Grow thick, etch deep: Novel waveguide geometries and material systems for integrated photonics

Simen Mikalsen Martinussen

Research output: ThesisPhD Thesis - Research UT, graduation UT

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Integrated optics is a key enabler both for the most futuristic and most mundane high tech developments. Quantum computing, searching for exoplanets, rapid medical diagnosis, shorter refresh times on social media and sewage monitoring illustrate the scope of optics. To be useful in such a wide range of applications, it is essential that integrated optical devices can have many functionalities.

Electronic devices can have diverse requirements like fast switching times and low power consumption for a computer, or low noise and high power operation for an amplifier. In the same way, optical devices can have requirements like low loss and low confinement for a sensor, or low loss, high confinement, and dispersion engineering for a frequency comb.

Reaching such different requirements requires different approaches to the very structuring of the device. Often the technique to create one device is antithetical to another. For example, a thin waveguide with low confinement in a sensor is very different from a thick, dispersion engineered waveguide in a frequency comb. Having the technology for one does not guarantee that you can create the other. A wide process window is therefore necessary to make a material system truly versatile.

This thesis documents the development of techniques that extend our range of options for designing optical components in potassium yttrium double tungstate (KY(WO4)2), silicon nitride (Si3N4) and aluminum oxide (Al2O3). The focus is on developing dispersion engineered ring resonator structures suitable for nonlinear optics.

Each material system has its own strengths and weaknesses: KY(WO4)2 is an excellent laser and amplifier material, but developing high index contrast waveguides has been highly challenging so far. Silicon nitride is one of the most successful and versatile materials in integrated optics, however thick layers cannot be grown by the standard methods. Aluminum oxide is also a promising material for lasers, sensors and integration with other materials, but until now the technology to create frequency combs has not existed.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • University of Twente
  • García Blanco, Sonia, Supervisor
Award date9 Apr 2021
Place of PublicationEnschede
Print ISBNs978-90-365-5157-1
Publication statusPublished - 9 Apr 2021


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