U-shaped fiber-optic refractive-index sensor and its applications

A Ushaped fiberoptic refractive index sensor and its aI ications are described. For longdistance measurements fabrication method using si I ca glass fibers is investigated. The lowloss silica class fiber sensor is applied to multi point measurements based on optical time domain reflectometry(OTDR). Application of the sensor to humidity measurement and the monitoring of human skin condition are also proposed.