Strong increase of the derivative of the carrier-induced index change of semiconductor lasers at low injected carrier density

The carrier-induced index change of a semiconductor laser was measured for injected carrier density ranging from 3 * 10/sup 16/ cm/sup -3/ to 2 * 10/sup 18/ cm/sup -3/. A strong nonlinear behavior between index change and carrier density is observed. The derivative of the index change versus carrier density at low carrier density can be 15 times larger than the derivative of the index change at high carrier density.<
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