Quantum well intermixing (QWI) is a technique whereby quantum wells (QWs) can be altered following epitaxial growth. This technique provides a means for controlling the QW bandedge selectively across a semiconductor wafer, allowing for the realization of novel optoelectronic devices and photonic integrated circuits. For the InGaAsP material system, ion-implantation-enhanced interdiffusion is one of the more successful QWI techniques demonstrated. With this technique, ion implantation is used to create vacancies that promote intermixing of atoms at the interfaces of QWs and barriers during a subsequent annealing step. The intermixing reshapes the QWs and effectively increases the bandgap energy. In this work, we have developed a QWI technique specifically tailored for the bandedge shift required to realize a novel multi-section semiconductor optical amplifier (SOA) that is based on the slab-coupled optical waveguide (SCOW). The performance of SOAs can be improved with a multi-section device architecture incorporating a pre-amplifier region and a post-amplifier region. We have proposed using QWI to create a novel multi-section SOA whereby the bandedge and in turn gain spectrum can be tailored along the length of the device to improve the inherent tradeoff between gain and output power, and to increase efficiency. The QWI process used for fabricating the multi-section SOAs entails a dielectric masked selective implant of Phosphorous ions, removal of the dielectric mask by wet chemical etching, dielectric encapsulation of the sample to prevent desorption during the subsequent annealing steps, and high temperature annealing. The initial implant and the processing steps should be designed to minimize damage to the underlying QW layers. It is therefore desirable to minimize the ion distribution in the vicinity of the QWs. The implant energy and dose need to be considered, as well as high temperature processing steps prior to the annealing steps that could lead to premature diffusion of vacancies. The annealing for interdiffusion can damage the QWs by forming traps; however the damage is also repaired by the annealing. This damage can be quantified by monitoring photoluminescence (PL) peak intensity. For the multi-section SOA described, it is beneficial to tailor the QWI process based on the amount of bandedge shift desired while subsequently minimizing damage. Here we have optimized a QWI process for desired bandedge shifts for a multi-section SCOW SOA. The device design requires bandedge wavelength shifts in the range of 30-60 nm; therefore it is desirable that the PL intensity, used to quantify recovery of the damage material, be maximized for such shifts. Following experimentation, it was shown that with an implant energy and dose of 80 keV and 3.0e14 cm<SUP>-2</SUP>, corresponding to an implant range and straggle of 89 nm and 44 nm, the PL intensity was fully recovered following the QWI process.