Fabrication of heavily Er2O3 doped aluminophosphosilicate glass fibers

This work examines vapor-phase doping of aluminophosphosilicate (APS) glasses with erbium oxide using Er(dpm)(3) (erbium dipivaloylmethanate) as a metalorganic precursor. We describe two vapor-phase processes for Er2O3 doping of APS glasses for fiber cores. In one of them, a standard MCVD procedure, all the oxides of the glass core are deposited simultaneously. With this procedure, the erbium content of the APS glasses does not exceed 1 wt % because of the reaction of AlCl3 with POCl3 and Er(dpm)(3). In the other procedure, a porous Al2O3-P2O5-SiO2 layer is infiltrated with Er2O3 from the vapor phase. Owing to the separation of the reactant flows, this procedure ensures considerably higher rare-earth doping levels in the APS glasses, up to several weight percent.