Silicon optical diode with 40 dB nonreciprocal transmission

Area of Science:

• Photonics
• Materials Science
• Optical Engineering

Background:

• Optical diodes are crucial for preventing back-reflections in photonic circuits.
• Existing optical diodes often rely on complex structures or rare-earth materials.
• Developing compact, all-silicon nonreciprocal devices is a key challenge in integrated photonics.

Purpose of the Study:

• To demonstrate a passive all-silicon optical diode.
• To achieve a record high nonreciprocal transmission ratio (NTR).
• To explore the underlying nonlinear power dynamics and identify pathways for improvement.

Main Methods:

• Fabrication of an all-silicon optical diode composed of microring resonators.
• Experimental characterization of the device's transmission properties.
• Analysis of nonlinear power dynamics within individual microrings.

Main Results:

• Achieved a record nonreciprocal transmission ratio (NTR) of 40 dB.
• Observed nonlinear power dynamics in the microring resonators contributing to nonreciprocity.
• Identified a trade-off between NTR and insertion loss.

Conclusions:

• The demonstrated all-silicon optical diode offers unprecedented nonreciprocity.
• Understanding nonlinear dynamics is key to optimizing device performance.
• This work paves the way for high-performance on-chip optical information processing.