基于偏振模干涉的可变系数微波光子滤波器

基于偏振调制和光的干涉原理，设计了同时具有正系数和负系数特性的微波光子滤波器，并通过搭建实验模型证实了方案的可行性。利用偏振调制及光的偏振特性实现载波和一阶边带的正交偏振，并通过改变偏振调制器的偏置电压分别对载波和一阶边带引入相移。当载波和一阶边带的相位差为0或90时，利用保偏光纤快慢轴上两正交偏振光在同一偏振态上的干涉效应，分别对应实现具有负系数或正系数特性的微波光子滤波器。最后，测量并验证了0~15 GHz频率范围内滤波器的频率响应。

Microwave photonic filter with variable coefficients based on polarization mode interference

Based on the principle of polarization modulation and optical interference, a microwave photonic filter with positive coefficients and negative coefficients is proposed and an experimental model is set up to verify the feasibility of the project design. With polarization modulation and the polarization property of light, it is achieved that the carrier and the first order sidebands are in two orthogonal polarization directions. Then, the phase shift is introduced to the carrier and the first order sidebands by adjusting the bias voltage of the polarization modulator. With the optical interference effect between the two orthogonal polarization lights in the fast and slow axes of the polarization maintaining fiber when they are in the same polarization state, a microwave photonic filter is achieved with negative coefficients or positive coefficients when the phase difference is 0 or 90. Finally, the frequency response of the filter with a frequency range between 0 GHz and 15 GHz is measured and verified.