Characterization of porous core layer for controlling rare earth incorporation in optical fiber

Abstract

The porous core layer deposited by modified chemical vapour deposition process has been analyzed in terms of thickness, pore size distribution, homogeneity and characteristics of the soot particles to investigate their variation with deposition temperature and input vapour composition. The compositions selected were SiO(2), SiO(2)-GeO(2) and SiO(2)-P(2)O(5). Rare earth ions were incorporated into the deposit by a solution doping technique. The analysis of deposited microstructures was found to provide a quantitative indication about the rare earth incorporation and its variation with respect to process conditions. Thus the characterization provides a method of controlling rare earth doping and ultimate preform/fiber properties.

Study of gain flatness for multi-channel amplification in single stage EDFA for WDM applications

“…An optimal EDF for WDM applications requires both fibre waveguide design and doping composition design (Dhar et al 2006;Wang 2004). Fibre waveguide parameters, such as numerical aperture (NA), cut-off wavelength and erbium dopant distribution in the core determine the overlap between optical field mode and erbium ions which controls the fibre performance.…”

An Improved Method of Fabricating Rare Earth Doped Optical Fiber

“…A correlation has been worked out with regard to final Er incorporation in three different soot layers deposited with variation in temperature and composition. The absorption at 980 nm due to Er content differs by about 0.90 dB/m for two GeO 2 doped fibers where the deposition temperatures had a difference of 40C [Dhar et al 2006]. This corresponds to an Er concentration difference of 200 ppm.…”

Demonstration of ultra-low NA rare-earth doped step index fiber for applications in high power fiber lasers

“…Therefore, in order to control the core refractive index it is necessary to control the dopants incorporation. Dopants incorporation depends on several aspects like soot porosity, solution doping condition, solution draining speed, and soot oxidation temperature etc for a particular solution strength [21][22][23]. However, soot porosity is the most important aspect as it not only decides the amount of the RE ion incorporation but also the uniformity of the profile.…”