Symmetry Broken Localized Structures in a Coherently-Driven Fabry-Pérot Kerr Resonator

Spontaneous symmetry breaking (SSB) is an ubiquitous phenomenon of fundamental interest, potentially leading to promising applications in nonlinear optics. In coherently-driven Kerr ring resonators, SSB has been observed between counter-propagating beams [1] and co-propagating waves of orthogonal polarizations [2]. Experimental demonstrations of polarization SSB in optical fibre rings have also unveiled peculiar nonlinear dynamics such as topological protection of SSB phenomena as well as novel localized vectorial structures, including polarization domain walls (PDWs) [3], vectorial cavity solitons (CSs) [4], and polarization faticons [5]. Complementary to ring architectures, Fabry-Pérot (FP) Kerr resonators are also good candidates for practical applications including frequency comb generation [6] and polarization SSB [7]–[8]. FP Kerr resonators are typically made of a short segment of optical fibre encapsulated in-between two Bragg dielectric mirrors [6]–[7]. They benefit from the flexibility, interconnectivity, and stability of fibre-based systems, free-spectral ranges (FSR) from hundreds of MHz to tens of GHz, dispersion engineering using various types of optical fibres or mirror properties, whilst preserving high quality-factors. Here we show that fibre-based FP resonators can provide an efficient protection of polarization SSB phenomena through the introduction of a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pi / 2$</tex> -phase birefringent defect between the two orthogonal eigenmodes of the cavity, enabling the generation of robust vectorial localized temporal structures such as PDWs and CSs.