Broadband all-optical isolator based on all-passive graded index

Nazari, Fakhroddin; Karimkhani, Arash; Mobini, Alireza; Samsami-Khodadad, Farid

doi:10.1016/j.spmi.2017.09.023

Cited by 3 publications

(2 citation statements)

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“…The main obstacle for the application of the developed optical integrated circuits with magneto-optical isolators in a practical system is their low output intensities, due to high losses. Moreover, to implement asymmetrical light propagation, in recent years, nonlinear 2D-photonic crystals [5][6][7][8][9][10][11], nonlinear parity-time symmetric (PTS) structures [12][13][14][15][16][17][18], tunable plasmonic waveguides [19][20][21], optomechanical and optoacoustic configurations [22][23][24][25], structures involving indirect interband transitions [26], asymmetric linear passive structure [27], nonlinear passive graded-index [28], asymmetrically light-absorbing structures using nonlinear materials [29] have been used. Most of the nonlinear PhC based isolators, the Fano resonances created via the interplay between the non-linear effect and the asymmetry round-trip in the structure play a critical role in the isolator efficiency, and its isolation rate [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…In [27], the heterojunction between two different silicon 2D squarelattice PhC slabs with directional band gap mismatch and different mode transitions results in an integrated optical isolator. Furthermore, using a passive nonlinear graded refractive index proposed a cavity-less based optical isolator that operates in a wide frequency range [28].…”

Section: Introductionmentioning

confidence: 99%

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Tunable optical isolator using Graphene-photonic crystal-based hybrid system

2021

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In this article, an optical isolator is designed and simulated based on a hybrid configuration of the photonic crystal (PhC) and graphene. The PhC membrane is a hexagonal lattice of air holes arranged in a nonlinear silicon substrate. To provide a nonreciprocal transmission (optical isolator), breaking the symmetry of the light propagation path (the forth and back routes) is an essential condition. Here, the asymmetrical round trip of the light propagation and the Kerr-nonlinear effect are employed to obtain asymmetric propagation. The isolator structure includes a PhC waveguide that asymmetrically side-coupled to a specific embedded cavity. Then, to attain a tunable asymmetric transmission, a Nano-layer of graphene is located on the top of the mentioned PhC configuration. By altering the chemical potential of graphene one can control the isolation rate, frequency, and bandwidth of offered structure and thus possess a tunable optical isolator. The simulation results show that a 0.5 nm frequency shift can attain by the graphene chemical potential alterations from 0.45 eV to 0.65 eV in which it is suitable for Dense Wavelength Division Multiplexing (DWDM) communication and integrated optical circuits. Furthermore, as another advantage, a high forward normalized transmission (0.6) has resulted in a large average isolation rate of 32.5 dB due to low losses of the proposed structure.

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