PhD Defence by Ayman Nassar Kamel

Title: Towards Highly Efficient On-chip Frequency Comb Generation in AlGaAs-on-Insulator Microresonators


Principal supervisor:  Prof. Karsten Rottwitt
Co-supervisor: Prof. Jan Westenkær Thomsen
Co-supervisor: Senior Researcher Minhao Pu

Evaluation Board

Associate Prof. Andrei Lavrinenko, DTU Fotonik/Denmark

Associate Prof. Victor Torres Company – Chalmers University, Sweden

Dr. Alfredo De Rossi, Thales Research and Technology, France


Master of Ceremony
Associate Prof. Michael Galili, DTU Fotonik


The rapidly increasing demand for data transfer poses a challenge to the current communications technology. In order to satisfy this demand in a sustainable way, our communications networks must become more energy-efficient. The backbone of communications networks uses optical signals to carry data in optical fibers. In each optical fiber, multiple streams of data travel simultaneously in slightly different light wavelengths. Each wavelength is emitted from a chip-integrated laser. Optical frequency combs, which provide multiple coherent optical signals from a single device, can provide an energy-efficient source for optical communications. These optical sources use the interaction between intense light and matter to convert one optical wavelength into multiple wavelengths in a chip-integrated microresonator. Among many nonlinear optical materials, Aluminum Gallium Arsenide (AlGaAs) is distinguished by its very high Kerr nonlinear parameter and high refractive index. Through the integration of AlGaAs with low-index dielectrics, the AlGaAs-on-Insulator platform provides highly-confining optical waveguides that are very promising for nonlinear photonics. However, this integration poses serious obstacles that reduce the frequency conversion efficiency that the bulk properties of AlGaAs promise. In this thesis, these obstacles are identified and tackled in order to pave the way for the AlGaAs-on-Insulator platform to reach its potential.



tor 05 sep 19
13:30 - 16:30


DTU Fotonik



Lyngby Campus
Building 421, room 73
29 NOVEMBER 2020