Journal of Applied Physics

Reconfigurable optical diode based on asymmetrically coupled slow-light waveguide

Shuang Liu, Jun-Fang Wu, Chao Li

Published Jan 25, 2023• 6 citations

Abstract

Controlling the flow of light is fundamental for on-chip optical signal processing. In this paper, we investigate how to realize high contrast, high unidirectional transmission rate, and reconfigurable nonreciprocal light transmission, based on a nonlinear nanocavity asymmetrically side-coupled with a specially designed slow-light waveguide. We analytically and numerically demonstrate that the unusual multiple threshold pump power points for trigging the photon transitions between bistable states, as well as the sensitivity of the dynamic interactions to the relative delay time between the signal light and pump pulse, play crucial roles in this optical diode system. Based on these findings, a high contrast (over 22 dB) and high unidirectional transmission rate (over 70%) optical diode is achieved. More importantly, the conducting direction of the optical diode can be controllably reversed, without the need of changing the signal's wavelength or power as usually done. This approach is promising in the fields of optical information processing and quantum computing.

DOI: 10.1063/5.0133804

Related papers

Realization of Nonlinear Optical Nonreciprocity on a Few-Photon Level Based on Atoms Strongly Coupled to an Asymmetric Cavity

Pengfei Yang, Xiuwen Xia, Hai Yan He +8 more

Optical nonreciprocity is important in photonic information processing to route the optical signal or prevent the reverse flow of noise. By adopting the strong nonlinearity associated with a few atoms in a strongly coupled cavity QED system and an asymmetric cavity configuration, we experimentally demonstrate the nonreciprocal transmission between two counterpropagating light fields with extremely low power. The transmission of 18% is achieved for the forward light field, and the maximum blocking ratio for the reverse light is 30 dB. Though the transmission of the forward light can be maximized by optimizing the impedance matching of the cavity, it is ultimately limited by the inherent loss of the scheme. This nonreciprocity can even occur on a few-photon level due to the high optical nonlinearity of the system. The working power can be flexibly tuned by changing the effective number of atoms strongly coupled to the cavity. The idea and result can be applied to optical chips as optical diodes by using fiber-based cavity QED systems. Our work opens up new perspectives for realizing optical nonreciprocity on a few-photon level based on the nonlinearities of atoms strongly coupled to an optical cavity.

arXiv:1906.00123Physical Review LettersDec 4, 2019134 citations

Broad-bandwidth, reversible, and high-contrast-ratio optical diode

Chao Li, Min Wang, Jun-Fang Wu

Fano resonance is widely used to realize high-contrast nonreciprocal transmission. However, resonance-enhanced all-optical diodes (AOD) are bandwidth-limited, and their transmission rates are normally low, which restricts realistic application. In this Letter, we analytically and numerically demonstrate that this limitation can be overcome once multistability of cascaded nonlinear cavities is appropriately excited. By precisely molding the transiting of the signal light between multistable states, a high-contrast-ratio, high-unidirectional-transmission-rate, and reversal-controllable AOD is achieved with a bandwidth over 2.4 nm, which is about two orders of magnitude wider than the reported results obtained by other methods based on Fano resonances. This approach may pave the way for dynamic control of on-chip all-optical information processing.

Optics LettersJan 10, 201724 citations

Reconfigurable nonreciprocal light transmissions for multiband signals

Jun-Fang Wu, Yang Si-fang, Chao Li

In practical signal processing and optical computing, multiple signals in different frequency bands usually require nonreciprocal transmission. However, to date, most proposed nonreciprocal systems based on nonlinear resonators only support a single working band. Here, we demonstrate that nonreciprocal light transmissions can be realized in multiple distinct spectral bands, solely via a single nonlinear multimode nanocavity triggered by a control pulse. More importantly, our results further show that the multiband nonreciprocal light transmission is reconfigurable, with high contrasts and reasonably broad per-band bandwidths. The underlying physical mechanism is revealed. The approach presented here is promising in the fields of optical signal processing, quantum computing, optical routers, and rectifiers.

Optics ExpressMay 25, 20260 citations

Quantum Squeezing Induced Optical Nonreciprocity

Lei Tang, Jiang-Shan Tang, Mingyuan Chen +3 more

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 χ^{(2)}-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 quasicirculator. 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 quasicirculator, 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.

arXiv:2110.05016Physical Review LettersFeb 23, 2022191 citations

Quantum optical diode with semiconductor microcavities

H. Z. Shen, Y. H. Zhou, X. X. Yi

The semiconductor diode, which acts as an electrical rectifier and allows unidirectional electronic transports, is the key to information processing in integrated circuits. Analogously, an optical rectifier (or diode) working at specific target wavelengths has recently become a highly sought-after device in optical communication and signal processing. In this paper, we propose a scheme to realize an optical diode for photonic transport at the level of few photons. The system consists of two spatially overlapping single-mode semiconductor microcavities coupled via ${\ensuremath{\chi}}^{(2)}$ nonlinearities. The photon blockade is predicted to take place in this system. These photon blockade effects can be achieved by tuning the frequency of the input laser field (driving field). Based on those blockades, we analytically derive the one- and two-photon current in terms of a zero and a finite time-delayed two-order correlation function. The results suggest that the system can serve as a one- and two-photon quantum optical diode which allows transmission of photons in one direction much more efficiently than in the other.

arXiv:1403.5620Physical Review AAug 26, 2014120 citations

Squeezing-induced nonreciprocal transparency and the slow-to-fast-light switch

Deng Wang, Yin Bin, Jie Wang +4 more

We propose a theoretical method to realize nonreciprocal light transmission in an optomechanical device assisted by directional quantum squeezing. Specifically, we consider the device consisting of an optomechanical resonator and a nonlinear optical resonator with directional pumping. We find that optical squeezing occurs along the pump direction when the nonlinear resonator is directionally pumped, enabling nonreciprocal light transmission as well as nonreciprocal group delay (slow light) or advancement (fast light). Furthermore, we find that the efficiency of the second-order sidebands can be enhanced in one direction compared with the opposite direction. Our work provides a promising design for the application of directionally squeezed optomechanical devices in nonreciprocal optical communication and signal processing.

Physical Review AMay 15, 20254 citations