Isotropic polarization modulational instability in single-mode conventional telecom fibers

In this work, we report on the experimental observation of isotropic polarization modulational instability processes in various types of conventional normally dispersive telecom fibers. In particular, dispersion-shifted fibers, highly nonlinear fibers, spun fibers, and dispersion-compensating fibers are tested, and all provide polarization modulational instabilities under high-power ns pumping around 1.55 μm. This study reveals that the high quality of modern telecom fibers associated with their manufacturing process based on a fast spinning of the perform during the drawing stage results in a very low level of birefringence, which allows for the emergence of polarization modulation instability in commonly used optical fibers.