毫米波光载无线系统的结构优化

下一代接入网需要实现高带宽和低成本的便携性，基于宽带光通信和无线接入的无缝融合的毫米波光载无线（RoF）通信技术被认为是一个很有前景的解决方案。但是由于其实现成本较高，需要对其系统结构进行相应优化。在毫米波光产生部分，光外差法可利用低频信号源产生高频的毫米波信号，同时采用对半导体激光器的注入锁模可以提高其利用效率。在下行链路中，使用单边带调制可以提高光传输距离，而基于注入锁模半导体激光器的单模调制（单边带调制）是一种较为简单的方案；上行链路中，采用对于光外差信号的调制，可以实现上行毫米波信号的直接光学下变频，从而简化中心站接收机系统结构。在波分复用毫米波光载无线双向系统中，利用上下链路的波长重用可以节省波长资源，提高系统使用效率。

System-Structure Optimization for Millimeter-Wave Radio over Fiber System

Based on the seamless integration of broadband optical and wireless access networks, millimeter wave Radio over Fiber （RoF） technology is considered a promising solution for the next generation access networks which will provide high capacity and flexibility with low cost. However, due to its large realization cost, the system architecture needs to be optimized. In the millimeter wave optical generation part, optica heterodyning method can be introduced to generate a high-frequency millimeter-wave signal using a low-frequency signal source; and the system efficiency can be greatly improved based on injection-locking of a semiconductor laser. In the downlink, the transmission distance can be greatly enhanced by single-sideband modulation, which, based on an injection-locked semiconductor laser, is a much simpler solution. In the uplink, direct modulation of optical heterodyning signal can be used to realize the down-conversion of uplink millimeter-wave signal, which simplifies the receiver structure at the centre office. In the wavelength division multiplexing millimeter wave RoF duplex system, the wavelength reuse in both downlink and uplink can save the wavelength resource in the whole system, which improves its efficiency.