Researchers at the University of Wisconsin-Madison and Coherent Inc. have produced diode lasers with aluminum-free active areas, which they expect will operate more reliably than AlGaAs-active diodes and will provide roughly twice the power. Writing in Applied Physics Letters, the researchers say they developed an 830-nm InGaAsP/GaAs device that operates at 2.35 W per facet (4.7 W for both facets), with power limited by catastrophic optical mirror damage. Carrier leakage in previous InGaAsP/GaAs-active diodes has caused high threshold current requirements and low efficiency. The recent success, according to the paper, came after adding 0.1-µm electron-blocking layers and altering the cladding material.