A high-sensitivity and a high-power photo-receiver is preferred in coherent lidar system. In this work, we demonstrate top-illuminated APDs, which can simultaneously exhibit low excess noise (k<0.1) and wide 3-dB bandwidth (14GHz) with high responsivity (6.7A/W) under the operation at saturation output (3 mA).
Superior performance of digital alloy APDs is attributed to the formation of "minigaps" in the material bandstructure. However, no improvement is observed in dilute nitride APDs in presence of minigaps. We propose criteria which can judge the effectiveness of these minigaps.
A previously reported CMOS-compatible dual avalanche photodiode design is exploited to develop a maximum-likelihood spectral-sensing algorithm, which maps the dual photocurrents to the monochromatic light’s wavelength. Optimization over the reverse biases of the two APDs yields a spectral resolution of 10 nm within 440-650 nm.
Avalanche photodiodes are fabricated and characterized, using a single diffusion fabrication process with the surface patterned by selective area growth prior to diffusion. Raster mapping of the photocurrent near the breakdown voltage is used to characterize the electric field distribution in the multiplication layer.
We study the optical and electrical overload of high-speed InGaAs/InAlAs avalanche photodiodes for PON applications. We achieve robust optical overload at +4dBm with successful suppression of surface charge accumulation and multiplication-layer junction breakdown. Physical model of surface state charge accumulation under optical stress is presented.
In this work, low frequency noise spectroscopy and temperature varied photoluminescence was used to characterize the defect levels in InGaAsBi photodetector. Both of these independent techniques have found some deep levels, and some of which are the consistent.