Quantum-cascade laser structure has been grown on InP:S(001) substrate pre-patterned with SiO(2) mask. The structure has grown coherently on InP substrate material in 40 mu m-wide stripe-windows of the SiO(2) mask. Material deposited on SiO(2) most layer is polycrystalline. The structure was processed in wide ridges, involving polycrystalline material at the sides and in narrow ridges, consisting exclusively of the center part of the crystalline region. These two kinds of ridges have both lased at comparable threshold current densities of 2-3 kA/cm(2) at lambda=10.5 mu m at room temperature. This result demonstrates the feasibility of integration of quantum-cascade laser into integrated photonic circuits. (C) 2011 Elsevier B.V. All rights reserved.