Preparation and Properties of Er ‐Doped ZrO ₂ Nanocrystalline Phase‐Separated Preforms of Optical Fibers by MCVD Process

The fabrication of Er ‐doped ZrO ₂ ‐based nanocrystalline phase‐separated silica optical preforms by the modified chemical vapor deposition process and solution‐doping techniques is presented. Fabricated preform cores are nearly transparent and contain phase‐separated rare‐earth‐doped nanocrystalline particles with diameters mainly in a range from 20 to 80 nm. High concentrations of erbium and aluminum in preform cores of about 0.3 and 14 mol%, respectively, have been achieved without defects on the core–cladding interface. Spectral losses in a range 800–1600 nm and fluorescence spectra of erbium ions around 1550 nm measured on a fiber drawn from the preform are reported.