基于Sagnac干涉仪的紫外超短脉冲放大技术

 介绍了一种基于Sagnac干涉仪形式的超短脉冲多路放大技术，能够实现多个激光脉冲的自动复合，并且在理论上能够实现锁相输出。分析了调节偏差对于干涉仪性能的影响，在仔细调节好干涉仪的情况下，起主要限制作用的是放大器介质折射率的随机变化，同时给出了一种利用偏振分束片的多路放大方法及实验结果，将直径为50mm，能量为2~3mJ的脉冲激光放大为最大输出能量为120mJ，稳定运行在100mJ的脉冲。     

A dual-loop Sagnac interferometer

A new type of all-fibre Sagnac interferometer composed of two loops is proposed and analysed in detail. It can be used with a very long transmission line while maintaining excellent performance characteristics due to the automatic compensation of any birefringence effects in the trunk fibre. Preliminary experiments at 1310~nm wavelength with a 70~km long trunk fibre demonstrated an interference visibility as high as 98%, indicating that this scheme has promising potential applications.     

Microscopy of non-birefringent transmissive phase samples using Sagnac laser interferometer

A cyclic interferometer, appropriately combined with a long working distance microscope objective, is adapted for quantitative phase microscopy. In such an arrangement, the sample information, in terms of the diffracted orders emerging from the sample, is carried by both the counter propagating beams within the cyclic interferometer. However, positioning the sample close to the input/output cube beam splitter and use of a suitably converging laser beam of light as the input to the interferometer ensure that only one of the counter propagating beams carries the object information to the objective while the other beam, which serves as the reference, allows only the undiffracted component to contribute to the process of image formation. Use of suitable polarization optics renders the interferometer its polarization phase shifting property. Using the proposed arrangement, the experimental results showing the quantitative 3D phase rendering of polystyrene microspheres and micro-wells etched in glass are presented.     

Two-parameter estimation in a matter-wave Sagnac interferometer

We explore the general characteristics of a matter-wave Sagnac interferometer in a two-parameter estimation scheme. We find that the measurement precisions of both parameters cannot reach the Heisenberg limit (HL) simultaneously when the input state is maximally entangled. Only one of the parameters’ uncertainties can approach the HL while the other is scaled by the standard quantum limit. We provide the conditions with which the measurement precision of the specific parameter can reach the HL. We also discuss and figure out the concrete expressions of the constraint conditions for saturating the quantum Cramér–Rao bound. To satisfy these constraint conditions, the evolution time has to be a series of discrete values. Additionally, we calculate the variances of the parameters through some examples under these constraint conditions. The results provided in our work show some intrinsic features of the matter-wave Sagnac interferometer for the two-parameter estimation, which can be valuable in actual experiments.     

Sagnac干涉仪与光纤环形激光器

依据相干光学理论,以现代激光干涉侧试技术中的光纤Ｓａｇｎａｃ干涉仪为例,分析和讨论了光纤环形激光器的基本工作原理,并结合其物理原理简要介绍了光纤环形激光器和光纤陀螺（ＦＯＧ）的应用的发展前景。     

基于成像光谱仪的Sagnac干涉仪的优化设计

为了满足仪器的轻量化设计要求,研究了成像光谱仪系统中Sagnac干涉仪的优化设计方法,讨论仪器轻量化设计中干涉仪尺寸与系统前置望远镜倍率的制约关系,通过将Sagnac干涉仪展开为平板玻璃的方法对干涉仪的结构和光路进行分析,根据几何关系推导出Sagnac干涉仪几何尺寸与入射干涉仪的光束孔径和视场角的关系表达式,通过该关系式可以求出干涉仪的尺寸极值和对应的系统前置望远镜倍率大小。以某短波红外光谱仪为例,运用推导出的关系式,计算并给出了优化设计结果。     

Twist sensor based on Sagnac single-mode optic fiber interferometer

An optical fiber twist sensor based on Sagnac single-mode optic fiber interferometer is proposed. The stress-induced birefringence of single-mode optical fiber is obtained by applying a transverse force against a short length of singlemode fiber. A high sensitivity and resolution of the twist angle measurement of 0.19 nm/° and 0.002° is achieved experimentally, respectively. The proposed sensor is more convenient and simple than that of standard polarization-maintaining fibers.     

