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标签归档:光传感

1. 用于光学传感的可调谐光波

   2023年11月29日下午3:40 请留下评论

   OFS AcoustiS实体® 光纤在随机OPO系统中的应用 

   By Regina Pynn， OFS工业传感 & 网络市场经理

   再一次, OFS光纤 are paving the way for researchers to bring cutting-edge technology out of the lab 和 into practical applications. 这一次，我们要深入研究 光纤传感 – a technology that relies on a carefully tuned light source with specific traits like wavelength, 权力, 脉冲宽度. 

   一般来说，光纤传感是从激光开始的, but they come with a catch: lasers have their materials carefully selected to emit stable light pulses at a specific desired wavelength, 限制他们的灵活性. A system with wavelength modulation promises exciting innovations for fields as diverse as quantum computing 和 激光雷达遥感.  

   

   进入光学参量振荡器(OPO). It transforms regular laser light into controlled wavelength pulses by guiding the laser light into an optical cavity, 它在非线性晶体和谐振器周围反弹. As the light moves through the cavity 和 is sent back over itself multiple times the system changes wavelengths 和 creates parametric amplification.  

   然而, there’s a hiccup in this dazzling performance: OPOs are quite s实体itive to temperature 和 environmental changes. Even small changes impact the wavelength 和 权力 of the light as it exits the cavity, 将opo主要限制在高维护的实验室环境中. 

   研究人员推测，随机激光, 在光源中，什么会促进散射, would make the system more robust because the scattering would come from the controlled design of the laser 和 not be at the mercy of environmental changes in the optical cavity. 

   一篇来自渥太华大学的开创性论文 验证了这个概念. A team demonstrated, for the first time, that an augmented s实体ing 光纤 like OFS’ AcoustiS实体 能让这个想法成为现实吗. AcoustiS实体 is manufactured with enhanced Rayleigh scattering 和 this scattering allowed the OPO system to have stable, 在一个简单而坚固的光学腔中调谐波长. 

   Congratulations to the University of Ottawa team 和 to all the technologists working to unshackle OPOs from the lab. 

2. 光纤网络电缆有助于监测里奇克莱斯特余震

   2019年8月9日12:10 请留下评论

   Seismologists from the California Institute of Technology (Caltech) are using 光纤网络电缆 to monitor 和 record aftershocks from the July 4 和 5 Ridgecrest, CA, earthquakes. 通过使用 光纤, 科学家们可以聚集, track, 和 analyze data in much greater depth from the thous和s of daily aftershocks.

   To do this, the scientists send a beam of light down 光纤 in an unused or “暗”光缆. 当光线到达光纤上的微小瑕疵时, 一小部分光被反射回来并被记录下来. In this way, each fiber imperfection acts as a trackable location along the buried fiber optic cable. When seismic waves move through the ground, the cable exp和s 和 contracts slightly. 这种变化会影响光在两个位置之间的传播时间. By monitoring these changes, seismologists can monitor the motion of seismic waves.

   根据加州理工学院, the miniscule fiber imperfections occur often enough so that every few meters of 光纤 act as an individual seismometer. 事实上, monitoring 50 kilometers of fiber optic cable in three different locations is roughly equal to deploying more than 6,在该地区安装了000个地震仪.

   Caltech launched the project within days of the two large earthquakes 和 began contacting groups in a search for unused fiber optic cable that would be close enough 和 long enough to be useful. The scientists finally contacted the California Broadb和 Cooperative’s Digital 395 project. 数字395项目的目标是建立一个新的 583英里的光纤网络 that will run north to south, along the eastern Sierra Nevada, passing near Ridgecrest. Digital 395 offered three segments of its fiber cable to which Caltech connected s实体ing instruments.

   Information gathered from the Ridgecrest fiber network will help seismologists learn more about the way that earthquakes move through the earth, 和 specifically how seismic waves move through the area around Ridgecrest.

3. 光纤“感知”周围环境的变化

   2018年8月3日下午5:27 请留下评论

   公司使用光纤作为传感器来检测温度的变化 温度和压力. This technique is often used to monitor structures including bridges 和 gas pipelines.

   Now researchers at Ecole Polytechnique Fédérale De Lausanne (EPFL) have discovered a new method where 光纤 当它们接触到液体或固体时能识别吗. The researchers accomplished this by generating a sound wave with help from a light beam inside the 光纤.

   一种不会干扰光线的传感器

   影响玻璃光纤所载光的四个因素:强度, 阶段, 偏振和波长. These factors can change when something stretches the fiber or the temperature varies. 这些变化 让纤维充当传感器 通过检测结构裂缝或温度变化. 然而, 直到现在, users could not know what was actually happening around the fiber without letting light escape, 是什么阻断了光的路径.

   EPFL的方法是利用光纤内部产生的声波. 这种超高频波有规律地从光纤壁反射回来. This echo varies at different locations depending on the type of material that the wave contacts. The echoes leave an imprint on the light that users can read when the beam exits the fiber. While users can study this imprint to detect 和 map out the fiber’s surroundings, 它非常微弱，几乎不会干扰纤维内的光. 事实上, users could employ this technique to s实体e what is occurring around a fiber 和 send light-based information at the same time.

   在实验中, 研究人员先将纤维浸入水中，再浸入酒精中, 然后把他们丢在外面. Each time, their system correctly identified the change in the fibers’ surroundings. The group expects their technique to have many potential applications by detecting water leakage, 以及接触纤维的液体的密度和盐度.

   时空检测

   该方法通过基于时间的方法来识别周围环境的变化. 每个波脉冲都有一个轻微的时间间隔. 然后，当光束到达时，延迟被反射. The researchers can see what any disturbances were 和 determine their location. 该小组目前可以定位10米以内的干扰, but have the technical means 和 expect to increase accuracy down to one meter.

   想要阅读和学习更多，去吧 在这里.