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

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 (R-m) increases with the increase of the MF concentration, while modal birefringence ( increment 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, R-m is improved to over 93%, and increment n is reduced to close to 10(-6). Whereas, R-m decreases to 89.59 and increment n increases to 6 x 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.

Automated summary

Through numerical analysis, it is found that in a magnetic photonic crystal fiber filled with magnetic fluid, the mode conversion efficiency increases and modal birefringence decreases with the increase of magnetic fluid concentration. The fiber filled with 1.75% magnetic fluid concentration shows the best performance in designing magneto-optical isolators.