High-power quantum cascade lasers with active-photonic-crystal structure for single, in-phase mode operation

A semiconductor laser array device comprising:

• (a) a quantum cascade laser structure comprising a core;
• (b) an optical confinement structure comprising at least one upper layer of optical confinement material above the quantum cascade laser structure and at least one lower layer of optical confinement material below the quantum cascade laser structure;
• (c) a cladding structure comprising at least one upper layer of cladding material above the optical confinement structure;
• and
• (d) a plurality of laterally-spaced trench regions extending transversely, at least partially into the quantum cascade laser structure, wherein each trench region comprises a lower trench layer comprising a semi-insulating material and an upper trench layer comprising a material having a refractive index that is higher than the refractive index of the semi-insulating material;
• wherein the trench regions define interelement regions separated by element regions in the laser array device, and further wherein the element regions are characterized by a non-uniform structure across their widths, whereby array modes composed of coupled first-order lateral modes of the element regions are preferentially suppressed relative to array modes composed of coupled fundamental lateral modes of the element regions;
• the laser array device characterized in that it is designed to produce an array mode composed of coupled fundamental lateral modes meeting a lateral resonance condition in which there is strong coupling via leaky waves between all of the element regions.