Theory Study Of Photonic Crystal Polarization Beam Splitter

Photonic crystal which consists of different materials arranging periodically in space has the characteristics of photonic band gap and photon localization. Nowadays, a lot of photonic crystal devices are designed based on the characteristics of the photonic crystal, such as photonic crystal fiber, wavelength division multiplexing, photonic crystal filter, photonic crystal switch and photonic crystal polarization beam splitter et al. Photonic crystal polarization beam splitters can split light into two orthogonal polarized states (TE and TM). The photonic crystal polarization beam splitters have been proposed,such as photonic crystal polarization beam splitters based on the self-collimation effect, directional coupler effect, photonic band gap of photonic crystal.The main work of this paper is as following:1. The design and the simulation of Y type two-dimensional photonic crystal polarization beam splitter with same beam splitting radius are presented based on the different properties of the light waves with different polarization modes propagating in two-dimensional photonic crystal. The splitting properties of the PBS are numerically simulated and analyzed by using the finite difference time domain method. It is shown that a high efficient and parallel splitting for TE mode and TM mode can be achieved. The transmission probability can reach over97%for TE mode and over93.5%for TM mode at the wavelength of1.55μm Gaussian incident and the size is only6.3μm×6.8μm. Owing to these excellent features, the PBS makes a promising candidate in the future photonic integrated circuits.2. The design of a polarization beam splitter is presented according to different band gaps with different photonic crystals and photon localization with defect. The defect is led in the corner of photonic crystal waveguide, The splitting properties of the PBS are numerically simulated and analyzed by using the finite difference time domain method and the plane wave expansion method. It is shown that a high efficient splitting for TE mode and TM mode can be achieved. The transmission probability is improved by importing the defect in the corner of photonic crystal waveguide. The transmission probability is over92%for both TE mode and TM mode while the incident wave is Gaussian and the wavelength range is1.5μm to1.58μm. Especially the transmission probability can reach95.5%for TE mode and99%for TM mode at the wavelength of1.55μm Gaussian incidence, and its size is only10μm×11.5μm. The PBS makes a promising candidate in the future integrated optical circuit.