Quantum-confinement stark effect optical modulator

A method for fabricating a quantum confinement Stark effect (QCSE) optical modulator comprising the steps of:

• forming a layer structure on an InP substrate, said layer structure including a multiple quantum well (MQW), pair of cladding layers sandwiching therebetween said MQW and an Al-containing layer overlying said MQW;
• configuring at least a portion of said layer structure including said Al-containing layer to form a ridge stripe;
• and
• selectively oxidizing Al in said Al-containing layer to form a current confinement structure in said ridge structure, said current confinement structure having a pair of Al-oxidized regions of said Al-containing layer sandwiching therebetween an un-oxidized region of said Al-containing layer.

A method for fabricating a semiconductor optical device comprising the steps of:

• forming a first layer structure on first and second areas of an InP substrate, said layer structure in said first area constituting a semiconductor laser device;
• forming an area-selective growth mask on a portion of said first layer structure in said first area of said InP substrate;
• selectively removing said first layer structure to expose said second area of said InP substrate;
• forming a second layer structure on said second area, said second layer including a multiple quantum well (MQW), pair of cladding layers sandwiching therebetween said MQW and an Al-containing layer overlying said MQW;
• configuring at least a portion of said second layer structure including said Al-containing layer to form a ridge structure;
• selectively oxidizing Al in said Al-containing layer to form a current confinement structure in said ridge stripe, said current confinement structure having a pair of Al-oxidized regions of said Al-containing layer sandwiching therebetween an un-oxidized region of said Al-containing layer;
• forming a quantum confinement Stark effect optical modulator including said ridge stripe on said second area.

A method for forming a semiconductor optical device comprising the steps of:

• forming an area-selective growth mask on an InP substrate;
• selectively growing a layer structure by using said area-selective growth mask, said layer structure including a multiple quantum well (MQW), and a pair of cladding layers sandwiching therebetween said quantum well on said InP substrate;
• consecutively forming an Al-containing layer and at least another cladding layer on said layer structure;
• configuring said a portion of said layer structure including said Al-containing layer to form a ridge stripe;
• and
• selective oxidizing Al in said Al-containing layer to form a current confinement structure in said Al-containing layer, said current confinement structure including a pair of Al-oxidized regions sandwiching therebetween an un-oxidized region;
• said selectively growing step except for the step of growing well layers in said MQW using a material gas including an etchant for removing polycrystalline substance formed on said area-selective growth mask.