Patent ID: 9711944
Date: 2017-07-18
CPC Classifications: H01S

Claim:
1. A quantum cascade laser comprising: a substrate having a principal surface; a laser body region disposed on the principal surface of the substrate, the laser body region including a semiconductor laminate structure including a core layer disposed on the principal surface, the laser body region having a waveguide structure extending along a waveguide axis, the semiconductor laminate structure including an end facet intersecting with the waveguide axis; and a distributed Bragg reflection region disposed on the principal surface of the substrate, the distributed Bragg reflection region including one or more low refractive index portions and one or more high refractive index portions, a high refractive index portion of the one or more high refractive index portions having a refractive index higher than that of a low refractive index portion of the one or more low refractive index portions, the one or more low refractive index portions and the one or more high refractive index portions being alternately arranged in a direction of the waveguide axis, wherein the laser body region and the distributed Bragg reflection region are arranged in a direction of the waveguide axis, the end facet of the semiconductor laminate structure is optically coupled to the distributed Bragg reflection region, each of the one or more high refractive index portions includes a semiconductor wall extending in a direction intersecting with the principal surface of the substrate, each semiconductor wall includes an upper portion and a lower portion that are arranged in the direction intersecting the principal surface of the substrate with the principal surface being disposed between the upper portion and the lower portion, and the lower portion of each semiconductor wall includes a part of the substrate.