Study On Temperature Sensing Characteristics Of Coreless Side-polished Fiber Wrapped With Polydimethylsiloxane

Owning the advantages of immunity to electromagnetic interference,chemical inertness,compact size and high sensitivity,temperature fiber sensors attract widespread interest in sensing application,such as bio-medical detection,bio-chemical detection,environmental monitoring,and food safety.The measurement sensitivity of temperature fiber sensors can be achieved by using temperature sensitive material and fiber-optic refractive index sensor.This type of temperature sensor has been widely studied and reported due to its advantages of simple structure,low cost,stable performance.In this paper,a novel fiber structure of coreless side-polished fiber(CSPF)is exploited to realize a fiber temperature senor by wrapping the sensitive material polydimethylsiloxane(PDMS).Beam propagation method(commercial BPM module from Rsoft Inc)is employed to simulate the transmission spectra and field evolution of the coreless side-polished fiber wrapped with polydimethylsiloxane(PDMSW-CSPF).The effects of the flat's length(Lf),transition's length(Lt),residual thickness(RT)and reference wavelength(RW)on the sensitivity of the temperature are analyzed by simulation.The simulation results show that the Lf and Lt of CSPF have no significant effect on temperature sensitivity.By contrast,the RT and RW have a significant effect on the temperature sensitivity of the sensor.What's more,the experiments show the sensitivity of the PDMSW-CSPF could be enhanced further by reducing the residual thickness and choosing the dip at a longer wavelength.In the temperature range of 30~85°C,the PDMSW-CSPF with RT = 43.26 ?m exhibits a high temperature sensitivity of-0.4409 nm/°C,the high linearity of 0.9974,the high repeatability with low relative sensitivity deviation(RSD)of ± 0.068%,and the high stability with low standard deviation(RD)of 0.141 nm.Thus,it can be concluded,the PDMSW-CSPF has higher comprehension performance.