Energy efficient 850 nm VCSELs operating error-free at 25 Gb/s over multimode optical fiber up to 600 m

We demonstrate error-free 25 Gb/s optical interconnects with 850 nm vertical-cavity surface-emitting lasers. At 25°C through 100, 303, and 603 meters of fiber we achieve record heat-to-bit-rate ratios of 99, 122, and 188 mW/Tbps, respectively.