Performance enhancement of photodetector using defect subwavelength metallic Grating

A defect subwavelength metallic grating is proposed to improve light transmittance and quantum efficiency, leading to better responsivity of photodetector at 1550 nm wavelength. We mainly focus on the refractive index of rectangle defect influence on performance. With optimizing the parameter, responsivity can be increased 4.5 times, compared to the photodetector with uniform subwavelength metallic grating. In addition, response bandwidth of the structure can reach 76 GHz.