相干光通信的关键技术研究

发布时间：2018-04-01 05:09

本文选题：相干光　切入点：扩散片　出处：《东南大学》2017年硕士论文

【摘要】：随着互联网技术以及物联网技术的发展,人们对于无线通信带宽的要求越来越高,与此相对的是无线频谱资源越来越稀缺。光通信具有容量大、速率高、与光纤兼容性好的特点,而相干光通信相比强度调制/直接检测(Intensity modulation with direct detection,IM/DD)方式的可见光又具有更高的频谱效率和更宽的信道带宽,近年来逐渐引起了学术界和工业界的关注。本文对相干光通信技术进行了研究,设计并实现了一个基于近红外激光的室内相干光无线通信系统。首先,本文对相干光通信中的关键器件进行调研,基于收发端的关键器件的数学模型对系统性能进行推导,理论上论证了通过扩散片在接收机附近产生信号光斑,从而实现室内相干光无线通信的可行性。然后,本文基于已有的光纤通信和无线通信技术,针对室内相干光无线通信系统,设计并实现了一套数字信号处理(Digital Signal Processing,DSP)算法流程。通过全数字手段主要修复了信号的正交不平衡损伤、定时误差、频率偏移和相位噪声。接着,本文搭建并实现了相干光无线通信平台。通过对实验平台指标和器件性能参数的分析,选取合适的设备和器件,并自主设计实现了激光器控制接口、光电二极管(Photodiodes,PD)信号放大电路等器件的外围电路。最后,本文对搭建的硬件平台进行了调试以及测试分析。测试内容包括光路中各个节点的光功率以及光谱、接收端时域信号波形、系统传输速率与误比特率等。通过多组实验数据得到系统运行在不同的通信速率下误比特率与光信噪比的关系。测试结果表明,系统在1m的通信距离上,采用20Gbps的通信速率,光信噪比大于13dB时,系统误比特率能够达到10-5,光信噪比大于9dB时,系统能够通过使用前向纠错码实现无误码传输。
[Abstract]:With the development of Internet of things and Internet of things, the requirement of wireless communication bandwidth is becoming higher and higher, and the wireless spectrum resource is becoming more and more scarce.Optical communication has the characteristics of large capacity, high rate and good compatibility with optical fiber. Compared with coherent optical communication, the visible light of intensity modulation / direct detection of intensity modulation with direct detection / IM-DDD has higher spectral efficiency and wider channel bandwidth than coherent optical communication.In recent years, it has gradually attracted the attention of academia and industry.In this paper, the coherent optical communication technology is studied, and an indoor coherent optical wireless communication system based on near infrared laser is designed and implemented.Firstly, this paper investigates the key devices in coherent optical communication, deduces the performance of the system based on the mathematical model of the key devices at the transceiver, and proves theoretically that the signal spot is produced near the receiver by the diffusion chip.Thus, the feasibility of indoor coherent optical wireless communication is realized.Then, based on the existing optical fiber communication and wireless communication technology, a digital signal processing Signal processing algorithm is designed and implemented for the indoor coherent optical wireless communication system.The orthogonal unbalance damage, timing error, frequency offset and phase noise of the signal are repaired by all-digital means.Then, the coherent optical wireless communication platform is built and implemented.Based on the analysis of the experimental platform and the performance parameters of the device, the suitable equipments and devices are selected, and the peripheral circuits of the laser control interface, photodiode photodiode photodiode (PDD) signal amplification circuit and so on are designed and realized.Finally, the hardware platform is debugged and tested.The measurement includes the optical power and spectrum of each node in the optical path, the time domain signal waveform of the receiver, the transmission rate of the system and the bit error rate.The relationship between bit error rate (BER) and optical signal-to-noise ratio (SNR) of the system at different communication rates is obtained from multiple sets of experimental data.The test results show that the BER of the system can reach 10-5 when the optical signal-to-noise ratio is larger than 13dB at the communication distance of 1m. When the optical signal-to-noise ratio is larger than 9dB, the system can realize the error-free transmission by using forward error correction code.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.1

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