Title :
Unidirectional Transmission Based on a Passive PT Symmetric Grating With a Nonlinear Silicon Distributed Bragg Reflector Cavity
Author :
Ye-Long Xu ; Liang Feng ; Ming-Hui Lu ; Yan-eng Chen
Author_Institution :
Dept. of Mater. Sci. & Eng., Nanjing Univ., Nanjing, China
Abstract :
A silicon waveguide consisting of passive parity-time (PT) symmetry optical potentials connected with a distributed Bragg reflector (DBR)-based resonator is proposed to achieve nonreciprocal waveguide transmission. The unidirectional reflectionless waveguide implementing PT symmetry is discussed by consistent coupling mode theory and finite-difference time-domain (FDTD) simulation results. Due to the high field confinement in the DBR cavity, transmission of a light pulse through the device is analyzed in the nonlinear optical regime using FDTD simulations. The combination of the nonlinear DBR cavity and the passive PT symmetric grating results in unidirectional transmission in the silicon waveguide, while still keeping the reflection minimum in the desired direction. The numerical simulation shows an extinction ratio of about 20 dB at the telecom wavelength of around 1550 nm.
Keywords :
diffraction gratings; distributed Bragg reflectors; elemental semiconductors; finite difference time-domain analysis; optical waveguides; silicon; DBR cavity; distributed Bragg reflector cavity; finite-difference time-domain simulation; high field confinement; nonlinear silicon; passive PT symmetric grating; passive parity-time symmetry optical potentials; silicon waveguide; unidirectional transmission; Cavity resonators; Distributed Bragg reflectors; Modulation; Nonlinear optics; Optical resonators; Optical waveguides; Silicon; Silicon waveguide; nonlinear distributed Bragg reflector (DBR) cavity; unidirectional reflectionless parity-time (PT) grating;
Journal_Title :
Photonics Journal, IEEE
DOI :
10.1109/JPHOT.2013.2295462
