8. Polarization attraction without pump wave: self-polarization concept

A further step can be taken to improve the polarization stabilization device by doing away with the need for a polarized pump wave.

Let's recall the principle of "classic" polarization attraction with a pump: the pump's fixed polarization (in theory circular), via a non-linear four-wave mixing effect, forces the signal to adopt a polarization of the same ellipticity (also in theory circular) in order to form a stable polarization domain at the end of the fiber where the pump is injected.

The role of the pump, which attracts the signal thanks to its fixed polarization, therefore seems essential to the process. However, it is possible to do away with this pump beam by incorporating a partially reflective device at the end of the fiber, as shown in figure