A Hybrid Multimode Interference Structure-Based Refractive Index and Temperature Fiber Sensor

Abstract

A novel all-fiber sensor based on cascaded singlemode-no-core-singlemode (SNS) and siglemode-multimodesinglemode (SMS) fiber structure is proposed and investigated. Simulation results show that for the given fibers, by appropriately choosing the lengths of no-core fiber (NCF) and multimode fiber (MMF), the transmission spectrum will exhibit two distinguishable dips corresponding to SNS and SMS, respectively. The simultaneous measurement of liquids' refractive index and temperature can be realized by monitoring the two dips' central wavelength shifts. According to simulations, a corresponding sensor is fabricated and tested. The experimental results demonstrate the feasibility of the sensor and show that the sensor has the RI and temperature sensitivities of 113.66 nm/RIU and 9.2 pm/ o C, respectively.Index Terms-Optical fiber sensors, refractive index, temperature, multimode interference.

Multiparameter fiber-optic sensors: a review

“…Splicing of fibers with dissimilar modal fields. [19][20][21][22][23][24][25] Fibers with dissimilar modal fields are spliced together to facilitate the transfer of optical power from one mode of the lead fiber to two or more modes of the sensing fiber. Typical examples representing this group include sensor structures that utilize splices between single-mode and step-index few-mode or multimode fibers or core-less fibers, as shown in Fig.…”

“…The two most often reported approaches utilize either a single MZI 23,24,27,29,30,[33][34][35][36][37] or a cascading of two MZIs. [19][20][21]26,31,38 a. Using a single MZI for temperature and RI sensing.…”

“….16(b)]. Similarly, the combination of a short core-less fiber section and a section of multimode fiber19 can be used to create an RI-temperature-sensitive interferometer pair [Fig. 16(a)].…”

Up-down Taper Based In-Fiber Mach-Zehnder Interferometer for Liquid Refractive Index Sensing

“…Optical fiber refractive index (RI) sensors are used in biological fields, medicine and environment [1][2][3]. So far, lots of fiber optic RI sensors have been reported in the literature, such as Mach-Zehnder (MZIs) [4][5][6], Fiber Grating [7], Fabry-Pérot (FPIs) [8], Sagnac [9] and multi-mode interferometer [10][11][12]. Among them, Quan [8] prepared an open-cavity FPI by splicing a section of the fused silica fiber tube between photonic crystal fiber (PCF) and single mode fiber (SMF), an ultra-high sensitivity of 30,899 nm/RIU is obtained.…”

Intensity Demodulated Refractive Index Sensor Based on Front-Tapered Single-Mode-Multimode-Single-Mode Fiber Structure

“…Fiber refractive index (RI) sensors play a significant role in the fields of biology, chemistry, and medicine [ 1 ]. And the schemes based on fiber Bragg gratings [ 2 ], long-period fiber gratings [ 3 ], photonic crystal fiber [ 4 , 5 ], multimode interference (MMI) [ 6 ] and surface Plasmon resonance (SPR) [ 7 , 8 ] are frequently reported. Comparatively, the MMI-based sensors have received great attention due to the advantages of high sensitivity, low cost, and ease of fabrication.…”