物理学报2017，Vol.66Issue(14)：353-362,10.DOI:10.7498/aps.66.144102
基于混合光模式阵列的自由空间编码通信
Free-space optical communication based on hybrid optical mode array encoding
摘要
Abstract
The generation, propagation and application of optical vortex have been hot research topics in recent years. Optical vortex carries orbital angular momentum (OAM) that potentially increases the capacity and the spectral efficiency of optical communication system as a new degree of freedom. The optical vortex can be used not only as information carrier for space-division multiplexing, but also for encoding/decoding. We present a novel free-space optical communication system based on hybrid optical mode array encoding/decoding. The array includes four modes that can easily be identified by image processing. The four modes are Gaussian beam, single optical vortex, and two different composite optical vortices. In this paper, the computer generated hologram (CGH) of the hybrid optical mode array is generated based on the object-oriented conjugate-symmetric extension Fourier holography. When the CGH is loaded onto the electronic addressing reflection-type spatial light modulator (SLM), a single light beam illuminates the SLM, and the desired hybrid optical mode array is generated. In the experiment, a 32 pixel×32 pixel Lena gray image is transferred. At the transmitter, the Lena gray image is scanned line by line. The gray value (0–255) of each pixel with 8-bit information is extracted from the image and converted into a 2 × 2 hybrid optical mode array, which is encoded into the CGH. Hence, the 32 pixel × 32 pixel Lena gray image is corresponding to a sequence with 1024 CGHs. By switching the CGHs loaded onto the SLM, the Lena gray image is transmitted in the form of the hybrid optical mode array. At the receiver, each hybrid optical mode array is decoded to a pixel value. To distinguish different modes conveniently, two cross lines are set at the center of each mode. By counting the peaks of two intensity distribution lines, the modes can easily be identified. We demonstrate the image reproduction of Lena with zero bit error rate (BER). The experimental result shows the favorable performance of the free-space optical communication link based on hybrid optical mode array encoding/decoding. Compared to that of the traditional single-vortex encoding communication system, the information capacity of our system with 2 × 2 hybrid optical mode array increases by four times. In addition, the presented experimental system is feasible and has strong expansibility. The information capacity can increase by 16 times with a 4 × 4 hybrid optical mode array based on the same experimental setup. Therefore, the presented free-space optical communication system using hybrid optical mode array encoding/decoding has great significance for improving the capacity of free-space optical communication system.关键词
光学涡旋/计算全息图/编码/空间光调制器Key words
optical vortices/computer-generated hologram/encoding/spatial light modulator引用本文复制引用
解万财,黄素娟,邵蔚,朱福全,陈木生..基于混合光模式阵列的自由空间编码通信[J].物理学报,2017,66(14):353-362,10.基金项目
Project supported by the National Natural Science Foundation of China (Grant No. 61475098) and the Shanghai Science and Technology Commission Research Plan, China (Grant No. 14440500100). 国家自然科学基金 (批准号: 61475098) 和上海市科委科研计划 (批准号 14440500100) 资助的课题. （Grant No. 61475098）
