Gyrotropy and magnetic fluid dependences of magneto-optical properties in YIG-magnetic photonic crystal fiber

Abstract

In this work, a kind of magnetic photonic crystal fiber (MPCF) design based on yttrium iron garnet (YIG) structure filled with magnetic fluid (MF) is presented. In order to improve the magneto-optical (MO) properties of isolator devices, a numerical study has been developed to investigate the non-reciprocal TE-TM mode conversion. This technique consists in producing, under the influence of a magnetic field parallel to the direction of propagation, a coupling between the modes. The influence of gyrotropy and MF infiltration at different magnetic nanoparticle volume fraction concentrations is investigated. The results revealed that the mode conversion efficiency (Rm) increases with the increase of the MF concentration, while modal birefringence (∆n) is inversely proportional to its increase. Thus, the higher concentration provides the best results. For MF concentration and gyrotropy equal respectively to 1.75% and 0.0125, Rm is improved to over 93%, and ∆n is reduced to close to 10–6. Whereas, Rm decreases to 89.59 and ∆n increases to 6 × 10–6 for MF concentration equal to 0.25%. From these results, it can be seen that this MPCF filled with MF concentration equal to 1.75% is well suited to the design of MO isolators.