基于Sagnac光纤干涉仪的管道泄漏检测和定位技术

研制了一种基于Sagnac干涉仪的分布式光纤传感器,可实时进行管道泄漏检测与定位.阐述了该传感技术的工作原理和泄漏点定位方法,并推导了泄漏引起的光信号相位变化表达式。管道泄漏实验结果表明,水压为0.3MPa时,该技术能有效地检测到管道泄漏的发生并准确定位。     

Wavefront measurement with a phase-shifting lateral-shearing Sagnac interferometer operating in broadband light

A phase-stepping lateral shearing Sagnac interferometer for wavefront measurement is described. Phase shifting is implemented using a polarisation modulator operating on the wavelength independent Pancharatnam's phase allowing accurate measurement of phase maps even with broadband light. We demonstrate the interferometer by measuring a range of different wavefront shapes using both laser and white light.     

基于Sagnac干涉仪的紫外超短脉冲放大技术

介绍了一种基于Sagnac干涉仪形式的超短脉冲多路放大技术,能够实现多个激光脉冲的自动复合,并且在理论上能够实现锁相输出。分析了调节偏差对于干涉仪性能的影响,在仔细调节好干涉仪的情况下,起主要限制作用的是放大器介质折射率的随机变化,同时给出了一种利用偏振分束片的多路放大方法及实验结果,将直径为50mm,能量为2~3mJ的脉冲激光放大为最大输出能量为120mJ,稳定运行在100mJ的脉冲。     

Unambiguous measurement of surface profile using a Sagnac interferometer with phase feedback

The fringe profiles from a two beam interferometer with phase feedback are almost unambiguous over a range of 2π or more. This allows phase and therefore surface profile to be determined directly from output intensity of an interferometer. In this paper we describe how feedback can be applied to a polarisation Sagnac common path interferometer using a parallel aligned nematic liquid crystal spatial light modulator. Initial experiments have shown that the device is capable of measuring profiles to accuracies greater than one tenth of a wavelength.     

超低温度系数的光子晶体光纤Sagnac压力传感器

 提出了一种基于光子晶体光纤Sagnac干涉仪的横向压力传感器。使用的光子晶体光纤为低双折射光纤,首先预先在Saganc环中的光子晶体光纤上施加初始压力,使Sagnac干涉仪产生正弦干涉光谱,然后再将被测物体放在光子晶体光纤上,由于被测物体重力的作用,Saganc干涉仪输出的光谱产生移动,实现横向压力传感测量。传感器具有高灵敏度0.529 nm/(N·mm)及超低的温度系数-0.4 pm/℃,其环境温度的影响可以忽略。     

An experimental investigation of the optical switching characteristics using an optical Sagnac interferometer incorporating one and two ring resonators

We present the use of a fiber optic Sagnac interferometer incorporating one and two fiber optic ring resonators to characterize experimentally the optical switching behaviors. These prototypes were formed by the Sagnac interferometer and serially connected to the ring resonators. The input optical signal was launched via one end of the interferometer, where the polarization control was employed to obtain the maximum optical transmission power. Results obtained have shown that the increasing in switching time (i.e. narrower spectral width) and power can be achieved.     

光纤Sagnac干涉仪中单光子干涉及路由控制

介绍一种光纤中稳定的单光子干涉以及单光子路由控制方式. 使用Sagnac单光子环形干涉仪，通过分时相位调制，改变其顺时针和逆时针两路光子间的相位差. 在Sagnac单光子环形干涉仪中，顺时针和逆时针两路光子走过的是同一段光纤，简便有效地补偿了光纤长度随时间缓变带来的相位涨落，而且两路光子经历了相同的偏振模色散，较好地抑制了偏振态波动对单光子干涉的影响. 在长达5km的1550nm单模光纤中，获得大于98%的单光子干涉和大于90%单光子路由控制；在长度为27和50km光纤环路中，分别获得大于94%和84%单 关键词： 单光子路由 单光子干涉 Sagnac单光子环形干涉仪 量子保密通信     

