Application of computer vision and laser interferometer to the inspection of line scale

In the paper machine vision, laser interferometer and coordinate measuring machine (CMM) are combined to develop a vision inspection system. The measurement capability of the developed system is investigated by measuring the distances between the lines on a standard line scale. The vision camera is used to replace the probe of the CMM to take the images of the interested lines on a line scale at two different positions. Meanwhile, the displacement of the CCD camera is measured using laser interferometer. Using subpixel edge localization and outlier-excluding least-squares regression, the distance between two interested lines is computed under an image plane coordinate system. By adding the displacement of the CCD camera measured using laser interferometer, the line space can be determined. Experiments have been performed repeatedly to measure the line space on the 1.00 and 300.0 mm line scales. Results indicate that the measured data only have a little fluctuation and are close to those obtained by the NML (National Measurement Laboratory, Taiwan).     

Design and analysis of a new silicon-on-insulator waveguide Michelson interferometer sensor

A new designed and analyzed silicon-on-insulator (SOI) waveguide Michelson interferometer (SMI) sensor is proposed in this paper. The authors compare an optical SMI sensor, a silicon-on-insulator Bragg waveguide grating (SBG) sensor, and a fiber Bragg grating sensor (FBG) for temperature sensing in medicine applications. The SMI sensor has 20 times sensing more accuracy than the FBG sensor. Moreovr, the full width at half maximum (FWHM) of the pass-band frequency responses of our proposed SMI can be designed much narrower than FBG and SBG sensors for sensing resolution enhancement. Further, the improved characteristics of the SMI demonstrated in this paper could pave the way for future high density temperature monitoring medicine applications.     

Determination of path length difference by low coherence interference spectrum

Path length difference is the key parameter in two-beam interferometer, especially in low coherence interferometer. It determines the visibility of the interference fringes. In this study, we present a method to determine the path length difference between two arms of a fiber optic Mach–Zehnder interferometer by evaluating the peaks of power distribution of the interference spectrum with a wide band light source. The experimental results are in close agreement with the theoretical calculations.     

一种新型全光纤速度干涉仪

 基于传统速度干涉仪(VISAR)和光纤速度干涉仪(AFVISAR)的特点，提出了一种由光纤和光纤耦合器组成的工作波长为532 nm的新型全光纤速度干涉仪（NAFVISAR）。该干涉仪采用多模光纤器件构成分离系统,单模光纤器件组成核心部分。由于有两路携带不同信息的光束经不同路径传输到耦合器中，当这两路光束满足干涉条件时，可利用它们的干涉场信息来调解出被测靶的信息，从而区分波面的加减速变化。用该系统进行了Hopkinson森杆一维应力加载下的入射杆端面的速度剖面测试，实测速度最大值为49.36 m/s，与理论速度的最大值50.16 m/s基本符合，实现了全光纤速度干涉仪的实用化。     

多道HCN激光干涉仪在HL－1装置上的电子密度分布测量

本文描述了为测量ＨＬ－１装置电子密度分布而研制的多道远红外（ＦＩＲ）激光干涉仪系统及其特点。首次对装置在弹丸加料以及拉瓦尔（Ｌａｖａｌ）超声分子束注入实验条件下的等离子体电子密度时－空分布进行了观测和初步分析。同时，介绍一种处理密度相移信号的新方法。     

Geometric Phase Observation with Dispersed Fringes

Geometric and dynamic phases are separately observed using dispersed fringes, and the difference between them is clearly demonstrated. Independence of geometric phase of wavelength is straightforwardly shown in the dispersed fringe.     

Mach–Zehnder interferometers in photonic crystals

Photonic crystal technology allows the creation of optical waveguides with low sharp-bending losses as well as ultra-low group velocity. This last property is particularly interesting to develop highly-compact optical devices based on the controlled modification of the optical phase of the signals traveling through the waveguides. Among these devices, the Mach–Zehnder interferometer acquires fundamental importance because it can be used as a building block of more complex optical devices and functionalities such as optical filters, wavelength demultiplexers, channels interleavers, intensity modulators, switches and optical gates. In this paper, the performance of a Mach–Zehnder interferometer consisting of two coupled-cavity waveguides with different lengths created in a two-dimensional photonic crystal is theoretically analyzed. We also provide simulation results using a finite-difference time-domain code that confirm the theoretical analysis. The main limitations in the performance of the structure are addressed and discussed.     

光纤传输速度干涉仪

介绍一种用多模光纤传输入射和反射激光的速度干涉仪，阐述了这种干涉仪的原理和结构，并将其与传统的速度干涉仪进行比较。给出了用这种干涉仪测量电爆管的弹丸速度和钨样品在铁飞片冲击压缩下的自由面速度的实验装置和结果。文中最后总结了这种干涉仪的性能及特点。     

基于光纤智能夹层传感结构的应力测量研究

制作了一种模块化的光纤传感夹层,对夹层内的光纤传感器的应力特性进行了实验研究。分析了应变对传感系数的影响,对埋入到光纤智能夹层中的两种光纤传感器的输出特性进行了比较。实验结果表明:光纤Bragg光栅传感器的波长漂移与应变之间具有理想的线性关系,但应变灵敏度由1.2pm/με降至1.15pm/με;由于制作工艺的局限,对于非本征F-P光纤传感器,当应变达到350με后,应变与载荷具有较好的线性响应。与非本征F-P光纤传感器相比,光纤Bragg光栅传感器是光纤智能夹层首选的应变传感器。将埋入了Bragg光栅传感器的智能夹层粘贴于某型飞机的翼-身连接构件内部进行监测,实验结果为光纤智能夹层应用于复合材料结构的应变监测提供了参考。     

迈克耳孙干涉仪的数字化设计

使用硅光电晶体三极管作为光干涉条纹传感器,采用变间隙动极板电容传感器代替传统微距测量的设计方案,利用单片机对干涉条纹进行计数并自动测量反射镜的微小位移,实现了迈克耳孙干涉仪的数字化测量.制作了检测系统及电路,完成系统的软件设计.He-Ne激光波长的测量实验结果表明,采用该方案能够缩短测量时间,提高测量精度.