Method for fabricating an optical semiconductor device

Claim 1

A method for fabricating an optical semiconductor device, comprising the steps of: forming a dielectric layer on a semiconductor substrate, said dielectric layer being formed as two dielectric stripes which are parallel to each other and defining a predetermined interval therebetween; growing a crystal selectively on said semiconductor substrate, using said dielectric stripes as a mask, to form a multi layer structure having a width which is determined by said predetermined interval; etching portions of said dielectric stripes to change the size of said predetermined interval; and selectively growing an additional crystal between said predetermined interval after said etching step.

Claim 2

A method for fabricating an optical semiconductor device, comprising the steps of: forming a dielectric layer on a semiconductor substrate, said dielectric layer being formed as two dielectric stripes which are parallel to each other and defining a predetermined interval therebetween; growing a crystal selectively on said semiconductor substrate, using said dielectric stripes as a mask, to form a multi layer structure having a width which is determined by said predetermined interval; etching portions of said dielectric stripes to change the size of said predetermined interval; and selectively growing an additional crystal between said predetermined interval after said etching step.

Claim 3

A method for fabricating an optical semiconductor device, comprising the steps of: forming a dielectric layer on a semiconductor substrate, said dielectric layer being formed as two dielectric stripes which are parallel to each other and defining a predetermined interval therebetween; growing a crystal selectively on said semiconductor substrate, using said dielectric stripes as a mask, to form a multi layer structure having a width which is determined by said predetermined interval; etching a portion of each of said dielectric stripes which faces the other of said dielectric stripes to expose a portion of the surface of said dielectric substrate; and growing a crystal selectively to form a clad layer on said semiconductor substrate on at least the area between said two dielectric stripes as etched.

Claim 4

A method for fabricating an optical semiconductor device, comprising the steps of: forming a dielectric layer on a semiconductor substrate, said dielectric layer being formed as two dielectric stripes which are parallel to each other and defining a predetermined interval therebetween; growing a crystal selectively on said semiconductor substrate, using said dielectric stripes as a mask, to form a multi layer structure having a width which is determined by said predetermined interval; etching a portion of each of said dielectric stripes which faces the other of said dielectric stripes to expose a portion of the surface of said dielectric substrate; and growing a crystal selectively to form a clad layer on said semiconductor substrate on at least the area between said two dielectric stripes as etched.

Claim 8

A method for fabricating an optical semiconductor device, comprising the steps of: forming first and second regions on a semiconductor crystal substrate, said first region having a surface having diffraction lattices and said second region having a flat surface; forming a multi-layer semiconductor substrate including a semiconductor guide layer on said fabricated surface of said semiconductor crystal substrate; forming at least two stripes of dielectric layer sandwiching an optical waveguide region on said multi-layer semiconductor substrate, said stripes extending parallel to each other with a predetermined interval therebetween and each of said stripes having a width which is wider in said first region and is narrower in said second region; forming a multi-layer semiconductor layer including an active layer by selective growth on a surface of said multi-layer semiconductor substrate including said optical waveguide region; and forming a semiconductor laser and a semiconductor optical modulator in said first and second regions, respectively.

Claim 9

A method for fabricating an optical semiconductor device, comprising the steps of: forming first and second regions on a semiconductor crystal substrate, said first region having a surface having diffraction lattices and said second region having a flat surface; forming a multi-layer semiconductor substrate including a semiconductor guide layer on said fabricated surface of said semiconductor crystal substrate; forming at least two stripes of dielectric layer sandwiching an optical waveguide region on said multi-layer semiconductor substrate, said stripes extending parallel to each other with a predetermined interval therebetween and each of said stripes having a width which is wider in said first region and is narrower in said second region; forming a multi-layer semiconductor layer including an active layer by selective growth on a surface of said multi-layer semiconductor substrate including said optical waveguide region; and forming a semiconductor laser and a semiconductor optical modulator in said first and second regions, respectively.

Claim 10

A method for fabricating an optical semiconductor device, comprising the steps of: forming first to third regions on a semiconductor crystal substrate, each of said first and second regions having a flat surface and said third region having a surface having diffraction lattices; forming a multi-layer semiconductor substrate including a semiconductor guide layer on said fabricated surface of said semiconductor crystal substrate; forming at least two stripes of dielectric layer sandwiching an optical waveguide region on said multi-layer semiconductor substrate, said stripes extending parallel to each other with a predetermined interval therebetween and each of said stripes having a width which is wider in said first region and is narrow and the same in said second and third regions; forming a multi-layer semiconductor layer including an active layer by selective growth on a surface of said multi-layer semiconductor substrate including said optical waveguide region; and forming a light emission unit, a phase control unit and a wavelength variable braggy reflector in said first to third regions, respectively.

Claim 11

A method for fabricating an optical semiconductor device, comprising the steps of: forming first to third regions on a semiconductor crystal substrate, each of said first and second regions having a flat surface and said third region having a surface having diffraction lattices; forming a multi-layer semiconductor substrate including a semiconductor guide layer on said fabricated surface of said semiconductor crystal substrate; forming at least two stripes of dielectric layer sandwiching an optical waveguide region on said multi-layer semiconductor substrate, said stripes extending parallel to each other with a predetermined interval therebetween and each of said stripes having a width which is wider in said first region and is narrow and the same in said second and third regions; forming a multi-layer semiconductor layer including an active layer by selective growth on a surface of said multi-layer semiconductor substrate including said optical waveguide region; and forming a light emission unit, a phase control unit and a wavelength variable braggy reflector in said first to third regions, respectively.