Viewing structural inhomogeneities at the core-cladding interface of re-heated MCVD optical fiber performs with optical microscopy.

Optical microscopy has been used to observe structural inhomogeneities at the core-cladding interface of re-heated MCVD optical fiber preforms. Experimental results show that the heat treatment has enhanced these core-cladding interface inhomogeneities. Their formation mechanism and effects on optical applications are also discussed.