DOCTORAL CANDIDATE
Itisha Tyagi

SUPERVISORS
Marc Sciamanna, CentraleSupélec
Delphine Wolfersberger, CentraleSupélec
Alex Fuerbach, Macquarie University (MQ)

Non linear optics, photonics and engineering optics

The era of multimode photonics has already begun, ushering in a transformative shift in the design and application of optical systems. While the development of nonlinear photonics has been driven by numerous factors, significant advancements have emerged in fields like optical telecommunications, imaging, and spectroscopy, all closely tied to the evolution of advanced nonlinear photonic light sources. Traditionally, single-mode structures such as fibers and cavities enabled the creation of highly coherent and intense light sources, which led to groundbreaking applications. However, the current trend is moving towards multimode systems, which harness a broader range of optical interactions to not only enhance existing single-mode applications but also open entirely new possibilities in fiber-optic communications and nonlinear optics.

This research focuses on the transmission of signals in nonlinear optical fibers, particularly within multimode and nonlinear regimes, where effects such as self-phase modulation, cross-phase modulation, and stimulated Raman and Brillouin scattering have a significant impact on signal integrity. Using a combination of experimental and computational approaches, we aim to explore how these nonlinearities, when combined with dispersion effects, can contribute to more stable data transmission and enable the signal to propagate over long distances. High-resolution optical diagnostics, ultrafast laser characterization, and numerical simulations based on the Nonlinear Schrödinger Equation (NLSE) will be employed to analyze pulse propagation and nonlinear interactions. By correlating experimental data with theoretical models, this research will provide valuable insights into the behaviour of nonlinear optical effects in multimode fiber systems.

The outcomes of this study will help optimize the design of next-generation optical networks by improving signal stability and mitigating the challenges posed by nonlinear effects. As multimode photonics continues to advance, the findings will contribute to the development of innovative fiber architectures, such as photonic crystal fibers and dispersion-engineered structures, to enhance the efficiency of data transmission. Beyond telecommunications, these insights will also benefit applications in optical sensing, high-power laser systems, and quantum technologies, ultimately promoting the broader integration of multimode photonic systems across a wide range of scientific and industrial domains.