Thermo-elastic gigahertz-frequency oscillator through surface acoustic wave-silicon photonics

Area of Science:

• Photonics
• Opto-electronics
• Acoustics

Background:

• Opto-electronic oscillators are crucial for generating low-noise microwave frequencies.
• Photonic integrated devices are increasingly explored for oscillator realization.

Purpose of the Study:

• To propose and demonstrate a thermo-elastic opto-electronic oscillator.
• To utilize a standard silicon-photonic integrated circuit for microwave signal generation.

Main Methods:

• Modulating an optical pump wave with a microwave signal.
• Generating surface acoustic waves via thermo-elastic actuation in a silicon-on-insulator substrate.
• Reconverting the waveform to optical domain using photoelastic modulation in a racetrack resonator.

Main Results:

• Demonstration of a 2.213 GHz thermo-elastic opto-electronic oscillator.
• Radio-frequency selective thermo-elastic actuation and photoelastic modulation achieved.
• Oscillator operates without piezoelectricity and is scalable to tens of GHz.

Conclusions:

• The developed oscillator offers a new approach for integrated microwave-photonic signal processing.
• The principle is applicable to elastic analysis of surfaces and thin layers.
• The device can be realized on various substrates with potential for compact designs and long acoustic delays.