For the development of a temperature sensor with still higher sensitivity

this paper proposes to selectively fill thermosensitive fluid into the PCF by using the photonic bandgap effect so as to achieve highly sensitive temperature sensing.It calculates the bandgap using the full vector plane wave expansion method and the bandgap and its width drift regularly with temperature.When the thermosensitive fluid is selectively filled in the different locations and structures of the cladding air holes it is found that when only the inner air holes are filled

the variation caused by the bandgap with temperature drift is the maximum;When the 1st-layer air holes of the cladding is filled with the fluid

the lattice periodΛ =9μm and air-filling ratio are repectively selected as d/Λ = 0.9and d/Λ = 0.5

the temperature sensitivity in bandgap boundary wavelength detection and band-gap width detection can be 22.07 and 7.01nm/℃ respectively

which shows the advantages in high accuracy and simple system structure.