Optical circulators based on iron garnets without external magnetization

• Grant number: 19/13667-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: January 01, 2020
• End date: May 31, 2024
• Field of knowledge: Engineering - Electrical Engineering - Telecommunications
• Principal Investigator: Hugo Enrique Hernández Figueroa
• Grantee: Gianni Masaki Tanaka Portela
• Host Institution: Faculdade de Engenharia Elétrica e de Computação (FEEC). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 15/24517-8 - Photonics for next generation internet, AP.TEM
• Associated scholarship(s): 22/02391-6 - Magnetless circulators based on cobalt ferrite films for optical communication systems, BE.EP.PD

Abstract

Circulators are nonreciprocal devices normally used for the protection of signal sources against parasitic reflections that arise from unmatched loads in a communication system. The operating principle of circulators is related to the breaking of the time reversal symmetry due to the application of a DC magnetic field to a magneto-optical material that constitutes such devices. This external magnetic field is responsible for keeping the magneto-optical material magnetically saturated, which in turn is a necessary condition for the proper operation of the circulator. The magnetization circuit of circulators often consists of permanent magnets or electromagnets, which in turn are usually bulky and complicate the project of circulators with reduced dimensions, suitable for utilization in communication systems with high integration density. In order to overcome this problem, new circulators based on the utilization of a magneto-optical material that does not require the application of a DC magnetic field to keep its saturated magnetic state will be projected. This material, the bismuth iron garnet with the incorporation of europium and molecular formula BiX(EuZHo1-Z)3-XFe5-YGaYO12, will allow the project of compact circulators because there will be no need for bulky magnetization circuits based on permanent magnets or electromagnets. Specifically, it will be developed, at least, two new compact optical circulators with 3 or 4 ports, suitable for optical communication systems with high integration density. They will be based on the connection of resonant cavities, including the aforementioned magneto-optical material, to photonic crystal waveguides (PBG waveguides) or ARROW waveguides (non-PBG waveguides). (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

PORTELA, GIANNI; LEVY, MIGUEL; HERNANDEZ-FIGUEROA, HUGO E.. Magnetless Optical Circulator Based on an Iron Garnet with Reduced Magnetization Saturation. Molecules, v. 26, n. 15, AUG 2021. (15/24517-8, 19/13667-0)

PORTELA, GIANNI; LEVY, MIGUEL; HERNANDEZ-FIGUEROA, HUGO E.. Novel compact magnetless isolator based on a magneto-optical garnet material. OPTICS AND LASER TECHNOLOGY, v. 157, p. 7-pg., 2023-01-01. (15/24517-8, 19/13667-0)