap than the band gap of said cladding layer of a second conductivity type, said saturable light absorbing layer being located in a portion in which said current confined to said width W flows or at least in a region facing a portion in which said current confined to said width W flows.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2000-03-03	2000-09-02	2001-03-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2004-03-03	2004-09-02	2005-03-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2008-03-03	2008-09-02	2009-03-04	$7700.00	Window Closed / Lapsed

Semiconductor laser device and method of designing the same

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