Reduced diameter fibers for high-density optical interconnects

Data centers (DCs) are continually striving to meet the challenge of delivering more bandwidth, and a key part of that endeavor will be the deployment of higher capacity interconnects. Proposed technologies for achieving this higher capacity include higher line rates, advanced modulation formats, wavelength division multiplexing, spatial division multiplexing and reduced diameter fibers. In this paper, we focus on reduced diameter fibers that can be incorporated into higher density cables and connectors. We have prototyped optical fibers in which the glass diameter is 80 microns and the coating diameter has been reduced to as small as 125 microns. These fibers enable up to twice as many optical interconnects in a given footprint, which will allow transceiver arrays to be collinearly located on small chips with dimensions on the order of (5x5mm 2 ) 1 . We have also incorporated these reduced diameter fibers into small form-factor, flexible 8-fiber ribbons which can enable as much as a 3x increase in fiber density and can simplify routing constraints inside modules and optical backplanes.