Broadband single-mode single-polarization passive fully-aperiodic large-pitch fibers

Two evolutions of fully-aperiodic large-pitch fiber designs employing few stress-applying parts are presented. The induced elasto-optic stress discriminates the two orthogonal polarization modes (LP01x and LP01y) of the fundamental mode, selectively delocalizing one of them into the cladding via a suitable coupling to one or several cladding modes. This ensures the propagation of a single linear polarization mode. For the largest core dimensions, the applied stress can however strongly influence the intensity distributions of core modes and a tailored design process must thwart this. The polarization properties are investigated experimentally with core scalability over a large spectral bandwidth into passive structures, leading to the evidencing of a singlemode single-polarization over a large span from 1μm to 1.6μm with a core dimension of 80μm and notably at 1400nm for a core dimension of 140μm. The polarization extinction ratio is also determined.