Intersubband transitions in the communications wavelength range (λ~1.55 μ) In GaN/AlGaN multiple quantum wells

Summary form only given. Fueled by the recent success of mid-infrared quantum cascade lasers, optical devices based on intersubband (IS) transitions face a rising interest also in other wavelength ranges. In particular, the intrinsically ultrafast electron dynamics associated with IS-transitions warrants research into the latter for the communications wavelength range (λ~1.55 μm). Few material systems, however, provide a sufficiently large band-discontinuity for the quantum wells (QWs) to accommodate the large subband spacing needed for such short wavelengths, Sb-based materials or group-III-nitrides presently being the best candidates. The rapid success of GaN-based interband light emitting diodes and lasers makes this material system particularly attractive. We present the first IS-transitions in the communications wavelength range, with peak absorption wavelengths as short as 1.4 μm