Widely tunable narrow linewidth laser source based on photonic molecule microcombs and optical injection locking

Area of Science:

• Optics and Photonics
• Laser Physics
• Quantum Optics

Background:

• Tunable laser sources with narrow linewidths are crucial for various applications, including spectroscopy and optical communications.
• Existing tunable laser technologies often face limitations in terms of tuning range, linewidth, output power, or side mode suppression ratio.

Purpose of the Study:

• To demonstrate a novel method for generating a widely and arbitrarily tunable laser source.
• To achieve a laser source with a very narrow linewidth, high output power, and high side mode suppression ratio.
• To explore the potential for extending the performance of the demonstrated laser system.

Main Methods:

• Seeding a coupled-cavity microcomb with a highly coherent single-frequency laser.
• Utilizing injection locking of a Fabry-Perot laser to select a single output comb tone.
• Characterizing the laser source across the 1530–1585 nm wavelength range.

Main Results:

• Generation of a widely and arbitrarily tunable laser source.
• Achieved linewidth below 8 kHz.
• Obtained 5 dBm output power and a side mode suppression ratio of at least 60 dB across the demonstrated wavelength range.

Conclusions:

• The demonstrated method provides a viable approach for creating high-performance tunable laser sources.
• The system offers significant advantages in terms of tunability, linewidth, power, and side mode suppression.
• Further improvements in performance are anticipated with system optimization and extension to broader wavelength ranges.