US5249191A — Waveguide type second-harmonic generation element…

Claim 1

Independent Claim 149 words

A waveguide type second-harmonic generation element comprising: a substrate made of LiTaO 3 and having a top surface; a plurality of domain inversion regions formed on the top surface of said substrate and extending in a first direction approximately parallel to each other, said domain inversion regions having a first depth into said substrate; a plurality of domain non-inversion regions formed on the top surface of said substrate and extending in the first direction approximately parallel to each other, said domain inversion region and said domain non-inversion regions alternately occurring on said substrate; and an optical waveguide formed on the top surface of said substrate and traversing said domain inversion regions and said domain non-inversion regions, said optical waveguide having a second depth and extending in a second direction which is approximately perpendicular to the first direction and wherein said domain inversion regions have a uniform refractive index distribution.

Claim 2

Dependent Claim 149 words

A waveguide type second-harmonic generation element comprising: a substrate made of LiTaO 3 and having a top surface; a plurality of domain inversion regions formed on the top surface of said substrate and extending in a first direction approximately parallel to each other, said domain inversion regions having a first depth into said substrate; a plurality of domain non-inversion regions formed on the top surface of said substrate and extending in the first direction approximately parallel to each other, said domain inversion region and said domain non-inversion regions alternately occurring on said substrate; and an optical waveguide formed on the top surface of said substrate and traversing said domain inversion regions and said domain non-inversion regions, said optical waveguide having a second depth and extending in a second direction which is approximately perpendicular to the first direction and wherein said domain inversion regions have a uniform refractive index distribution.

Claim 3

Dependent Claim 43 words

The waveguide type second-harmonic generation element as claimed in claim 1, wherein said domain inversion regions have an approximate semi-circular shape in a cross section taken along a plane parallel to the second direction and perpendicular to the top surface of said substrate.

Claim 4

Dependent Claim 103 words

The waveguide type second-harmonic generation element as claimed in claim 1, wherein said domain inversion regions have a first width l 2 in the second direction at the top surface of said substrate, said domain non-inversion regions have a second width l 1 in the second direction at the top surface of said substrate, and a ratio l 2 :l 1 =2n-1:1 when a period of said domain inversion regions in the second direction is n times a minimum period of domain inversion required for a quasi phase matching of a second harmonics generated in said optical waveguide, wherein n is an integer.

Claim 5

Dependent Claim 13 words

The waveguide type second-harmonic generation element as claimed in claim 3, wherein n=2.

Claim 6

Dependent Claim 24 words

The waveguide type second-harmonic generation element as claimed in claim 1, wherein the top surface of said substrate is an optically polished -Z face.

Claim 7

Dependent Claim 30 words

The waveguide type second-harmonic generation element as claimed in claim 1, wherein the second depth of said optical waveguide is smaller than the first depth of said domain inversion regions.

Claim 8

Independent Claim 175 words

A method of producing a waveguide type second-harmonic generation element, said method comprising the steps of: (a) forming periodic proton (H + ) exchange blocking layers on a top surface of a substrate which is made of LiTaO 3 , said proton (H + ) exchange blocking layers being approximately parallel and extending in a first direction which is approximately perpendicular to a second direction in which the proton (H + ) exchange blocking layers are periodically arranged; (b) forming proton exchange layers on the top surface of the substrate not covered by the proton (H + ) exchange blocking layers; (c) forming periodic domain inversion regions by heating the substrate to a predetermined temperature immediately below a Curie point and inverting domain of the proton (H + ) exchange layers; (d) diffusing the proton (H + ) by subjecting the substrate to an annealing process; and (e) forming an optical waveguide on the top surface of the substrate so as to traverse the domain inversion regions, said optical waveguide extending in the second direction.

Claim 9

Independent Claim 175 words

A method of producing a waveguide type second-harmonic generation element, said method comprising the steps of: (a) forming periodic proton (H + ) exchange blocking layers on a top surface of a substrate which is made of LiTaO 3 , said proton (H + ) exchange blocking layers being approximately parallel and extending in a first direction which is approximately perpendicular to a second direction in which the proton (H + ) exchange blocking layers are periodically arranged; (b) forming proton exchange layers on the top surface of the substrate not covered by the proton (H + ) exchange blocking layers; (c) forming periodic domain inversion regions by heating the substrate to a predetermined temperature immediately below a Curie point and inverting domain of the proton (H + ) exchange layers; (d) diffusing the proton (H + ) by subjecting the substrate to an annealing process; and (e) forming an optical waveguide on the top surface of the substrate so as to traverse the domain inversion regions, said optical waveguide extending in the second direction.

Claim 10

Dependent Claim 44 words

The method as claimed in claim 7, wherein said steps (c) and (d) form the domain inversion regions having a first depth into said substrate, and said step (e) forms the optical waveguide having a second depth which is smaller than the first depth.

Claim 11

Dependent Claim 45 words

The method as claimed in claim 7, wherein said steps (c) and (d) form the domain inversion regions having an approximate semi-circular shape in a cross section taken along a plane parallel to the second direction and perpendicular to the top surface of the substrate.

Claim 12

Dependent Claim 123 words

The method as claimed in claim 7, wherein said steps (c) and (d) form the domain inversion regions having a first width l 2 in the second direction at the top surface of the substrate and domain non-inversion regions having a second width l 1 in the second direction at the top surface of the substrate so that a ratio l 2 :l 1 =2n-1:1 when a period of the domain inversion regions in the second direction is n times a minimum period of domain inversion required for a quasi phase matching of second harmonics generated in the optical waveguide, said domain inversion regions and said domain non-inversion regions alternately occurring on the substrate in the second direction, wherein n is an integer.

Claim 13

Dependent Claim 9 words

The method as claimed in claim 10, wherein n=2.

Claim 14

Dependent Claim 30 words

The method as claimed in claim 7, wherein said step (a) forms the periodic proton (H + ) exchange blocking layers on an optically polished -Z face of the substrate.

Claim 15

Dependent Claim 22 words

The method as claimed in claim 7, wherein said step (c) heats the substrate to the predetermined temperature within approximately 30 minutes.

Claim 16

Dependent Claim 29 words

The method as claimed in claim 13, wherein said step (c) heats the substrate to the predetermined temperature which is in a range of approximately 590° to 595° C.

Claim 17

Dependent Claim 26 words

The method as claimed in claim 7, wherein said step (d) carries out the annealing process at a temperature which is lower than the predetermined temperature.

Claim 18

Dependent Claim 29 words

The method as claimed in claim 7, wherein said step (d) carries out the annealing process at a temperature of approximately 500° C. for at least approximately 2 hours.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1996-09-27	1997-03-29	1997-09-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2000-09-27	2001-03-29	2001-09-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2004-09-27	2005-03-29	2005-09-28	$7700.00	Window Closed / Lapsed

Waveguide type second-harmonic generation element and method of producing the same

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