High-resolution distributed-gain measurements in erbium-doped fibers

For the first time, the distributed gain along erbium-doped fibers was measured with high-resolution reflectometry. The coherent optical frequency-domain reflectometry detection technique intrinsically filters amplified spontaneous emission, allowing precise measurements of Rayleigh backscattering levels and nondestructive determination of the optimum length of the doped fiber for different pump and probe conditions.