Length optimization of single-mode rare-earth doped waveguides using saturated absorption

Absorption saturation was demonstrated to provide a high, uniform population inversion over a length of waveguide longer than the material absorption length. The small signal gain was measured experimentally in single-mode waveguides, made by silver ion exchange, on a commercially available neodymium doped glass. The ratio of the excited states was calculated as a function of waveguide length and was shown to be a convenient criteria to determine the optimum device length.<
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