High-repetition-rate GaAs-on-SiN mode-locked laser using a Fabry-Pérot cavity

Area of Science:

• Photonics
• Materials Science
• Electrical Engineering

Background:

• Silicon nitride (SiN) photonics offers a scalable platform for integrated optical circuits.
• Mode-locked lasers are crucial for generating high-speed optical pulses used in communications and sensing.
• Heterogeneous integration is key to combining different material functionalities on a single chip.

Purpose of the Study:

• To demonstrate a 23.3 GHz mode-locked laser integrated onto a silicon nitride platform.
• To explore the potential of micro-transfer printing for heterogeneous integration of III-V materials on silicon nitride.
• To provide a scalable solution for on-chip optical pulse generation.

Main Methods:

• Heterogeneous integration of GaAs-on-SiN using micro-transfer printing.
• Fabrication of a compact Fabry-Pérot cavity with a saturable absorber.
• Utilizing colliding-pulse, second-harmonic mode locking.
• Characterization using optical power measurements and autocorrelation.

Main Results:

• Successful demonstration of a 23.3 GHz mode-locked laser on a SiN platform.
• Achieved up to 1 mW on-chip optical power from a single output port.
• Generated eight comb lines within a 10 dB optical bandwidth.
• Measured a deconvolved pulse width of 4.8 ps via autocorrelation.

Conclusions:

• Micro-transfer printing enables efficient heterogeneous integration of GaAs-on-SiN for photonic applications.
• The demonstrated laser is a viable high-repetition-rate pulse source for nonlinear SiN photonic circuits.
• This approach offers a scalable pathway toward advanced integrated photonic systems.