Optical Science and Engineering ETDs

Publication Date

Fall 12-5-2018

Abstract

In this dissertation, transverse Anderson localization (TAL) of light mediated by disordered optical fibers is exploited for high-quality optical wave transmission and novel random lasing applications. En route, we first establish a powerful numerical platform for detailed investigation of TAL optical fibers (TALOF). Our approach is based on a modal perspective as opposed to beam propagation method (BPM) which was primarily used in the previous studies of TAL in disordered optical fibers. The versatile numerical tools developed in our simulations result in a potent methodology for simulation of TALOFs; the result is a fast and effective algorithm which can be implemented on personal computers in contrast to the previous efforts which required high performance computing and were quite time consuming. In addition, the modal perspective is more robust and reliable because it is independent of the initial excitation properties, encompasses the full vectorial nature of light, and depends solely on the features of the disordered fiber.

As one of the significant applications of TALOFs, the first laser device mediated by these fibers is reported. The complex nature of the disordered fiber in combination with lasing action result in a rich physical system which is of fundamental and practical importance in the context of random lasers. Most of the previously reported random lasers suffer from multi-directional emission and spectral instability which have prevented these otherwise versatile light sources from being main stream photonic devices. Random laser action in TALOF is directional and free of spectral instability; light amplification in TALOF occurs in transmission channels which are induced by transversely localized modes. We demonstrate that the strong isolation of these transmission channels reduces the mode competition significantly and the resulting random fiber laser is highly directional and free of chaotic spectral fluctuations.

As another major contribution of this dissertation, we show that while disorder is always considered as a source of noise and deviation from the ideal performance in optical devices, if the randomness is strong enough, high-quality single-mode wave transmission is supported in completely disordered optical fibers, thanks to the peculiar Anderson localization phenomenon. Our detailed numerical and experimental analysis on the beam quality of the Anderson localized modes proves that a substantial number of them possess M2required.

Degree Name

Optical Science and Engineering

Level of Degree

Doctoral

Department Name

Optical Science and Engineering

First Committee Member (Chair)

Arash Mafi

Second Committee Member

David Dunlap

Third Committee Member

Mani Hossein-Zadeh

Fourth Committee Member

Alejandro Manjavacas

Keywords

Tansverse Anderson localization, Disorder, Optical fiber, Random laser, High-quality wave transmission, Modal perspective

Document Type

Dissertation

Language

English

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