Narrow line width frequency comb source based on an injection-locked III-V-on-silicon mode-locked laser

Area of Science:

• Integrated photonics
• Optical communications
• Semiconductor lasers

Background:

• Mode-locked lasers generate short optical pulses.
• Narrow linewidths are crucial for high-capacity optical communication.
• III-V-on-silicon technology offers integrated laser solutions.

Purpose of the Study:

• To reduce the linewidth of a III-V-on-silicon mode-locked laser.
• To achieve coherent frequency comb generation on a chip.
• To enable high spectral efficiency optical communication systems.

Main Methods:

• Optical injection locking using a narrow linewidth continuous wave (CW) source.
• Exploration of two locking techniques: hybrid and passively mode-locked lasers.
• Characterization of laser line width reduction and coherence.

Main Results:

• Reduced the MHz linewidth of the mode-locked laser to 50 kHz.
• Demonstrated coherence between over 50 laser lines and the CW source.
• Successfully implemented two distinct injection locking strategies.

Conclusions:

• Optical injection locking is effective for linewidth reduction in III-V-on-silicon lasers.
• Coherent frequency combs on a chip are achievable.
• This technology supports the development of advanced optical transceivers.