Integrated tunable green light source on silicon nitride

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Quantum Technologies

Background:

• On-chip green light sources are crucial for telecommunications and quantum applications.
• Current integrated green light generators face limitations in power output and tunability.

Purpose of the Study:

• To demonstrate efficient and tunable on-chip green light generation using silicon nitride microresonators.
• To explore photo-induced nonlinearities for enhanced light source performance.

Main Methods:

• Utilizing silicon nitride microresonators to achieve second-harmonic generation (SHG).
• Employing photo-induced second-order nonlinearities for light generation.
• Implementing all-optical poling (AOP) with a milliwatt-level threshold.
• Demonstrating non-cascaded sum-frequency generation (SFG) assisted by coherent frequency combs.

Main Results:

• Achieved up to 3.5 mW of green power via SHG.
• Demonstrated densely tunable green light generation over a 29 nm range.
• Reported milliwatt-level AOP threshold enabling amplifier-free continuous-wave AOP.
• Showcased comb-assisted AOP for switching green light generation over an 11 nm range.

Conclusions:

• The developed silicon nitride microresonators provide a low-threshold, high-power, and widely-tunable on-chip green light source.
• The combination of efficient photo-induced nonlinearity and multi-wavelength AOP overcomes previous performance limitations.
• This technology is promising for advancing integrated photonics for telecommunications and quantum applications.