Abstract:
A remote water sensing system and method with optical fiber, comprises a water sensor which is an optical element designed in accordance with the principle of optical path return loss and provided with reusable features to measure the state of having water or not. A monitoring equipment is provided which is an Optical Time Domain Reflectometer (OTDR), an Optical Frequency Modulated Continuous Wave (OFMCW), or a light source power meter, and used to emit monitoring light signals and accept optical signals returned from the water sensor. A signal processing control unit analyzes the optical signal returned from the water sensor to determine whether the monitoring position is touching the water or not. The method can be used in other fields, such as optical closure watering monitoring, telecommunications facilities flooding alarm, and monitoring and alarm for a low-lying area or river water level of a bridge.
Abstract:
Distributed fiber optic chemical and physical sensors provide a relatively highly uniform response over the length of the fiber by, for example, varying such properties as the core/cladding index of refraction ratio to compensate for the non-linearity in sensitivity due for example to the loss of higher order modes in multi-mode fibers. The variation of the ratio changes the absorption coefficient of the fiber and can be used to compensate for any non-linearity in response. Other techniques for compensation also are disclosed. In particular, the invention enables compensation for the duration of the spatial transient by varying a parameter relating to the fiber.
Abstract:
Distributed fiber optic chemical and physical sensors provide a relatively highly uniform response over the length of the fiber by, for example, varying such properties as the core/cladding index of refraction ratio to compensate for the non-linearity in sensitivity due for example to the loss of higher order modes in multi-mode fibers. The variation of the ratio changes the absorption coefficient of the fiber and can be used to compensate for any non-linearity in response. Other techniques for compensation also are disclosed.
Abstract:
Methods and devices are disclosed for measuring barrier properties of a barrier coating or coating arrays where each barrier coating has a small cross section. To reduce the edge effects in the measurements of barrier properties, measurements are made using a substrate which can be flat, cylindrical or spherical structure coated with a chemically sensitive layer, a solvent resistant layer and an array of barrier coatings. The coated substrate which can be flat, cylindrical or spherical is exposed to a material of interest that has the ability to produce an analyzable variation in the chemically sensitive layer, thereby providing the ability to detect an impact of the material of interest on the barrier coatings. In one variation, an optical radiation interacts with the substrate structure, a resulting initial optical radiation associated with the initial optical radiation and each barrier coating is detected, and any impacts on the coatings by the material of interest are correlated to a value of a barrier property for each of the array of barrier coatings.
Abstract:
Distributed fiber optic chemical and physical sensors provide a relatively highly uniform response over the length of the fiber by, for example, varying such properties as the core/cladding index of refraction ratio to compensate for the non-linearity in sensitivity due to the loss of higher order modes in multi-mode fibers. The variation of the ratio changes the absorption coefficient of the fiber and can be used to compensate for any non-linearity in response. Other techniques for compensation also are disclosed.
Abstract in simplified Chinese:一种光纤水感知系统与方法。组成包括有:(1)水传感器,此水传感器是利用侦测光回路反射损失原理所设计出来之光学组件;具可重复使用之特性,用以传感有水或无水的状态(2)监测设备,此监测设备为光时域反射器(OTDR)、光频域反射频谱仪(OFMCW)或者光源及光功率计,用以发送监测光源信号及接收水传感器回传的光信号(3)信号处理控制单元,用以分析水传感器回传的光信号,判断监测点有无触水状况。本方法也可应用于光缆接续盒进水监测、电信设施淹水警示、低洼地区、桥梁河川水位监测与告警…等领域。