A METHOD OF FABRICATING RARE EARTH DOPED OPTICAL FIBRE

摘要

The present invention provides a method of fabricating rare earth doped preforms and optical fibres by a combination of modified chemical vapour deposition (MCVD) process and solution doping technique said (MCVD) process is used to develop matched or depressed clad structure inside a silica glass substrate tube followed by deposition of porous silica soot layer containing GeO2, P2O5 or such refractive index modifiers by the backward deposition method for formation of the core and presintering the deposited particulate layer by backward pass with flow of GeCl4 and/or corresponding dopant halides, soaking the porous soot layer into an alcoholic/aqueous solution of RE-salts containing codopants such as AlCl3 in definite proportion, drying, oxidation, dehydration and sintering of the RE containing porous deposit and by collapsing at a high temperature to produce the preform followed by drawing the fibres by known technique to produce fibres with suitable core-clad dimensions and geometry.