Compact wavelength de-multiplexer design using slow light regime of photonic crystal waveguides

Ahmet E Akosman,Ekmel Ozbay,Hamza Kurt,Mehmet Mutlu

doi:10.1364/oe.19.024129

Abstract

We demonstrate the operation of a compact wavelength de-multiplexer using cascaded single-mode photonic crystal waveguides utilizing the slow light regime. By altering the dielectric filling factors of each waveguide segment, we numerically and experimentally show that different frequencies are separated at different locations along the waveguide. In other words, the beams of different wavelengths are spatially dropped along the transverse to the propagation direction. We numerically verified the spatial shifts of certain wavelengths by using the two-dimensional finite-difference time-domain method. The presented design can be extended to de-multiplex more wavelengths by concatenating additional photonic crystal waveguides with different filling factors.

Highlights

Photonic crystals (PCs) are strongly wavelength sensitive, high-index contrast dielectric materials
We demonstrate the operation of a compact wavelength demultiplexer using cascaded single-mode photonic crystal waveguides utilizing the slow light regime
The presented design can be extended to de-multiplex more wavelengths by concatenating additional photonic crystal waveguides with different filling factors

Summary

Introduction

Photonic crystals (PCs) are strongly wavelength sensitive, high-index contrast dielectric materials. There have recently been various techniques studied by exploiting the different aspects of the wavelength selectivity features of PCs. For example, PC waveguide (PCW) directional couplers employing two parallel waveguides have been proposed and investigated for wavelength selectivity [8,9,10]. A rather different approach can be adapted such that the cutoff frequency of the PCW mode can be changed by structural modifications, for example by changing the radii of the border holes. This principle has been implemented in Refs. The disadvantages of these early proposed DEMUX solutions such as occupying large areas or utilizing complex operation principles can be partially avoided by allowing PCW to operate at the close proximity of the slow light region

Proposed wavelength selective structure

Conclusion