Numerical calculation of temperature sensing in seawater based on microfibre resonator by intensity-variation scheme

Abstract

A seawater temperature sensing and detection method based on microfibre resonator (MR) by intensity-variation scheme is proposed, which has the advantages of high sensitivity and low detection limit. The dependences of sensitivity on probing wavelength, fibre diametre and ring diametre are studied. Results show that probing wavelength influences the sensitivity by the absorption loss predominantly. Larger absorption loss results in lower sensitivity, which is much different with resonant-wavelength-shift scheme. And sensitivity increases with the increasing ring diametre due to the decreasing bending loss and increasing Q-factor. In addition, there may exist an optimal fibre diametre, with which the sensitivity is maximized. By tuning the parameters of system, sensitivity can be tuned from 0.0784 NI/ • C to 13.79 NI/ • C (NI is the abbreviation of normalized intensity). Correspondingly, dynamic range changes from 11.77 • C to 0.08 • C. Additionally, the dependences of detection limit on wavelength, fibre diametre, and ring diametre are also investigated, which are opposite to that of sensitivity. For different temperatures, the dependences of sensitivity and detection limit at some typical temperatures are studied, which shows that high sensitivity and low detection limit are related to high temperature, and the optimal fibre diametres for high sensitivity and low detection limit are the same at different temperatures. The lowest detection limit is estimated to be 10 -7• C level, which is four orders of magnitude smaller than that of the traditional method. Results shown here are beneficial to find the optimal parameters for the temperature sensors, and offer helpful references for assembling micro-photonics device used in seawater sensing and detection.

A Highly-Sensitive Temperature-Sensor Based on a Microfiber Knot-Resonator Packaged in Polydimethylsiloxane

“…The temperature sensitivity was 20.6 pm/ o C, with good linearity for 30 to 130 o C. By coating a layer of PDMS, with a thickness of 5 μm, on the surface of the MKR, which had a microfiber diameter of 1 μm, the temperature sensitivity for seawater could reach 0.197 nm/ o C at 1550nm. The experimental results reveal that the sensitivity depends on the ratio of the external power around the microfiber and the bending-and absorption-losses [18]. The MKR device was inserted between two flexible PDMS graphene composite films and had a temperature sensitivity of 0.544 dB/ o C in the range of 30-60 o C [19].…”

Tri‐core photonic crystal fiber based refractive index dual sensor for salinity and temperature detection

“…With this convenient, micro ring and photonic crystal based structural were experimentally proposed and monitored for the application of salinity and temperature sensing for seawater as stated in Refs. . In addition, simultaneous measurements for dual sensing is used by fiber Bragg grating (FBG), surface plasmon resonance dip probe, microfiber directional coupler, ring resonator with polymide/hydrogel‐coated photonic crystal fiber (PCF), directional coupler based micro/nanofibers, high‐birefringence elliptic fiber, Fabry‐ Perot interferometer, Mach‐Zhender interferometer, and D‐Shaped PCF .…”

Analytical Modelling of a Refractive Index Sensor Based on an Intrinsic Micro Fabry-Perot Interferometer

“…In recent years fiber optic refractive index (RI) sensors have gain attention since these have interesting characteristics which allow them to be used in a broad range of chemical and biological sensing applications [ 1 , 2 ]. Moreover, fiber optic RI sensors can be implemented in different ways, such as by using fiber Bragg gratings [ 3 , 4 , 5 , 6 ], long period gratings [ 7 , 8 , 9 ], interferometers [ 10 , 11 , 12 ], resonators [ 13 , 14 , 15 , 16 ] and tapers [ 2 , 9 , 17 , 18 ]. Among these the Fabry-Perot interferometer (FPI) is a very popular option since it can be fabricated in different ways [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”