Temperature-insensitive lateral force sensor based on photonic crystal fiber Sagnac interferometer

A lateral force sensor based on low birefringence photonic crystal fiber Sagnac interferometer is proposed. The sinusoidal interference spectrum is produced due to the initial lateral force which is pre-applied on the low birefringence fiber. The load placed on the fiber introduces extra birefringence and corresponding spectrum shift for measurement. The sensitivity achieved is 0.529 nm/(N·mm). The property of temperature-insensitivity is verified in the experiment with the temperature coefficient of -0.4 pm/℃ which can be neglected.