Triply resonant coupled-cavity electro-optic modulators for RF to optical signal conversion

Area of Science:

• Photonics
• Integrated Optics
• Electro-optics

Background:

• Conventional microring modulators face efficiency limitations at high RF frequencies due to photon lifetime constraints.
• Achieving efficient RF-to-optical conversion is crucial for advanced communication and sensing systems.

Purpose of the Study:

• To propose and theoretically analyze a novel on-chip triply resonant electro-optic modulator architecture.
• To optimize device geometries for maximum RF-to-optical conversion efficiency.
• To overcome the limitations of existing modulators for high-frequency operation.

Main Methods:

• Theoretical analysis of device geometries for simultaneous resonant enhancement of RF drive, CW optical pump, and generated optical sideband.
• Utilizing a two-coupled-cavity optical resonator system for optical resonance.
• Incorporating LC circuits for RF signal enhancement.

Main Results:

• The proposed architecture offers a 15-50 dB improvement in conversion efficiency compared to conventional microring modulators.
• Achieved efficient operation at high RF carrier frequencies, independent of photon lifetime.
• Demonstrated two configurations: a basic design for narrowband signals and a generalized design for wider bandwidths.
• RF drive signal enhancement via integrated LC resonance provides an additional 5-20 dB gain.

Conclusions:

• The novel triply resonant modulator architecture enables compact, efficient, and high-frequency RF-to-optical signal conversion.
• The design overcomes critical limitations of existing modulators, paving the way for advanced CMOS RF-electronic-photonic systems.
• The architecture is versatile, applicable to various cavity designs and modulation mechanisms, including silicon photonics.