  In this paper, we report the observation and exploitation of the capability
of light to self-organize its state-of-polarization, upon propagation in
optical fibers, by means of a device called Omnipolarizer. The principle of
operation of this system consists in a counter-propagating four-wave mixing
interaction between an incident signal and its backward replica generated at
the fiber output thanks to a reflective fiber loop. We have exploited this
self-induced polarization tracking phenomenon for all-optical data processing
and successfully demonstrated the spontaneous repolarization of a 40-Gbit/s
On-Off keying optical signal without noticeable impairments. Moreover, the
strong local coupling between the two counter-propagating waves has also
revealed a fascinating aspect of the Omnipolarizer called polarization-based
tunneling effect. This intrinsic property enables us to instantaneously let
jump a polarization information onto the reflected signal, long before the
expected time-of-flight induced by the round-trip along the fiber span.
Finally, we discuss how the concept of self-organization could be generalized
to multimode fibers, which paves the way to new important applications in the
framework of spatial-mode-multiplexing.
