Determining erbium distribution in optical fibers using phase-sensitive confocal microscopy

Confocal optical microscopy augmented by the phase-sensitive detection technique has been used to determine the erbium ion distribution in the core of single-mode optical fibers. The fluorescence at 565 nm generated by erbium ions under 488 nm excitation has been used to map the distribution of these ions in several doped fibers and the total ion concentration was estimated. The minimum concentration of erbium ions that can be measured using this technique is estimated to be of the order of a part per million.