Study on Power Synthesis of THz Continuous-Wave Signal by Multiple Optical Beats

用两个光拍实现了6 GHz连续信号的同相和反相相干合成。通过调整SMF长度或DFB-LD波长，实现了6 GHz连续信号的空间合成。同相合成的6 GHz信号与单光拍合成的6 GHz信号相比，测量功率提高了近6分贝。在此基础上，用两个光拍相干合成了20 GHz连续信号，并用SBD探测器进行了探测。同相合成的20 GHz信号与单光拍合成的信号相比，测量功率提高了4分贝左右，6 GHz连续信号除相干合成外，还实现了两个光拍的非相干合成。非相干合成的6 GHz信号的功率比一个光拍产生的功率提高了3dB。利用偶极子天线实现了6 GHz连续信号的空间合成，微波功率提高了近3分贝。

6-GHz continuous signal was coherently synthesized with in-phase and reversed-phase by two optical beats. 6-GHz continuous signal was synthesized spatially by adjustment of SMF length or DFB-LD wavelength. Measured power of 6-GHz signal synthesized with in-phase was increased by almost 6dB compared with that generated by one optical beat. Furthermore, 20-GHz continuous signal was coherently synthesized by two optical beats and detected by SBD detector. Measured power of 20-GHz signal synthesized with in-phase was increased by around 4 dB compared with that generated by one optical beat.In addition to the coherent synthesis, 6-GHz continuous signals were incoherently synthesized by two optical beats. The power of incoherently synthesized 6-GHz signal was increased by 3dB compared with that generated by one optical beat. 6-GHz continuous signals were also synthesized spatially using dipole antennas and the microwave power was increased by almost 3dB.