Study Of The Characteristics Of Photonic Crystals Resonant Cavity Using Fdtd Method

As a periodic electrolyte structure with the characteristics of photonic band gap, photonic crystal has its own advantages in the transmission rate, bandwidth and loss, etc over semiconductor materials. By using the photonic crystal, high-performance optical devices can be otained, which have profound impact on the optical communications, optoelectronics, and information science. The finite difference time domain (FDTD) is one of commonly used methods for solving the electromagnetic. In the studying of transmission characteristics of photonic crystals resonator, FDTD method can real-timely observe the intensity distribution of light field, which also has the advantages of high computing efficiency and broadband results which can be directly obtained.In this paper, through using FDTD method, the transmission characteristics of two dimensional square photonic crystal were discussed. By considering the characteristics of photonic crystal band gap, the photonic crystal ring resoriator(PCRR) structure model and the transmission characteristics of PCRR were analyzed to designed photonic crystal devices with different structures. The main content includes:1). The FDTD method and perfectly matched layer(PML) absorbing boundary condition were used. When TM waves incidented on the photonic crystal surface, the transmission curve of photonic crystal were calculated by fast fourier transform(FFT). Moreover, the distribution of light intensity was simulated.2). By the introduction of ring line defects and straight waveguide in photonic crystals, PCRR model was constructed, and the transmission characteristics of photonic crystal resonant cavity were analyzed. Besides, the effects of scattering media column, radius of coupling rods and dielectric constant on the transmission characteristics of PCRR were also discussed.3). Based on PCRR and photonic crystal waveguides, The model of a three-wavelength photonic crystal wavelength division multiplexer / demultiplexer was established, which can merge/separate effectively three different frequencies beams. Following, a photonic crystal beam splitter was design, and the splitting properties have been studied. Numerical results show that uniform splitting can be achieved by using two PCRR with the symmetrical structure. Forward and backward dropping of the photonic crystal filters can be achieved by adjusting the number of the coupling medium rod between the two PCRR.