Coupling Efficiency Analysis of Different Top Coupling Grating for Quantum Well Infrared Photo-Detector

The relative coupling efficiency of different top coupling grating for quantum well infrared photo-detector is calculated by finite difference time domain algorithms. The relative coupling efficiency respect to the grating parameters, such as, grating period and grating depth is analyzed for both square lattice and hexagonal lattice structure gratings. By comparison, it can be concluded that the optimization grating parameters is differential for different grating structure.