基于小信号的电光调制器半波电压测量方法

A method of measuring half wave voltage of electro-optic modulator based on small signal

针对马赫-曾德尔(Mach-Zehnder,M-Z)型电光调制器高频半波电压测量方法复杂、测量仪器昂贵、测量成本高等问题,提出了一种基于小信号的高频半波电压测量方法。该方法利用光功率计的积分特性,仅使用光源、信号发生器、直流电源及光功率计,通过测量待测器件在有射频信号输入和无射频信号输入下输出功率极值的变化,即可实现对M-Z型电光调制器高频半波电压的高精度测量。采用OptiSystem开展了测量方法的仿真验证,采用Matlab完成了测量误差分析,并在1 kHz频率下对测量方法进行了实验验证。仿真及实验结果表明:该测量方法可以仅利用小信号完成M-Z型电光调制器半波电压的准确测量,1 kHz下绝对误差小于0.5%,换算所得的1 dB压缩点在10 GHz~40 GHz频率范围内与频响曲线的相对误差小于±0.3 dB。

In this paper,a measurement method based on small signal is proposed to solve the problems of complex high-frequency half wave voltage measurement method and expensive instrument of M-Z electro-optic intensity modulator.By using the integral characteristics of the optical power meter and using only the light source,signal generator,DC power supply and optical power meter,the high-precision measurement of high frequency half wave voltage of M-Z electro-optic intensity modulator can be achieved by measuring the change of the extreme output power of the device with and without RF signal input.In addition,the simulation verification of the measurement method is carried out by using OptiSystem,measurement error analysis is performed with Matlab,and the measurement method is verified at 1 kHz frequency.Simulation and experimental results show that the proposed method can accurately measure the half wave voltage of M-Z electro-optic modulator only with small signal.The absolute error at 1 kHz is less than 0.5%,and the relative error is less than±0.3 dB in the range of 10 MHz~40 GHz.