Tunable dual-wavelength fiber laser based on a single fiber Bragg grating in a Sagnac loop interferometer

We propose a simple dual-wavelength Er-doped fiber laser configuration based on a dual-wavelength fiber Bragg grating written on the splice joint between two different fibers for wavelength-selective filter in the Sagnac loop interferometer. The wavelength separation between the adjacent lasing wavelengths is 1.12 nm and the side-mode suppression ratio (SMSR) is over 55 dB. The output power variation is less than 0.8 dB over a two-minute period. Moreover, the lasing wavelength can be effectively tuned using the thermal heating method.     

Simultaneous measurement of strain and temperature with a long-period fiber grating inscribed Sagnac interferometer

A Sagnac interferometer with a long-period fiber grating (LPG) inscribed in the polarization-maintaining fiber (PMF) is proposed and experimentally demonstrated for simultaneous measurement of strain and temperature. Due to the different responses of the LPG and the Sagnac interferometer to strain and temperature, simultaneous measurement can be achieved by monitoring the wavelength shifts and the intensity changes of a resonance dip of the sensor setup. The experimental results show that the achieved sensitivities to strain and temperature are 6.4 × 10^− 3 dB/με and 0.65 nm/°C, respectively.     

基于全光纤萨格纳克干涉仪的温度不敏感磁场测量

研究了双折射磁光光纤萨格纳克 (Sagnac) 干涉仪透射谱的磁场和温度敏感性. 实验表明, 干涉仪透射谱会随着温度的增加向短波长移动 (温度系数为-0.435 nm/℃), 其波长依赖性则随着磁场的增加而降低. 据此, 通过调节干涉仪内偏振控制器状态实现了温度不敏感的磁场测量, 磁场系数为189 mW/T², 实验结果与理论分析一致. 关键词： 磁场测量 磁光效应 双折射 萨格纳克干涉仪     

Instrument forward model of the modified Sagnac interferometer for atmospheric wind measurement

The instrument forward model of the modified super-wide-Sagnac imaging interferometer based on liquid crystals on Silicon (MSASII-LCoS) is developed as an integrated code package with Matlab language to simulate the images of satellite observations. There are five sub-models in the forward model including radiation model of O(¹S), orbit attitude, filter, interferometer and array detector. The principle of each sub-model is described separately and then the overall forward model equation is derived. The four simulation images are obtained. Based on the integrated signal level for the daytime observations, the apparent measurement error of wind is less than 3 m/s and the signal noise ratio (SNR) is greater than 194 with a binning of 2 × 25 pixels at the tangent height range of 70-190 km.     

Switchable dual-wavelength erbium-doped fiber-ring laser based on one polarization maintaining fiber Bragg grating in a Sagnac loop interferometer

A switchable erbium-doped fiber-ring laser providing dual-wavelength outputs with orthogonal polarizations when operating at room temperature is proposed. One polarization-maintaining fiber Bragg grating (PMFBG) in a Sagnac loop interferometer is used as the wavelength-selective filter. Due to the enhancement of the polarization hole burning (PHB) by the PMFBG, the laser can be designed to operate in stable dual-wavelength or wavelength-switching modes with a wavelength spacing of 0.336 nm at room temperature by adjusting a polarization controller (PC). The optical signal-to-noise ratio (OSNR) is over 42 dB. The amplitude variation over 90 min is less than 0.6 dB for both wavelengths.     

Compact phase-shifted Sagnac interferometer for ultrasound detection

A compact fibre, phase-shifted Sagnac interferometer for ultrasound detection has been developed. The interferometer is a truly path-matched device, and therefore requires no path stabilization or heterodyning. It is a less expensive and more robust alternative to the heterodyne or path-stabilized Michelson interferometer. The device provides high spatial resolution of ultrasonic detection. It has been used in conjunction with conventional piezoelectric transducers (PZT) to detect Rayleigh and Lamb waves and to image a crack in a thin plate, rivet cracks in riveted plates, and for ultrasonic beam profiling.