光栅

Based on the principle of grating diffraction, by using television measuring system to measure the offset between the imaging of incident laser and the optical axis to confirm the angle of incidence and the angle of diffraction of the grating, a method of measuring incident laser wavelength in far field with grating is brought up.

依据光栅衍射原理，采用电荷耦合器件CCD作为探测器，通过测量入射激光成像点在电视靶面坐标系中的脱靶量，确定光栅的入射角和衍射角，提出了一种利用固定式平面反射光栅测量远场未知方位入射激光波长的方法。

Grating-mirror is designed, and it can be not only used as a grating but also a mirror. It reflects moiré fringe image formed by grating imaging back into autocollimator which will be acquired by CCD detector.

设计了光栅反射镜，使其同时起到光栅和反射镜的作用，将光栅叠加成像后得到的莫尔条纹图反射回自准直光管，并被CCD探测器接收。

FBG sensing technology and its recent progress in applications isintroduced systematically;the coupled-mode theory and the sensing principleof FBG are expatiated and the Bragg formula and reflectivity formula arededuced;the work principle, variety and essential characteristic of PZT areexpatiated in detail, and the configuration of PZT parts of an apparatus issummarized. The mechanism of piezoelectric electrostriction is analyzeddeeply, and the normalized control model is introduced aiming at analyzinghysteresis characteristic, and an electrical polarization intensity control methodbased on the aforementioned model which can effectively reduce the hysteresischaracteristic is discussed.

论文系统地介绍了光纤光栅传感技术及其应用的研究进展状况；详细地阐述了光纤光栅的耦合模理论及光纤布喇格光栅的传感机理；推导出了光纤布喇格光栅的布喇格公式和反射率公式；详细地阐述了压电陶瓷的工作原理、种类和基本特性，总结了压电陶瓷器件的结构形式，深入地分析研究了压电陶瓷逆压电效应及电致伸缩机理，并针对其迟滞特性给出了压电陶瓷归一化控制模型，在此模型基础上采用电极化强度控制方法有效地降低了压电陶瓷的迟滞特性。

Additionally, we analyzed the thermal-decay rules of LPGs. We use temperature-compensating package to reduce the sensitivity of temperature of LPGs. At the end of this paper, we summarized the key technologies required during practical application of LPGs, During this paper, we obtained some inventional results as follow: 1. We deduced waveguide modes of single and many mode fibers by use of Maxwell equation.

论文工作期间，主要取得了以下几方面的成果：一、我们利用Maxwell方程，推导了单模和多模光纤的导波模式，同时利用耦合模原理，简要推导了反射式光纤光栅的模式场分布及相应的模式特征方程；采用弱导光纤近似理论，严格推导了透射式长周期光纤光栅的模式场分布，得到了光栅周期与光波长间的对应关系，这是分析长周期光纤光栅光谱特性的有力工具。

Analytical formulae are presented for the first time to describe the shift in the resonance wavelength of LPG in response to etching of the fiber cladding or a change in the external refractive index. The accuracy of the formula is confirmed by comparision with numerical simulations and experimental results. We demonstrated that the resonance wavelengths of an etched LPG are more sensitive refractive index than those of an unetched grating. The bending properties of long period fiber grating written in different type fiber are studied experimentally. The transmission peaks and the central wavelength of LPG change with the bending of the fiber. A new peak appears at the shorter wavelength when the fiber is being bent. The changes of the peaks are different for different photosensitive fiber. Those properties have broad application foreground in fiber sensors and tunable filters.

分别从理论和实验上对长周期光栅的折射率特性以及光纤包层半径对长周期光栅特性的影响进行了研究，首次给出了描述光纤包层半径腐蚀和外界折射率改变与长周期光栅共振波长关系的理论表达式，实验与理论和数据模拟的结果很好符合，利用腐蚀光纤包层的方法可以有效地提高LPG的折射率灵敏度；对不同光纤中写入的长周期光栅的弯曲特性进行了实验研究，LPG的透射峰形状及其中心波长随光纤弯曲而发生变化，并且随着弯曲将在短波方向出现新的透射峰，其透射峰的变化规律因所用光敏光纤的不同而不同，这一特性在光纤传感和可调谐滤波器方面有重要的应用前景。

The pressure responses of polymer packaged fiber Bragg grating sensor are analyzed, a special kind of pressure-resistant polymer is used to coat FBG in a metal tube. A kind of soft elastic material is used to reduce the friction between tube and polymer, and to eliminate chirp effect caused by different friction distribution to improve the pressure response of FBG.

