Homogeneous Distribution of Polymerizable Coumarin Dyes for Active Few Mode POF

• Main Authors: Florian Jakobs, Kristoffer Harms, Jana Kielhorn, Daniel Zaremba, Pen Yiao Ang, Wolfgang Kowalsky, Hans-Hermann Johannes
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Materials
• Subjects: dye doped fiber; analysis method; dye distribution; copolymerization; few mode
• Online Access: https://www.mdpi.com/1996-1944/13/8/1975

For most kinds of active polymer optical fibers, a homogeneous distribution of dye molecules over the entire fiber length and cross section is required. In this study, chemical bonding of dyes to <i>poly</i>(methyl methacrylate) (PMMA) by copolymerization is achieved within the polymerization process instead of dissolving the dyes in the monomers. In combination with an improved fabrication mechanism, this leads to homogeneous dye distribution within the preforms. A method for proving the integration of the dyes into the polymer chains has been developed using high-performance liquid chromatography (HPLC) and size exclusion chromatography (SEC). Prestructured core-cladding preforms with dye-doped <i>poly</i>(cylohexyl methacrylate-<i>co</i>-methyl methacrylate)-core have been prepared with the Teflon string technique and were heat-drawn to few mode fibers.