Optical nonreciprocal devices based on magneto-optical phase shift in silicon photonics. (20th November 2015)

• Record Type: Journal Article
• Authors: Shoji, Y; Miura, K; Mizumoto, T
• Is Part Of: Journal of optics. Volume 18:Number 1(2016:Jan.)
• Publication Date: 2015-11-20
• Subjects: magneto-optical effect -- optical isolator -- optical circulator -- direct bonding -- phase shift -- silicon photonics; Optics -- Periodicals; 535.05
• DOI: 10.1088/2040-8978/18/1/013001
• Languages: English
• ISSNs: 2040-8978

Abstract

Abstract: Silicon waveguide optical nonreciprocal devices that use the magneto-optical phase shift are reviewed. The phase shift caused by the first-order magneto-optical effect is effective in realizing optical nonreciprocal devices on semiconductor waveguide platforms. In a silicon-on-insulator waveguide, the low refractive index of the buried oxide layer contributes to the large penetration of the optical field into a magneto-optical material used as an over-cladding layer. This enhances the magneto-optical phase shift and, hence, contributes greatly to reducing the device footprint. A surface-activated direct bonding technique plays a key role in the fabrication of magneto-optical nonreciprocal devices. This technique makes it possible to use a high-quality single-crystalline magneto-optical garnet that exhibits a large first-order magneto-optical effect. An optical isolator based on the magneto-optical phase shift was demonstrated in a silicon waveguide with an optical isolation ratio as high as 30 dB and an insertion loss of 13 dB at a wavelength of λ = 1548 nm. Furthermore, a four-port optical circulator was demonstrated with maximum isolation ratios of 33.5 and 29.1 dB in the cross and bar ports, respectively, at λ = 1543 nm.