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Structural Long period gratings (LPGs) in photonic crystal fiber (PCF) were successfully fabricated using the femtosecond laser micromachining system by introducing periodic side-holes.High temperature characterizations of the fabricated gratings have been performed.The gratings written with the femtosecond laser micromachining technique suffer a low shift of the resonance wavelengths with sensitivity of 23pm/℃ while the temperature is increased from 20℃ to 1200℃.The LPGs have been found to have negligible temperature sensitivity whilst exhibiting useful strain (-1.86pm/με) and strong directional bend sensitivity bending sensitivities with -4.40nm·m (180°) and -2.79nm·m (0°) at low temperature.The unique sensing characteristics enable many potential sensing applications in high temperature environments.such as space aircraft,nuclear power plants,and the chemical industry.