We compare InP-based materials systems for multiple quantum well modulator application in the 1.06-mu-m wavelength range. Quantum well/barrier systems studied are the lattice-matched system InxGa1-xAsyP1-y/InP, the strained system InAsyP1-y/InP, and the strain-balanced system InAsyP1-y/InGa1-xP. 50 period samples were grown on InP substrates by chemical beam epitaxy. We find the ternary systems to be better than the quaternary in terms of exciton peak sharpness. The InAsyP1-y/InxGa1-xP system was best overall, with our results suggesting that it is coherently strained to the InP substrate.