High-brightness fiber laser sources usually utilize active rare-earth-doped fibers cladding-pumped by multimode laser diodes(LDs), but they operate in limited wavelength ranges. Singlemode-passive-fiber based Raman la...High-brightness fiber laser sources usually utilize active rare-earth-doped fibers cladding-pumped by multimode laser diodes(LDs), but they operate in limited wavelength ranges. Singlemode-passive-fiber based Raman lasers are able to operate at almost any wavelength being pumped by high-power fiber lasers. One of the interesting possibilities is to directly pump graded-index(GRIN) multimode passive fibers by available high-power multimode LDs at 915–940 nm,thus achieving high-power Raman lasing in the wavelength range of 950–1000 nm, which is problematic for rare-earthdoped fiber lasers. Here we review the latest results on the development of all-fiber high-brightness LD-pumped sources based on GRIN fiber with in-fiber Bragg gratings(FBGs). The mode-selection properties of FBGs inscribed by fs pulses supported by the Raman clean-up effect result in efficient conversion of multimode pump into a high-quality output beam at 9 xx nm. GRIN fibers with core diameters 62.5, 85 and 100 μm are compared. Further scaling capabilities and potential applications of such sources are discussed.展开更多
Atoms ionization by the simultaneous absorption of multiple photons has found applications in fiber optics,where it leads to unique nonlinear phenomena.To date,studies of the ionization regime have been limited to gas...Atoms ionization by the simultaneous absorption of multiple photons has found applications in fiber optics,where it leads to unique nonlinear phenomena.To date,studies of the ionization regime have been limited to gas-filled hollow-core fibers.Here,we investigate multiphoton ionization of standard optical fibers,where intense laser pulses ionize the atoms constituting the fiber structure itself,instead of that of the filling gas.We characterize material modifications produced by optical breakdown.Their formation affects laser beam dynamics over hours long temporal scales.The damage features are studied by means of optical microscopy and X-ray microtomography.In the framework of glass photonics,our results pave the way for a novel glass waveguide micromachining technique.展开更多
基金financial support of Russian Science Foundation(grant 14-22-00118)
文摘High-brightness fiber laser sources usually utilize active rare-earth-doped fibers cladding-pumped by multimode laser diodes(LDs), but they operate in limited wavelength ranges. Singlemode-passive-fiber based Raman lasers are able to operate at almost any wavelength being pumped by high-power fiber lasers. One of the interesting possibilities is to directly pump graded-index(GRIN) multimode passive fibers by available high-power multimode LDs at 915–940 nm,thus achieving high-power Raman lasing in the wavelength range of 950–1000 nm, which is problematic for rare-earthdoped fiber lasers. Here we review the latest results on the development of all-fiber high-brightness LD-pumped sources based on GRIN fiber with in-fiber Bragg gratings(FBGs). The mode-selection properties of FBGs inscribed by fs pulses supported by the Raman clean-up effect result in efficient conversion of multimode pump into a high-quality output beam at 9 xx nm. GRIN fibers with core diameters 62.5, 85 and 100 μm are compared. Further scaling capabilities and potential applications of such sources are discussed.
基金European Research Council(740355)Ministero dell’Istruzione,dell’Universitàe della Ricerca(PIR01-00008,R18SPB8227)+1 种基金Ministry of Education and Science of the Russian Federation(14.Y26.31.0017)Agence Nationale de la Recherche(ANR-10-LABX-0074-01,ANR-18-CE080016-01)。
文摘Atoms ionization by the simultaneous absorption of multiple photons has found applications in fiber optics,where it leads to unique nonlinear phenomena.To date,studies of the ionization regime have been limited to gas-filled hollow-core fibers.Here,we investigate multiphoton ionization of standard optical fibers,where intense laser pulses ionize the atoms constituting the fiber structure itself,instead of that of the filling gas.We characterize material modifications produced by optical breakdown.Their formation affects laser beam dynamics over hours long temporal scales.The damage features are studied by means of optical microscopy and X-ray microtomography.In the framework of glass photonics,our results pave the way for a novel glass waveguide micromachining technique.
