High-resolution tunable frequency beamsplitter enabled by an integrated silicon pulse shaper

TL;DR

This paper presents a high-resolution, tunable on-chip frequency beamsplitter using an integrated pulse shaper, achieving near-ideal quantum gate performance and enabling advanced quantum photonics applications.

Contribution

It introduces a scalable, resource-efficient integrated frequency beamsplitter with ultrafine spectral resolution and arbitrary splitting ratios, surpassing prior bulk implementations.

Findings

Achieved fidelity > 0.9995 in frequency beamsplitting.

Supported frequency spacings as narrow as 2 GHz.

Enabled arbitrary splitting ratios through spectral phase control.

Abstract

We demonstrate high-fidelity, tunable, and ultrafine-resolution on-chip frequency beamsplitters using a quantum frequency processor based on an integrated pulse shaper with six spectral channels. Near-ideal Hadamard gate performance is achieved, with fidelity F > 0.9995 and modified success probability P > 0.9621 maintained across frequency spacings from 2-5 GHz and down to as few as four spectral pulse shaper channels. The system's support of frequency spacings as narrow as 2 GHz significantly surpasses prior bulk demonstrations and enables arbitrary splitting ratios via spectral phase or modulation index control. These results establish a scalable and resource-efficient platform for integrated frequency-bin quantum photonics, opening new directions in quantum information processing, including densely parallel single-qubit operations and multidimensional gate implementations.