基于硅基片上布里渊散射效应的低相噪集成化光电振荡器的机理与器件研究

With the rapid developement of large capacity of wireless communication, high speed data interconnect system, higher end of radar, monolithic integration, low phase noise microwave and millimeter-wave signal source are urgently required. The realization of a low phase noise microwave or millimeter-wave oscillator needs a high Q value resonator. Usually, the product of the Q value and the operating frequency of the traditional resonator is a constant value. With the increasing of the operating frequency, the Q value of the resonator is decreased. It limits the phase noise performance of the high frequency microwave and millimeter-wave oscillator. In addition, the high performance resonators are off-chip devices. It is hard to integrated the resonators with the other components of the oscillator. The optoelectronic oscillator based on an optical cavity is one of a key technology to realize a low phase noise oscillator. Furthermore, the high Q optical storage element based on silicon photonics is a key device for a monolithic integrated optoelectronic oscillator. This subject makes a study of sillicon on-chip stimulated Brillouin scattering based integrated optoelectronic oscillator. The contents are shown as follows: the mechanism of the confinement of optical mode and acoustic mode in silicon photonic chip, the mechanism of the coupling between the photon and phonon, the mechanism of the transfer of the nonlinear noise between the optical wave and microwave. The goal is to obtain a high Q optical storage element towards the integration of an optoelectronic oscillator. It provides theory and technology for the realization of low phase noise, monolithic integrated microwave and millimeter-wave sources in the future.

随着大容量无线通信、高速数据互联、高性能雷达的发展，迫切需要单片集成化、低相位噪声的微波与毫米波源。实现低相噪声的微波与毫米波振荡器需要高Q值的谐振腔。然而，对于传统的谐振器，其Q值与工作频率的乘积一般为一常数。随着频率的提高，谐振器的Q值下降，限制了微波与毫米波振荡器的相位噪声性能。并且，高性能的电谐振器都是片外器件，难以实现振荡器的单片集成。基于光学谐振腔的光电振荡器，是实现极低相位噪声电振荡器的关键技术之一。特别是硅基高Q光学能量存储单元，是单片集成化光电振荡器的核心。本课题计划重点展开基于硅基片上布里渊散射效应的集成光电振荡器的基础理论和关键技术研究。内容包括：硅基片上光场与声场的束缚机理，硅基波导光子-声子耦合机理，基于布里渊散射效应微波光子滤波的光波-微波非线性噪声转移机理。最终实现面向集成化光电振荡器的高Q光学谐振器。为未来高性能集成化微波毫米波源的发展提供理论与技术支撑。

单片集成化的低相位噪声微波与毫米波源是高性能雷达、通信、传感等系统的关键器件之一，而高品质因子的片上谐振腔是实现低相噪声微波振荡的核心。本项目目标着眼于研究和实现基于光子谐振腔的低相位噪声光电混合振荡器，创新性地利用了集成光波导中的光声非线性互作用所引入的受激布里渊散射效应来实现光电混合振荡器中所需的高品质因子微波毫米波谐振器。本课题深入地研究了硅基波导中的光场与声场的束缚机理及其耦合机理；研究了基于光域受激布里渊散射效应的微波谐振器对光电混合振荡的射频相位噪声转移机理；仿真和设计了高布里渊增益的硅基光波导；提出并实验探索了可降低激光器频率噪声对射频振荡信号相位噪声转移的高性能硅基布里渊散射光电混合振荡器系统。在此基础上，实验验证了基于反斯托克斯窄带衰减谱的布里渊光电混合振荡器能有效地抑制泵浦激光频率噪声对射频相位噪声的转移，相位噪声低于-125dBc/Hz@10kHz，这为实现极低相位噪声集成化硅基布里渊光电混合振荡器提供了全新的思路。与此同时，本项目实现了基于布里渊光电混合振荡器的宽带、低相位噪声微波频率合成器，频率合成精度高达8Hz，有望应用于高性能雷达以及宽带无线接收机等。首次实现了基于光电混合振荡器的高灵敏度微波相位噪声分析仪，10GHz频点测量灵敏度高达-139dBc/Hz@10kHz，有望应用于超高灵敏度微波相位噪声分析系统。实现了基于光电混合振荡器的10GHz频率捷变微波合成器，频率切换时间低于176ns，相位噪声低于-140dBc/Hz@10kHz，有望应用于频率捷变雷达和跳频通信系统。实现了可自动锁相的低相噪10GHz锁相光电混合振荡器，自动相位锁定时间低于120ms，相位噪声低于-135dBc/Hz@10kHz，有望作为高性能时钟源应用于频率合成和数据转换系统中。