OPTICAL-FIBER CHARACTERIZATION BY SIMULTANEOUS MEASUREMENT OF THE TRANSMITTED AND REFRACTED NEAR-FIELD

We present an experimental setup which permits, in a routine way for R & D purposes, simultaneous measurement of the transmitted near field at 1300 nm and 1550 nm, and the refracted near field at 820 nm. A new method for the calibration of the refractive index is proposed. The ob tained accuracy for the refractive index is dn +/- 0.0002. The reprodu cibility of measurements of geometrical parameters like the mode field diameter, the core and cladding diameters, and concentricity error, i s +/- 0.1 mum. Measurements of the mode field in function of polarizat ion state for four different hi-bi fibers are also presented.