Small-core single-mode microstructured polymer optical fiber with large external diameter

A preform sleeving technique is demonstrated that allows the fabrication of single-mode polymer microstructured fiber with the smallest core and hole dimensions yet reported to our knowledge. For a fixed triangular hole pattern a range of fibers is produced by adjustment to the operating conditions of the draw tower. Numerical modeling is carried out for one of the fibers produced with a $570-\mathit{\mu }\mathrm{m}$ external diameter, a core diameter of $2.23 \mathit{\mu }\mathrm{m}$, an average hole diameter of $0.53 \mathit{\mu }\mathrm{m}$, and an average hole spacing of $1.38 \mathit{\mu }\mathrm{m}$. This fiber was shown to be endlessly single mode.