phd defence by Erik Nicolai Christensen

Title: Four-wave mixing in Higher Order Mode Optical Fibers



Principal supervisor:  Prof Karsten Rottwitt


Evaluation Board

Assoc. Prof Michael Galili, DTU Fotonik, Denmark

Assoc. Prof Magnus Karlson, Chalmers Universitet, Sweden

Dr. Periklis Petropoulos, University of Southampton, United Kingdom



Master of the Ceremony





Due to the imminent capacity crunch in single-mode optical fiber networks, a host of novel few-mode and multi-mode fibers have been developed in recent years. The unique properties of the nonlinear interactions between the higher order modes in these fibers have not yet been fully elucidated. This thesis deals with discovering and using these in classical signal processing, and in quantum information science. The work exploits the non-Gaussian intensity distribution of higher order modes to suppress stimulated Brillouin scattering (SBS) by engineering the opto-acoustic overlap. We show that these higher order modes have a significantly higher SBS threshold, while maintaining a large nonlinear coefficient. Furthermore the diverse phase-matching options in few-mode fibers are used to phase-match four-wave mixing beyond the Raman peak and this is utilized for creating a Raman free heralded single photon source. Finally the intermodal phase-matching in a fiber with modes carrying orbital angular momentum (OAM) is demonstrated, and the process is shown to conserve OAM. In addition, seeded intermodal four-wave mixing is demonstrated creating kilowatt peak power pulses at 1327 nm.


fre 28 jun 19
13:30 - 17:00


DTU Fotonik



Lyngby Campus

Building 341, Auditorium 22