Improved Refractive Index Sensitivity Utilizing Long-Period Gratings with Periodic Corrugations on Cladding

Abstract

A new structure of Long-Period Gratings (LPGs) sensor is introduced as a sensitive ambient RI sensor. This structure consists of creating periodic corrugations on the cladding of the LPG. The experimental results show that this LPG structure has good performances in terms of linearity and sensitivity and serves as a highly sensitive and cost-effective sensor. It also has the advantage of portability as the corrugation can also serve as the reservoir for the specimen collection to be tested.

Bent fused fiber taper intermodal interferometer as a refractive index sensor

“…near 1.45. The sensitivity around 1.33 is thus an order of magnitude higher than that of the thin-core abrupt fiber taper [5], twice better than for periodically tapered small core fibers [8] and comparable to the improved sensitivity of corrugated LPGs [9].…”

“…Optical fiber tapers have for long been used for refractometric sensing [4][5][6][7][8]. The other most popular fiber optic structure for refractometric sensors are long period fiber gratings (LPGs) [9] with sensitivities depending on the type of fiber, the coating and additional processing such as etching.…”

Vibration and Magnetic Field Sensing Using a Long-Period Grating

“…However, FBGs and LPGs, fabricated in standard optical fibers, usually present a high cross-sensitivity to temperature. In LPGs, in addition, the refractive index (RI) of the external medium is also a major source of cross sensitivity, strongly affecting the sensor response [16], [17] and requiring the use of low refractive index coatings that impact on the overall sensor response.…”

Fiber-Optic Bend Sensor Based on Double Cladding Fiber

“…Such sensors are utilized for measurements of temperature, various types of deformations, refractive index and chemical composition of the medium, and other parameters [1][2][3]. The principle of operation of these sensors is that the cladding modes are highly sensitive to influences exerted on the fiber guiding the cladding modes.…”