Dynamic Brillouin gratings: A new tool in fibers for all-optical signal processing

Abstract

Abstract:The recent possibility to generate dynamic Bragg gratings by the interaction of 2 optical waves through stimulated Brillouin scattering in highly birefringent fibers has opened a new field to realize all-optical fiber-based functions. The generation of dynamic Bragg gratings by the interaction of 2 optical waves through stimulated Brillouin scattering has offered the possibility to implement all-optical functions that were so far impossible to realize in optical fibers. Using this feature a local and temporary grating can be placed at any position along an optical fiber and can be repositioned dynamically with a total flexibility through a purely optical interaction. This new tool has found direct applications in all-optical delay lines, demonstrating a tunable delaying capacity of more than 1 microsecond with an ideal reconfiguration time. But it turns out that its field of application is much vaster, from optical storage and analog operations on the signal (time reversal, derivative, integration) to distributed sensing with an extreme spatial resolution.

Inducing and harnessing stimulated Brillouin scattering in photonic integrated circuits

“…Recently, dynamic gratings were, however, demonstrated using SBS in several meter long single-mode [41], polarization maintaining [45], and few-mode [40] optical fibers. These gratings, often called BDGs, provide a new tool for sensing [7,38,43], microwave photonics and all-optical processing [46,168], filtering [32], tunable delay [169], true-time reversal [37], and on-chip microwave signal processing for true-time delay (TTD) [32,46,168]. However, their implementation in long fibers makes them incompatible with photonic integration.…”

“…However, SBS has been extremely useful in a number of areas, notably in ultra-narrowbandwidth lasers [2][3][4][5][6], sensing [7], slow-and fast-light , and microwave signal processing [30][31][32][33][34][35][36]. SBS can also be used to create dynamic acoustic gratings in the propagation material [23,32,[37][38][39][40][41][42][43][44][45][46][47][48]-these gratings can be used to reflect cross-polarized signals or to produce strong phase-conjugate beams through a process known as Brillouin-enhanced four-wave mixing (BEFWM) [49]. In recent years, there has been a remarkable surge of interest in SBS, largely driven by the ability to harness the effect on the nanoscale.…”

On-chip stimulated Brillouin scattering and its applications

“…Dynamic gratings provide a novel platform for applications such as sensing, microwave signal processing and tunable delay [17,18]. Recently Brillouin dynamic gratings (BDGs) have been demonstrated in tens-of-meter long polarization maintaining fibres (PMFs) [19], in single-mode fibers (SMFs) [20], and in few-mode fibres (FMFs) [21].…”