Patent ID: 6455338
Filing Date: 2002-09-24
Classification: H01S

Abstract:
A process for manufacturing an integrated semiconductor laser-modulator device comprising:preparing a layer structure including, depositing a first waveguide layer having a first conductivity type on a first main surface of a semiconductor substrate, the first waveguide having an active layer with a bandgap energy, depositing a first cladding layer having a second conductivity type on the first waveguide layer, and depositing a second cladding layer having an embedded diffraction grating between the first waveguide layer and one of the first cladding layer and the substrate; forming a stripe-shaped first dielectric layer extending along a laser emitting direction and overlapping the diffraction grating, the first dielectric layer having a length shorter than the substrate, and etching, using the first dielectric layer as a mask, until the semiconductor substrate is exposed; forming, in sequence, a second waveguide layer having a beam waveguide layer with a bandgap energy larger than the bandgap energy of the active layer and a third cladding layer of a second conductivity type semiconductor, using the first dielectric layer as a mask, on an etched and exposed surface of the semiconductor substrate; removing the first dielectric layer, forming a stripe-shaped second dielectric layer on the second and third cladding layers, the second dielectric layer covering and extending farther in a laser emitting direction than a portion of the first dielectric layer, and etching, using the second dielectric layer as a mask, until the substrate is exposed; sequentially forming a third waveguide layer and a fourth cladding layer having the second conductivity type on the etched and exposed substrate, the third waveguide layer including a beam absorption layer having a bandgap energy larger than the bandgap energy of the active layer but smaller than the bandgap energy of the beam waveguide layer; and removing the second dielectric layer, forming a stripe-shaped third dielectric layer on the second, third, and fourth cladding layers, the third dielectric layer covering and extending farther in the laser emitting direction than the second, third, and fourth cladding layers, etching, using the third dielectric layer as a mask, until the substrate is exposed, to form a ridge, and forming a current blocking layer on the etched and exposed substrate.