Quantum cascade laser

A quantum cascade laser comprising a laser structure comprising a first end face and a second end face opposite to the first end face, the laser structure including a substrate having a principal surface, a semiconductor laminate region, and a first embedding semiconductor region, the semiconductor laminate region and the first embedding semiconductor region being disposed on the principal surface of the substrate, the laser structure including a first region and a second region that are arranged in a direction of a first axis extending from the first end face to the second end face,

• each of the first region and the second region including the semiconductor laminate region,
• the semiconductor laminate region of the first region having a recess extending in the direction of the first axis,
• the semiconductor laminate region of the first region having a first side face and a second side face that extend in the direction of the first axis to form the recess,
• the semiconductor laminate region of the second region having a semiconductor mesa extending in the direction of the first axis, the semiconductor mesa having a core layer,
• the semiconductor mesa having an end face extending in a direction of a second axis intersecting the first axis,
• the semiconductor mesa and the recess being aligned with each other,
• the first embedding semiconductor region being disposed in the recess so as to embed the end face of the semiconductor mesa and the first and the second side faces of the semiconductor laminate region, and
• the semiconductor mesa and the semiconductor laminate region supporting the first embedding semiconductor region on the end face of the semiconductor mesa and the first and the second side faces of the semiconductor laminate region.