  Current research efforts are focussed on overcoming the apparent limits of
communication in single mode optical fibre resulting from distortion due to
fibre nonlinearity. It has been experimentally demonstrated that this Kerr
nonlinearity limit is not a fundamental limit; thus it is pertinent to review
where the fundamental limits of optical communications lie, and direct future
research on this basis. This paper details recently presented results. The work
herein briefly reviews the intrinsic limits of optical communication over
standard single mode optical fibre (SMF), and shows that the empirical limits
of silica fibre power handling and transceiver design both introduce a
practical upper bound to the capacity of communication using SMF, on the order
of 1 Pbit/s. Transmission rates exceeding 1 Pbit/s are shown to be possible,
however, with currently available optical fibres, attempts to transmit beyond
this rate by simply increasing optical power will lead to an asymptotically
zero fractional increase in capacity.
