Investigation of the characteristics of the electromagnetic induction transparent-like spectrum with counter-propagating waves coupling mechanism for waveguide and micro-ring coupled system

TL;DR

This paper introduces a counter-propagating waves coupling mechanism that enhances electromagnetically induced transparency-like effects in waveguide systems, enabling better control of slow light and optical storage.

Contribution

It proposes a novel counter-propagation coupling method that improves transparency window width and phase profile, advancing slow-light device applications.

Findings

Enhanced transparency window breadths compared to previous mechanisms

Flat or square phase shift profiles achieved

Significant reduction in group velocity near transparency edges

Abstract

In this paper, a new counter-propagation waves coupling mechanism is proposed which is expected to realize an electromagnetically induced transparency (EIT)-like effect. Comparing the travelling waves coupling mechanism (see J. Mod. Opt. 2015,62:313-320 [9]) with the counter-propagating waves coupling mechanism, we find out that the transparency window breadths of transmission spectra are greatly enhanced and the corresponding phase shift spectra possess a flat profile or a square profile. Our numerical simulated results are in good agreement with the theoretical analysis. The EIT-like effect can significantly reduce the group velocity near the edge of the square profile transparent window. We believe that the counter-propagating waves coupling mechanism is particularly beneficial for the realization of active manipulation of slow light devices (such as delay lines) required in the conventional EIT scheme. In the vicinity of the transparency peak, we can obtain a large group delay, may gain more significant potential applications in slow-light transmission and optical storage.