A Monte-Carlo-based methodology for determining the fabrication yield of fibers for lasers

摘要

With the rapid progress of fiber lasers, there is increasing demand to develop optical waveguides providing large fundamental mode (FM) effective areas. Several of these fibers possess structural features, beyond the traditional core and cladding of a step-index fiber, in order to suppress higher-order modes (HOMs); however, their mode filtering capabilities are limited by imperfections in fabrication. In this work, we propose an approach based on Monte Carlo method that takes into account practical fabrication tolerances to determine the fabrication yields of complex fiber designs. Importantly, for a fiber design to be viable in applications, it must not only perform well optically, but also be robust against fabrication imperfections. We applied the methodology to an exemplary 33-μm W-type fiber, and assume independent uniform distributions of ±10% in all dimensions and numerical apertures (NAs). In total, 500 fabrication iterations are simulated, and the cumulative yield that simultaneously satisfies α_FM <; 0.1 dB/m, α_hom > 10 dB/m and A_{eff, fm} > 400 μm2 is found to be 21.6% ± 3.6% (95% confidence level) across coil radii between 10.2 cm and 27.0 cm. We expect this methodology to be particularly useful in predicting yields of fibers whose properties are based on resonant coupling (i.e. 3C and anti-resonant fibers), where imperfections in fabrication modify their resonance conditions.