Highly sensitive curvature sensor based on a multicladding fiber sandwiched dual no-core fibers structure

Abstract

In this paper, we present a simple, compact, and highly sensitive optical fiber curvature sensor. It consists of dual no-core fibers for coupling energy from the lead-in single-mode fiber (SMF), and recoupling the energy into the lead-out SMF. The sensing section is constituted by multicladding fiber with a length of 5 cm. In the experiment, the spectrum shows a blueshift, and the energy corresponding to the resonant wavelength shows a cosine series with a bending of the sensing segment. The curvature sensitivity around the wavelength of 1550 nm shows -39.02 nm/m(-1) within the curvature range from 0.3 to 2.14 m(-1). The temperature sensitivity is 78.2 pm/°C in the temperature range of 10 °C-60 °C. It implies the possibility of temperature measurement.

Fiber curvature sensor based on concave‐heterotypic cascaded fiber Sagnac interferometer

“…6,7 In generally, the curvature sensors based on gratings characterize low bending sensitivity. To enhance the detection sensitivity, some modifications in waveguide structures, such as dual side-hole fiber, 8,9 eccentric core fiber (ECF), 10 multicore fiber, 11 holey fibers 12 and multicladding fiber, 13 have been employed for curvature sensing. Others employing optical fiber interferometers, such as Mach-Zehnder interferometer MZI, 14 Fabry-Pérot interferometer (FPI), 15 and Sagnac interferometer 16 are widely investigated for measurement of curvature.…”

Cost-Effective Optical Fiber Curvature Sensor With Ultrahigh Sensitivity Based on Two Microcollapses in Silica Capillary

“…Fiber curvature sensors based on the single-multi-single mode fiber (SMS) structure are also with high sensitivities [18]. Meanwhile, they have advantages of simple fabrication process, low cost and good mechanical property, and their sensitivities can be further improved by replacing the multi-mode fiber section in the SMS structure with coreless fiber [19], twin-core fiber [20] or multi-cladding fiber [21] to extend the light field distribution. However, the curvature sensitivities of most of these sensors are still less than 100 nm/ m −1 , and some interferometer-based curvature sensors are also impaired by the crosstalk to temperature [20], [21].…”

A Compact Fiber Inclinometer Using a Thin-Core Fiber with Incorporated an Air-Gap Microcavity Fiber Interferometer

“…For example, the twin core fiber-based interferometers have been developed for highly sensitive bending sensing [ 12 , 13 ]. Another common technique is to employ splices between similar or dissimilar fibers with core-mode-field mismatching, in which the expected interference spectrum may be achieved via the interference between core and cladding modes [ 14 , 15 , 16 , 17 , 18 ]. For example, a hollow-core photonic crystal fiber (PCF) was spliced between two SMFs with a lateral offset to form an interferometer.…”