Ultralow confinement loss anti-resonant fibers designed by swarm intelligence.

Anti-resonant fibers featured with multiple cladding tubes are promising light guiding media with a broadband low-loss transmission window in the optical spectrum. Herein, we numerically demonstrate anti-resonant fibers with ultra-low confinement loss and good single mode property, which is automatically designed by swarm intelligence. The basic idea of the particle swarm optimization algorithm is to find the optimal solution by the cooperation and information sharing among particles in the group. It is demonstrated that the particle swarm optimization algorithm can be utilized to design such anti-resonant fibers with multiple geometry parameters. By breaking the mirror symmetry of the fiber's cross section, the coupling between the fundamental mode and cladding mode is further suppressed than the mirror symmetry one. As a result, ultra-low confinement loss as small as 2.2 × 10−8 dB/m can be achieved in simulation. Our results might facilitate the advanced applications of nested anti-resonant fibers in optical communication and high energy pulsed laser, etc. • Ultralow loss anti-resonant fiber designed by swarm intelligence is demonstrated. • The confinement loss is 10-8 dB/m and the higher order mode extinction ratio is ∼ 500. • The symmetry breaking effect can substantially suppress the modes coupling. [ABSTRACT FROM AUTHOR]