Array OAM-coded data transmission is a potential method to improve the information capacity and has important research value for realizing high-capacity optical communication.However,there are problems related to high system complexity and inflexible regulation.In this paper,an optical communication method and system for flexible tunable array multi-channel OAM-coded image transmission is proposed.In order to obtain an array beam,we first generate an array Gaussian beam using a specially designed Dammann grating instead of a conventional way of generating an array Gaussian beam through the combination of multiple beam-splitting prisms and mirrors,which reduces the complexity of the system.Subsequently,we obtained a 2×2 array vortex beam by designing an integrated vortex holographic grating and matching the generated array Gaussian beam.In our 2×2 array vortex setup,each subchannel of the array vortex beam can be freely and independently regulated,and the experimental setup is simple and easy to operate.Based on this,we built an array OAM-coded image transmission system to encode and transmit a 110-pixelxl10-pixel 256-grayscale puppy image.The experimental results show that zero-BER(bit error rate)image recovery is achieved without any interference;in the presence of turbulence interference,the BER of image transmission is 0.001;in the presence of severe turbulence interference,the BER reaches 0.089.To address the problem of high transmission BER in harsh environments,in our future work,we will consider introducing a deep learning technique to improve the accuracy of the calculation of the bright'petals'of the array,to reduce the BER and improve the transmission performance.In addition,the use of a 2×2 array optical mode expands the information capacity by a factor of 4 compared with the conventional single-channel optical coding data transmission method.In the follow-up work,m×m(m＞2)array OAM-coded information transmission will be investigated to further improve the information capacity.The results of this research can provide an important reference for realizing high-capacity optical communication.
关键词
涡旋光束/阵列光束/轨道角动量/光通信
Key words
vortex beam/array beam/orbital angular momentum/optical communication
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