Narrow linewidth semiconductor multi-wavelength DFB laser array simultaneously self-injection locked to a single...

Area of Science:

• Photonics and Optical Engineering
• Semiconductor Lasers
• Resonator Optics

Background:

• Semiconductor lasers often exhibit broad linewidths and significant frequency noise.
• Narrow linewidth lasers are crucial for high-resolution spectroscopy, optical communications, and sensing.
• Integrating multiple narrow linewidth lasers on a single chip presents a significant challenge.

Purpose of the Study:

• To demonstrate simultaneous injection locking of a multi-wavelength distributed feedback (DFB) laser array to a single microring resonator.
• To significantly reduce the frequency noise and narrow the instantaneous linewidth of semiconductor lasers.
• To explore the generation of frequency combs from injection-locked lasers.

Main Methods:

• Experimental demonstration of simultaneous injection locking of multiple DFB lasers to a single microring resonator.
• Utilizing a microring resonator with a high quality factor (Q-factor) of 2.38 million.
• Characterization of frequency noise reduction and linewidth narrowing using optical spectrum analysis.

Main Results:

• Achieved more than 40 dB reduction in white frequency noise for all DFB lasers.
• Narrowed the instantaneous linewidths of all DFB lasers by a factor of 10^4.
• Observed frequency combs generated through non-degenerate four-wave mixing (FWM) between the locked lasers.

Conclusions:

• Simultaneous injection locking of multi-wavelength lasers to a single on-chip resonator is experimentally feasible.
• This technique enables the integration of narrow-linewidth semiconductor laser arrays on a single chip.
• The method facilitates the generation of multiple microcombs within a single resonator, promising for WDM coherent optical communication and metrology.