分析了聚合物封装光纤光栅的压力响应特性，通过采用特殊聚合物材料将光纤光栅封装于金属套管中，并通过在金属套管预涂覆一层软弹性材料，以消除封装过程中由于聚合物固化收缩以及聚合物与套管壁粘接与摩擦产生的光纤光栅啁啾化，改善了光纤光栅压力响应特性。

Compare with tunable filter detection technique, the wavelength measurement technique using tunable source is analyzed theoretically. We design a kind of all-fiber sensing interrogation system, by using long-period fiber grating as edge filter to interrogate the sensing signal of the FBG sensor. The wavelength resolution of the sensing measurement is 0.05nm.A novel FBG Bourdon tube sensor has been constructed, utilizing the pressure mechanic amplify function of Bourdon tube. The measured pressure sensitivity is two orders of magnitude higher than a simple monomode fiber with an in-fiber grating. Especially the pressure sensitivity of the sensor can be determined by changing the parameters of the cantilever beam. Adopting polymer package technique, we coat fiber Bragg grating by using polymer with different mechanic properties.

利用波登管对于压力的机械放大作用，研制了一种新颖的光纤光栅波登管压力传感器，将FBG的压力灵敏度提高了两个数量级，特别是这一传感器的压力灵敏度的大小可以通过改变悬臂梁自身的参数灵活控制；采用聚合物封装技术，将FBG封装于具有不同力学特性的有机聚合物基底中，利用基底的带动作用，将FBG对压力的灵敏度分别提高了20倍和31.7倍，由于我们采用了特殊的工艺，封装后的FBG不出现任何光栅啁啾；在成功封装的基础上对封装光栅的蠕变效应、FBG与封装材料之间的防滑处理等进行了实验研究；设计了外加圆柱形铝管的聚合物封装光纤光栅，将FBG的压力灵敏度提高了1430倍，可用于对微小压力变化的精确测量。

The wavelength resolution of the sensing measurement is 0.05nm. A novel FBG Bourdon tube sensor has been constructed, utilizing the pressure mechanic amplify function of Bourdon tube. The measured pressure sensitivity is two orders of magnitude higher than a simple monomode fiber with an in-fiber grating. Especially the pressure sensitivity of the sensor can be determined by changing the parameters of the cantilever beam. Adopting polymer package technique, we coat fiber Bragg grating by using polymer with different mechanic properties. Due to the driving effect of the polymer substrate, the enhanced pressure sensitivity is more than 20 times and 31. 7 times than that of a bare fiber grating. The packaged grating exhibits no significant chirp due to the adoption of special packaging technique.

全部采用国产元器件，成功地研制了掺铒光纤超荧光宽带光源，并将其组装成仪器；设计了利用可调谐FBG滤波器对光纤光栅传感信号进行检测的实验方案，对这一传感检测方案进行了理论分析和实验研究，由于采用了高性能的光电测量系统，传感测量的波长分辨率可达2pm，对应的应变分辨率为1.7με，在此基础上对FBG的波分复用传感特性进行了研究；对比调谐滤波检测技术，对光纤光栅可调谐光源波长检测技术进行了理论分析；采用长周期光纤光栅作为边带滤波器，对光纤布拉格光栅的传感信息进行解调，设计了一种全光纤传感测试系统，其波长分辨率可达0.05nm。

By adjusting the positions and angles of the two DVD optical pick-up heads, the relative distance of the two laser spots can be equivalent to one quarter of the grating pitch. When the grating moves, the surface profile of the grating can be measure directly, in order to obtain the two quadrature sinusoidal signals. Then by counting the zero crossing of these two quadrature sinusoidal signals and calculating the interpolation value of these two quadrature sinusoidal signals, the moving direction and moving displacement value of the grating can be obtained.

采用两个光学读取头，且两个光学读取头共用同一分光镜与同一聚焦物镜，於搭配光路的设计，可使两个光学读取头之光束打入同一聚焦物镜，藉由调整两个DVD光学读取头的位置与角度，使聚焦物镜聚焦的两相近聚焦光点的距离相等於四分之ㄧ光栅尺间距，当光栅尺移动时，可直接量测光栅尺的表面轮廓变化，以获得一组正交的弦波讯号，继而利用讯号四分割与细分割处理，计算出光栅尺之移动方向与移动量。

In this paper, progress of FBG sensing system demodulating technology in recent years was reviewed, problems exist in this field were analyzed, according to actual requirement of FBG sensing system, existing signal demodulating technology of FBG sensing system were classified combined with FBG sensing technology, on the basis of this, demodulating technology using amplified spontaneous emission light source linear sidebands and it's operational principle were introduced, temperature and strain sensing experiments were made based on the technology.

本文回顾了光纤光栅传感信号解调技术近年来的进展，分析了该技术领域存在的问题，结合光纤光栅传感技术，针对光纤光栅应变传感系统的实际需要，对现有光纤光栅传感信号解调技术进行了分类。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。