Ultrafast optical switching using parity–time symmetric Bragg gratings

Sendy Phang,Ana Vukovic,Phillip Sewell,Trevor M Benson,Hadi Susanto

doi:10.1364/josab.30.002984

Sendy Phang, Ana Vukovic + Show 3 more

Open Access

https://doi.org/10.1364/josab.30.002984

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Abstract

This paper reports on time-domain modeling of an optical switch based on the parity–time (PT) symmetric Bragg grating. The switching response is triggered by suddenly switching on the gain in the Bragg grating to create a PT-symmetric Bragg grating. Transient and dynamic behaviors of the PT Bragg gratings are analyzed using the time-domain numerical transmission line modeling method including a simple gain saturation model. The on/off ratio and the switching time of the PT Bragg grating optical switch are analyzed in terms of the level of gain introduced in the system and the operating frequency. The paper also discusses the effect the gain saturation has on the operation of the PT-symmetric Bragg gratings.

Highlights

A new class of optical waveguides, that compensates the inherent loss of photonic material by introducing gain, has opened new ways for the realization of functionalities such as unidirectional invisibility [1,2], double refraction and power oscillation [3], lasing and absorber cavities [4,5], isolating and beam-steering behavior [6] and optical switching [7,8,9]
In this paper we focus on the application of optical switching using PT-symmetric Bragg gratings
The purpose of this paper is to investigate and report on the application of the PT Bragg grating as an optical switch, where the switching response is triggered by suddenly switching on the gain in the system

Summary

INTRODUCTION

A new class of optical waveguides, that compensates the inherent loss of photonic material by introducing gain, has opened new ways for the realization of functionalities such as unidirectional invisibility [1,2], double refraction and power oscillation [3], lasing and absorber cavities [4,5], isolating and beam-steering behavior [6] and optical switching [7,8,9]. Several papers mention the possibility of realizing optical switches using PTsymmetric structures, the actual operation of a PT-grating in the time domain has not been numerically demonstrated. This is mainly due to the fact that the modeling of PT-symmetric structures has been done exclusively in the frequency domain using Coupled Mode Theory (CMT) [12,15], the transfer matrix method [1,21,22], Floquet-Bloch theory [3] and modal analysis [23].

THE PT-SYMMETRIC BRAGG GRATING STRUCTURE AND THE TLM MODEL

TIME-DOMAIN MODELING OF PULSE PROPAGATION THROUGH THE PT-BRAGG GRATING

PT BRAGG GRATING AS OPTICAL SWITCH

CONCLUSION