High power broad area quantum cascade lasers

Broad area quantum cascade lasers (QCLs) are studied with ridge widths up to 400 mu m, in room temperature pulsed mode operation at an emission wavelength around 4.45 mu m. The peak output power scales linearly with the ridge width. A maximum total peak output power of 120 W is obtained from a single 400-mu m-wide device with a cavity length of 3 mm. A stable far field emission characteristic is observed with dual lobes at +/- 38 degrees for all tested devices, which suggests that these broad area QCLs are highly resistant to filamentation.