High CW-Power Phase-locked Semiconductor Laser Arrays

Very high coherent optical power can be achieved from recently developed GaAlAs laser arrays consisting of 10 to 40 closely spaced laser stripes integrated on a common substrate. Phase-locked operation of such a large number of lasers has been rendered possible by the high uniformity of the expitaxial layers grown by metal-organic vapour phase epitaxy (MO VPE). The achievable output povi/er (up to 1.6 W per facet from a 40-stripe array) and the high overall conversion efficiency (up to 36 %) considerably exceed the performance of single stripe lasers. 12-stripe arrays delivering some hundred milliwatts at an emission wavelength ranging from 805 to 880 nm have been processed on a larger scale. They show very reproducible laser characteristics with a standard deviation of less than 5 % both for threshold current and differential efficiency across a 20 mm MO VPE wafer.