Extended cavity lasers fabricated using photo-absorption induced disordering

Photo-absorption induced disordering (PAID) has emerged as a laser induced quantum well intermixing technique of particular applicability to the GaInAsP/InP material system. Blue shifts in the bandgap of >100 meV in standard MQW laser structures are typically obtainable. The spatial selectivity of the technique is, however, limited by lateral heat flow. Here we show that extended cavity lasers can be fabricated by the PAID process, provided the graded interface region is pumped. The PAID process is modelled, and the ultimate spatial resolution is deduced.