高Q值跳频带通微波光子滤波器

The Frequency Hopping Bandpass Microwave Photonic Filter with High Q-factor

提出一种基于Lyot-Sagnac滤波器和级联结构的高品质因数跳频带通微波光子滤波器.在该滤波系统中,利用宽带光源和Loyt-Sagnac滤波器原理实现波长间隔可变的连续光载波.利用相位调制器与单模光纤形成第一级单通带微波光子滤波器,光纤环形谐振器作为第二级滤波结构.经两级滤波器级联,实现高品质因数跳频单通带微波光子滤波器.在使用三段保偏光纤的情况下,通过调整偏振控制器的偏振状态,可实现滤波器中心频率在1.012 1GHz,1.214 5GHz,1.416 9GHz,1.619 3GHz,1.821 7GHz之间跳跃.由于采用了级联结构,所设计的滤波器继承了前后两级滤波器的共同优点,故滤波器的滤波特性良好,品质因数最高可达13 155.69;主旁瓣抑制比均在18dB以上,最高达25.51dB.且该装置结构简单,调谐便利.

A frequency hopping bandpass microwave photonic filter based on Lyot-sagnac filter and cascaded structure was proposed. In the filtering system, a continuous optical source with variable wavelength separation is achieved by using broadband source and Loyt-sagnac filter. The first order filter is composed of a phase modulator and a signal mode fiber. A ring resonator is cascaded to he the second order filtering structure. A frequency hopping single-bandpass microwave photonic filter with high Q- factor is achieved by cascading the two filters. In the case of choosing three sections of polarization maintaining fiber, the central frequency of the filter is hopped among 1.012 1 GHz,l.214 5 GHz, 1.416 9 GHz,1. 619 3 GHz and 1. 821 7 GHz by adjusting the polarization state of polarization controller. Since a cascaded structure is used in this article, the implementation of the filter inherited advantage of both filters. So the filter has good frequency response. The highest Q-factor is 13 155.69. Main side lobe suppression radio varies from 18 dB to 25.51 dB. Besides, the device has simple structure and is easy to control.