An in-fiber Michelson interferometer (MI) formed by seven-core fiber (SCF) for low-temperature sensing is proposed and experimentally demonstrated. The sensor head is constructed by a section of seven-core fiber splicing a single-mode fiber (SMF) with a taper. When the external temperature changes, the interference spectrum of the MI will shift due to thermal expansion and thermo-optic effects. By measuring the wavelength variations of the interference dip, the external temperature can be determined. Experimental results proves that the sensor exhibits a maximum linear temperature sensitivity of −0.0775 nm/°C in the temperature range of −60 °C to 15 °C, and the standard deviation is 5% in stability test. The sensor possesses high sensitivity and easy fabrication, which makes it could be a good candidate in low-temperature sensing application.

中文翻译：

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基于迈克尔逊干涉仪的七芯光纤高灵敏度低温传感器


提出并实验证明了一种由七芯光纤（SCF）形成的光纤内迈克尔逊干涉仪（MI），用于低温传感。传感器头由一段七芯光纤与带有锥度的单模光纤 (SMF) 熔接而成。当外部温度变化时，MI的干涉光谱会因热膨胀和热光效应而发生偏移。通过测量干涉凹的波长变化，可以确定外部温度。实验结果证明，该传感器在-60℃~15℃温度范围内表现出最大线性温度灵敏度为-0.0775 nm/℃，稳定性测试标准偏差为5%。该传感器具有高灵敏度和易于制造的特点，这使得它成为低温传感应用的良好候选者。