Nematicons: Spatial Optical Solitons in Nematic Liquid Crystals

Chapter 13: Time Dependence of Spatial Solitons in Nematic Liquid Crystals

Jeroen Beeckman and Kristiaan Neyts

Department of Electronics and Information Systems, Ghent University, Ghent, Belgium

13.1 Introduction

Although quite a number of applications of spatial solitons can be envisaged, the main application is their use as a dynamic optical interconnection. Depending on the speed at which the optical interconnection can be redirected from one output to another, different possibilities arise. If the switching time is in the order of a second, then typically only reconfigurable interconnects are possible, for example, protective switching (when one optical path fails, the optical signal is switched to a backup optical path). More interesting is the use as high-speed optical modulators, but then typically switching times in the order of a nanosecond are necessary. It is clear that the switching speed will determine for which application solitons can be of practical use, but in general one can state: the faster the switching speed, the better.

In this chapter, when we speak about switching time, we refer to the time it takes for the soliton to form when the optical beam is switched on. For applications as reconfigurable interconnects, the switching time is actually the time it takes to switch the optical signal from one output to another, but as this is much harder to describe theoretically, we stick to the simpler problem of switching on (or off) the soliton beam. Obviously, the ...