基于法拉第旋转镜的相位可调光电振荡器

Phase tunable optoelectronic oscillator based on the Faraday rotator mirror

摘要:

为了有效实现光电振荡器(OEO)输出信号相位可调 ,提出了一种基于法拉第旋转镜的OEO。利用放大器 和滤波器构成电增益环腔,电增益环腔、直接调制半导体激光器(DFB-LD)和光 电检测器构成OEO环路。通过光分路器 得到经过调制后的光信号,结合级联光环形器和法拉第旋转镜结构,改变级联法拉第旋转镜 的个数,可以对应得到 相位延迟90～360°的射频(RF)信号,在实验结构简单的条件下,有 效实现了OEO输出信号的相位调谐。实验结果表 明,每增加一组光环形器和法拉第旋转镜结构,输出的RF信号相位延迟90°。当光纤长为2km,电增益环腔长 为0.5m时,得到频率为10.8GHz、边模抑制比大于50dB和相位噪声为－104.8 dBc/Hz@10kHz的RF信号。

Abstract:

A kind of optoelectronic oscillator (OEO) based on the structure of th e Faraday rotator mirror is demonstrated in order to realize a novel optoelectronic oscillator whose phase can be tu rned.An electrical amplifier and an electrical delay line construct the electrical gain ring resonator,and the OEO loop consists of t he electrical gain ring resonator cavity,the directly modulated distributed feedback (DFB) laser diode and the photodetecto r.The modulated optical signal gen erated by the structure of OEO is injected into the structure of optical circulator and Faraday rotator mirror,and the phas e delay could be changed from 90° to 360° with different numbers of the Faraday rotator mirror.With the single structur e,the phase of OEO signal can be changed.In the experiment,the length of fiber is 2km and the length of electrical loop is 0.5m,the structure achieves 10.8GHz fundamental oscillation with more than 50dB side mode suppression ratio,and the phase noise of the OEO signal is －104.8dBc/Hz at 10kHz.