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Femtosecond laser inscribed fiber Bragg grating sensors.

机译：飞秒激光内接光纤布拉格光栅传感器。

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摘要

A study of developing harsh environment multi-parameter fiber Bragg grating sensors using femtosecond IR laser irradiation was conducted. The overall technical objective is to develop an intelligent multi-parameter optical fiber sensor system for real-time temperature, pressure, vibration or chemical concentration monitoring in high temperature (above 1000 ° C) harsh environments.;Femtosecond laser pulses have opened up a new phase in the exploration and applications of optical breakdown, revealing new physical processes and scenarios behind the laser damage of materials on the femtosecond timescale. The fiber gratings inscribed by femtosecond laser illumination have annealing characteristics similar to type II fiber gratings and demonstrate stable operation at much higher temperature than conventional UV laser induced gratings on photosensitive fibers.;In this dissertation, six types of fiber Bragg grating sensors were fabricated via femtosecond laser inscription and their applications were investigated -- single mode silica fiber Bragg grating sensor (SMFBG), multi-mode silica fiber Bragg grating sensor (MMFBG), ultra thin multi-mode silica fiber Bragg grating sensor (ThMMFBG), polarization maintaining single mode silica fiber Bragg grating sensor (PMFBG), ultra thin polarization maintaining silica fiber Bragg grating sensor (ThPMFBG) and multi-mode sapphire single-crystal fiber Bragg grating sensor (SaFBG).;The SMFBG sensor shows good distributed sensing capability and excellent long term thermal stability in high temperature environment (up to 1000 ° C). The novel multi-parameter (temperature, strain, vector bending) sensor based on asymmetric Bragg gratings fabricated in MM silica fiber and PM fiber have more than one resonant dip in the transmission spectrum. Bending and ambient temperature fluctuations affect the shapes of multiple transmission dips in different ways. In bending, different dips have different sensitivities. Temperature fluctuations tended to influence the dips uniformly across different dips. By analyzing the changing spectra of the dips, one can distinguish the changes induced by bending or temperature fluctuations.;THMM and THPM grating sensors are also investigated for liquid pressure sensing applications. After etching away most of the cladding, both MM and PM fiber grating spectra become sensitive to ambient refractive index changes, and their sensitivity to bending and strain is also enhanced. This enables the application for multi-parameter chemical/bio and pressure sensing. Furthermore, an ultrahigh temperature harsh environment sensor with operation temperature higher than 1500 ° C is developed by fabricating higher-order mode rejected fiber Bragg gratings in sapphire crystal fiber. This unique in-fiber grating in single crystal sapphire fiber is very promising in extreme high temperature environmental sensing applications.;The fabrication method and grating writing mechanism is described in Chapter 2, then in Chapters 3 and 4, a detailed discussion about their applications in harsh environments multi-parameter sensing such as temperature, bending, pressure, bio and chemical sensing etc. is conducted. Finally, extremely high temperature sensing using higher-order-mode rejected sapphire single-crystal fiber is demonstrated in Chapter 5. The grating was tested in a high temperature furnace up to 1600 ° C.
机译：进行了飞秒红外激光辐照开发恶劣环境多参数光纤布拉格光栅传感器的研究。总体技术目标是开发一种智能多参数光纤传感器系统，用于在高温（1000°C以上）恶劣环境中进行实时温度，压力，振动或化学浓度监控。飞秒激光脉冲开辟了一个新的领域在光学击穿的探索和应用阶段，揭示了飞秒时间尺度上材料受到激光损伤的新物理过程和场景。飞秒激光照射刻画的光纤光栅具有与II型光纤光栅相似的退火特性，并且在光敏纤维上比传统的UV激光诱导光栅在更高的温度下具有稳定的工作性能。飞秒激光铭文及其应用进行了研究-单模石英光纤布拉格光栅传感器（SMFBG），多模石英光纤布拉格光栅传感器（MMFBG），超薄多模石英光纤布拉格光栅传感器（ThMMFBG），保偏单模式石英光纤布拉格光栅传感器（PMFBG），超薄偏振保持石英光纤布拉格光栅传感器（ThPMFBG）和多模式蓝宝石单晶光纤布拉格光栅传感器（SaFBG）。； SMFBG传感器具有良好的分布式传感能力和出色的长距离高温环境（高达1000°C）中的长期热稳定性。基于不对称布拉格光栅的新型多参数（温度，应变，矢量弯曲）传感器是用MM石英纤维和PM纤维制造的，在透射光谱中具有多个共振谷。弯曲和环境温度波动会以不同的方式影响多个变速箱倾角的形状。在弯曲过程中，不同的倾角具有不同的灵敏度。温度波动往往会在不同的跌落之间均匀地影响跌落。通过分析倾角的变化频谱，可以区分出弯曲或温度波动引起的变化。；还研究了THMM和THPM光栅传感器用于液体传感应用。蚀刻掉大部分包层后，MM和PM光纤光栅光谱对环境折射率的变化都变得敏感，并且它们对弯曲和应变的敏感度也提高了。这使多参数化学/生物和压力传感应用成为可能。此外，通过在蓝宝石晶体光纤中制造高阶模拒绝光纤布拉格光栅，开发了一种工作温度高于1500°C的超高温恶劣环境传感器。这种在单晶蓝宝石纤维中独特的光纤光栅在极端高温环境传感应用中非常有前途。第2章介绍了制造方法和光栅写入机理，然后在第3和4章中详细讨论了它们的应用。在恶劣的环境下，进行多参数感测，例如温度，弯曲，压力，生物和化学感测等。最后，在第5章中演示了使用高阶模态拒绝蓝宝石单晶纤维进行的极高温度感测。在高达1600°C的高温炉中测试了光栅。

著录项

  • 作者

    Zhan, Chun.;

  • 作者单位

    The Pennsylvania State University.;

  • 授予单位 The Pennsylvania State University.;
  • 学科 Engineering Electronics and Electrical.;Physics Optics.;Physics Radiation.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 149 p.
  • 总页数 149
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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