In this paper, we report on a multicore fiber-based (MCF) temperature sensor that operates in a wide thermal range and that is robustly packaged to withstand harsh environments. To develop the sensor, the fundamentals concerning the effect of temperature on such fibers have been analyzed in detail to predict the most temperature sensitive MCF geometry. Thanks to it, the device, which operates in reflection mode and consists of a short segment of strongly coupled MCF fusion spliced to a standard single mode fiber, shows higher sensitivity than other devices with identical configuration. Regarding its packaging, it consists of an inner ceramic and two outer metallic tubes to provide rigidity and protection against impacts or dirt. The device was calibrated for a thermal range from −25 °C to 900 °C and a K-type thermocouple was used as reference. Our results suggest that the manufactured optical thermometer is as accurate as the electronic one, reaching a sensitivity up to 29.426 pm/°C with the advantage of being passive, compact and easy to fabricate and interrogate. Therefore, we believe this device is appealing for industrial applications that require highly sensitive temperature sensing in very demanding environments, and that the analysis included in this work could be analogously applied to develop sensitivity-optimized devices for other parameters of interest.

在本文中，我们报告了一种基于多芯光纤 (MCF) 的温度传感器，该传感器可在较宽的热范围内运行，并且经过稳健封装以承受恶劣环境。为了开发传感器，详细分析了有关温度对此类纤维影响的基本原理，以预测对温度最敏感的 MCF 几何形状。多亏了它，该设备以反射模式运行，由一小段强耦合 MCF 熔接与标准单模光纤组成，显示出比具有相同配置的其他设备更高的灵敏度。关于它的包装，它由一个内部陶瓷和两个外部金属管组成，以提供刚性和抗冲击或防尘保护。该设备在 -25 °C 至 900 °C 的热范围内进行了校准，并使用 K 型热电偶作为参考。我们的结果表明，制造的光学温度计与电子温度计一样准确，灵敏度高达 29.426 pm/°C，具有无源、紧凑、易于制造和查询的优点。因此，我们相信该设备对于在非常苛刻的环境中需要高灵敏度温度传感的工业应用很有吸引力，并且这项工作中包含的分析可以类似地应用于开发针对其他感兴趣参数的灵敏度优化设备。