A Designed Twist Sensor Based on the SPR Effect in the Thin-Gold-Film-Coated Helical Microstructured Optical Fibers

Abstract

The traditional optical fiber-based twist sensing has the disadvantage of low sensitivity and difficulty of distinguishing the twist direction. Moreover, chiral isomerism may lead to sensing errors. In this paper, a six-hole helical microstructured optical fiber (HMSF) with a thin-gold-film-coat based on the surface plasmon resonance (SPR) effect was designed. The twist sensing characteristics of this fiber were further analyzed. Numerical calculation and analysis show that the combination of helical effect and SPR effect can design an HMSF-based sensor that is very sensitive to distortion. In the torsion range of ±300°, the distortion sensitivity can reach 2470.7 pm/(rad/m), and the linear correlation coefficient is 0.99996. Based on the special sensing mechanism, it has a good linear coefficient over a large range. Additionally, the direction of the twist can be easily discerned. The HMSF in this work not only has high sensitivity, high linearity, high fault tolerance rate, and a wide range of measurement, but is also easy to manufacture. Therefore, it is promising in the field of twist sensing and has a good application prospect.

Experimental researches and testing of silica twisted six-GeO2-doped core microstructured optical fiber. Part I: fusion splicing with telecommunication optical fibers and differential mode delay map measurements

“…At the same time, there is a series of known published works [59][60][61][62][63][64][65][66][67][68][69][70][71][72] , which suppose and further confirm, based on performed both simulations and experimental researches, that induced twisting over MOFs and PCFs with specified configuration also adds new unique waveguide features. These spun, helical or twisted MOFs are declared as alternative mode converters 59 , special optical fibers for polarization maintenance and generation of optical activity [60][61][62][63] , and new kind of fiber optic electric current / magnetic field sensors 64 or twisting / strain sensors [65][66][67] as well as they are considered as new type of optical fibers with great potentiality for guiding and transmission of orbital angular momentum (OAM) modes [68][69][70][71] . Therefore, we supposed, that combination of two basic complicated fiber optic structuresmulti-core MOFs and twisted MOFswill add novel unique properties to this new type of optical fibers.…”

Functionalized Chiral Twisted Optical Fibers: A Review

“…Introducing twisting into an optical fiber leads to changes in the refractive index distribution of the material. In electromagnetics, these variations in the material can be translated into changes in the coordinates from {x, y, z} to {x , y , z } [5,31,32]. The new coordinate system's permeability and permittivity tensors are provided by…”

Technological issues of twisted microstructured optical fiber fabrication

“…There are number of known published theoretical and experimental works, that demonstrate unique properties of twisted MOF in polarization maintaining and optical activity generation processes [11][12][13][14][15]. They are also considered as new (alternative to fiber Bragg gratings / tapered optical fibers) fiber optic probes for measuring strain and twisting [16][17][18] and sensors for measuring magnetic field and electric current [19]. Twisted or spun MOFs are also utilized as spectral and mode filters [20], optical tweezers and optical orbital angular momentum shaper in telecommunication systems, that utilize spatial division multiplexing technique [21][22][23][24][25][26][27][28][29][30][31].…”