Asymmetric 980nm InGaAs/InGaAsP laser structures have been grown by low-pressure metalorganic chemical vapor deposition, and broad-waveguide diode lasers of very large equivalent transverse spot size (0.80 mum) have been fabricated. High-quality, relatively thick (> 0.7 mum), high-bandgap InGaAsP (E-g = 1.80 eV) layers were developed, as needed for the successful implementation of a device design for high-power, single-transverse-m ode operation. Uncoated 100-mum-wide stripe, 2-mm-long lasers exhibit a threshold-current density of 188 A/cm(2), an internal loss coefficient of 1.4 cm(-1), a differential quantum efficiency of 66%, and high characteristic temperatures for the threshold-current density and the external quantum efficiency (i.e., T-0 = 190 K and T-1 = 520 K). (C) 2002 Elsevier Science B.V. All rights reserved.