title: Fiber-optic bend sensor using LP21 mode operation.
abstract: A novel fiber-optic bending sensor based upon the propagation of LP21 mode is demonstrated. The sensor, comprised of an S-bend fiber on an elastic film, measures LP21 mode specklegram rotation, which increments linearly with bending angle by the stress-optic effect. The sensor is capable of experimentally achieving a sensitivity as high as 4.13 rad/m(-1). The theoretical analysis of the sensor, which is a combination of fiber coupled-mode theory and elastic-optic theory, validates the accuracy of the sensor. The sensor is also shown to be temperature-immune, and can detect both bending direction and bending angle with a large dynamic range. Furthermore, the sensor implementation incorporates inexpensive single-mode fiber at 650 nm for few-mode operation, enabling low-loss transmission and compatibility with existing interfaces.
authors.affiliation: Department of Optical Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China.
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Fan
authors.forename: George
authors.initials: G
authors.lastname: Wu
authors.forename: Wanting
authors.initials: W
authors.lastname: Wei
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Yuan
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.forename: X
authors.initials: X
authors.lastname: Wu
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004548:Elasticity; D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation*; D006801:Humans; D008027:Light; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation; D012542:Scattering, Radiation; D013314:Stress, Mechanical; D013718:Tensile Strength