ASE and laser emission in double-clad EDTF

Summary from only given. We present a detailed study of emission properties of newly fabricated double-clad Er/sup 3+/-doped tellurite single mode fibers. Using a 980 nm pump, a spectrally very broad erbium amplified spontaneous emission (ASE) is observed around 1.5 micron and, at sufficiently high powers, resonance lines are seen at the peak of the ASE curve. Fibers of different lengths have been measured and all found to laze efficiently in the 1530-1600 nm range. Both ASE and the laser lines shift to longer wavelengths with increasing fiber length. Tellurite glass fibers appear to facilitate radiative transitions over a broad spectral range.