高分辨低抖动光信号相位噪声测量方法研究

Timing jitter is one of the most important properties of the optical frequency comb, photonic analog-to-digital conversion, ultra-short optical pulse generation, microwave photonic system and so on. Accurate measurement of the optical signal’s timing jitter plays a key role on the stability optimization of optical frequency comb system and improving quantization precision of photonic analog-to-digital conversion, attosecond pulse generation, high frequency ultra-low-noise microwave signals generation and processing etc. The accuracy of traditional timing jitter measurement method, composed of photoelectric detector, filter and microwave signal analyzer, is limited to about 10fs due to access noise in photoelectric conversion process, resolution of microwave mixer, phase noise of synthesizers and PLLs. New measurement methods (for example: balanced optical cross-correlation) with attosecond accuracy have been restricted to widely application because of requirement of double devices under test, which could result in huge volume, high cost and complicated operating. We show an attosecond resolution timing jitter measurement method adopting the external-cavity optical delay precise locking technique and dual-wavelength-interference balanced cross-correlation detection method without another similar device under test. We will focus on wide-tunable-range high-precision external-cavity locking technique, dual-wavelength-interference balanced cross-correlation detection method and high precision timing jitter testing algorithm. Finally, we plan to built one integrated measurement system.

时间抖动是光频梳、光子模数转换、超短光脉冲产生、微波光子系统等领域核心参数，精确测量光信号时间抖动是优化光频梳系统稳定度、提高光子模数转换垂直精度、产生阿秒脉冲、生成处理高频超低噪声微波信号等方向的关键技术。由光电探测器、滤波器和微波信号分析仪组成的传统时间抖动方法,由于受到光电转化附加噪声、混频器分辨率、频率综合器与锁相环电路相位噪声的限制，其测量精度限制在10fs左右；而阿秒量级测量精度的光互相关均衡探测等测量方法，由于需要双套被测系统，导致系统庞大、成本昂贵、操作复杂，应用受到极大限制。本项目拟采用外腔光延迟精确锁定与双波长光谱相干互相关均衡探测技术，摆脱了双套被测系统的限制，可使相位噪声测量精度达到阿秒量级，为实用化的高精度时间抖动测量提供新方法。着重解决大延迟高精度外腔锁定、双波长光谱相干互相关均衡探测技术和开发高精度时间抖动测量算法，并搭建小型化测量系统。

本项目针对传统测量精度不够，新的测量方法系统庞大、操作复杂和应用受限等不足，采用了外腔光延迟精确锁定与双波长光谱相干互相关均衡探测方案，先后经过了数据仿真、测试平台搭建、数据测试和环境适应性测试四个阶段，实现了超低噪声抖动测试从理论仿真到实验样机的搭建，先后搭建了50MHz，1.06GHz,2.6GHz光纤激光器作为被测试源，研制了200MHz光频梳系统一台套，500MHz光频梳系统两台套，在此基础上我们搭建了阿秒级抖动测试实验平台，完成了既定任务。在此项目的牵引下获得重大测试仪器项目一项（500万），获得了横向课题两项（小计120万），发表SCI文章6篇，中文EI文章1篇，培养5名研究生和1名博士生，参加国际国内会议3次。