基于相位调制等效展宽激光线宽的极低相噪光电振荡器

Ultra-low phase noise optoelectric oscillator based on equivalent broadening of laser line-width by phase modulation

摘要:

光电振荡器是一种采用光电结合方式的新型微波频率源，其利用光学长时储能，可以实现极低相位噪声的信号输出。本文研究了光纤中散射噪声对光电振荡器相位噪声的影响，重点介绍了基于相位调制等效展宽激光线宽抑制布里渊散射噪声架构，通过理论公式推导以及实验验证，表明了上述架构可极大改善光电振荡器的相位噪声。实验中采用调制频率为50MHz、调制幅度为3.1的相位调制信号对激光线宽进行等效展宽，得到了在10GHz频率下为-157.3dBc/Hz@10kHz的极低相位噪声信号输出。

Abstract:

Optoelectronic oscillator is a new type of microwave frequency source with optoelectronic combination. It can realize signal output with ultra-low phase noise by using optical long-term energy storage. In this paper, the influence of scattering noise in optical fiber on the phase noise of optoelectronic oscillator is studied. The structure of suppressing Brillouin scattering noise based on equivalent broadening of laser line-width by phase modulation is emphatically introduced. Through theoretical formula derivation and experimental verification, it is shown that the above structure can greatly improve the phase noise of optoelectronic oscillator. In the experiment, a phase modulation signal with a modulation frequency of 50MHz and a modulation amplitude of 3.1 is used to broaden laser line-width, and a ultra-low phase noise signal of -157.3dBc/Hz@10kHz at a frequency of 10GHz is obtained.