Quantum cascade laser element and quantum cascade laser device

A quantum cascade laser element comprising:

• a semiconductor substrate;
• a semiconductor laminate formed on the semiconductor substrate to include an active layer having a quantum cascade structure and to have a first end surface and a second end surface facing each other in a light waveguide direction;
• a first electrode formed on a surface on an opposite side of the semiconductor laminate from the semiconductor substrate;
• a second electrode formed on a surface on an opposite side of the semiconductor substrate from the semiconductor laminate;
• an insulating film continuously formed from the second end surface to a region on a second end surface side of at least one surface of a surface on an opposite side of the first electrode from the semiconductor laminate and a surface on an opposite side of the second electrode from the semiconductor substrate;
• and
• a metal film formed on the insulating film to cover at least the active layer when viewed in the light waveguide direction,
• wherein an outer edge of the metal film does not extend over the at least one surface of the surface of the first electrode and the surface of the second electrode when viewed in the light waveguide direction.