We propose and demonstrate an efficient coupler for compact mode conversion between a fiber and a submicrometer waveguide. The coupler is composed of high-index-contrast materials and is based on a short taper with a nanometer-sized tip. We show that the micrometer-long silicon-on-insulator-based nanotaper coupler is able to efficiently convert both the mode field profile and the effective index, with a total length as short as 40 μm . We measure an enhancement of the coupling efficiency between an optical fiber and a waveguide by 1 order of magnitude due to the coupler.
© 2003 Optical Society of America
(130.3120) Integrated optics : Integrated optics devices
(230.3120) Optical devices : Integrated optics devices
(230.7380) Optical devices : Waveguides, channeled
(230.7390) Optical devices : Waveguides, planar
(250.5300) Optoelectronics : Photonic integrated circuits
Vilson R. Almeida, Roberto R. Panepucci, and Michal Lipson, "Nanotaper for compact mode conversion," Opt. Lett. 28, 1302-1304 (2003)