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Masaaki Hirano11:00 a.m.
August 25, 2008
Tech L324
Masaaki Hirano, Optical Communications R&D Laboratories
"Silica-based highly nonlinear fibers and their applications"
| Abstract: Prof. Recent progresses on optical characteristics of silica-based highly-nonlinear fibers (HNLFs) are presented. HNLFs have been widely used as platforms of all-optical signal processings and contributed to various fantastic demonstrations such as Raman amplification, optical parametric amplification and supercontinuum generation. Among the optical characteristics of HNLFs, the chromatic dispersion is one of key characteristics to realize optical signal processings. In order to generate the nonlinearities with high efficiency, realizing of phase-matching condition along whole length of fiber is essential, therefore the longitudinal uniformity in zero-dispersion wavelength is critical. When such uniform zero-dispersion wavelength is realized, higher-order dispersions are then come to be important for practical usages. 4th-order dispersion of beta-4 determines the phase-matching conditions in the broad wavelength range. We design the refractive index profiles and actually fabricate HNLFs with low or high beta-4. We demonstrate the broad FWM-based wavelength conversion with 222nm bandwidth and the selective and tunable conversion using low or high beta-4 HNLF, respectively. Supercontinuum generations by various kinds of HNLFs are briefly described, and future challenges for practical applications are also discussed.
Bio:
Mr. Masaaki Hirano received M.S. degree in chemistry from Keio University, Japan, in 1997. The same year, he joined Sumitomo Electric Industries, ltd, Yokohama, Japan. He is now with Optical Communications R&D Laboratories, and has been involved in design and fabrication of optical fibers, such as pure silica core fibers, dispersion shifted fibers, dispersion compensating fibers, and highly nonlinear fibers.
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