Bending properties in oxidized porous silicon waveguides

The greatest limit in high-speed communications between different circuit b locks is due to the delays introduced by metal interconnections. Knock-down wire communication bottleneck is, therefore, one of the best goals that cu rrent research could reach in the held of fast electronics. A possible solu tion is to build fast optical links and even better if the technology is ba sed on silicon. To attain these ends, we have made studies into possibility to fabricate optical waveguide based on oxidized porous silicon. In the la st few years, such a device: was realized and characterized. Waveguiding in the visible and in the near infrared was demonstrated, With propagation lo sses of about 3-5 dB/cm for a light with a wavelength of 632.8 nm. Moreover , a design feature of an integrated waveguide based on oxidized porous sili con is that it offers a spontaneous bending of the waveguiding layer at its ends. The edge bending is provided by a convex camber of a leading edge of forming porous silicon. This bending can be exploited to promote a vertica l light output with no use of any additional devices. The paper discusses t he properties of edge bending, evaluation of the light losses depending on the radius of curvature, and analysis of possibilities to reduce these loss es. (C) 2001 Elsevier Science Ltd. All rights reserved.