Measurement of the recombination lifetime in semiconductor lasers using rf techniques

Abstract

Two techniques have been used for determining the recombination lifetime in semiconductor lasers: A capacitance bridge at 10 MHz, or a network analyzer in the range from 45 to 245 MHz. The latter, although more tedious than the former, has the advantage of allowing detection and inclusion of parasitic contributions. The AlGaAs ridge graded-index separate confinement heterostructure lasers studied here are well described by a simple equivalent circuit consisting of an ideal laser and a series resistance. Below threshold, the inverse lifetime squared exhibits a linear dependence on the forward current, as expected from simple theory. The measurements yield non-radiative lifetimes of 2.5 … 5 ns. The bimolecular recombination constant B = 0.24 … 0.56 x 10-10cm3/s is smaller than the bulk values; possible reasons are discussed. © 1990 SPIE.