Analysis of the tunable filtering properties of a photonic crystal with symmetric dual defects

Abstract

A dual channel tunable filter structure has been proposed based on the local characteristic of photonic crystals and the mesoscopic calender effect of photonic crystals. The optical transmission characteristics of the filter have been derived theoretically using the transfer matrix method, and the relationship between the transmission spectrum and structural parameters of photonic crystals has been established. Problems how the mesoscopic calender effect influences the transmission spectrum of photonic crystals with dual defects have been discussed and the structure of photonic crystals has been numerically simulated. The emulational results show that defect modes have a blue shift with the increase of the incident angle, while they have a red shift with the increase of dielectric layers' refractive index or geometrical thickness. When in photonic crystals occurs axial stretched strain, the locations of defect modes will move towards long wavelength side, but the values of defect peaks keep constant generally. Thereby, the filter's tunable property has been verified. This photonic crystal filter with good tunability has a compact structure, which may provide a certain theoretical reference for the design of photonic crystal lasers and sensors.