基于外调制器的全双工无线信号光传输系统

Full-duplex wireless signal optical transmission system based on external modulator

提出了一种基于双平行马赫-增德尔调制器的全双工矢量信号传输系统。传统的光学倍频技术只适用于NRZ(not return to zero)等强度调制格式,而不适用于无线通信中常用的MPSK、MQAM等矢量信号调制技术,用传统的倍频技术生成光毫米波后,用滤波器将其2个边带分开,在其中一个边带上调制矢量信号,这样幅度和相位信息被正确保留,且使用了8倍频模块,降低了传输过程中对光电器件的带宽要求。理论分析和仿真结果表明:通过此方法产生的携带在60GHz载波上的625-Msymbol/s的4QPSK信号,经过20km单模光纤传输后,误差向量幅度损耗可以忽略不计。

A full duplex vector signal transmission system based on double parallel Mach-Ze- hnder modulator was proposed. Traditional optical frequency doubling technology was only suitable for NRZ （not return to zero） that was intensity modulation format and not suitable for MPSK and MQAM vector signal modulation technique in wireless communication. Two sides of optical millimeter wave generated by the traditional multiplier were separated with a filter, and vector signal was modulated in a sideband so that the amplitude information and phase in- formation were properly retained. Bandwidth requirements of optoelectronic device were re- duced by using octonary module in the transmission process. Theoretical analysis and simula- tion results show that after 20 km single-mode optical fiber transmission, the error vector magnitude loss of 625-Msymbol/s 4QPSK signal generated by this method and carried in the carrier of 60 GHz can be neglected.