PCRR Based Bandpass Filter for C and L+U Bands of ITU-T G.694.2 CWDM Systems

S Robinson,R Nakkeeran

doi:10.4236/opj.2011.13024

Abstract

A two Dimensional (2D) Photonic Crystal Ring Resonator (PCRR) based Bandpass Filter (BPF) is designed to cover C and L+U bands of Coarse Wavelength Division Multiplexing (CWDM) systems. It is devised with two quasi waveguides and a circular PCRR. The simulation results are obtained using 2D Finite Difference Time Domain (FDTD) method. The Photonic Band Gap (PBG) is calculated by Plane Wave Expansion (PWE) method. The BPFs allow the entire C-band (BPF1) and L+U bands (BPF2), which are extended from 1530 to 1565 nm (C band) and 1565 to 1675 nm (L+U bands). The computed bandwidth of BPF1 and BPF2 is 32 nm and 97 nm respectively. The size of the device is minimized from a scale of few tens of millimeters to the order of micrometers. The overall size of the BPF1 is around 12.8 µm × 11.4 µm and 11.4 µm × 11.4 µm for BPF2.

Highlights

Two Dimensional Photonic Crystals (2DPCs) have acquired worldwide fascinating interest in the past two decades due to the existence of band gap and the capability to control the electromagnetic waves [1,2]
The periodicity of the structure and the completeness of the band gap are revealed by introducing a defects, which allows the propagation of light in the Photonic Band Gap (PBG) region
The PBG is the main characteristics of photonic devices and can be observed using the band diagrams obtained through the Plane Wave Expansion (PWE) method

Summary

Introduction

Two Dimensional Photonic Crystals (2DPCs) have acquired worldwide fascinating interest in the past two decades due to the existence of band gap and the capability to control the electromagnetic waves [1,2]. The periodicity of the structure and the completeness of the band gap are revealed by introducing a defects (point or line or both), which allows the propagation of light in the PBG region. This can lead to design PC based optical devices in the PBG region [4]. The Multiplexer and/or Demultiplexer may be designed using a series of BPFs which transmits only a specific wavelength In the literature, it has been done by introducing point defects and/or line defects, for L-Band, biperiodic structures [22,23,24] and using liquid crystal photonic band gap fibers [25]. The structure design of BPFs and simulated results are discussed in Section 3 and Section 4 concludes the paper

Numerical Analysis

PWE Method

FDTD Method

PCRR Based Bandpass Filter

Findings

Conclusions