Quantum Squeezing Induced Optical Nonreciprocity

Abstract

We propose an all-optical approach to achieve optical nonreciprocity on a chip by quantum squeezing one of two coupled resonator modes. By parametric pumping a nonlinear resonator unidirectionally with a classical coherent field, we squeeze the resonator mode in a selective direction due to the phase-matching condition, and induce a chiral photon interaction between two resonators. Based on this chiral interresonator coupling, we achieve an all-optical diode and a three-port quasi-circulator. By applying a second squeezed-vacuum field to the squeezed resonator mode, our nonreciprocal device also works for single-photon pulses. We obtain an isolation ratio of > 40 dB for the diode and fidelity of > 98% for the quasi-circulator, and insertion loss of < 1 dB for both. We also show that nonreciprocal transmission of strong light can be switched on and off by a relative weak pump light. This achievement implies a nonreciprocal optical transistor. Our protocol opens up a new route to achieve integrable all-optical nonreciprocal devices permitting chip-compatible optical isolation and nonreciporcal quantum information processing.

Nonreciprocal single-photon band structure

“…Various theoretical schemes and experimental methods have been reported to circumvent the constraint of magnetic fields by using optical nonlinearity [7][8][9][10][11][12][13][14], optomechanical resonators [15][16][17], spinning resonators [18,19], tempospatial modulation of the medium [20][21][22] or chiral quantum optics systems [23][24][25][26][27][28][29][30][31]. In contrast to classical methods, a chiral quantum optics system can realize optical nonreciprocity in the quantum regime [9-11, 24-26, 28] and can perform chiral quantum information processing [32][33][34][35].…”