A Quantum Walk Comb Source at Telecommunication Wavelengths

TL;DR

This paper presents a novel quantum walk comb source operating at telecommunication wavelengths, producing a broad, tunable, and stable frequency comb with potential applications in high-speed communications.

Contribution

It introduces a new quantum walk comb source using a semiconductor optical amplifier in a ring cavity, achieving broad bandwidth and high repetition rate stabilization.

Findings

Bandwidth of 1.8 THz at 1 GHz repetition rate

Stable comb operation locked to RF drive

Harmonic generation up to 14.1 GHz

Abstract

We demonstrate a quantum walk comb in synthetic frequency space formed by externally modulating a semiconductor optical amplifier operating in the telecommunication wavelength range in a unidirectional ring cavity. The ultrafast gain saturation dynamics of the gain medium and its operation at high current injections is responsible for the stabilization of the comb in a broad frequency modulated state. Our device produces a nearly flat broadband comb with a tunable repetition frequency reaching a bandwidth of 1.8THz at the fundamental repetition rate of 1GHz while remaining fully locked to the RF drive. Comb operation at harmonics of the repetition rate up to 14.1GHz is also demonstrated. This approach paves the way for next-generation optical frequency comb devices with potential applications in precision ranging and high-speed communications.