Laser induced quantum well intermixing for optoelectronic devices

Laser induced quantum well intermixing (QWI), using CW and pulsed Nd:YAG lasers, is a powerful photonic integration technology. The bandgap of the intermixed alloy is larger than that of the original QW structure and the refractive index is modified, thus providing a route to the formation of low loss waveguides, laser structures, gratings and other optical components. Results from the InP and GaAs systems, covering wavelengths from 1.5 /spl mu/m to the visible, are presented. The photo-absorption induced disordering (PAID) and pulsed-PAID (P-PAID) QWI techniques are described and their application to several material systems reported. Despite their apparent similarities, the underlying physical processes involved in the two techniques are very different. PAID is essentially the result of sample heating through single photon absorption, whilst P-PAID is the result of bond breaking through rapid transient heating through multi-photon processes. In both cases, bandgap tuned optoelectronic devices have been fabricated in the intermixed material, so demonstrating that the material is of high electrical and optical quality.