The Information Capacity of the Fiber-Optic Channel: Bounds and prospects

We discuss the challenges in assessing the theoretical limits to the throughput of fiberoptic communications systems and argue that the uncertainty of available information capacity limits is within a range of 1.17 bit/s/Hz. We show that record experiments are within 20 to 30 percent from these limits in terrestrial single-mode fiber systems for metro to long-haul transmission. It appears that the continued scaling of optical communications will have to rely on parallelism and space-division multiplexed fiber transmission