Regular Article

Enhancement of coupling ratios in SOI based asymmetrical optical directional couplers

Photonics Research Lab, Department of Physics, Osmania University, Hyderabad, India

^* e-mail: pnrphysics84@osmania.ac.in

Received: 12 May 2017
Received in final form: 22 October 2017
Accepted: 10 November 2017
Published online: 29 November 2017

Abstract

A novel design of slab structured asymmetrical optical directional coupler with S-bend waveguides on silicon-on-insulator (SOI) platform has been designed by using R-Soft CAD tool. Beam propagation method (BPM) is used for light propagation analysis. The simulation results of asymmetrical optical directional couplers are reported. We find that the asymmetrical directional coupler has lower coupling ratios and higher extinction ratios with waveguide parameters such as width, wavelength, waveguide spacing, and coupling length. Simulation results designate that the coupling efficiency for transverse electric (TE) and transverse magnetic (TM) modes can reach about more than 95% and extinction ratio about 6 dB when the coupling length is 6 mm for both the polarization modes and insertion loss is 17 dB with same coupling length 6 mm at central wavelength 1550 nm.