FEEDBACK EFFECTS IN TAPERED BROAD-AREA SEMICONDUCTOR-LASERS AND AMPLIFIERS

A detailed experimental investigation of the effect of optical feedback upon the operation of high-power broad area semiconductor lasers Is presented, In particular, we examine the effect optical feedback has upon the beam quality of high-brightness lasers employing a tapered electrical contact, The far-field of such lasers is shown to degrade rapidly with power feedback ratios exceeding -30 dB, leading to a significantly reduced power in the central diffraction-limited far-field lobe, Far-field degradation is accompanied by dynamic instability and spectral broadening, Good beam quality and low intensity noise can be recovered, however, by rotating the feedback polarization.