  A memoryless interference network model is introduced that is based on
non-linear phenomena observed when transmitting information over optical fiber
using wavelength division multiplexing. The main characteristic of the model is
that amplitude variations on one carrier wave are converted to phase variations
on another carrier wave, i.e., the carriers interfere with each other through
amplitude-to-phase conversion. For the case of two carriers, a new technique
called interference focusing is proposed where each carrier achieves the
capacity pre-log 1, thereby doubling the pre-log of 1/2 achieved by using
conventional methods. The technique requires neither channel time variations
nor global channel state information. Generalizations to more than two carriers
are outlined.
