Optimized magneto-optical isolator design based on cerium-substituted yttrium iron garnet fiber

Numerical analysis of a magneto-optical (MO) fiber based on cerium-substituted yttrium iron garnet (Ce:YIG) is presented to design a kind of MO isolator. The unique MO properties of garnets are used to produce the non-reciprocal (NR) effect. The aim of this work consists of optimizing the properties of the fiber by reducing modal birefringence (∆n) using the NR TE-TM mode conversion. Therefore, the performance of the proposed structure is investigated to study the MO behavior under the influence of magnetic gyration (g). The optimized mode conversion isolation ratio of 93.88% is attained. Next, Faraday rotation (FR) and ∆n have been calculated, the results reveal a proportional relation between FR and g. Another relationship between ∆n and g is demonstrated, where the two limits values are 0.0022 × 10–5 and 0.7 × 10–5 for g = 0.0037 and g = 0.032, respectively. The enhanced MO properties could improve the efficiency of the designed MO isolator.