Simultaneous measurements of lifetime, gain and emission cross section in a neodymium-doped fiber

A method for measuring the gain and the emission cross section of the four-level neodymium system in doped waveguides is presented. The method is based on a temporal analysis of the fluorescence decay occurring when the pump is switched off, after establishing a steady-state with high levels of absorbed power. For the case of doped fibers, results obtained using this method are compared with the usual low signal amplification technique, using a launched signal in the fiber, and the agreement is good. It is shown that the technique allows a rapid, simple method of determining low signal gain.<
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