Bloch-mode extraction from near-field data in periodic waveguides

TL;DR

This paper presents a method to extract both propagating and evanescent Bloch-modes from a single near-field measurement in periodic waveguides, extending spectral techniques to spatial data and confirming robustness against noise.

Contribution

It introduces a systematic procedure for Bloch-mode extraction from near-field data, incorporating symmetry considerations and applicable to complex photonic structures.

Findings

Successful extraction of Bloch-modes from a single measurement

Method is robust to noise in the data

Applicable to photonic crystal waveguide interfaces

Abstract

We demonstrate that the spatial profiles of both propagating and evanescent Bloch-modes in a periodic structure can be extracted from a single measurement of electric field at the specified optical wavelength. We develop a systematic extraction procedure by extending the concepts of high-resolution spectral methods previously developed for temporal data series to take into account the symmetry properties of Bloch-modes simultaneously at all spatial locations. We apply our method to a photonic crystal waveguide interface and confirm its robustness in the presence of noise.