High-performance polymer optical fiber lasers and amplifiers

We report on the lasing action of the graded-index polymer optical fibers (GI POF) containing dyes, such as Rhodamine B, Rhodamine 6G, Perylene Orange, and Pyrromethene 567. These dyes have been incorporated into poly(methyl methacrylate-co-2-hydroxyethyl methacrylate). These fibers were transversely pumped at 532 nm with a frequency-doubled Q-switched Nd:YAG laser. Slope efficiency of 24% and output of 1.2 mJ were obtained with a Rhodamine 6G-doped fiber. A Lifetime of 200,000 pulses at 10 Hz was achieved with a Rhodamine B-doped fiber. GI POF containing a Nd-chelate have also been fabricated. The absorption spectrum of the fiber exhibited several strong bands in the visible and infrared regions. We have observed infrared fluorescence (0.90, 1.06, and 1.3 μm) of the Nd³⁺ ion of the fiber at room temperature when it was pumped with an Ar⁺-pumped dye laser at 580 nm. The Judd-Ofelt theory was applied to the absorption spectrum of Nd³⁺ in polymer to determine the Judd-Ofelt parameters. From the theory, various radiative properties, such as transition probability, branching ratio, and emission cross section for various emission levels, have been determined and reported.