Method of forming waveguide lens having refractive index distribution

Claim 1

A method of forming in a two-dimensional waveguide formed on a substrate a waveguide lens having a predetermined distribution of refractive index, for converging or diverging light rays which propagate through said two-dimensional waveguide, comprising the steps of: forming a film of a diffusion metal having a constant thickness, in a region of a surface of said waveguide on the substrate in which said waveguide lens is to be formed; forming an etching mask of a photo resist on said film of the diffusion metal, said mask having a multiplicity of separate openings and separate non-open portions defined by said separate openings, said separate openings being formed such that a ratio of an area of said openings to an area of said non-open portions per unit area of said mask is continuously varied in a direction which intersects a direction of propagation of said light rays through said waveguide, said separate openings corresponding to local portions of said film; effecting an etching operation to remove said local portions of said film which are exposed through said multiplicity of separate openings, so that a density of the removed local portions of said film per unit area of said film is continuously varied in said direction; and effecting thermal diffusion of a remainder of said film into said waveguide on said substrate, such that a density of diffusion of said diffusion metal in said region of said waveguide is continuously varied in said direction, to thereby form said waveguide lens such that the refractive index of the waveguide lens is continuously varied in said direction.

Claim 2

A method of forming in a two-dimensional waveguide formed on a substrate a waveguide lens having a predetermined distribution of refractive index, for converging or diverging light rays which propagate through said two-dimensional waveguide, comprising the steps of: forming a film of a diffusion metal having a constant thickness, in a region of a surface of said waveguide on the substrate in which said waveguide lens is to be formed; forming an etching mask of a photo resist on said film of the diffusion metal, said mask having a multiplicity of separate openings and separate non-open portions defined by said separate openings, said separate openings being formed such that a ratio of an area of said openings to an area of said non-open portions per unit area of said mask is continuously varied in a direction which intersects a direction of propagation of said light rays through said waveguide, said separate openings corresponding to local portions of said film; effecting an etching operation to remove said local portions of said film which are exposed through said multiplicity of separate openings, so that a density of the removed local portions of said film per unit area of said film is continuously varied in said direction; and effecting thermal diffusion of a remainder of said film into said waveguide on said substrate, such that a density of diffusion of said diffusion metal in said region of said waveguide is continuously varied in said direction, to thereby form said waveguide lens such that the refractive index of the waveguide lens is continuously varied in said direction.

Claim 3

A method of forming in a two-dimensional waveguide formed on a substrate a waveguide lens having a predetermined distribution of refractive index, for converging or diverging light rays which propagate through said two-dimensional waveguide, comprising the steps of: forming a mask in a region of a surface of said waveguide on the substrate in which said waveguide lens is to be formed, said mask being made of a photo resist and having a multiplicity of separate openings and separate non-open portions defined by said separate openings, said separate openings being formed such that a ratio of an area of said openings to an area of said non-open portions per unit area of said mask is continuously varied in a direction which intersects a direction of propagation of said light rays through said waveguide; applying to a multiplicity of separate exposed areas of said region of the waveguide, which are aligned with said separate openings, a material which serves to change a refractive index of said waveguide, whereby a density of said material in said region is continuously varied in said direction; and effecting thermal diffusion of said material into said waveguide on said substrate, such that a density of diffusion of said material in said region of said waveguide is continuously varied in said direction, to thereby form said waveguide lens such that the refractive index of the waveguide lens is continuously varied in said direction.

Claim 4

A method of forming in a two-dimensional waveguide formed on a substrate a waveguide lens having a predetermined distribution of refractive index, for converging or diverging light rays which propagate through said two-dimensional waveguide, comprising the steps of: forming a mask in a region of a surface of said waveguide on the substrate in which said waveguide lens is to be formed, said mask being made of a photo resist and having a multiplicity of separate openings and separate non-open portions defined by said separate openings, said separate openings being formed such that a ratio of an area of said openings to an area of said non-open portions per unit area of said mask is continuously varied in a direction which intersects a direction of propagation of said light rays through said waveguide; applying to a multiplicity of separate exposed areas of said region of the waveguide, which are aligned with said separate openings, a material which serves to change a refractive index of said waveguide, whereby a density of said material in said region is continuously varied in said direction; and effecting thermal diffusion of said material into said waveguide on said substrate, such that a density of diffusion of said material in said region of said waveguide is continuously varied in said direction, to thereby form said waveguide lens such that the refractive index of the waveguide lens is continuously varied in said direction.

Claim 7

A method of forming in a two-dimensional waveguide formed on a substrate a waveguide lens having a predetermined distribution of refractive index, for converging or diverging light rays which propagate through said two-dimensional waveguide, comprising the steps of: forming a mask in a region of a surface of said waveguide on the substrate in which said waveguide lens is to be formed, said mask being made of a photo resist and having a multiplicity of separate openings and separate non-open portions defined by said separate openings, said separate openings being formed such that a ratio of an area of said openings to an area of said non-open portions per unit area of said mask is continuously varied in a direction which intersects a direction of propagation of said light rays through said waveguide; applying to a multiplicity of separate exposed areas of said region of the waveguide, which are aligned with said separate openings, a material which serves to change a refractive index of said waveguide, whereby a density of said material in said region is continuously varied in said direction; and moving ions of said material which serve to change the refractive index of the waveguide into an interior of the waveguide, and moving ions of said waveguide which are exchanged for said material toward said surface of the waveguide, such that a density of diffusion of said material into said interior of the waveguide is continuously varied in said direction, to thereby form said waveguide lens such that the refractive index of the waveguide lens is continuously varied in said direction.

Claim 8

A method of forming in a two-dimensional waveguide formed on a substrate a waveguide lens having a predetermined distribution of refractive index, for converging or diverging light rays which propagate through said two-dimensional waveguide, comprising the steps of: forming a mask in a region of a surface of said waveguide on the substrate in which said waveguide lens is to be formed, said mask being made of a photo resist and having a multiplicity of separate openings and separate non-open portions defined by said separate openings, said separate openings being formed such that a ratio of an area of said openings to an area of said non-open portions per unit area of said mask is continuously varied in a direction which intersects a direction of propagation of said light rays through said waveguide; applying to a multiplicity of separate exposed areas of said region of the waveguide, which are aligned with said separate openings, a material which serves to change a refractive index of said waveguide, whereby a density of said material in said region is continuously varied in said direction; and moving ions of said material which serve to change the refractive index of the waveguide into an interior of the waveguide, and moving ions of said waveguide which are exchanged for said material toward said surface of the waveguide, such that a density of diffusion of said material into said interior of the waveguide is continuously varied in said direction, to thereby form said waveguide lens such that the refractive index of the waveguide lens is continuously varied in said direction.