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Tag Archive: sensing

  1. Tuneable Light Waves for Optical Sensing

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    OFS AcoustiSens® Optical Fibers used in random OPO system demonstration 

    By Regina Pynn, OFS Industrial Sensing & Networking Market Manager

    Once again, OFS optical fibers 是否在为研究人员将尖端技术从实验室带到实际应用中铺平道路. This time, we’re delving into the realm of optical fiber sensing 一种依赖于具有特定特征(如波长)的精心调谐光源的技术, power, and pulse width. 

    Generally optical fiber sensing starts with a laser, 但它们也有一个问题:激光的材料是经过精心挑选的，可以在特定的波长上发射稳定的光脉冲, limiting their flexibility. 波长调制系统有望在量子计算和其他领域带来令人兴奋的创新 LiDAR sensing.  

    opo可以利用AcoustiSens光纤中的故意散射来改变光脉冲的波长.
    OPOs can use the deliberate scattering in AcoustiSens optical fiber to change the wavelength of light pulses

    Enter the optical parametric oscillator (OPO). 它通过引导激光进入光学腔，将常规激光转换成可控波长的脉冲, bouncing it around nonlinear crystals and resonators. 当光穿过腔体并多次返回时，系统会改变波长并产生参数放大.  

    However, 这种令人眼花缭乱的表现有一个小问题:opo对温度和环境变化非常敏感. 即使很小的变化也会影响光的波长和功率，因为它离开了腔体, confining OPOs mostly to high-maintenance lab settings. 

    Researchers theorized that a random laser, which encourages scatter in the light source, 是否会使系统更加健壮，因为散射将来自激光的受控设计，而不受光学腔内环境变化的影响. 

    A groundbreaking paper from the University of Ottawa validates this concept. 一个团队首次展示了像OFS这样的增强传感光纤， AcoustiSens can make this idea a reality. AcoustiSens具有增强的瑞利散射，这种散射使OPO系统具有稳定性, tuned wavelengths in a simple and robust optical cavity. 

    祝贺渥太华大学的团队和所有致力于将opo从实验室中解放出来的技术人员. 

  2. Enhancing Distributed Sensing with a Dual-Brillouin-Peak Optical Fiber

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    双布里渊峰光纤是由OFS的研究人员设计和制造的

    In an era of advanced sensing technologies, 双布里渊峰光纤是解决几乎所有光纤传感器中存在的应变-温度交叉敏感问题的一种新的实用解决方案. Its potential spans across a multitude of fields, demanding precision over long distances and high resolutions. 这项突破性的技术将重新定义基于布里渊散射的分布式光纤传感的边界.

    双布里渊峰单模光纤可以同时测量应变和温度. This is a very useful feature for applications such as structural health monitoring, oil and gas exploration, and power transmission.

    双布里渊峰单模光纤的布里渊增益谱中有两个不同的峰，其振幅水平相似. By measuring the frequency shifts of these two peaks, we can determine both the strain and the temperature along the fiber.

    This is different from conventional single-mode optical fibers, 它们只有一个显性布里渊峰，只能测量应变或温度, but not both at the same time. To measure both parameters, 我们需要使用两种不同的纤维或一种特殊的纤维，这种纤维的涂层具有不同的热膨胀系数，这通常会导致病态的区分.

    The dual-Brillouin-peak optical fiber has several advantages over these methods. 首先，它通过减少组件和连接的数量来简化测量系统. 其次，它消除了校准或补偿热膨胀系数的需要. Third, 它通过提高高阶声模的布里渊增益来提高测量的精度和分辨率.

    研究人员展示了他们的光纤在25公里的传感长度和5米的空间分辨率下的性能. 他们实现了2°C的温度分辨率和40微应变的应变分辨率.

    光纤与标准单模通信光纤可互换，拼接损耗低. 该光纤与市场上现有的BOTDR/BOTDA(布里渊光时域反射计/分析仪)询问器完全兼容. 双布里渊峰光纤是一种很有前途的同时测量分布应变和温度的技术. 它在需要远距离和高分辨率传感的各个领域具有潜在的应用前景.

    To learn more, read the whitepaper: Request PDF | OFS (basilinfracon.com)

  3. Optical Fiber “Senses” Change in Surroundings

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    Companies use optical fiber as a sensor to detect changes in temperature and pressure. 该技术通常用于监测桥梁和天然气管道等结构.

    现在，洛桑理工学院(EPFL)的研究人员发现了一种新的方法 optical fibers can identify when they are in contact with a liquid or a solid. 研究人员通过在光纤内的光束的帮助下产生声波来实现这一目标.

    A Sensor That Doesn’t Disrupt the Light

    Four factors affect the light carried by a glass optical fiber: intensity, phase, polarization and wavelength. 当某些东西拉伸纤维或温度变化时，这些因素会发生变化. These changes let the fiber act as a sensor by detecting cracks in structures or temperature changes. However, until now, 如果不让光线逃逸，用户就无法知道光纤周围到底发生了什么, which interrupts the light path.

    The method from EPFL uses a sound wave generated inside the fiber. This hyper-frequency wave regularly bounces off of the fiber’s walls. 这种回声在不同位置的变化取决于波接触的材料类型. 当光束离开光纤时，回声会在光线上留下印记，用户可以读取. While users can study this imprint to detect and map out the fiber’s surroundings, it is so faint that it barely disturbs the light within the fiber. In fact, 用户可以利用这项技术来感知光纤周围发生的事情，同时发送基于光的信息.

    In experiments, the researchers submerged their fibers in water and then in alcohol, and left them out in the open air. Each time, their system correctly identified the change in the fibers’ surroundings. 该小组希望他们的技术在检测漏水方面有许多潜在的应用, as well as the density and salinity of fluids that touch the fiber.

    Spatial and Temporal Detection

    This method discerns changes in the surroundings with a time-based method. Each wave impulse is created with a slight time jag. Then, when the beam arrives, the delay is reflected. The researchers can see what any disturbances were and determine their location. The group can currently locate disturbances to within 10 meters, but have the technical means and expect to increase accuracy down to one meter.

    To read and learn more, go HERE.