Investigation of point defects in silica-based optical fibers by cathodoluminescence

We demonstrate the high potential of cathodoluminescence (CL) spectroscopy for the study of point defects in the main classes of optical fibers: Telecom-grade, radiation-hardened, and radiation sensitive. Canonical samples, differently doped in their core (Ge, P, N) or their cladding (F), have been investigated by CL using electrons of energy ranging from 5 to 30 keV. Advantages and limitation of the CL tool are discussed on the basis of the obtained experimental results.