Slow and fast light in optical fibers using acoustooptic coupling between two co-propagating modes

Abstract

We demonstrate numerically that acoustooptic interaction between two co-propagating modes in an optical fiber can be utilized to obtain positive and negative delays. A single acousto-optic interaction region, and a configuration based on two acousto-optic interaction regions, separated by a section of unperturbed fiber, are simulated. It is found that the delays and advancements can be several pulse lengths in the configuration with two acoustooptic coupling regions separated by a section of unperturbed fiber. These results are not in conflict with relativistic causality, but are a consequence of the difference in group velocity between the two coupled modes.

Recent progress of dynamic mode manipulation via acousto-optic interactions in few-mode fiber lasers: mechanism, device and applications

“…Acousto-optic mode converters (AOMCs) employ acoustic waves to create acoustically induced fiber gratings (AIFGs), providing a tunable spatial mode generation with high switching speed [43][44][45][46][47][48][49][50]. The pioneered discovery in 1986 that Kim et al firstly proposed and demonstrated the mode conversion with a frequency shift by a two-mode fiber-based AOMC [43], which has opened a door to novel researches on acousto-optic interactions (AOI) in fibers and various derived components.…”