Optical waveguide preform - comprises glass core rod and oxide powder sheath heat stabilised to avoid deformation

摘要

Preform has a glass core rod with a sheath of oxide powder, which is stabilised and compacted in a He atmos. in a chamber with an isothermal temp. distribution, at a max. of 1200 deg.C, relative density of 25-50%. The sheath is sintered at more than 1250 deg.C. ADVANTAGE - Sheath layer is not deformed during stabilisation.