Optical Nonreciprocity in Asymmetric Optomechanical Couplers

Abstract

We propose an all-optical integrated nonreciprocal device on the optomechanical platform with a large nonreciprocal bandwidth and low operating power. The device is based on an asymmetric silicon coupler consisting of two branches. One of them is a conventional strip waveguide fixed on the substrate, and the other is a freestanding nanostring suspended above a groove in the substrate. When light is launched into the coupler, the optical gradient force between the freestanding nanostring and the underlying substrate leads to the deflection of the nanostring, and finally results in destruction of the initial phase-matching condition between the two branches. The suspended branch would achieve distinct deflections when light is incident from different ports. The simulation results show a nonreciprocal bandwidth of 13.1 nm with operating power of 390 μW. With the advantages of simple structure, low power consumption and large operating bandwidth, our work provides a promising solution for on-chip passive nonreciprocal device.

Classical dynamical gauge fields in optomechanics

“…This approach fails in the other regimes since there we are not able to adiabatically eliminate the photons. We also want to mention that both p F = + 2 and p F = -2 are fixed points of equation (8). It turns out that for a resonant drive on site j=1, p F = -2 is an unstable fixed point of equation (8).…”

“…We also want to mention that both p F = + 2 and p F = -2 are fixed points of equation (8). It turns out that for a resonant drive on site j=1, p F = -2 is an unstable fixed point of equation (8). The asymmetry between p + 2 and p -2 is due to the breaking of translational invariance, necessarily produced by the link directions.…”

Waves in hyperbolic and double negative metamaterials including rogues and solitons

“…Rudimentary designs like split ring resonators [26] led to backward-wave effective media with numerous applications are working with a structural asymmetry creating the necessary sharp resonances. Even the concept of non-reciprocity which is utilised in any signal manipulation except for filtering, is based on emulating asymmetries in the macroscopic description [27] mainly through external bias in a variety of oscillating wavelengths from mid-infrared [28], to radio [29] and acoustical [30].…”

Nonreciprocity via Nonlinearity and Synthetic Magnetism

“…The combination of synthetic magnetism and nonlinearity is a general method to show both nonreciprocal transmission and nonreciprocal photon blockade simultaneously, and could be implemented in photonic systems, microwave superconducting circuits, and optomechanical systems [55,56]. Our work can also be extended to a wide range of systems with the Kerr nonlinearity replaced by second-order nonlinearity [57], optomechanical interaction [15][16][17], and the interaction to a two-level quantum emitter [18] or two-level atomic ensemble [19].…”

“…In recent years, many works have reported the construction of optical isolators in an asymmetric nonlinear optical molecule, which consists of two coupled cavities with one of them containing nonlinear interactions, such as Kerr nonlinear interaction [13,14], optomechanical interaction [15][16][17], and the interaction to a two-level quantum emitter [18] or two-level atomic ensemble [19]. To demonstrate nonreciprocity in these isolators, the amplitude of the input field is usually pretty large, and such isolators are constrained by a dynamic reciprocity relation for the input fields with small amplitude [20].…”