A photodetector for visible light communication with bandpass filtering function

Abstract

The invention relates to the technical field of visible light photoelectric detectors, in particular to a photoelectric detector with a band-pass filtering function for visible light communication. The photoelectric detector with the band-pass filtering function for visible light communication comprises a substrate, a buffer layer, an n-type GaN layer, an InGaN / GaN multi-quantum well active layer, a p-type GaN layer, P-type electrodes and a one-dimensional defect mirror symmetry photon crystal filter or the one-dimensional defect mirror symmetry photon crystal filter, and N-type metal electrodes, wherein the buffer layer, the n-type GaN layer, the InGaN / GaN multi-quantum well active layer and the p-type GaN layer sequentially grow on the substrate by an epitaxial growth method; and by electron beam evaporation equipment, the P-type metal electrodes and the one-dimensional defect mirror symmetry photon crystal filter are deposited on the p-type GaN layer, or the one-dimensional defect mirror symmetry photon crystal filter is deposited on the back surface of the substrate which is transparent to a visible light; and an N-type metal electrode is deposited on the n-type GaN layer. The filter can carry out selective filtering on incident signals, and filters out interference signals which are not in a VLC system signal source emission spectrum range; meanwhile, a filter does not need to be added; and the integration level is high.

Description

technical field [0001] The present invention relates to the technical field of visible light photodetectors, and more specifically, to a photodetector for visible light communication with a band-pass filtering function. Background technique [0002] In recent years, as white light emitting diodes (Light Emitting Diode, LED) are applied to the signal transmitting end of communication systems, visible light communication technology (Visible Light Communication, VLC) has gradually attracted people's attention. Because white light-emitting diodes (LEDs) have high response sensitivity and excellent modulation characteristics, while they are used as lighting appliances, they can also modulate signals into their emission bands for transmission, so that white LED lighting and communication can be realized. Function. Compared with the current wireless communication technologies such as WiFi, VLC has a series of advantages such as (1) fast transmission rate; (2) good confidentiality;...

AI Technical Summary

Problems solved by technology

[0003] However, in the current VLC technology, some outstanding problems are exposed: in the VLC communication system, there are strong background noise and inherent circuit noise; at the same time, with the increase of the transmission distance, the signal received by the optical receiver It gradually becomes weaker, often resulting in a signal noise ratio (Signal Noise Ratio, SNR) received by the receiving end less than 1

However, due to the background noise interference that usually exists in the working environment of the visible light communication system, the signal-to-noise ratio of using a GaN-based LED as a detector at the receiving end of the VLC system is too low; at the same time, due to the polarization electric field in the active region of the quantum well , and the expansion of the depletion layer to the p-type GaN region, resulting in a shift in the peak wavelength of the response spectrum of the LED chip, and a strong photoresponse in the short wavelength region, which is not conducive to improving SNR

Images