Abstract: A method for adjusting the position of two ends of a pair of aligned optical fibers during formation of a connection or a splice between the two ends either to repair a break in a fiber or to add another fiber characterized by coupling a light pulse into a free end of one of the pair of fibers, measuring the intensity of a back-scattering of the light pulse received at the free end, determining an abrupt change in the intensity of the back-scattered light at the free end corresponding to the point of the connection to be made for the pair of fibers, and adjusting the position of the two ends of the pair of fibers to decrease the amount of the abrupt change in the intensity being determined to the smallest determined value.

Abstract: A gradient optical fiber with an optimized index of refraction profile characterized by the normalized difference in the index of refraction .DELTA. is in a range of 0.005 to 0.011, with -(k.sub.o /.DELTA..multidot.d.DELTA./dk.sub.o) being in a range of 0.09 to 0.11, an index of refraction profile function f(r/a) according to a formula of f(r/a)=(r/a).sup..alpha.+ A((r/a).sup..alpha.- (r/a).sup.2.alpha.) and a profile dispersion function F.sub.N according to F.sub.N =f.sup.g wherein .alpha. is in the range of 2.013 to 2.015, A is in a range of 0.114 to 0.116, and g is in a range of 2.4 to 2.6.

Abstract: A gradient optical fiber has an index of refraction profile according ton.sup.2.sub.(r) =n.sub.0.sup.2 (1-2.DELTA.((r/a).sup..alpha. -A((r/a).sup..alpha. -(r/a).sup.2.alpha.)))and has decreased differences for transit times of different modes.