Research on Novel Antimony Sulfide Detectors for Underwater Visible Light Communication

Abstract

Visible Light Communication (VLC) has become an effective underwater communication technology due to its advantages such as fast transmission speed and strong confidentiality. When light propagates underwater, it is prone to scattering, resulting in a decrease in the energy of light propagation with the increase of transmission distance. Therefore, improving the responsiveness of the receiving end is the key technology to achieve underwater VLC. This article first designs a new holographic waveguide focusing system for the front end of the detector, which can effectively improve the signal-to-noise ratio of underwater detectors. Then, we construct a low-cost antimony sulfide thin film detector with weak light detection capability. Based on the built VLC system, the experimental results show that the dark current of the receiver detector is only 10-7 A/cm2, with a 3 dB bandwidth of 220 kHz, a response of 0.2 A/W, and an external quantum efficiency of over 70% in the blue green light band. Therefore, the new antimony sulfide thin film detector combined with a holographic waveguide focusing system can achieve weak light detection of visible light, making it a very effective underwater visible light receiving system.

Keywords

• underwater VLC;Sb₂S₃;detector;holographic grating;optical waveguide