Resonant Bend Loss in Leakage Channel Fibers

TL;DR

This paper investigates the resonant bend loss phenomenon in leakage channel fibers, revealing that at specific radii of curvature, the fundamental mode experiences increased radiative decay due to resonant coupling with cladding modes, which is characterized experimentally.

Contribution

It provides the first experimental characterization of resonant bend loss in leakage channel fibers and explains the physical mechanism behind it.

Findings

Resonant power loss occurs at specific radii of curvature.

The loss is caused by radiative decay via resonant coupling to cladding modes.

Outside resonance, bend loss levels recover to normal values.

Abstract

Leakage channel fibers, designed to suppress higher-order modes, demonstrate resonant power loss at certain critical radii of curvature. Outside the resonance, the power recovers to the levels offset by the usual mechanism of bend-induced loss. Using C$^2$-imaging, we experimentally characterize this anomaly and identify the corresponding physical mechanism as the radiative decay of the fundamental mode mediated by the resonant coupling to a cladding mode.