Tellurite glass is a material with advantageous optical properties, such as high transparency from visible to mid-infrared wavelengths, high nonlinearity, and high solubility of light-emitting rare earth dopants. Although tellurite has been investigated in fibers and in some waveguide studies, there is still much to explore about it in integrated photonics. Here, we use a hybrid platform that monolithically combines tellurite with commercially available silicon nitride chips. The platform leverages silicon nitride’s many advantages, including its low propagation losses, mature fabrication techniques with small feature sizes, and low cost for mass production, to enable the development of new on-chip tellurite glass light sources. This thesis aims to study the optical properties of distributed Bragg reflector cavities and explore their potential for lasing when the tellurite is doped with different rare earths, namely erbium and thulium. Chapter 1 provides an overview of the context of this work, introducing the materials and cavity used here. Chapter 2 introduces the basic theory behind waveguides and Bragg gratings, as well as rare earth rate equation gain models, coupled mode theory, and a laser model based on the shooting method. Chapter 3 discusses the design, fabrication, and characterization of passive properties of distributed Bragg reflector cavities using undoped tellurite. Chapters 4 and 5 present proof-of-concept laser demonstrations, by using tellurite doped with erbium and thulium, respectively. These lasers constitute the first demonstrations of distributed Bragg reflector lasers in this hybrid tellurite-silicon nitride platform. Chapter 6 combines the laser model introduced in Chapter 2 with the designs and results from Chapters 3–5 to investigate different routes to optimize the laser performances by studying how their efficiencies vary with different parameters, such as background loss, cavity and grating lengths, and rare earth concentration. Chapter 7 summarizes this work and provides insights into future research work. / Thesis / Doctor of Philosophy (PhD) / Integrated photonics is an emerging technology that revolves around tiny circuits on chips, similar to electronics, but using light instead of electricity. Photonic integrated circuits can help achieve faster and more power-efficient devices for a wide range of applications. In this work, we explore the potential of tellurite glass, a material that has promising optical properties, to achieve on-chip lasers. Lasers are one of the fundamental components in these light-driven circuits but are challenging to be realized on a chip-scale. We achieved compact lasers, which are more than ten times thinner than a strand of hair, a couple of centimeters long, and emit invisible (infrared) eye-safe light. These devices are compatible with volume production and there is much room for optimizing them. The lasers investigated here are highly promising for applications including imaging systems (LiDAR) for autonomous vehicles, augmented and virtual reality, data communications, and chemical and physical sensors.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/29963 |
| Date | January 2024 |
| Creators | Segat Frare, Bruno Luis |
| Contributors | Bradley, Jonathan David Barnes, Engineering Physics and Nuclear Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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