In this paper, an annular winding structure made of single-mode optical fiber is proposed as the core of a cost-efficient and reliable annular optical fiber temperature sensor (AOFTS). The sensor is mainly due to the multi-mode interference effect to achieve real-time response to external temperature changes. The experimental results show that the average temperature sensitivity of the sensor is about 255.5 pm/°C in the temperature range of − 20 ∘ C − 110 ∘ C ; it has higher sensitivity at low temperatures. At − 20 ∘ C , the sensitivity of the AOFTS reaches 450 pm/°C. The sensor has the advantages of simple fabrication, low fabrication cost, strong stability, and good reproducibility and repeatability. It has great application prospects in the field of low-temperature detection.

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