Date of Award

2020

Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy

Department

Physical Sciences

First Advisor

Dr Stephen P. Hegarty

Abstract

Silicon photonics takes advantage of the mature complementary metal-oxide semiconductor (CMOS) infrastructure and processes, and is actively pursued for the implementation of complex optical components and photonic integrated circuits (PICs) at low cost and high volumes. Despite a constant refinement of silicon photonics technology to meet the evolving requirements for applications, the poor light emission ability of silicon remains a constraint. As a result, the most essential building block of an optical system, an efficient light emitter, remains absent in PICs based on silicon. This thesis is focused on study of the potential of an external cavity (EC) hybrid III-V - Si laser design, comprising an InP re ective semiconductor optical amplifier (RSOA) and a silicon reflector chip. The Si resonant structure was acting as a wavelength selective element determining the lasing wavelength. Two types of EC lasers were studied. The first, utilized a Si3N4 1D photonic crystal (Bragg grating) and the second, exploits a 2D Si photonic crystal (PhC) vertically coupled to a low refractive index waveguide. Both types of lasers demonstrated a single mode mW-level continuous-wave (CW) power output at room temperature with SMSR > 40 dB. The Si3N4 reflector laser demonstrated a thermal wavelength stability of ±0.55 nm in the range of 20 - 80 ℃, and the Si PhC reflector laser showed a ±0.38 nm deviation for the same range. Finally, using the thermal modulation of the refractive index of the PhC cavity, the frequency (wavelength) modulation of the short cavity EC laser was demonstrated. The studied architecture eliminates the necessity for wavelength matching between a source and modulator, as both roles were accomplished by the tunable resonant iv PhC cavity, which together with a low power consumption is a good candidate for practical applications in silicon photonics.

Comments

Thesis 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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