Fluorescence-based measurement of g* (λ) for erbium-doped fluoride fiber amplifiers

Experimental studies of the multiwavelength characteristics of individual fluoride fiber amplifiers and of systems of concatenated fluoride amplifiers have shown that these devices can exhibit a wider and flatter optical bandwidth than their silica-based counterparts. Theoretical calculations of erbium-doped fluoride fiber amplifier performance depend on a knowledge of the gain coefficient g^* (λ). While indirect measurements of g^* (λ) have been described, no direct measurement using amplified spontaneous emission (ASE) has been reported, to our knowledge. Here we present a method for determining g^* (λ) for an Er-doped ZBLYAN fluoride fibers from the longitudinal ASE spectrum of a 980-nm pumped amplifier