News in Brief Optics // Novel Optical Connection Between Semiconductor Chips © Based on Material by KIT, Germany

A team of KIT researchers directed by Professor Christian Koos has succeeded in developing a novel optical connection between semiconductor chips. The researchers first fix the chips and then structure a polymer-based optical waveguide in a perfectly fitting manner. To adapt the interconnection to the position and orientation of the chip, the scientists developed a method for the three-dimensional structuring of an optical waveguide. They used so-called two-photon polymerization which reaches a high resolution. A femtosecond laser writes the free-form waveguide structure directly into a polymer that is located on the surface of the chip. For this purpose, the KIT researchers use a laser lithography system made by the Nanoscribe company, a spinoff of KIT. Prototypes of the photonic wire bonds reached very small losses and a very high transmission bandwidth in the range of infrared telecommunication wavelengths around 1.55 micrometers. In first experiments, the researchers already demonstrated data transmission rates in excess of 5 terabits per second. Potential applications of photonic wire bonds lie in complex emitter-receiver systems for optical telecommunication as well as in sensor and measurement technology.

The wire bond is adapted to the position and orientation of the chips. © N. Lindenmann and G. Balthasar N. Lindenmann, G. Balthasar, D. Hillerkuss, R. Schmogrow, M. Jordan, J. Leuthold, W. Freude, and C. Koos: Photonic wire bonding: a novel concept for chip-scale interconnects, In: Optics Express, Vol. 20, No. 16, 30 July 30, 2012, Pages 17667-17677, DOI:10.1364/OE.20.017667: http://dx.doi.org/10.1364/OE.20.017667