Abstract

Deployment of single-mode optical fibers in communication networks requires an accurate determination of the fibers' zero-dispersion wavelengths. Some common techniques currently employed for measuring fiber dispersion are (1) an interferometric method,¹ and (2) measuring the change in group delay as function of wavelength by using several pulsed lasers operating at different wavelengths.² With the former method it is difficult to measure fibers longer than a few meters owing to the loss of fringe visibility with increasing fiber length. On the other hand, the latter method generally requires distances greater than several kilometers in order to provide accurate measurements of small differences in pulse group velocities. It is of interest to measure the dispersion of fibers with intermediate lengths that cannot be conveniently and accurately measured with either of these methods, including specialty fibers, which may be available only in lengths shorter than a kilometer, or Er⁺-doped fiber amplifiers, with typical lengths of tens or hundreds of meters. In this paper we report a new method to measure the zero-dispersion wavelength that can provide accurate data for these intermediate fiber lengths. The method makes use of the interaction of ultrashort pulses with self-phase modulation and higher-order dispersion in fibers.

© 1991 Optical Society of America