YDFL operating in 1150-1200-nm spectral domain

A family of high-power Yb-doped fiber lasers operated in the range of 1150-1180 nm with output powers of up to 35 W and optical efficiencies up to 60% is realized. Operation at 1200 nm is also demonstrated. Amplified spontaneous emission increase with output power increase is analyzed in frames of the inhomogeneous broadening concept

Method of the stressed-deformed state description for plates and envelopes from composition materials

Static problems of the bending theory for plates and envelopes from composition materials are considered in the paper aiming at the possibility investigation of the more rational account of the cross shift deformation in plates and envelopes from composition materials, the development and application of the Green's function construction method to the normal deflection of orthotropic plates of variable thickness. As a result the method for the separate solution of teh source problem has been developed as well as the method of the Green's function construction for the normal deflection of plates of variable thickness. Green's functions for three classes of plates of variable thickness have been constructed. Boundary-value problems for plates and envelopes of constant thickness have been solved by the separation method developedAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Effect of gamma-neutron nuclear reactor radiation on the properties of Bragg gratings written in photosensitive Ge-doped optical fiber

We have experimentally studied the effect of mixed gamma-neutron nuclear reactor radiation on the effective refractive index of Bragg gratings fabricated in Ge-doped photosensitive optical fiber. We compared the effect of radiation on gratings written with and without hydrogen sensitization and show that the use of hydrogen loading results in an increase of the sensitivity to reactor radiation. Neither grating annealing at 500 °C nor pre-irradiation of the fiber results in a significant increase of the radiation hardness of the Bragg gratings. The best radiation stability is observed for gratings fabricated without hydrogen loading. © 2002 Elsevier Science B.V. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

UV-induced absorption in all-fiber frequency doublers: characterization and photobleaching

Periodic UV exposure of thermally poled optical fibers is usually used to produce efficient all-fiber frequency doublers based on second-order nonlinearity. To date, no data regarding UV-induced absorption in poled fibers have been reported. In this study, we measured this absorption and showed how it affects the conversion efficiency of second harmonic generation at wavelengths below ~800 nm. Color centers responsible for induced absorption in poled GeO2 -doped fibers were identified and photobleached by continuous-wave radiation at 532 nm. We demonstrated that photobleaching does not affect the value of nonlinearity but improves the conversion efficiency of all-fiber frequency doublers. The results obtained can be used to improve the efficiency of all-fiber second harmonic generation in the blue-green part of the spectrum

Effect of combined gamma-neutron radiation of multiplexed fiber Bragg grating sensors

Optical fiber technology is considered now for communication and sensing applications in various radiation environments, like space and nuclear industry. We report on results from an on-going experimental program, which aims at using multiplexed Fiber Bragg gratings (FBGs), essential photonic components, for in-pile temperature monitoring in a nuclear reactor. To the best of our knowledge, its is the first time that multiplexed FBG-sensors are used in such conditions. © 2000 SPIE.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Random Laser Based on Ytterbium-Doped Fiber with a Bragg Grating Array as the Source of Continuous-Wave 976 nm Wavelength Radiation

A random narrow-linewidth lasing at a wavelength of 976 nm was obtained in an ytterbium-doped germanophosphosilicate fiber with an array of weakly reflecting fiber Bragg gratings (FBGs). A random laser cavity was formed by implementing the standard phase mask method of FBG inscription directly during the fiber drawing process. The UV radiation pulses of a KrF excimer laser (248 nm wavelength) synchronized with the fiber drawing speed were used to fabricate the in-fiber array of hundreds of similar FBGs. The developed laser’s slope efficiency in the backward-pumping scheme was measured as high as 33%. The stable continuous-wave operation mode of the laser was detected. The magnitude of the laser power fluctuations depends linearly on the cavity length. The random laser cavity modified with a single highlyreflected (90%) FBG demonstrates significantly better power stability and higher slope efficiency than the same one without an FBG

Random Laser Based on Ytterbium-Doped Fiber with a Bragg Grating Array as the Source of Continuous-Wave 976 nm Wavelength Radiation

A random narrow-linewidth lasing at a wavelength of 976 nm was obtained in an ytterbium-doped germanophosphosilicate fiber with an array of weakly reflecting fiber Bragg gratings (FBGs). A random laser cavity was formed by implementing the standard phase mask method of FBG inscription directly during the fiber drawing process. The UV radiation pulses of a KrF excimer laser (248 nm wavelength) synchronized with the fiber drawing speed were used to fabricate the in-fiber array of hundreds of similar FBGs. The developed laser’s slope efficiency in the backward-pumping scheme was measured as high as 33%. The stable continuous-wave operation mode of the laser was detected. The magnitude of the laser power fluctuations depends linearly on the cavity length. The random laser cavity modified with a single highlyreflected (90%) FBG demonstrates significantly better power stability and higher slope efficiency than the same one without an FBG

Millijoule pulse energy 100-nanosecond Er-doped fiber laser

International audienceWe report, for the first time to our knowledge, on a single-mode millijoule-level 100-nanosecond Er-doped fiber laser operating near 1550 nm. The system features a newly developed 35-μm-core Yb-free double-clad Er-doped fiber based on P2O5-Al2O3-SiO2 glass matrix and produces pulses with energy as high as 1 mJ at repetition rates of 1–10 kHz