Patent ID: 7760784

Claim:
A laser diode, comprising: a substrate; a first conductive-type clad layer disposed on the substrate; a second conductive-type clad layer disposed on the first conductive-type clad layer; an active layer interposed between the first conductive-type clad layer and the second conductive-type clad layer; and column-shaped nano patterns arranged at a surface of the second conductive-type clad layer, wherein the nano patterns are protruding columns including the second conductive-type clad layer or are recessed portions surrounded by the second conductive-type clad layer on at least two adjacent sides of each nano pattern, wherein the respective nano patterns are formed in a circular-column shape having a diameter, wherein the nano patterns are spaced apart from one another at an interval equal to the diameter, and wherein cleavage mirrors are respectively formed at both opposite side surfaces of the laser diode, and each cleavage mirror is parallel with any one side of a regular triangle defined by three adjacent nano patterns.