We report on molecular beam epitaxial growth and structural characterisations of unintentionally-doped InAs/AlSb strained multiple quantum wells grown on GaSb substrates. The crystalline quality and the interface roughness obtained using different cell shutter sequences at the arsenide/antimonide interfaces are compared by high resolution X-ray diffraction and small angle X-ray reflectivity measurements. Optical characterisations by photo-induced absorption spectroscopy are then carried out. A strong e1 --> e2 p-polarised intersubband absorption is observed in the mid infrared with a narrow broadening factor, revealing the good material quality of the sampler.