Does these calculations make sense? glass has density of 2.5 g/cm^3 typical single mode fiber core diameter 8.3 micrometers. geosynchronous orbit: 42,164km radius; 265,000km circumference. volume of glass for geosynchronous fiber: pi*(8.3µm/2)^2*265000km = 0.014334011188882 m^3 (?) density of glass = 2500kg/m^3 Mass of geosynchronous glass = 36 kg (?) I'm quite sure that today's geosynchronous satellites weigh more than 80 pounds! (Yes, I know, this is only for the core of the fiber; a geosynchronous fiber would also require cladding, but one might optimize the cladding for this particular application if one were to really pursue this technology.) So a geosynchronous optical fiber ring is eminently doable with today's technology! Such a ring could conceivably transmit 1 Tbit/second at ~2/3 c (= 200,000km/s) This ring would hold 1.3 seconds of data = 1.3 Tbits = 162 GBytes.