Generalized nonreciprocity in an optomechanical circuit via synthetic magnetism and reservoir engineering

TL;DR

This paper demonstrates how optomechanical circuits can achieve nonreciprocal photon transport and amplification by engineering synthetic magnetism and reservoir interactions, paving the way for advanced on-chip optical devices.

Contribution

It introduces a silicon optomechanical circuit that uses phase-controlled driving and dissipative coupling to realize nonreciprocity and optical amplification, advancing integrated photonic technology.

Findings

Achieved 35dB optical isolation in the circuit.

Demonstrated 12dB directional optical amplification.

Showed feasibility of creating topological phases for light and sound.

Abstract

Synthetic magnetism has been used to control charge neutral excitations for applications ranging from classical beam steering to quantum simulation. In optomechanics, radiation-pressure-induced parametric coupling between optical (photon) and mechanical (phonon) excitations may be used to break time-reversal symmetry, providing the prerequisite for synthetic magnetism. Here we design and fabricate a silicon optomechanical circuit with both optical and mechanical connectivity between two optomechanical cavities. Driving the two cavities with phase-correlated laser light results in a synthetic magnetic flux, which in combination with dissipative coupling to the mechanical bath, leads to nonreciprocal transport of photons with 35dB of isolation. Additionally, optical pumping with blue-detuned light manifests as a particle non-conserving interaction between photons and phonons, resulting in directional optical amplification of 12dB in the isolator through direction. These results indicate the feasibility of utilizing optomechanical circuits to create a more general class of nonreciprocal optical devices, and further, to enable novel topological phases for both light and sound on a microchip.