Magneto-Optical Isolator Based on Ultra-Wideband Photonic Crystals Waveguide for 5G Communication System

Abstract

This paper presents a novel magneto-optical isolator based on an ultra-wideband and high efficiency photonic crystals (PCs) waveguide and gyromagnetic ferrites. The three-dimensional numerical simulation finds that the photonic crystals waveguide’s (PCW) transmission efficiency rises with its height and width. The corresponding experiments are performed by using a triangular lattice Al2O3 dielectric posts array in 5G millimeter wave band. The measured transmission efficiency is up to 90.78% for the optimal PCs waveguide structure, which has ultra-wide operating bandwidth from 23.45 to 31.25 GHz. The magneto-optical isolator is designed by inserting two rectangular gyromagnetic ferrites into the PCs waveguide. Due to the contrast between the effective permeability of the left and right circular polarization waves passing through the magnetized ferrite sheets, the ferromagnetic resonance absorption of the forward and reverse waves is different. By using finite element method, the isolation is optimized to be 49.49 dB for the isolator and its relative bandwidth reaches 8.85%. The high isolation, broadband, and easy integration indicate that our designed magneto-optical isolator has significant advantage in 5G communication systems.

Preparation and properties of novel (Tb1−xCex)3Sc2Al3O12 magneto-optical transparent ceramics with different doping concentrations

“…[1][2][3] MO isolators have received extensive attention for their elimination of back-reflected light in applications, including high-power lasers, sensors and optical communication systems. [4][5][6][7][8][9] Matching high Verdet constants is required for MO isolators used in high-power lasers to enable device miniaturisation and overall cost reduction. 7 Furthermore, MO materials with high thermal conductivity and low optical weak absorption are necessary to facilitate the matching of a MO isolator and a high-power laser to reduce the thermal lens effect at high power.…”

Compact Photonic-Crystals Based Isolator Using Ni–Zn Gyromagnetic Ferrite Posts

“…A centimeter wave CESs isolator was experimentally realized by inserting two antennas in a 16 × 7 photonic crystal with the lattice constant of 40 mm [22], in which the electromagnetic CESs can travel in only one direction that is fundamentally different from how non-reciprocal isolators operate. In our previous work, a resonance isolator was envisaged by using an ultra-wideband photonic crystal waveguide (PCW) and two magnetized ferrite sheets [23]. Different from the CESs isolator, the operating principle of the resonance isolator is ferromagnetic resonance absorption effect.…”

“…Here, α = 3 × 10 −5 and M s = 2.39 × 10 5 A/m depend on material parameters. The external DC field is H 0 = 3.15 × 10 5 A/m, which is reduced twofold compared with that in[23]. The symbol of the off-diagonal element κ is decided by the direction of external DC magnetic field and the strength of Faraday rotation effect is determined by the quality factor Q = κ/µ.…”

A general method for calculation of Faraday rotation and transmittance in two-dimensional magneto-optic photonic crystals by solving vector-Helmholtz equation in anisotropic media

“…They have potential tunability emerging from the dependence of permeability on an external static magnetic field. Also, MOPCs can use in magneto-optical isolators for 5G communication systems and biosensors [14][15][16]. Sakoda has developed a method based on the plane wave expansion (PWE) and calculated the transmittance and reflectance in a slab of the two-dimensional photonic crystal [17].…”