Controllable multiple beam splitting in Hermitian and non-Hermitian symmetric coupled waveguide systems

TL;DR

This paper presents methods for high-fidelity multiple beam splitting in Hermitian and non-Hermitian coupled waveguides, utilizing adiabatic passage, shortcuts to adiabaticity, and non-Hermitian STA techniques, verified through beam propagation simulations.

Contribution

It introduces novel beam splitting techniques in symmetric waveguide systems using advanced adiabatic and non-Hermitian control methods, enhancing on-chip photonic device capabilities.

Findings

High-fidelity beam splitting achieved in Hermitian systems using STIRAP.

Robust beam splitting in non-Hermitian systems via non-Hermitian STA.

Feasibility confirmed through beam propagation method simulations.

Abstract

We investigate high-fidelity multiple beam splitting in Hermitian and non-Hermitian symmetric coupled waveguides with one input and 2N output waveguide channels. In Hermitian systems, we realize adiabatically light splitting in resonant case based on the stimulated Raman adiabatic passage (STIRAP) and arbitrary proportion from the middle waveguide to outer waveguides in propagation coefficients mismatch case using shortcuts to adiabaticity (STA) technique. In non-Hermitian systems with even waveguides being dissipative, the compact and robust beam splitting can be achieved by eliminating the non-adiabatic coupling via the non-Hermitian STA method. We further verify the feasibility of our theoretical predictions by means of the beam propagation method (BPM). The suggested multiple beam splitters open new opportunities for the realization of on-chip high-bandwidth photonics with high fidelity in short distances.