Pulse propagation in inhomogeneous optical waveguides. Progress report, September 15, 1993--September 14, 1994

Abstract

35,000 km. At the same time, remarkable progress with the presently used NRZ (non-return-to-zero) transmission mode makes it less clear that solitons will ultimately be used. The author has contributed in important respects to all these areas. In long-distance transmission systems, the length scale on which the birefringence varies randomly (30--100 m) is short compared to the nonlinear and dispersive scale lengths (100--1,000 km). Consequently, it is crucial to understand and characterize this randomly varying birefringence when studying long-distance evolution in optical fibers. That has been done in a series of studies that has also led to the proposal of a numerical scheme for modeling these systems that should be orders of magnitude faster than the schemes presently being used. In the studies of the fiber ring and figure-8 lasers, the author proposed that nonlinear polarization rotation is the mechanism responsible for fast saturable absorption in the fiber ring lasers--a result that was later verified experimentally. He also explored a new approach to determining the conditions for modelocking and self-starting in these lasers that uses the computer to determine the linear stability of both the pulsed and cw solutions. In all this work, the author has worked closely with leading experimentalists and their groups. Section 2 of this report describes in more detail some of the specific accomplishments.