An InxAlyGa1-x-yAs device layer structure that enables the monolithic integration of In0.25Al0.75As/In0.15Ga0.85As MODFETs and In0.25Al0.35Ga0.40As/In0.25Ga0.75As MQW modulators is reported. Current gain cutoff frequencies of 10 GHz are measured for 1 µm gate length MODFETs. MQW modulators operating at 1.05 µm demonstrate 20% transmission modulation for an applied 8 V.