Abstract
In the thesis, we propose a new device structure using waveguide metallic photonic crystals monolithically integrated on a Ge photodiodes to implement a wavelength selective NIR photodetector. This metallic nanoplasmonic grating is capable of selectively coupling normally incident light to the waveguide layer for enhancing light transmission to the bottom Ge photodiodes at a specific wavelength, which can be controlled by the grating period. Without changing the thickness of device layers, this structure can be utilized for implementing an on-chip spectrometer. The grating period is designed from 750 nm to 950 nm, and the wavelength shift from 1.22 μm to 1.5 μm. The FWHM of the transmission band is less than 30 nm. By measuring the responsivity, we have successfully demonstrated devices at grating period 840nm and 860nm, corresponding to the resonance wavelength at 1315nm and 1350nm respectively.