Multimode optically adiabatic silica glass submicron taper

TL;DR

This paper introduces a novel method for fabricating multimode submicron silica fiber tapers that can adiabatically transmit multiple higher-order modes, enabling high-efficiency nonlinear and quantum optical applications.

Contribution

It presents the first realization of multimode adiabatic tapers with deep wet-etching, allowing simultaneous transmission of multiple modes including LP02, and demonstrates high-efficiency third-harmonic generation.

Findings

Successful fabrication of multimode submicron tapers

High conversion efficiency in third-harmonic generation

Potential for advanced multimode nonlinear and quantum optics

Abstract

Silica nanofibers fabricated by tapering optical fibers have attracted considerable interest as an ultimate platform for high-efficiency light-matter interactions. While previously demonstrated applications relied exclusively on the low-loss transmission of only the fundamental mode, the implementation of multimode tapers that adiabatically transmit several modes has remained very challenging, hindering their use in various emerging applications in multimode nonlinear optics and quantum optics. Here, we report the first realization of multimode submicron tapers that permit the simultaneous adiabatic transmission of multiple higher-order modes including the LP02 mode, through introducing deep wet-etching of conventional fiber before fiber tapering. Furthermore, as a critical application, we demonstrate 'fundamental-to-fundamental' all-fiber third-harmonic generation with high conversion efficiencies. Our work paves the way for ultrahigh-efficiency multimode nonlinear and quantum optics, facilitating nonclassical light generation in the multimode regime, multimode soliton interactions and photonic quantum gates, and manipulation of the evanescent-field-induced optical trapping potentials of atoms and nanoparticles.