Patent ID: 11870213
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Optics (Instruments)
Classification: CPC H | IPC H

Claim 11:
12. A method of manufacturing the semiconductor laser comprising:
sequentially forming part of a back surface side cladding layer and a cladding layer for diffraction grating formation through crystal growth on a substrate on which each part of a DFB unit, a DBR unit adjacent to the DFB unit, and a PD unit adjacent to the DBR unit is to be formed;
forming a first diffraction grating layer in the cladding layer for diffraction grating formation corresponding to the DFB unit and a second diffraction grating layer in the cladding layer for diffraction grating formation corresponding to the DBR unit by etching;
forming a remnant of the back surface side cladding layer on the cladding layer for diffraction grating formation through crystal growth;
injecting carriers into the back surface side cladding layers of the DFB unit and the PD unit;
forming a light emitting layer having a first MQW structure on the back surface side cladding layer through crystal growth;
after removing the light emitting layer in the DBR unit and the PD unit, forming a core layer having a second MQW structure having an effective bandgap energy smaller than that of the first MQW structure through crystal growth;
sequentially forming a front surface side cladding layer and a contact layer on the light emitting layer and the core layer through crystal growth;
injecting carriers into the front surface side cladding layer and the contact layer of the DFB unit and the PD unit;
removing the substrate by grinding;
forming front surface side electrodes on the contact layers of the DFB unit and the PD unit respectively; and
forming a back surface side electrode on a surface of the back surface side cladding layer exposed by removing the substrate.