Hybrid materials integration of wide bandgap semiconductors for chip-scale photonics

Student thesis: Doctoral Thesis

Abstract

Presented in this thesis are efforts to develop a hybrid integrated optics platform consisting of the materials gallium nitride (GaN) and diamond. Wide-bandgap materials such as these are important for short wavelength (UV-visible) applications, or applications spanning broad bands of the electromagnetic spectrum. First, a passive GaN photonic chip was fabricated and characterised. Racetrack resonators featured low losses of 3.13 dB/cm and intrinsic quality (Q) factors of 1.22 × 105 were measured. A second chip featuring actively tunable devices using thermal micro-heaters featured a tuning efficiency of 11.658 pm/mW and a 3 dB full peak-switching bandwidth of 13.4 kHz. This is the first example of an actively tunable GaN micro-resonator. A high-Q diamond micro-disk resonator (intrinsic Q = 1.6×105) was then integrated with the passive GaN chip using a micro-transfer printing technique. It was printed in series with a monolithic GaN micro-resonator, so that their respective performances could be measured effectively simultaneously. Finally, the performance of the hybrid wide-bandgap device for the application of photonic thermometry was examined. The high accuracies afforded by the dual-material device lead to a fivefold improvement in single-shot temperature errors over similar silicon devices.
Date of Award22 Dec 2022
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsEPSRC (Engineering and Physical Sciences Research Council) & University of Strathclyde
SupervisorMichael Strain (Supervisor) & Erdan Gu (Supervisor)

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