Résumé
We present an investigation on the electrical and optical properties of tapered quantum cascade lasers emitting at 14-15 μm, based on the InAs/AlSb system. In tapered lasers the active zone volume is increased to obtain higher optical power outputs without degrading the beam quality. Devices with three different taper angles of 1°, 2° and 3° were examined in terms of electrical, optical, and spectral properties and were compared with conventional ridge waveguide lasers.