基于光外差理论的毫米波RoF系统研究

摘要

从理论上介绍了利用光外差法产生毫米波RoF系统的原理,并分析了制约其性能的因素.基于光外差理论,对传统的光外差系统结构进行了改进.实验证明,与传统的光外差系统相比,改进的光外差系统受相对强度噪声的影响更小,在相同的接收光功率的情况下,误码率平均降低了3～4dB;同时,在一定范围内,改进的光外差系统性能几乎不受激光器线宽的影响.在无中继放大的情况下,速率为2.5Gb/s的基带数据传输64km后,系统误码率能控制在10-10以下.%This paper analyzes the principle of the millimeter-wave RoF system using optical heterodyne method and the facts that constrain the performance of the system. A novel system is proposed based on this method. The experiments demonstrate that the proposed system is less influent by the phase noise. The BER of the system reduces 3～4 dB under the same received optical power. What's more, the performance of the proposed system doesn't affect by the laser linewidth. After 64 km's transmission without relay amplification,the BER is under 10-10 with the data rate of 2.5Gb/s.