High power (600 mW CW) phase-locked semiconductor laser arrays

Optical output power levels as high as 600 mW CW/facet have been obtained from a phase-locked semiconductor injection laser array. The laser threshold current is 135 mA, it emits at ≈8000 Å, differential quantum efficiency is 68%, and the maximum measured total power conversion efficiency is 23%. Devices have been operated up to 105°C at power levels of 200 mW CW per facet. These types of phased array lasers generate a coherent low divergence (1-1.5°) far-field beam parallel to the plane of the p-n junction. The coherence which arises from optical coupling among the filaments of the array permits the beam to be focused into a nearly diffraction limited spot. We report, for the first time, 90 mwatts concentrated in a 2.5 µm diameter circle, thus illustrating the utility of the device for high speed recording applications. These lasers have also coupled 150 mW CW into an optical fiber.