An investigation of the intermixing enhancement in an InGaAs/InGaAsP/InGaP partial laser structure following phosphorous implantation at 30, 80, and 7000 keV was carried out. We find that for the 30 and 80 keV implant energies, band gap shifts in excess of 80 meV could be imparted to a single embedded 8.5 nm InGaAs quantum well (QW) lying several thousand angstroms beyond the maximum ion range. As both the 30 and 80 keV implants kept the end of range damage spatially separate from optical mode region, the optical quality (inferred from photoluminescence intensity measurements) of the QW material was preserved to a greater extent than that resulting from the 7000 keV implants (where implant damage was directly created in the QW during ion bombardment). This result suggests that device structures containing InGaP cladding layers are well suited for monolithic integration as the masking of low energy ions with high lateral resolution can be achieved using routinely available masking techniques. ©1998 American Institute of Physics.