Analysis And Research Of GaN-based Guided-mode Resonance Filters

Guided-mode resonant filter because of its simple structure, small size, ease of integration, and the results that narrow-band filter and high diffraction efficiency, has attracted widespread attention. And with the development of semiconductor materials and MEMS technology, the use of guided-mode resonance effect based on the third generation of semiconductor material gallium nitride on behalf of tunable optical filters, for promoting the development of optical communication and optical fields related change is necessary.In the light of the rigorous coupled wave theory and equivalent medium theory, calculation and derived the guided mode resonant resonance condition. Based on the GaN grating, the reflection of the theoretical design of guided-mode resonant filters and their optical properties were studied. First, a detailed analysis of the diffraction waves in meeting with conduction-mode phase matching conditions, the impact of the system is designed to emphasize the weak modulation, cover type, relief-type and three-waveguide grating structure on the spectral properties of the resonance wavelength. Studies have shown that: for a high spatial frequency waveguide grating, the modulation coefficient on the coupling strength, reflectance response of diffraction efficiency, the width of the bandwidth of the regulatory effect; grating and the waveguide film thickness, location and number of sidebands can be played on the formant inhibition of different degrees. In addition, the incident mode, the duty cycle of the grating thickness and resonant reflection filter of the guided mode are also discussed. Finally, based on the grating period and the incident light angle to the influence of the working wavelength, designed the two kinds of GaN grating and the electrostatic actuator integrated tunable optical filter structure. One is the use of comb actuator with a single layer of gallium nitride grating integrated intensity modulation, by application of the actuation voltage pull grating period, to achieve resonant wavelength matches the position of the grating period in the range of 552nm-568 nm adjustable grating period filters, which are in line width 3nm or less. Another use of the actuator and the plate capacitor with anti-reflection layer relief type grating integrated, by applying actuation voltages controlling the angle of incidence angles, to achieve resonance filter covering optical communications C band(1530nm-1565nm), and the half-width of the peak satisfy angle 100 GHz DWDM systems require channel tunable filter. Provides data support for the design of the new filter.