Open AccessOptical isolation enabled by two time-modulated point perturbations in a ring resonator
Author(s) -
Arezoo Zarif,
Khashayar Mehrany,
Mohammad Memarian,
Hesam Heydarian
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.392914
Subject(s) - isolator , resonator , optics , optical isolator , modulation (music) , physics , wavelength , ring (chemistry) , phase modulation , materials science , acoustics , phase noise , electronic engineering , optical fiber , engineering , chemistry , organic chemistry
In this paper we achieve non-reciprocity in a silicon optical ring resonator, by introducing two small time-modulated perturbations into the ring. Isolators are designed using this time-perturbed ring, side-coupled to waveguides. The underlying operation of the time-modulated ring and isolator is analyzed using Temporal Coupled Mode Theory (TCMT). The TCMT is used to find the angular distance, phase difference and thickness of the two time-modulated points on the ring resonator and also to find and justify the optimum values for the modulation frequency and amplitude, which yields maximum isolation in the isolator arrangements. Insight into the major players that determine isolation are also presented, with the aid of TCMT. Our proposed structure is much simpler to implement compared to other ring-based optical isolators, as it does not require spatio-temporal modulation, or large regions with modulation, but only two point perturbations on the ring. All results are obtained using realistic values of modulation and validated using an in-house full-wave solver. We achieve 21 dB isolation and -0.25 dB insertion loss at the telecommunication wavelengths.