Programmable Photonic Quantum Circuits with Ultrafast Time-bin Encoding

TL;DR

This paper introduces a scalable quantum photonic platform using ultrafast time-bin encoding, demonstrating high-fidelity programmability of unitary transformations and scalable optical networks with stable interferometric phases.

Contribution

It presents a novel ultrafast time-bin encoding scheme for photonic quantum computing, enabling scalable, stable, and programmable quantum circuits in a single spatial mode.

Findings

Successfully programmed 362 unitary transformations in 8 dimensions.

Built a passive optical network with up to 36 modes demonstrating scalability.

Achieved fidelities exceeding 97% with phase stability over several days.

Abstract

We propose a quantum information processing platform that utilizes the ultrafast time-bin encoding of photons. This approach offers a pathway to scalability by leveraging the inherent phase stability of collinear temporal interferometric networks at the femtosecond-to-picosecond timescale. The proposed architecture encodes information in ultrafast temporal bins processed using optically induced nonlinearities and birefringent materials while keeping photons in a single spatial mode. We demonstrate the potential for scalable photonic quantum information processing through two independent experiments that showcase the platform's programmability and scalability, respectively. The scheme's programmability is demonstrated in the first experiment, where we successfully program 362 different unitary transformations in up to 8 dimensions in a temporal circuit. In the second experiment, we show the scalability of ultrafast time-bin encoding by building a passive optical network, with increasing circuit depth, of up to 36 optical modes. In each experiment, fidelities exceed 97\%, while the interferometric phase remains passively stable for several days.