Study On The Coupling Characteristics Of Photonic Crystal Waveguide And Wavelength Division Multiplexing

Photonic crystal is a new type of artificial materials. Research shows that photonic band gap and photon localization are the two basic characteristics of photonic crystal. Photonic crystal waveguide is the important component of realizing the transmission of light and photonic integrated. Coupling is an important energy transfer mode of light in photonic crystal.It is significant for us to study the photonic crystal waveguide and the coupling characteristics. This paper focuses on the transmission characteristics of photonic crystal waveguide with the two waveguides coupling structure characteristics and a new type of high efficiency heterostructure four-wavelength wavelength division multiplexing is further proposedThe main research works are as follows:1. We calculated the photonic band gap of two-dimensional photonic crystal with a square lattice and the relation between photonic band gap for TM polarization and the radius of dielectric cylinder with refractive index. The photonic band gap of two-dimensional photonic crystal with a triangular lattice and the relation between photonic band gap and the radius of air holes is also calculated. We analyzed the photonic band gap for TM polarization of two-dimensional photonic crystal of square lattice with point defects and simulated the defect states of two-dimensional photonic crystal.2. The transmission spectra of TM mode in the straight waveguide,90 degrees bend waveguide with square lattice of dielectric rods and 60 degrees bend waveguide with triangular lattice of dielectric rods are analyzed. We also calculated the transmission spectra of TE mode in 60 degrees bend waveguide with triangular lattice of air holes. The electric field distributions of waves transmitting in straight waveguide and various bent waveguides are simulated3. We analyzed the coupling and decoupling feather of the two photonic crystal waveguides coupling structure. We can control the light output port as through-state or cross-state by setting the coupling length. The coupling feather is validated by the finite-difference time-domain method. The effect of the coupling length and the radius of coupling structure for coupling feather are studied.4. A new type of high efficiency heterostructure four-wavelength wavelength division multiplexing is designed based on coupling characteristics of photonic crystal waveguide. The plane wave expansion method and the finite-difference time-domain method are utilized to simulate and analyze the properties of the device. It consists of two parts:straight waveguide and 90 degrees bend waveguide. It is shown that four waves can be separated by the wavelength division multiplexing.We further got the higher transmittance by optimizing the structure. Its size is very small and may have potential applications in future integrated circuits.