Probing the erbium ion distribution in silica optical fibers with fluorescence based measurements

Investigation of erbium dopant distribution in silica optical fibers with fluorescence-based measurements using a near-field scanning microscope

“…18 Using a simple theoretical study of the spectroscopic characteristics of Er 3þ doped silica optical fibers, we recently confirmed that information about the Er 3þ ion distribution in optical fibers can be obtained by exciting the Er 3þ ions using a 514-nm source and then monitoring the intensity of the backscattered fluorescence signal (540 to 560 nm) originating from the radiative transition of ions between the 4 S 3∕2 upper energy level and the ground state. In the work presented here, we extend the relevance of this theoretical model as previously applied to the case where a confocal optical microscope fluorescence intensity confocal optical microscopy (FICOM) was used 16,17 to our current effort to improve spatial resolution using a nearfield scanning optical microscope (NSOM).…”

“…[14][15][16][17] In most cases, the intensity of the backscattered fluorescence originating from the de-excitation of the 2 H 11∕2 and 4 S 3∕2 upper energy levels ( Fig. 1) is monitored and is taken as an indication of the local dopant concentration of the Er 3þ ions at a point.…”

Contributed Review: A review of the investigation of rare-earth dopant profiles in optical fibers

“…38,39 A simple theoretical model consisting of an ensemble of rate equation systems, characteristic of the most likely electronic transitions that take place in the vicinity of Er doped silica glasses, was developed and solved. Through this theoretical study, it was established that information about the relative Er ion distribution in fibers could be inferred by simply monitoring the backscattered fluorescence signal originating from the de-excitation of the specific energy levels used in the investigated samples.…”

“…37 Furthermore, the validity of the proposed theoretical model was confirmed through a comparison of the Er ion distribution profiles acquired using the FICOM technique and those obtained from the application of a powerful analytical ion probe. [37][38][39]44 …”

“…38 As a result, NSOM studies of Er doped optical fibers were attempted by monitoring the backscattered fluorescence signal originating from the de-excitation of the 4 S 3/2 energy level, 38 which has been found to be independent of possible interionic effects. [37][38][39] It was recently also shown 43 that initial concerns regarding practical limitations such as weak fluorescence signal and stray light contaminations can be overcome and that good qualitative agreement can be established on data acquired from different techniques (Fig. 2).…”