[OPTICAL REVIEW Vol. 18, No. 1 (2011) 47-53]
© 2011 The Japan Society of Applied Physics

Laser-Assisted Magnetic Recording Light-Delivery System with a Coupling Element and a Laterally Tapered Vertically Multistepped Waveguide

Shin-ya HASEGAWA and Wataru ODAJIMA1

Human Centric Computing Laboratories, Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0124, Japan
1Technical Computing Solutions Unit, Fujitsu Ltd., 9-3 Nakase 1-chome, Mihama-ku, Chiba 261-8588, Japan

(Received January 8, 2010; Accepted October 15, 2010)

In a light-delivery system for laser-assisted magnetic recording, which provides high-areal-density storage by heating the storage medium during the writing process, a laser diode light source and a near-field transducer must be efficiently coupled using inexpensive optical devices. We describe a light-delivery system using an element for end-fire coupling and a spot-size converter. To couple the light emitted from the end of an optical fiber to a spot-size converter inexpensively, a couple element requiring no other lens elements between the fiber and converter was developed. A vertically multistepped and laterally tapered waveguide suitable for fabrication by planar processing was also developed. These devices are well suited for practical use.

Key words: optical waveguide, laser-assisted magnetic recording, light delivery, end-fire coupling, coupling, FDTD method, mode propagation by Fourier expansion method, off-axis optics