Magnetless Optical Circulator Based on an Iron Garnet with Reduced Magnetization Saturation

Area of Science:

• Photonics
• Materials Science
• Optical Communication

Background:

• Traditional optical circulators often require bulky external magnetic components.
• Achieving nonreciprocal light propagation in compact devices is a significant challenge.

Purpose of the Study:

• To propose and simulate a novel three-port optical circulator.
• To demonstrate a compact circulator design using a self-magnetizing magneto-optical material.

Main Methods:

• Utilized a photonic crystal slab made of a europium-doped magneto-optical material.
• Performed two- and three-dimensional simulations using finite element method (FEM) based electromagnetic solvers.
• Analyzed device performance at a 1550 nm wavelength.

Main Results:

• The proposed circulator operates without an external DC magnetic field.
• Achieved insertion loss, isolation, and reflection levels of -1 dB, -14 dB, and -20 dB, respectively.
• Demonstrated a footprint reduction of three orders of magnitude compared to existing designs.

Conclusions:

• The novel magneto-optical material enables self-magnetization, simplifying circulator design.
• The compact circulator design offers significant advantages for optical communication systems.
• The results are applicable to the development of other miniaturized nonreciprocal optical devices.