Integrated photonics is a major emerging technological field with the potential for massive impact on the biomedical, security, defence, transportation, telecoms and other sectors. Specifically, integrated high-Q optical microresonators could form the basis for a vast array of new devices including handheld optical clocks, trace gas detectors, ultraprecise lidar, narrow-linewidth lasers, low-noise microwave sources, biosensors, gyroscopes and optical data transmitters. This project addresses two of the main challenges in bringing such devices to fruition: achieving ultra-high-Q waveguide ring resonators and integrating these with semiconductor lasers on the same chip.
The project will focus on developing silicon nitride waveguide ring resonators with Q factors approaching 108 and above, building upon the latest and most advanced techniques for deposition, nanolithography and etching, and modelling the waveguide geometry to optimise dispersion. The resonators will then be used for frequency comb generation, with emphasis on self-referenced octave-spanning combs for optical clocks and dual-comb spectroscopy. Time permitting, the student will also research techniques to integrate III-V semiconductor lasers with the silicon platform of the silicon nitride resonators in order to realise self-contained monolithic devices.
The new knowledge generated by this project will bring us closer to commercialising a range of exciting on-chip ultra-high-Q microresonator-based technologies.
– A bachelor’s degree in physics, engineering or a similar subject with class 2:1 (or equivalent) or above
– An inquisitive and analytical mind, self-motivation and the ability to work independently
– Inclination towards experimental work
– A master’s degree with courses on photonics and/or nanofabrication
– Previous experience of experimental research
For the first half of their project, the student will be based primarily at the James Watt Nanofabrication Centre (https://www.gla.ac.uk/research/az/jwnc) at the University of Glasgow. This is a world-leading cleanroom facility where the student will have access to a comprehensive range of cutting-edge equipment for growing, etching, imaging and characterising integrated photonics devices on both III-V and silicon platforms, all supported by full-time technical staff. Here, they will develop and hone the process of fabricating silicon nitride waveguide ring resonators on silicon wafers, from growing and depositing silica and silicon nitride all the way through to patterning, etching and polishing, with the aim of achieving record Q factors. They will also be able to build upon considerable in-house experience in working towards integrating a III-V semiconductor laser source with their resonators.
During the remainder of their project and short trips before that, the student will work at the National Physical Laboratory within the Time and Frequency Department, where they will characterise their resonators and use them to generate frequency combs. They will have the use of two laboratories and a cleanroom that are fully equipped for these purposes as well as femtosecond laser writing and silica microresonator and tapered fibre fabrication. They will also benefit from close collaboration with NPL experts in optical frequency metrology and gas spectroscopy.
The student will be co-supervised by Prof. Marc Sorel at the University of Glasgow, a leading expert in integrated optics, silicon photonics and semiconductor lasers, and by Dr Jonathan Silver, who leads NPL’s Microphotonics activities and is currently an RAEng UK Intelligence Community Postdoctoral Research Fellow. The University of Glasgow boasts a vibrant student life, and NPL has over 100 doctoral students and a Postgraduate Institute that organises regular events including an annual student conference.
Flexible Research Working
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