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

A detailed experimental investigation of the effect of optical feedbac k upon the operation of high-power broad area semiconductor lasers Is presented, In particular, we examine the effect optical feedback has u pon the beam quality of high-brightness lasers employing a tapered ele ctrical contact, The far-field of such lasers is shown to degrade rapi dly with power feedback ratios exceeding -30 dB, leading to a signific antly reduced power in the central diffraction-limited far-held lobe, Far-held degradation is accompanied by dynamic instability and spectra l broadening, Good beam quality and low intensity noise can be recover ed, however, by rotating the feedback polarization.