A paradigm for universal quantum information processing with integrated acousto-optic frequency beamsplitters

TL;DR

This paper introduces a new integrated acousto-optic approach for universal quantum information processing using frequency and transverse mode control, enabling scalable, high-fidelity on-chip quantum operations.

Contribution

It proposes a novel paradigm using acousto-optic scattering for universal quantum processing in frequency-bin encoding, with analytical methods for synthesizing any unitary operation.

Findings

Feasibility of high-fidelity quantum gates with existing technology

High bandwidth utilization in quantum operations

Scalable on-chip quantum processing potential

Abstract

Frequency-bin encoding offers tremendous potential in quantum photonic information processing, in which a single waveguide can support hundreds of lightpaths in a naturally phase-stable fashion. This stability, however, comes at a cost: arbitrary unitary operations can be realized by cascaded electro-optic phase modulators and pulse shapers, but require nontrivial numerical optimization for design and have thus far been limited to discrete tabletop components. In this article, we propose, formalize, and computationally evaluate a new paradigm for universal frequency-bin quantum information processing using acousto-optic scattering processes between distinct transverse modes. We show that controllable phase matching in intermodal processes enables 2$\times$2 frequency beamsplitters and transverse-mode-dependent phase shifters, which together comprise cascadable FRequency-transverse-mODe Operations (FRODOs) that can synthesize any unitary via analytical decomposition procedures. Modeling the performance of both random gates and discrete Fourier transforms, we demonstrate the feasibility of high-fidelity quantum operations with existing integrated photonics technology, highlighting prospects of parallelizable operations achieving 100\% bandwidth utilization. Our approach is realizable with CMOS technology, opening the door to scalable on-chip quantum information processing in the frequency domain.