Computational temporal ghost imaging for long-distance underwater wireless optical communication

Abstract

This work proposes an underwater wireless optical communication (UWOC) system based on computational temporal ghost imaging (CTGI) and a low-bandwidth high-sensitivity avalanche photodiode. After measuring the attenuation coefficient of water, a series of neutral density filters is used to attenuate the optical power to estimate the distance of UWOC. Experimental results show that under the conditions of 4 GHz transmitting frequency and 144.37 m estimated distance, through CTGI, we can achieve error-free transmission, and the peak signal-to-noise ratio is much higher than on–off keying. Additionally, after adopting the segmented reconstruction method, under the condition of 4 GHz transmitting frequency and 193.10 m estimated distance, we can also achieve error-free transmission. At the same time, the relationship between UWOC performance and the number of segments is also studied. This research provides a novel UWOC technique that enables high-frequency transmission signals to be detected by a low-bandwidth photodetector for long-distance UWOC.

Improved Synchronization Scheme for the Photon- Counting-Based Underwater Optical Wireless Communication System

“…At the receiver, a PMT (Hamamatsu CR315) is adopted to detect the number of received photons. To attenuate the optical power and simulate long-distance transmission, an optical attenuator (Thorlabs NE30A with an optical density of 3.0) is placed in front of the PMT [26]- [28]. An optical filter (Smerock FF01-523/20-25) is also employed to filter out the light of other wavelengths.…”

BM3D-based color computational ghost imaging

“…Ghost imaging, also known as correlation imaging, is one of the frontiers and hot spots in the field of quantum optics in recent years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Ghost imaging is a new imaging technology based on the correlation characteristics of quantum entanglement or classical light field fluctuations, which can obtain the target object information non locally through the intensity correlation between the reference light field and the target detection light field.…”

Quasi-Tandem Photodetector with Tunable Narrowband Response and Submicrosecond Response Time: Charge-Selected Transmitting Narrowing

“…The liner dynamic range (LDR) recorded for the optimized devices was as high as 162 dB, and the response time was 39.5/60.8 μs. Devices providing ultra-fast response and characterized by low time delays are attractive for use in the field of optical communication and military applications as these can be used to achieve optimized signal overlap, trailing, and misjudging. ,− However, the response speed of the reported NPDs was severely limited, and therefore a big progress needs to be made for ultra-fast NPDs to meet the application requirements. Meanwhile, the role of the quasi-tandem structure in improving the performance and response time of the devices and the applicability of the quasi-tandem system in the field of fabrication of tunable NPDs are yet to be explored in detail.…”