Spectral Shaping in a Multimode Fiber by All-fiber Modulation

TL;DR

This paper introduces a novel method to create tunable spectral filters in multimode fibers by mechanically deforming the fiber and using optimization algorithms, enabling precise spectral control for various optical applications.

Contribution

It presents an all-fiber, reconfigurable spectral filtering technique using mechanical deformation and optimization, advancing multimode fiber applications in spectroscopy and imaging.

Findings

Achieved spectral resolutions as low as 5 pm.

Demonstrated tunable bandpass and dual-band filters.

Controlled light propagation through mechanical deformation.

Abstract

In the past few years, there is a renewed interest in using multimode fibers for a wide range of technologies such as communication, imaging and spectroscopy. Practical implementations of multimode fiber in such applications, however, are held back, due to the challenges in dealing with modal dispersion, mode coupling and the fiber's sensitivity to mechanical perturbations. Here, we utilize these features of multimode fibers to generate all-fiber reconfigurable spectral filters. By applying computer-controlled mechanical deformations to the fiber, along with an optimization algorithm, we manipulate the light propagation in the fiber and control its output field. Using this approach we demonstrate tunable bandpass filters and dual-band filters, with spectral resolutions as low as 5pm.