A guided-light individual addressing scheme for trapped Ba+ ions in an open-access quantum information processor

Trapped ion quantum devices have been used as a proving ground for quantum technologies throughout the last 20 years. To keep the trapped ion platform at the forefront of quantum computing an increased focus must be placed on scaling into the Noisy Intermediate Scale Quantum (NISQ) era. QuantumION is a project at the University of Waterloo's Institute for Quantum Computing (IQC) which aims to improve scalability by providing an open-access quantum computer for the research community. All users will have access to the full control stack and the ability to submit experiments for autonomous execution. To accommodate the breadth of experiments across different user types each of the planned 16 Ba⁺ ion's quantum state must be individually controllable. To date, ion trap quantum processors have been limited in their qubit numbers due to the challenge of generating large arrays of switchable laser beams with low crosstalk to neighboring sites. To overcome this, a novel guided-light approach is presented in this poster which makes use of state-of-the-art glass micromachining techniques. A single laser beam is split into 16 individual channels using a path length matched Femtosecond Laser Direct Write (FLDW) waveguide. A fibre V-Groove Array (VGA) is butt coupled to the waveguide breaking each channel out into an individual fibre optic cable. Commercial fibre optic Acousto-Optic Modulators (AOMs) are then used to provide independent phase, frequency, and intensity control for each beam. This approach removes any crosstalk inherent to the AOMs. The pitch and beam waist at the ions is set by recombining the fibre optic cables into a VGA with a custom Micro-Lens at the output facet of each fibre. The output is re-imaged onto the corresponding equally spaced ion chain using a single telescope. This poster will present results on route to implementing this setup for QuantumION.