Two-dimensional bending vector sensing based on spatial cascaded orthogonal long period fiber

A novel bending vector sensor based on spatial cascaded orthogonal long period fiber gratings (SCO-LPFGs) written by high-frequency CO2 laser pulses has been proposed, and two-dimensional bending vector sensing characteristics based on the simple SCO-LPFGs have been experimentally demonstrated. A three-dimensional orthogonal sensing coordinate system has been established, and the measurement results of the proposed SCO-LPFGs sensor based on the above coordinate system is given, and furthermore both of curvature and bending-direction could be intuitively solved according to the three-dimensional orthogonal sensing coordinates. The research work presented in this paper would be helpful to improve the practicability of fiber vector sensors due to the distinguished characteristics such as simple structure, low-cost, ease of fabrication. (C) 2012 Optical Society of America