High-gain far-detuned nonlinear frequency conversion in optical fibers: intramodal vs. intermodal processes

TL;DR

This paper demonstrates high-gain, far-detuned nonlinear frequency conversion in graded-index silica fibers, achieving significant amplification across a broad spectral range through intramodal and intermodal four-wave mixing processes.

Contribution

It provides both theoretical and experimental insights into high-gain frequency conversion in multimode fibers, highlighting the potential for ultrabroad spectral applications.

Findings

Achieved gains of hundreds of dB per meter below 0.65 μm and beyond 3.5 μm.

Extended frequency conversion towards visible and mid-infrared ranges.

Highlighted the importance of intramodal and intermodal processes in high-gain conversion.

Abstract

We present theoretical and experimental evidence of high-gain far-detuned nonlinear frequency conversion, extending towards both the visible and the mid-infrared, in a few-mode graded-index silica fiber pumped at 1.064 $\mu$m, and more specifically achieving gains of hundreds of dB per meter below 0.65 $\mu$m and beyond 3.5 $\mu$m. Our findings highlight the potential of graded-index fibers in terms of strong modal confinement over an ultrabroad spectral range for enabling high-gain wavelength conversion. Such advancements require an accurate interpretation of intramodal and intermodal four-wave mixing processes.