Quantum wire lasers and modulators offer superior performance over their quantum well counterparts. We present simulations of an integrated InGaAs-InP quantum wire laser-modulator structure operating at 1.55 µm. In the case of quantum wire lasers, we have computed the optical gain as a function of current density for wires having widths ranging between 60 and 100 Å. For example, the threshold current density of 61 A/cm2 is computed for a wire with a width of 80 Å. In the case of quantum wire modulators, we compute the changes in the absorption coefficient and index of refraction due to an external electric field to implement electroabsorptive and electrorefractive optical modulators. For example, the absorption coefficient changes (Δα/α) by 450% when an applied electric field changes from 30 to 60 kV/cm for an 80 Å quantum wire. The corresponding change of refractive index is about 11%. A structure integrating an edge-emitting laser with an in-line type electroabsorptive or electrorefractive modulator is presented. The quantum wires are designed to operate the laser at a wavelength that corresponds to the Stark effect tuning of the modulator. We can maximize the changes in electroabsorptive and electrorefractive modulators by choosing the right combination of wire dimensions, operating wavelengths, and electric fields.