Vertical cavity surface emitting laser

A vertical cavity surface emitting laser comprising:

• a post provided at a major surface of a substrate and extending along a first axis intersecting the major surface of the substrate;
• and
• an electrode provided at an upper surface of the post and surrounding the first axis,
• wherein:
• the post includes a first distributed Bragg reflector, an active layer, a current confinement layer, and a second distributed Bragg reflector,
• the substrate, the first distributed Bragg reflector, the active layer, the current confinement layer, and the second distributed Bragg reflector are disposed in order in a direction of the first axis,
• the second distributed Bragg reflector includes a semiconductor region and a first high-resistance region surrounding the semiconductor region,
• the first high-resistance region has an electrical resistance that is higher than an electrical resistance of the semiconductor region,
• the current confinement layer includes an aperture portion and an oxidized portion surrounding the aperture portion,
• the first axis passes through the semiconductor region and the aperture portion,
• a length of a longest line segment of line segments connecting any two points on an inner edge of the oxidized portion in a section orthogonal to the first axis is D1, a length of a longest line segment of line segments connecting any two points on an inner edge of the first high-resistance region in the section orthogonal to the first axis is D2, and a value of D2/D1 is greater than 1 and is 2.5 or less,
• the second distributed Bragg reflector includes a second high-resistance region having an electrical resistance that is higher than the electrical resistance of the first high-resistance region,
• the second high-resistance region surrounds the semiconductor region,
• the second high-resistance region is disposed between the electrode and the first high-resistance region in the direction of the first axis,
• the second high-resistance region has an inner edge that is positioned farther away than an inner edge of the first high-resistance region from the first axis in a direction orthogonal to the first axis, and
• the first high-resistance region and the second high-resistance region respectively have a first thickness and a second thickness along the direction of the first axis, the second thickness being smaller than the first thickness.