Devision Fibre Optic Sensors, Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
Sensors (Basel). 2018 Nov 15;18(11):3952. doi: 10.3390/s18113952.
In this paper perfluorinated graded-index polymer optical fibers are characterized with respect to the influence of relative humidity changes on spectral transmission absorption and Rayleigh backscattering. The hygroscopic and thermal expansion coefficient of the fiber are determined to be C H E = (7.4 ± 0.1) · 10 - 6 %r.h. and C T E = (22.7 ± 0.3) · 10 - 6 K, respectively. The influence of humidity on the Brillouin backscattering power and linewidth are presented for the first time to our knowledge. The Brillouin backscattering power at a pump wavelength of 1319 nm is affected by temperature and humidity. The Brillouin linewidth is observed to be a function of temperature but not of humidity. The strain coefficient of the BFS is determined to be C S = (-146.5 ± 0.9) MHz/% for a wavelength of 1319 nm within a strain range from 0.1% to 1.5%. The obtained results demonstrate that the humidity-induced Brillouin frequency shift is predominantly caused by the swelling of the fiber over-cladding that leads to fiber straining.
本文主要研究相对湿度变化对光谱透过率、吸收和瑞利后向散射的影响。实验确定了光纤的吸湿系数和热膨胀系数分别为 C H E = (7.4 ± 0.1) · 10 - 6 %r.h. 和 C T E = (22.7 ± 0.3) · 10 - 6 K。据我们所知，这是首次报道湿度对布里渊后向散射功率和线宽的影响。在实验中，我们发现 1319nm 处的布里渊后向散射功率受温度和湿度的影响，布里渊线宽则仅与温度有关而与湿度无关。实验还确定了光纤在 1319nm 处的布里渊频移应变系数 C S = (-146.5 ± 0.9) MHz/%，应变范围为 0.1%到 1.5%。研究结果表明，湿度引起的布里渊频率移动主要是由光纤外包层的膨胀导致光纤应变引起的。
