NONDESTRUCTIVE POSITION-RESOLVED MEASUREMENT OF THE ZERO-DISPERSION WAVELENGTH IN AN OPTICAL-FIBER

We describe a new technique for mapping the distribution of the zero-d ispersion wavelength in a span of optical fiber. With this technique, which is based on four-wave mixing of short pulses, we obtained a spec tral accuracy of +/-0.2 nm and a spatial resolution of 700 m. Theoreti cal analysis agrees well with experimental results and points to an or der of magnitude improvement in spatial resolution using shorter pulse s. Spatial resolutions less than 100 m may be necessary because we fin d, by destructive measurements, variations in lambda-zero by as much a s 0.5 nm over spans of 500 m.