Two ten-stage interband cascade laser structures were grown by solid-source molecular beam epitaxy. The wafers were processed into both broad-area ridges for threshold characterization and Au-electroplated narrow ridges for high-temperature cw operation. Pulsed threshold current densities in the broad-area devices were as low as 3.8 A/cm(2) at 78 K and 590 A/cm(2) at 300 K. An 11-mu m-wide ridge exhibited a new maximum cw operating temperature of 288 K at lambda=4.1 mu m. An even longer-wavelength device emitted at 5.1 mu m with a maximum cw operating temperature of 229 K. (C) 2008 American Vacuum Society.