Progress towards board-level optical interconnect technology

Bandwidth demand is still growing and it is becoming more difficult for copper based interconnect technologies to meet system requirements. Considerable progress is being made in the development of optical interconnect technology. Recent publications have shown improved integration of turning mirrors and connectors for board level applications. This paper presents recent work on a siloxane-based waveguide material that is optimized for 850nm board level optical interconnect applications. The material under development is a negative acting photoimageable material that can be processed with conventional Printed Wire Board (PWB) or CMOS processing techniques and chemistries. Meter long waveguides have been fabricated on both silicon and FR4 substrates with optical loss performance of 0.027dB/cm and 0.067dB/cm respectively. Data illustrating the effect of bend radii and splitter performance is reported. Lastly, the ability of the siloxane material to withstand PWB fabrication and assembly processes such as lamination, metallization and reliability is demonstrated.