Novel mid-infrared quantum photonic component design in silicon

: big photons for bigger systems

Abstract

For silicon photonics to ever achieve the promise of quantum information processing, significant improvements to conventional technology must be made, and risks must be taken. Largely, these improvements pertain to the reduction of the linear, and nonlinear loss of the platform, so that it may truly scale to the size required for fault-tolerant quantum computation. Silicon photonics at ≈ 2.1 µm wavelengths is a promising candidate to address these issues, however, challenges remain. On industry-standard silicon-on-insulator film thicknesses, this wavelength regime is relatively unexplored. Here we develop an entire
library of photonic components on this platform – low-loss single-mode waveguides and bends, grating couplers, inverse taper edge couplers, directional couplers, and multimode interferometers – and characterise their performance. We then simulate, design, post-process and characterise a near-record performing fiber-chip coupler, with a transmission of –0.58 +0.21 –0.22 dB and a 1-dB bandwidth of 294.92 nm. Lastly, in a first for the platform, we measure quantum-correlated pair-photon generation in the TE1 mode, galvanising its potential for quantum photonics applications. With a coincidence-to- accidental ratio of 11.5 and a detected maximum coincidence rate of 118.12 Hz, this work will springboard future research via integration into larger systems without intrinsic limits to scalability.

Date of Award	6 Dec 2022
Original language	English
Awarding Institution	University of Bristol
Supervisor	Joshua W Silverstone (Supervisor) & John G Rarity (Supervisor)