He Caiyan, Fang Junbin, Zhang Yanan, Yang Yu, Yu Jianhui, Zhang Jun, Guan Heyuan, Qiu Wentao, Wu Pengjun, Dong Jiangli, Lu Huihui, Tang Jieyuan, Zhu Wenguo, Arsad N, Xiao Yi, Chen Zhe
Opt Express. 2018 Apr 16;26(8):9686-9699. doi: 10.1364/OE.26.009686.
A novel fiber structure, coreless side-polished fiber (CSPF) that is wrapped by polydimethylsiloxane (PDMS), is demonstrated to be highly sensitive to temperature because of the high refractive index sensitivity of the CSPF and the large thermal optic coefficient of the PDMS. Our numerical and experimental results show that the several dips in the transmitted spectra of PDMSW-CSPF is originated from the multimode interference (MMI) in the CSPF and will blueshift with the increase of temperature. Furthermore, for such a PDMSW-CSPF, we investigate its temperature sensing characteristics and the influences of residual thickness (RT) and dip wavelength on the sensitivity both numerically and experimentally. In the temperature range of 30~85°C, the PDMSW-CSPF with RT = 43.26 μm exhibits a high temperature sensitivity of -0.4409 nm/°C, the high linearity of 0.9974, and the high stability with low standard deviation of 0.141 nm. Moreover, in the cycle experiments, where the environmental temperature was set to automatically increase and then decrease, the PDMSW-CSPF exhibits a low relative deviation of sensitivity (RSD) of down to ± 0.068%. Here, the RSD is defined as the ratio of sensitivity deviation to the average sensitivity measured in the heating/cooling cycle experiments. The lower RSD indicates that PDMSW-CSPF has better reversibility than other fiber structure. The investigations also show that the sensitivity of the PDMSW-CSPF could be enhanced further by reducing the residual thickness and choosing the dip at a longer wavelength.
一种新型的光纤结构——由聚二甲基硅氧烷（PDMS）包裹的无芯侧面抛光光纤（CSPF），由于CSPF的高折射率灵敏度和PDMS的大热光系数，被证明对温度高度敏感。我们的数值和实验结果表明，PDMSW-CSPF传输光谱中的几个凹陷源于CSPF中的多模干涉（MMI），并且会随着温度的升高而蓝移。此外，对于这种PDMSW-CSPF，我们通过数值和实验研究了其温度传感特性以及残余厚度（RT）和凹陷波长对灵敏度的影响。在30~85°C的温度范围内，RT = 43.26μm的PDMSW-CSPF表现出-0.4409nm/°C的高温灵敏度、0.9974的高线性度以及0.141nm的低标准偏差的高稳定性。此外，在环境温度设置为自动升高然后降低的循环实验中，PDMSW-CSPF表现出低至±0.068%的灵敏度相对偏差（RSD）。这里，RSD定义为灵敏度偏差与加热/冷却循环实验中测量的平均灵敏度的比值。较低的RSD表明PDMSW-CSPF比其他光纤结构具有更好的可逆性。研究还表明，通过减小残余厚度并选择更长波长的凹陷，可以进一步提高PDMSW-CSPF的灵敏度。
