The growth conditions for realizing quantum cascade lasers on (111)B tilted GaAs substrates by molecular beam epitaxy are analyzed. AlGaAs/GaAs (111)B unipolar lasers emitting at 11.5 mum are fabricated and show encouraging performances which allow the nonlinear susceptibility of bulk GaAs to be exploited. The emission of coherent light at 5.75 mum is obtained by intracavity frequency doubling. Frequency doubling in quantum cascade lasers on (111) oriented substrates is very attractive and can be an alternative way to access the short mid-infrared wavelength region (3-4 mum). (C) 2004 American Vacuum Society.