为了有效解决太赫兹通信系统中信号难以调制, 影响通信系统性能的问题, 提出了一种基于级联马赫-曾德尔调制器的太赫兹通信系统。将要传递的伪随机不归零码与频率为10GHz的射频本振信号混频后调制到级联马赫-曾德尔调制器上, 通过调节两个调制器的偏置电压, 使其分别偏置在最大传输点和最小传输点上, 得到的光载波信号经过光放大器放大, 结合高非线性光纤的四波混频效应, 利用相移布喇格光栅进行模式选择, 经过光电转换后的太赫兹信号通过基带数据恢复, 可以得出该太赫兹通信系统传输的误比特率。结果表明,基于级联马赫-曾德尔调制器结构可以将太赫兹信号的产生与调制结合到一起。该研究对太赫兹通信系统的实用化有一定借鉴意义。

In order to effectively solve the problem of signal modulation in THz communication systems affecting the performance of communication systems, a Terahertz communication system based on cascade Mach-Zehnder modulators was introduced. Pseudo random nonreturn to zero(NRZ) code and radio frequency local oscillator signal with frequency 10GHz were mixed into cascade Mach-Zehnder modulators. By adjusting the bias voltage of both modulators, they were biased at the maximum transmission point and the minimum transmission point respectively. The generated optical signal was amplified by erbium-doped optical fiber amplifier(EDFA), THz signal was generated by four-wave mixing effect in high nonlinear fiber and mode was selected by phase shifted fiber Bragg grating(FBG). Error rate of the transmission of terahertz communication system can be obtained by the recovery ofthe base band data after photoelectric conversion. The results show that THz signal is generated and modulated in the communication system based on cascade Mach-Zehnder modulators. The system has the significance of applications of THz communication systems.