All-Optical Signal Processing Based on Self-Induced Polarization Control in Optical Fibers

In this contribution, we review our recent progress on the all-optical control of the state-of-polarization of light in optical fibers upon propagation in a system called Omnipolarizer. More precisely, in this device we exploit the unexpected capability of light to self-organize its own state-of-polarization, upon propagation in optical fibers, into universal and environmentally robust states. The underlying physical mechanism consists in a nonlinear cross-polarization feedback interaction between an arbitrary polarized incident signal and its own counter-propagating replica generated at the fiber end by means of a reflective element. Depending on the power ratio between the two waves, e.g., the reflective coefficient, this nonlinear self-repolarization phenomenon offers a rich variety of dynamics for which we have highlighted three main working regimes identified by first a bistable operating regime, a polarization alignment process as well as a genuine chaotic behavior. We have fully characterized these three operating regimes with an excellent agreement between numerical and experimental results. Moreover, beyond the fundamental aspect of these first studies, we have then exploited this self-induced repolarization phenomenon in order to implement several proof-of-principles for all-optical signal processing. In particular, we have successfully demonstrated the spontaneous repolarization of a 10-Gb/s return-to-zero optical signal without noticeable impairments. The bistability and associated hysteresis properties of the Omnipolarizer have been also exploited to implement an optical flip-flop memory as well as a 10-Gb/s polarization-based data packet router. Finally, we have taken advantage of the chaotic dynamics of our device to demonstrate an all-optical scrambler enabling truly chaotic polarization diversity for 10-Gb/s on/off keying wavelength division multiplexing applications.