首次提出了一种基于偏振稳定双波长保偏光纤光栅激光器的可调谐微波/毫米波产生技术,利用保偏光纤光栅选频产生两个偏振稳定的激光信号,采用扰偏器确保激光输出的两个正交偏振态功率的一致性,最后输入高速光电探测器产生微波/毫米波.通过对保偏光纤光栅施加不同大小的侧向应力,可以灵活调谐输出的毫米波频率.实验制作了基于偏振稳定双波长保偏光纤光栅激光器的可调谐微波/毫米波产生装置,通过对保偏光纤光栅施加不同的轴向拉力分别产生了20.407和22.050 GHz的微波信号.仿真产生了60 GHz的毫米波信号,并分析该毫米波在光纤无线通信下行链路的传输性能,结果表明该毫米波作为副载波调制到光波上从中心站传输80 km至基站后经天线发射至用户端,解调后仍然得到很好的眼图,充分证明了本方案的优越传输性能.
A technique for tunable microwave/millimeter-wave generation based on a polarization-stable dual-wavelength polarization maintaining fiber Bragg grating(PMFBG) laser is proposed in which the frequency selecting of PMFBG is used to produce two polarizationstable lasing signals,the polarization scrambler is adopted to ensure the consistency of the orthogonal polarization's power,and then the beating frequency in high-speed photodetector is used to generate the microwave/millimeter-wave.Lateral strain loading on the PMFBG allows the frequency of the microwave/millimeter to be controlled.In the experiment,a scheme for tunable microwave/millimeter-wave generation based on a polarization-stable dual-wavelength PMFBG laser is produced,and the microwave signals of 20.407 GHz and 22.050 GHz are generated by different axial pulls loading on PMFBG.In the simulation,the millimeter-wave of 60 GHz is generated and transmission performance of the millimeter-wave in radio-over-fiber downlink is analyzed.The results show that the eye diagrams demodulated in the mobile station are excellent when the optical carrier which is modulated as the millimeter-wave sub-carrier transmits over 80 kilometers from center station to base station.The excellent performance of the system is verified.