[16a-2F-1~12] 3.14 Optical control devices and optical fibers

△ [16a-2F-12] Study of thin-film magnet for self-holding optical switch using a magneto-optical effect

〇tomohiro ueno¹, Yuya Shoji^1,2, Yota Takamura¹, Shigeki Nakagawa¹, Tetsuya Mizumoto¹ (1.Graduate School of Sci. and Eng, Tokyo Tech., 2.QNERC, Tokyo Tech.)

Keywords:optical switch

An optical switch with low power consumption is demanded because of an increase in power consumption of the photonic network systems with the increase in communication traffic. Many of optical switches consume power to maintain the switching state. In this study, from the viewpoint of reducing the size and power consumption, it is intended to realize a stable integrated optical switch capable of self-holding operation of the switching state. The optical switch, using the magnet-optical material as the waveguide layer, has a magnetic recording material above the waveguide to apply the magnetic field. The non-volatility of magnetic recording material enables self-holding of the switching state. Since the power is consumed only during the switching state is changed, the power consumption is dramatically reduced for switching systems with low frequency.
In this report, we use a thin-film magnet FeCoB as the magnetic recording material. Discrete rectangular sections of the magnet film are aligned so that the easy axis of the magnetization (longitudinal of the rectangular) becomes transversally to the optical waveguide. The sample of 40 μm×10 μm sections with 150-nm-thick FeCoB film shows the saturation magnetization of about 20 kG and the remanent magnetization of 14 kG, which is almost sufficient to operate the optical switch.