Patent ID: 7180927

Claim:
A semiconductor laser diode comprising first and second material layers which are multi-material layers, and an active layer interposed between the first and second material layers to emit light wherein the first material layer has a surface exposed on a same side as said active and second material layers are formed, such that a step height exists between said surface of the first material layer and a top surface of the second material layer, characterized in that the semiconductor laser diode comprises: a ridge waveguide formed on a portion of the second material layer having a ridge shape such that a top material layer of the second material layer is selectively exposed to define a channel, and in which a first electrode layer which is in contact with the top material layer of the second material layer via the channel is formed; and a first protrusion, which is positioned at one side of the ridge waveguide and has a height not less than that of the ridge waveguide, wherein the first protrusion has a width wider than the width of the ridge waveguide.