Patent ID: 8637338

Claim:
A method for producing an integrated optical device, comprising the steps of: preparing a substrate including first and second regions arranged in a predetermined direction; growing, on the first and second regions of the substrate, a first stacked semiconductor layer including a first optical waveguiding layer, a first cladding layer positioned on the first optical waveguiding layer, and a side-etching layer positioned on the first cladding layer, the side-etching layer having a composition different from a composition of the first cladding layer; etching the first stacked semiconductor layer through a first etching mask formed on the first region until the first optical waveguiding layer is exposed; selectively growing, on the second region through the first etching mask, a second stacked semiconductor layer including a second optical waveguiding layer and a second cladding layer positioned on the second optical waveguiding layer, the second optical waveguiding layer being optically coupled to the first optical waveguiding layer; growing a third cladding layer and a contact layer on the first and second stacked semiconductor layers, and forming a ridge structure by etching the contact layer, the third cladding layer, the side-etching layer, and the first and second cladding layers through a second etching mask formed on the contact layer, the second etching mask longitudinally extending in the predetermined direction, wherein the step of etching the first stacked semiconductor layer includes a step of forming an overhang between the first cladding layer and the first etching mask by selectively etching the side-etching layer by wet etching with an etchant having a higher etching rate for the side-etching layer than for the first cladding layer, and wherein the step of forming a ridge structure includes a first wet-etching step of etching the third cladding layer by wet etching with an etchant having a higher etching rate for the third cladding layer than for the side-etching layer, a second wet-etching step of etching the side-etching layer by wet etching with an etchant having a higher etching rate for the side-etching layer than for the first, second, and third cladding layers, and a third wet-etching step of etching the first and second cladding layers by wet etching with an etchant having a higher etching rate for the first and second cladding layers than for the side-etching layer.