为了延长光毫米波的传输距离，提出了一种改进的光载波抑制产生光毫米波的方法。在中心站采用马赫－曾德尔调制器将射频信号调制到光载波上产生光载波抑制调制光信号，再将产生光信号的2个边带分离，将2．5Gbit／s数据信号调制到其中1个边带上，再与未调信号耦合后产生光毫米波并通过光纤传送至基站。在基站中通过光电转换器产生电毫米波。从理论上分析了这种光毫米波的传输特性并通过实验验证了光毫米波在光纤中可以传输40km。仿真和实验结果表明，这种方式产生的光毫米波具有很好的抗色散能力，延长了传输距离。

In order to increase the transmission distance for optical millimeter wave over an optical fiber,a novel scheme for optical millimeter wave generation with optical carrier suppression(OCS)modulation by external modulator in a radio over fiber(ROF)system was proposed. At the central station,a CW wave was intensity modulated by the RF signal to generate OCS signal.After the pure optical carrier was filtered,an optical interleaver was employed to separate the spectrum of the upper sideband and the lower sideband of the generated OCS signal. After the lower sideband signal was modulated with a baseband data at 2.5Gbit/s,it was recombined with the unmodulated signal to generate optical mm-wave,and then transmitted to the base station over a single mode fiber(SMF). In the base station,the electrical mm-wave signal was generated by optical electrical(O/E)conversion.The dispersion performance of the generated mm-wave was theoretically analyzed。The optical millimeter wave could betransmitted 40km over a single mode fiber in the experiment. The simulation and experiment results show that it can immune the fading effect and increase the transmission distance for optical millimeter wave over fibers with this method.