Vibration-insensitive fiber spool for laser stabilization

Excess frequency noise induced by mechanical vibration is the dominant noise source at low Fourier frequencies in fiber-delay-line stabilized lasers. To resolve this problem, a double-winding fiber spool is designed and implemented that has ultralow acceleration sensitivity in all spatial directions. By carefully choosing the optimal geometry parameters of the fiber spool, we achieve acceleration sensitivity of 8 × 10~(-11)/g and 3 × 10~(-11)/g(g denotes the gravitational acceleration) in axial and radial directions, respectively.     

All-fiber-based photonic microwave generation with 10-15 frequency instability

We demonstrate an all-fiber-based photonic microwave generation with 10^-15frequency instability.The system consists of an ultra-stable laser by optical fiber delay line,an all-fiber-based"figure-of-nine"optical frequency comb,a high signal-tonoise ratio photonic detection unit,and a microwave frequency synthesizer.The whole optical links are made from optical fiber and optical fiber components,which renders the whole system compactness,reliability,and robustness with respect to enviro...     

油菜蜂花粉中脂肪酸的GC-MS分析

以石油醚和乙醚为溶剂，采用索氏抽提法提取油菜蜂花粉中的粗脂肪，进行甲酯化处理，并用GC－MS技术对脂肪酸甲酯进行分离鉴定，共鉴定出10种脂肪酸；测定其相对含量，其中不饱和脂肪酸相对含量高达76.0%，多不饱和脂肪酸相对含量为53.2%。     

光纤1/f热噪声的实验研究

光纤热噪声是限制光纤传感、测量系统性能的最终因素.但是低频区域呈1/f谱特性的光纤热噪声的形成机制迄今仍然存在争论.实验研究了光纤1/f热噪声水平与光纤内杂质离子浓度和光纤施加张力的关系,验证了这类热噪声来源于光纤内部的机械耗散引起的长度自发抖动,符合热机械噪声的理论假设.     

All-fiber-based laser with 200 mHz linewidth

We demonstrate the frequency stabilization of a 1.55 μm erbium-doped fiber laser by locking it to a 5-km-long optical fiber delay line(FDL). The stabilized laser is characterized via comparison with a second identical laser system. We obtain a fractional frequency stability of better than 3 × 10~(-15) over time scales of 1–10 s and a laser linewidth of 0.2 Hz, which is the narrowest linewidth of an FDL-stabilized laser observed to date.