Interactions, applications and instabilities of optical solitons

• Main Author: Anastassiou, Charalambos
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2001
• Subjects: Electrical engineering; Optics
• ISBN: 0493233148; 9780493233147

This dissertation describes theoretical and experimental research on optical solitons, their stability, interactions, and applications. It is shown, for the first time, that the photovoltaic nonlinearity which gives rise to spatial solitons can be switched from self-defocusing to self-focusing (or vice versa) just by the application of a background illumination. It is shown that this reversal can be achieved if the photovoltaic current induced by the background illumination is stronger than that induced by the soliton beam. A method to eliminate transverse instabilities of spatial solitons is also devised. It is shown that a transversely stable one-dimensional [(1+1)D] bright soliton can exist in a 3D bulk medium. The transverse instability of the soliton is completely eliminated if the soliton is made sufficiently incoherent along the transverse dimension. A criterion for the threshold of transverse instability that links the nonlinearity to the largest transverse correlation distance for which the 1D soliton is stable. Applications of optical solitons are also investigated. It is shown that vector solitons can be utilized to perform useful computation through their interactions. We present the first experimental demonstration of cascading two vector soliton collisions and it is shown that information from one collision is carried into the next collision. Optical solitons induce waveguides inside the nonlinear media they propagate and those soliton induced waveguides can replace fixed waveguides. It is shown that a partially-spatially-incoherent soliton can be used to form a multimode waveguide in a photorefractive crystal and the modes of that waveguide can be used to transmit an incoherent image through this nonlinear medium.