PhD defence by Denis Bolotov

Abstract

In recent years, researchers have demonstrated the remarkable ability to convert light's frequency with nonlinear processes in the propagation medium, offering solutions for enhanced infrared imaging and integrating quantum sources into telecommunications. One of these transformative processes, known as intermodal Bragg-scattering four-wave mixing (IM BS FWM), enables tunable frequency conversion without pump noise interference. Through experimentation, efficient IM BS FWM frequency conversion was achieved across different spatial modes within few-mode fibers. By validating phase-matching conditions and leveraging modes dispersion properties, remarkable results were obtained, spanning a wavelength span exceeding 600 nm. With conversion efficiencies reaching -1.5 dB, this research bridges the gap between telecommunications and quantum devices. Furthermore, previously developed strategies were tested to overcome obstacles posed by stimulated Brillouin scattering, ensuring optimal FWM performance without undue idler broadening. This research not only sheds light on the nonlinear dynamics of light propagation but also opens doors to transformative advancements in photonic technology, promising enhanced quantum communication capabilities.

Supervisors

• Principal supervisor: Associate professor Lars Rishøj, Department of Electrical and Photonics Engineering, DTU
• Co-supervisor: Professor Karsten Rottwitt, Department of Electrical and Photonics Engineering, DTU

Evaluation Board

• Examiner: Professor Christophe Peucheret, Rennes University, France
• Examiner: Professor Periklis Petropoulos, University of Southampton, United Kingdom

Chairman

• Associate professor Edmund Kelleher, Department of Electrical and Photonics Engineering, DTU

Master of the Ceremony

• Associate professor Francesco Da Ros, Department of Electrical and Photonics Engineering, DTU