摘要:
Guided-wave photodetectors based on absorption of infrared photons by mid-bandgap states in non-crystal semiconductors. In one example, a resonant guided-wave photodetector is fabricated based on a polysilicon layer used for the transistor gate in a SOI CMOS process without any change to the foundry process flow (‘zero-change’ CMOS). Mid-bandgap defect states in the polysilicon absorb infrared photons. Through a combination of doping mask layers, a lateral p-n junction is formed in the polysilicon, and a bias voltage applied across the junction creates a sufficiently strong electric field to enable efficient photo-generated carrier extraction and high-speed operation. An example device has a responsivity of more than 0.14 A/W from 1300 to 1600 nm, a 10 GHz bandwidth, and 80 nA dark current at 15 V reverse bias.
摘要:
A non-paraxial Talbot spectrometer includes a transmission grating to receive incident light. The grating period of the transmission grating is comparable to the wavelength of interest so as to allow the Talbot spectrometer to operate outside the paraxial limit. Light transmitted through the transmission grating forms periodic Talbot images. A tilted detector is employed to simultaneously sample the Talbot images at various distances along a direction perpendicular to the grating. Spectral information of the incident light can be calculated by taking Fourier transform of the measured Talbot images or by comparing the measured Talbot images with a library of intensity patterns acquired with light sources having known wavelengths.