Miniature temperature sensor based on encapsulated silica microfibre–microsphere structure

Either microfibres or microspheres with different diameters were prepared from standard single-mode fibres with heating–stretching method. The influence of the different diameters of microspheres (from −49.4 to −208.04 μm) on the transmission spectra of silica microfibre with a diameter of −3 μm was studied through the whispering gallery modes. In addition, the temperature sensing characteristic of this microfibre–microsphere system was demonstrated with a sensitivity of −12.66 pm/°C in the interval of 30.18–38.52°C. Due to its simple, costless and miniature fabrication process, this microfibre–microsphere system will be the promising candidate for novel photonic devices and bio-chemical sensors.