Iain Butler
Iain Butler
Iain joined the CDT in September 2015, having previously completed a BSc in Computer Science with Electronic Engineering at the University of Exeter.
CDT PhD Project: Semiconductor Lasers for Harsh Environments
Supervisors:
Professor Richard Hogg, University of Glasgow
Dr David Childs, University of Glasgow
Professor Robert Bowman, Queen's University Belfast
The project will develop advanced quantum dot laser structures for operation in harsh environments such as high temperature and radioactive region. Lasers find applications in a range of diverse areas; for example:- delivering energy, allowing high speed communications, sensing, imaging, etc. Therefore, there is demand for lasers that can operate in inaccessible environments. Examples include high temperatures for next generation data storage (Heat Assisted Magnetic Recording [HAMR]), communications in hot environments (e.g. drill heads), radioactive environments, etc. The project tackles this need by investigating the physical characteristics of quantum dot (QD) lasers and engineering devices best suited to high temperature operations for both the delivery of high power and optical communications.
Quantum dot lasers have been predicted to be temperature invariant which should allow for predictable characteristics over a much larger range of temperatures compared to traditional laser designs of their active regions. Preliminary results show that QD lasers have some unusual behaviour patterns which have yet to be explored or understood. These unusual behaviours with further research may open up new secure ways of transmitting data optically. While some research has been undertaken in how temperature affects the laser characteristics of QD lasers, these measurements over a large range haven't been completed methodically.
The project has allowed the development of a range of project specific skills ranging from an understanding of the epitaxial process and the design of epitaxial structures for laser applications, through device fabrication, laser characterisation, laser engineering (for low threshold, high power, high modulation rate) and failure analysis. With full access to the facilities at the University of Glasgow with the James Watt Nanofabrication Centre and the Kelvin Nanocharacterisation Centre, along with Queens University Belfast with ANSIN (laboratory partnered with Seagate Technology [Ireland]) and the Centre for Nanostructured Media, full characterisation can be achieved. In addition, this project establishes a new international collaboration in Japan and China, with possible research visits and very different research environments. The project has proceeded to look at assessing the operation of conventional (quantum well), QD lasers in a radioactive environment and in developing new single-mode devices for such harsh environments.
Successful Funding:
SPIE Student Author Travel Grant and Newport Award - $750USD ~ £500
University of Glasgow Student Mobility Travel Scholarship - £1,600
JSAP-OSA Joint Symposia 2018 Travel Award - ¥80,000JPY ~ £550
Talks / Presentations:
07/2017 - Conference presentation at UK Semiconductors 2017, Sheffield
09/2017 - Conference presentation at UK-China Emerging Technologies (UCET) 2017 Workshop
01/2018 - Conference presentation at SPIE Photonics West 2018, San Francisco, USA
01/2018 - Named author - conference presentation "Room temperature tuneable THz generation based on excitonic optical nonlinearities in GaAs/AlGaAs Multi-quantum well structures"
07/2018 - Conference presentation at UK Semiconductors 2018, Sheffield
09/2018 - Conference presentation at JSAP Autumn Meeting 2018, Nagoya, Japan
Publications:
SPIE Proceedings Paper "Incorporating Structural Analysis in a QD Monte-Carlo Model" (http://doi.org/10.1117/12.2291004)
APL Paper “Size anisotropy inhomogeneity effects in state-of-the-art quantum dot lasers” (https://doi.org/10.1063/1.5021774)