IR Bismuth active centers in optical fibers: Combined excitation-emission spectroscopy

3D excitation-emission luminescence spectra of Bi-doped optical fibers of various compositions were measured in a wide wavelength range 450-1700 nm. Such luminescence spectra were obtained for Bi-doped pure silica and germania fibers, and for Bi-doped Al- or P-codoped silica fibers (at room and liquid nitrogen temperatures). The energy level schemes of IR bismuth active centers in pure silica and germania core fibers were derived from spectra obtained. The energy level schemes similarity of bismuth active centers in these two types of fibers was revealed.Comment: 12pages, 7 figures, 5 table

InorgMat9_07BubnovLO

Abstract -The GeO 2 yield in the reaction between GeCl 4 and oxygen has been determined as a function of the reaction time under typical MCVD fiber preform fabrication conditions. It is shown that the yield increases steadily over time and may attain 100%. In the case of the cooxidation of germanium and silicon tetrachlorides under the same conditions, there is an optimal reaction time corresponding to a maximum in GeO 2 yield. The temperature profile along the reaction zone has been optimized in terms of germania yield

Tm3+-doped CW fiber laser based on a highly GeO2-doped dispersion-shifted fiber,”

Abstract: All-fiber Tm-laser with 55GeO 2 -45SiO 2 core, pumped at 1560 nm with 37% slope efficiency was demonstrated at 1862 nm. Four-wave mixing owing to a high nonlinearity and shifted to 1.87 µm zero-dispersion-wavelength has been observed

Tm3+-doped CW fiber laser based on a highly GeO2-doped dispersion-shifted fiber

A novel all-fiber laser based on a highly GeO2-doped dispersion-shifted Tm-codoped fiber, pumped at 1.56 µm wavelength and lasing at 1.862 µm wavelength with a slope efficiency up to 37% was demonstrated. The single-mode Tm-doped fiber with the 55GeO2-45SiO2 core was fabricated for the first time by MCVD technique. The laser produces spectral side bands, resulting from the four-wave mixing owing to the shift of the zero-dispersion-wavelength of the fiber to the laser wavelength, thus, making it potentially particularly attractive for dispersion management and ultrashort pulse generation

Highly efficient one- and two-cascade Raman lasers based on phosphosilicate fibers

Characteristics of one-cascade (1.06 double right arrow 1.24 mum) and two-cascade (1.06 double right arrow 1.24 double right arrow 1.48 mum) phosphorus-doped fiber Raman lasers are studied. The cavities of both lasers are formed by Bragg gratings written directly in the active fiber. Double-cladding Yb3+ and Nd3+ ion fiber lasers with lambda similar to 1.06 mum were employed for pumping. These lasers were pumped, in their turn, by diode laser arrays with lambda similar to 0.98 mum (Yb) and lambda similar to 0.81 mum (Nd). The efficiency of the one-cascade laser with an unprecedentedly short length of 50 in was as high as 65% with 4.8-W pump radiation applied to the input of the laser. The maximum efficiency of the two-cascade Raman fiber laser was 40%. Gratings directly written in the active fiber reduced concentrated losses in laser cavities, which allowed the laser length to be decreased and the lasing threshold power of Raman fiber lasers to be lowered

CW highly efficient 1.24 μm Raman laser based on low-loss phosphosilicate fiber

We report the first demonstration of an extremely simple and efficient 1.24 μm phosphosilicate fiber-based Raman laser with Bragg gratings written directly in the fiber used. The laser pumped by Nd fiber laser exhibits a slope efficiency of 80