Shortening Solitons for Fiber-Optic Transmission

Solitons are stable localized pulses that do not disperse in optical fiber. When several solitons interact, they form a multi-soliton. Various fiber-optic communication systems based on multi-solitons have been investigated, but their spectral efficiencies are not competitive. One issue with using multi-solitons for communications is that their effective duration can vary widely with the number of interacting solitons. In this paper, we therefore introduce the concept of soliton shortening. In soliton shortening, a dispersive part is added to the nonlinear spectrum of a multi-soliton that reduces the pulse to a fixed finite duration, without changing the characteristics of the solitonic part. As a proof of concept, soliton shortening is shown to increase the spectral efficiency of a 2-soliton on-off keying system by 40%.