Magneto-optical properties of spin-coated bismuth-substituted yttrium iron garnet films on silicon substrates at 1550-nm wavelength

Yudeuk Kim,Yonghwan Kim,David Juseong Bang,Kyong Hon Kim

doi:10.1063/1.5137769

Yudeuk Kim, Yonghwan Kim + Show 2 more

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https://doi.org/10.1063/1.5137769

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Journal: AIP Advances	Publication Date: Feb 1, 2020
Citations: 11	License type: cc-by

Affiliation: Inha University

Abstract

Bismuth-substituted yttrium iron garnet (Bi:YIG) films were prepared by using spin coating processes with metal-organic-decomposition-method-based solutions on crystalline silicon (Si) substrates, and their magneto-optic properties at the 1550-nm wavelength region were investigated by performing various thermal treatments. The maximum Verdet constant of the Bi1Y2Fe5O12 film on the Si substrate with a middle buffer layer of Bi2Y1 Fe5 O12 was measured to be 1 072 038°/T/m at 1550-nm wavelength in the unsaturated linear magnetization region by accounting for the negative Verdet constant of the silicon substrate. The optimum thermal treatment condition was observed at the maximum annealing temperature of 700 °C and the annealing speed of 3 °C/min. These spin coating enabled processes may be included to the conventional complementary metal-oxide semiconductor fabrication processes to demonstrate integrated optical waveguide-type isolators on silicon-on-insulator wafers.

Highlights

A good magneto-optic (MO) material applicable to the complementary metal-oxide semiconductor (CMOS) processes is needed to demonstrate integrated optical isolators (IOIs) on silicon (Si) wafers, which are critical parts in photonic integrated circuits (PICs)
Bismuth-substituted yttrium iron garnet (Bi:YIG) films grown by the liquid phase epitaxy (LPE) method on gadolinium gallium garnet (GGG) substrates were used to be patterned into direct planar waveguides and to demonstrate the integrated optical waveguide-type isolator (IOWTI) with an external magnetic field applied5 and with sputter-deposited thinfilm magnets
The maximum Verdet constant of the Bi:YIG film measured in this experiment is 1 072 038○/T/m for the Bi2:YIG film on a Bi1:YIG buffer layer treated at an annealing temperature of 700 ○C and at an annealing speed of 3 ○C/min

Summary

Introduction

A good magneto-optic (MO) material applicable to the complementary metal-oxide semiconductor (CMOS) processes is needed to demonstrate integrated optical isolators (IOIs) on silicon (Si) wafers, which are critical parts in photonic integrated circuits (PICs). A thin layer of cerium-substituted YIG (Ce:YIG) fabricated by the sputtering method on the GGG substrate was bonded on the top of a waveguide-type Si Mach–Zehnder interferometer (MZI) or of a waveguide-type Si microring interferometer (MRI) as an upper cladding to form the IOWTIs.7–9 These approaches to IOWTI implementation using the direct Bi:YIG waveguide or the bonded Ce:YIG cladding layer are not suitable for mass production of PIC chips under the CMOS processes. A monolithic integration of the MO material layer directly on the Si waveguides has been pursued to demonstrate the IOWTI by using pulsed laser deposition (PLD).10 This PLD method is still a challenging approach to be adapted to the CMOS process for a full wafer scale PIC production. Further improvement is scitation.org/journal/adv needed to reduce the large optical insertion loss caused by this approach

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