The Design And Research On Two-dimensional Magnetic Photonic Crystal Devices

With the rapid development of modern science and technology, magneto-photonic crystal(MPC) devices play an important role in microwave and optical information technology. It has been regarded as the indispensable basic components of integrated optical system, providing a basis for the development of new photonic technology. At present, the main researches are the one-way features of MPCs and various optical-related phenomena which are the frontier of researches in photonics.In this paper, we start from the microscopic properties of magneto-optical(MO) materials. Then based on Maxwell's equations to derive MO material permeability tensor and based on photonic crystal(PhC), we put forward a new kind of two-dimensional photonic-crystal MO cavity structure which uses only a single MO material rod to realize the function of photonic devices. First of all, the plane wave expansion method was used to optimize the side length and rotation angle of the square rods forming the PhC to achieve maximum forbidden band: we have designed two kinds of structure forms. One kind of two-dimensional PhC with square rod of silicon has larger TE band gap whose side length of the square rods is 0.3a and reference medium rod axis direction 41 degrees; another is with square rod of air having a larger TM band gap for which the side length of the square rods is 0.8a. Second, analyzing the MO cavity mode by finite element method, we get a pair of harmonic degenerated modes with mutual vertical polarization directions, and discuss the influences of the parameters for the MO cavity structure, properties of MO materials, and the external bias magnetic field on transmission performance.With the external bias magnetic field, we study and design three kinds of MO devices:(1) magnetic-controlling either-or optical way PhC switch;(2) magnetic-controlling duty-ratio tunable, mutually reversed-phase, double-way, optical-clock signal generator;(3) MO PhC modulator. We use the plane wave expansion method and the finite element method to calculate the operating characteristic of these PhC-MO devices. The numerical results show that: the switch of light path gating switch contrast up to 48 dB and isolation of 46 d B, the switching time is in microsecond or sub-microsecond; the optical-clock signal generator's logic contrast is up to 48 dB. The rise time of pulse depends on the changing rate of the bias magnetic field, always in microsecond or sub-microsecond, and the clock frequency is equal to that of the bias magnetic field; the modulation sensitivity of the PhC magnetic modulator can reach 1.81 104 [w/T], and the corresponding modulation depth is 0.787, showing good modulation performance.