Date of Award

23-9-2022

Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy

Department

Physical Sciences

First Advisor

Dr William Whelan-Curtain (Liam O'Faolain)

Abstract

Light interaction with microscopic and nanoscopic structures enable manipulation of its characteristics which can be used to detect objects in 3D sensing, propel satellites to space using photonic propulsion and transmit data through optical communication. For optical communication, the basic components are lasers, modulators and photodetectors. The development of CMOS microfabrication foundries helps to manufacture silicon-based photonic devices with high yield that is directly co-integrated with electronics in a single chip. However, the lack of emission of photons efficiently in silicon propelled the necessity of hybrid photonic devices that inherits the combined advantage of different materials i.e. functionality and volume. In this thesis, a hybrid laser cavity is formed via butt-coupling an III-V Reflective Semiconductor Amplifier (RSOA) chip into a Si chip that encloses a vertically integrated PhC reflector mechanism. Due to optical mode matching, the vertically integrated waveguide maximizes the coupling efficiency from the RSOA waveguide into the Si PhC cavity. This unique configuration permits the realization of a hybrid laser with a die footprint as small as 20 (W) x 260 (L) μm2. Through engineering, a Fabry-Perot (FP) mode spacing, Ith * four times mode hopping free laser operation is demonstrated without any active locking mechanism. A resonant reflector induced optical bistability is investigated in various laser functioning regimes: i) single longitudinal mode ii) longitudinal mode hopping and iii) PhC mode hopping. The PhC integrated electro-optic modulator is demonstrated to modulate a laser frequency that has been converted into a change in laser power output through an external filter. Further, monolithic integration of silicon nitride on silicon-on-insulator is presented to demonstrate temperature-insensitive photonic devices and together with an efficient coupling mechanism with insertion loss of 0.05 dB per transition is reported.

Comments

This thesis is prepared in association with Tyndall National Institute.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Access Level

info:eu-repo/semantics/openAccess

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