Research on temperature-insensitive blood glucose concentration sensor with U-shaped SMF

In this manuscript, a temperature-insensitive U-shaped single-mode fiber (SMF) blood glucose concentration sensor is proposed. A balloon-shaped SMF is first burned by a flame to form a spindle shape, and then a U-shaped SMF is formed by the second burning. The U-shaped SMF sensor produced by this process is not sensitive to temperature. The bent fiber causes part of the energy to couple into the cladding modes, which results in modal interference. In the experiment, U-shaped SMF sensors with different bending diameters are made to study the sensitivities of blood glucose concentration and temperature. Experimental results show that the blood glucose concentration sensitivity of the sensors is up to -0.564 nm/(mmol/l) in the range of 1.1 mmol/l - 34.1 mmol/l. The sensors are insensitive in the temperature range of 5 & DEG;C - 45 & DEG;C. In addition, the sensors have the advantages of small size, low cost and simple process.