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

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

“…In this work, the issue of the dynamics of different emission lines observed in Er 3+ doped optical fibers and their relationship to the total Er 3+ ion concentration is addressed by developing and solving a system of rate equations characteristic to the most likely electronic transitions observed in a Er 3+ doped silica glass. This exploration validates the use of direct pumping of the 2 H 11/2 (at 514 nm, as shown in some of our previous work [17]) or the 4 F 7/2 (at 488 nm in the work of [16]) levels with the subsequent detection of the backscattered fluorescence signal (around 550 nm) from the de-excitation of the 4 S 3/2 level as a measure of the relative Er 3+ ion distribution in optical fibers. Furthermore, we extend the relevance of this theoretical model as applied in our previous work with the use of a confocal optical microscope [17] to our more recent efforts in trying to improve spatial resolution using a Near-field Scanning Optical Microscope (NSOM).…”

“…Although these techniques can offer adequate spatial imaging resolution for the direct investigation of optical fibers and they can offer information about the distribution of other dopants within the fiber core region, they normally require complex and time-consuming sample preparation and the use of high cost instrumentation. In an attempt to overcome such limitations, a number of optical imaging schemes have been applied over the years in order to provide information about the RE ion distribution in the core of optical fibers directly from the investigation of their cleaved endface [15][16][17]. With the exception of the work of Petreski et al [15], where a fluorescence lifetime confocal optical microscopy technique was developed for the investigation of praseodymium-doped optical fibers, the other optical based systems were capable of providing information about the Er 3+ ion distribution in optical fibers with the application of a fluorescence intensity confocal optical microscopy scheme [16,17].…”

Simultaneous multidopant investigation of rare-earth-doped optical fibers by an ion microprobe

“…In the second approach, measurements were made directly on the drawn fiber. Transmission electron microscopy (TEM), 8 Raman microscopy, 9 and fluorescence-intensity-based confocal microscopy 10 are some of the techniques previously used for that purpose. More recently, a Raman confocal imaging system has been used for the determination of the Er ion distribution in germano-alumino-silicate optical fibers.…”

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

“…One year later, this technique was expanded by introducing a phase sensitive detection scheme to improve sensitivity and obtain a better signal-to-noise ratio. 36 In both schemes, the 488 nm argon line was used for the stimulation of the samples while the intensity of the 565 nm fluorescence line was considered as an indication of the local erbium dopant concentration. The confocal microscope (model Biorad MRS 600) used for the detection of the backscattered fluorescence obtained high resolution linescans of the endface of a cleaved fiber by working in the fluorescence detection mode.…”