Raman Response Function and Supercontinuum Generation in an As2Se3-Based Chalcogenide-Glass Photonic
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Light can propagate in chalcogenide glasses in the wavelength region λ = 2–11 µm, in contrast to standard silica fiber in which light does not propagate beyond λ ≈ 2 µm. Consequently, they have important defense and biomedical applications. While silica-glass photonic crystal fibers have been extensively studied, that is not true for other glasses such as chalcogenide glasses. We have carried out this study in collaboration with researchers at the Naval Research Laboratory, who have provided the data that we use as input parameters to our simulations, as well as experimental results to compare to the simulations. In this talk, we present the measured Raman spectrum and dispersion in As2Se3-based chalcogenide fibers. The time-domain Raman response function is then calculated from the Raman spectrum. Using the nonlinear response function of the chalcogenide fiber, which includes both the instantaneous (Kerr) response and the delayed (Raman) response, we theoretically reproduce the measured bandwidth of the supercontinuum generation from 2.1 to 3.2 µm. We then theoretically find a bandwidth of more than 4 µm can be generated using an As2Se3-based chalcogenide-glass photonic crystal fiber with an air-hole-diameter-to-pitch ratio of 0.4 and a pitch of 3 µm.
Zhihang (Jonathan) Hu received the B.S. degree in electrical engineering from Zhejiang University, China, in 1997 and the PhD degree from the University of Maryland, Baltimore County, in 2008. His research interests include Raman amplifiers, erbium-doped fiber amplifiers, chalcogenide-glass photonic crystal fibers, and supercontinuum generation. He received the Chinese government award for outstanding self-financed students abroad in 2006, and the first place award in IEEE Baltimore and Washington-Northern Virginia LEOS chapter graduate student poster competition in 2008. His professional society memberships include the Optical Society of America (OSA) and IEEE Lasers & Electro-Optics Society (LEOS).