Interfaces to fiber image guide bundles for high density optical interconnects

This paper investigates different factors that influence the channel density of signals propagated through fiber imaging guides. These include the uniformity of the optical power transmitted through the guide, the geometrical structure of the guide, the optical crosstalk to adjacent signal channels, and modal noise. A model for the power uniformity and optical cross-talk is provided and is used to evaluate the channel density of different coupling modes. A commercially available fiber image guide is evaluated in the context of these density considerations and is experimentally tested. Modal noise is also experimentally measured for different coupling conditions to the fiber-imaging guide. The resultant signal channel based on these criteria was found to have a diameter approximately 3 times the center spacing of the fiber elements in the fiber imaging guide. This density compares favorably with electrical interconnect densities that are projected for tape automated bonding and flip-chip bonding techniques.