实验研究了一种采用马赫-曾德尔电光调制器产生60 GHz光毫米波的方法和相应的光纤无线传输(ROF)系统。在中心站采用单臂的马赫-曾德尔强度调制器(IM)通过光载波抑制(OCS)方式产生光毫米波,光毫米波的频率为2倍射频(RF)信号的频率。然后再利用另一个电光马赫-曾德尔调制器将下行基带数据信号调制到光毫米波上。下行信号经光纤链路传送至基站单元,光毫米波信号经高速光电转换器产生60 GHz的电毫米波,经过放大后,由天线发送出去。在用户单元通过天线接收到的电毫米波信号利用相干解调恢复下行的基带数据信号。实验显示采用频率为29 GHz射频信号产生光毫米波的频率为58 GHz,将下行链路中2.9 Gbit/s的数据在单模光纤中传输距离达20 km,且实现无线传输2.6 m。

An integrated radio-over-fiber (ROF) system with 60 GHz wireless mm-wave transmission by using optical carrier suppression (OCS) is proposed and experimentally demonstrated. A Mach-Zehnder single-arm intensity modulator (IM) is employed to generate 60 GHz millimeter-wave by OCS,and the 2.9-Gbit/s on-off keying (OOK) signal is modulated on mm-wave by using other IM. Then the downstream signal is transmitted from central office to base station by fiber link. In the base station,the mm-wave is detected by a high-speed optical/electrical (O/E) converter before it is amplified by an electrical amplifier and beamed by the antenna. The received wireless mm-wave is demodulated by coherent demodulate to retrieve the baseband signal. The experimental results show that the 58 GHz optical millimeter-wave will be generated by 29 GHz radio frequency resource,and 2.9 Gbit/s downstream and upstream data can be transmitted over 20 km in fiber,and 2.6 m wireless distance can be realized simultaneously.