Transverse mode stabilized Al<inf>x</inf>Ga<inf>1-x</inf>As injection lasers with channeled-substrate-planar structure

Abstract

A built-in passive waveguide mechanism is introduced in Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> Ga <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf> As injection lasers by growing planar double heterostructure (DH) layers on a grooved GaAs substrate. The lasing mode is confined to the channel region due to excess absorption loss outside the channel. Stable fundamental mode oscillation is achieved up to twice the threshold current for a channel width of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5-8 \mu</tex> . Undesirable lasing behavior usually induced by transverse mode instability, such as nonlinear kinks in the light output versus current characteristics, are significantly reduced in the present lasers. The dc threshold current is 40-90 mA at room temperature. Median lifetime of 780 hours has been obtained during preliminary aging tests at a heat sink temperature of 70°C.