Light source for integrating modulator and module for optical communication

An optical device comprising:

• a substrate;
• a distributed feedback (DFB) semiconductor laser formed on the substrate and including a diffraction grating having an asymmetrical λ/4 phase shift region, the diffraction grating extending along an optical axis of the DFB semiconductor laser;
• and
• a field absorbing modulator integrated with the DFB semiconductor laser on the substrate for modulating a light wave emitted from the DFB semiconductor laser,
• the optical modulator having a facet reflection rate between 0.02 and 0.03% at an output end thereof, the diffraction grating having a κL value between 1.2 and 1.3.

An optical device comprising:

• a substrate;
• a distributed feedback (DFB) semiconductor laser formed on the substrate and including a diffraction grating having an asymmetrical λ/4 phase shift region, the diffraction grating extending along an optical axis of the DFB semiconductor laser;
• and
• a field absorbing modulator integrated with the DFB semiconductor laser on the substrate for modulating a light wave emitted from the DFB semiconductor laser, the optical modulator having a facet reflection rate between 0.03 and 0.05% at an output end thereof, the diffraction grating having a κL value between 1.3 and 1.4.

An optical device comprising:

• a substrate;
• a distributed feedback (DFB) semiconductor laser formed on the substrate and including a diffraction grating having an asymmetrical λ/4 phase shift region, the diffraction grating extending along an optical axis of the DFB semiconductor laser;
• and
• a field absorbing modulator integrated with the DFB semiconductor laser on the substrate for modulating a light wave emitted from the DFB semiconductor laser, the optical modulator having a facet reflection rate between 0.05 and 0.1 % at an output end thereof, the diffraction grating having a κL value between 1.4 and 1.7.