CAREER: A Program for Research and Education in Fiber-OpticsInvolving Fabrication of Novel Bragg-Grating Devices and Sensors

9701538夏尔马该提案涉及使用光纤布拉格光栅制造新的器件和传感器。虽然反射式布拉格光栅的特性已被很好地理解，但对于抽头布拉格栅则不是这样。这是建议在这里完成的。我们将制作一种由两个并排的抽头布拉格光栅组成的新型定向耦合器。研究了它作为波长敏感光抽头的应用。许多串联制造的此类器件将用于智能结构中横向应变的分布式传感。这种传感器将补充众所周知的反射式布拉格光栅串联的分布式纵向应变传感。反射布拉格光栅还将被用来制造一种化学传感器，用于传感NH3、H2O和CH4等环境气体。在一种新型的相关光谱系统中，光栅将取代笨重的参照室。与传统的相关光谱学中斯塔克位移和谱线展宽的部分调制不同，在建立光栅后，可以获得气体吸收线与布拉格波长之间的100%调制。这项技术将用于环境气体的分布式传感。这将在大气污染监测和控制领域有重要的应用。学生将是提案中描述的所有研究活动不可或缺的一部分。在拟议的综合计划的四年期间的任何时候，一名博士生都将参与研究，努力攻读他/她的应用物理学学位。该大学为攻读物理/工程学位的本科生提供工作/学习计划。学生通常担任研究助理，并获得支付学费和其他费用的报酬。在任何时候，拟议的研究也将支持一名本科生，帮助一名研究生进行他/她的研究。最后，该提案描述了一项针对高中生的学徒计划，在该计划中，高中生将在夏季的4-6周内在光纤实验室获得基本设备的实践经验。***

9701538 Sharma The proposal deals with fabrication of new devices and sensors using fiber-optic Bragg gratings. While the characteristics of reflection Bragg gratings is quite well understood, this is not so for tapped Bragg gratings. This is proposed to be done here. A novel directional coupler consisting of two tapped Bragg gratings side-by-side will be fabricated. Its application as a wavelength sensitive light-tap will be inveqtigated. A number of such devices fabricated in series will be useful for distributed sensing of transverse strain in Smart Structures. Such a sensor will compliment the well known distributed sensing of longitudinal strain by reflection Bragg gratings in series. Reflection Bragg gratings will also be used to fabricate a chemical sensor for sensing environmental gases like NH3, H2O and CH4 in a novel correlation spectroscopy set up where a grating will replace the cumbersome bulky reference cell. With the grating set up 100% modulation of correlation between the gas absorption lines and the Bragg wavelength can be obtained unlike partial modulation by Stark shift and broadening of spectral lines as in conventional correlation spectroscopy. This technique will be used for distributed sensing of environmental gases. This will have important applications in the area of monitoring and control of atmospheric pollution. Students will be an integral part of all research activity described in the proposal. At any time over the four year duration of the proposed integrated plan one Ph.D. student will be involved in the research, working towards his/her degree in applied physics. The University has a work/study program for undergraduate students working towards their physics/engineering degrees. A student typically works as a research assistant and is paid to cover his tuition and other expenses. At any given time the proposed research will support one undergraduate student as well, assisting a graduate student in his/her research. Finally, the proposal d escribes an apprenticeship program for high school students in which they will spend 4-6 weeks of their summer getting a hands-on experience with basic devices in a fiber-optics laboratory. ***