Method for producing a distributed feedback semiconductor laser device

A method for producing a distributed feedback semi-conductor laser device include a structure for controlling a longitudinal mode of light to be emitted and a structure for controlling a transverse mode of the light, the method comprising:

• a first crystal growth step of sequentially growing a first cladding layer of a first conductive type, an active layer, and an optical waveguide layer of a second conductive type on a semiconductor substrate of the first conductive type;
• a step of forming a diffraction grating at a surface of the optical waveguide layer;
• a second crystal growth step of sequentially growing a first semiconductor layer of the second conductive type and a current block layer of the first conductive type on the optical waveguide layer having the diffraction grating, said second crystal growth step including a step of forming an etching stop layer on the optical waveguide layer;
• a step of selectively etching the current block layer to expose the first semiconductor layer and thus to form a stripe groove;
• and
• a third crystal growth step of growing a second semiconductor layer of the second conductive type on the first semiconductor layer inside the stripe groove and on the current block layer to form a second cladding layer.

A method for producing a distributed feedback semiconductor laser device including a structure for controlling a longitudinal mode of light to be emitted and a structure for controlling a transverse mode of the light, the method comprising:

• a first crystal growth step of sequentially growing a first cladding layer of a first conductive type, an active layer, and an optical waveguide layer of a second conductive type on a semiconductor substrate of the first conductive type;
• a step of forming a diffraction grating at a surface of the optical waveguide layer;
• a second crystal growth step of growing a second cladding layer of the second conductive type on the optical waveguide layer having the diffraction grating, said second crystal growth step including a step of forming an etching stop layer on the optical waveguide layer;
• a step of selectively etching the second cladding layer to expose the diffraction grating and thus to form a mesa ridge;
• and
• a third crystal growth step of selectively growing a current block layer of the first conductive type on the optical waveguide layer disposed on both sides of the mesa ridge.