Electro-Optic Frequency Beamsplitters and Tritters for High-Fidelity Photonic Quantum Information Processing

TL;DR

This paper demonstrates high-fidelity electro-optic frequency beamsplitters and tritters for quantum information processing, enabling scalable, frequency-encoded quantum gates with near-perfect fidelity across a broad spectrum.

Contribution

It introduces the first frequency-mode tritter and high-fidelity frequency Hadamard gates using electro-optic modulation and pulse shaping, advancing scalable quantum photonic technologies.

Findings

Achieved near-unity fidelity ($0.99998$) for frequency Hadamard gate.

Demonstrated a $3 imes 3$ frequency tritter with fidelity $0.9989$.

Operates across the entire C-band with multiple frequency modes without fidelity loss.

Abstract

We report experimental realization of high-fidelity photonic quantum gates for frequency-encoded qubits and qutrits based on electro-optic modulation and Fourier-transform pulse shaping. Our frequency version of the Hadamard gate offers near-unity fidelity ($0.99998\pm0.00003$), requires only a single microwave drive tone for near-ideal performance, functions across the entire C-band (1530-1570 nm), and can operate concurrently on multiple qubits spaced as tightly as four frequency modes apart, with no observable degradation in the fidelity. For qutrits we implement a $3\times 3$ extension of the Hadamard gate: the balanced tritter. This tritter---the first ever demonstrated for frequency modes---attains fidelity $0.9989\pm0.0004$. These gates represent important building blocks toward scalable, high-fidelity quantum information processing based on frequency encoding.