PMN-PT nanocrystal composite optical fibers with enhanced nonlinear response

Ferroelectric crystal materials constructed into one-dimensional optical fibers are attractive for optoelectronic applications. However, the development of ferroelectric optical fibers has been constrained by fabrication challenges, particularly the integration of a high-refractive-index ferroelectric crystal core with a low-refractive-index glass cladding. In this paper, PMN-PT nanocrystal composite optical fibers are drawn from a fiber preform combining a PMN-PT single-crystal rod into a silica glass tube, using a melt-in-tube method. The as-drawn fibers comprise a silica cladding and a coral-shaped core of PMN-PT nanocrystals embedded in a silica matrix. These PMN-PT nanocrystal composite optical fibers exhibit a graded-index optical waveguide characteristic and a high third-order nonlinear coefficient (approximately one hundred times higher than that of silica photonic crystal fibers), enabling broadband nonlinear wavelength conversion.