Noncascaded intersubband injection lasers and scaling with the number of stages in quantum cascade lasers

We demonstrate the first noncascaded intersubband injection laser based on a single active region. Several major advantages arise from this new structure: first, only few layers are necessary to build the active region core, which simplifies sample growth and preparation. Second, low operating voltage of 2 to 3 V was achieved which is essential for applications which have previously been optimized for interband diode lasers and their low voltage compliance requirements. The laser structure has been grown in the InGaAs-AlInAs on InP material system using molecular beam epitaxy