Fiber-optic curvature sensor with optimized sensitive zone

Femtosecond Laser Structuring of Polymer Optical Fibers for Backscatter Sensing

“…This approach can have limitations if the structure is very thick (strain at the sensor exceeding limits) or the structure is very thin (low sensitivity) [35], [36]. The advantage of fiber optic curvature measurement is that it is position-independent and can also be conducted in the neutral plane of the structure.…”

“…It can be expected that a considerable part of the backscatter change can be contributed to the redistribution of the guided light in the fiber with respect to the inscribed scatter centers when the fiber is bent. The interaction of light with the modified area is increased or decreased due to concentration of the optical intensity on the convex side of the fiber bend [35], [36]. However, a thorough simulation of backscattered intensity as a function of fiber bends using ray tracing models is tedious and rather complicated in this case.…”

Electric current measurement using fiber-optic curvature sensor

“…As polymer optical fiber is more flexibly than silica fiber and suitable for bending and connecting, the optical fiber used in this experimental setup is plastic optical fiber with a diameter of 0.25 mm and the numerical aperture of 0.51, which is made by Mitsubishi Company. In [18], we have given an optimization of this kind of optical fiber. According to optimization results, the parameters configuration of depth, height and the number of tooth are 90 μm, 30 μm and 50 respectively.…”

“…The experimental optimization of the sensor has been presented in [15] and the operation principles of the sensor are shown in [16]. In [17] and [18], mathematical models of such sensor are presented. This kind of sensor is a light intensity modulation fiber optic sensor and has following characteristics [19][20][21]:…”

Humidity sensor based on optical fiber attached with hydrogel spheres

“…Rather than coating the bare optical fiber core with an even-thickness coating, the reported sensor exploit hydrogel spheres on the fiber core. Its performance is firstly studied by commercial optical engineering software TracePro, which has been a powerful optical engineer tool and successfully applied in sensor design [13][14][15][16].…”