Patent ID: 8160116

Claim:
A semiconductor laser comprising: a first conductive type of a lower clad layer; an active layer provided on the lower clad layer, active layer including a plurality of quantum dots; a second conductive type of an upper clad layer that is opposite to the first conductive type, the upper clad layer being provided on the active layer so as to have an isolated ridge portion such that W 1 ≦W top+0.4 μm where Wtop is a width of a top of the ridge portion and W 1 is a width of the ridge portion at a height of 20 nm from a bottom of the upper clad layer; and an electrode provided on the upper clad layer, wherein the upper clad layer includes a first and a second layer provided on the first layer, the first layer being at a bottom layer of the upper clad layer, the first layer has a minimum width of the ridge portion, and the second layer has a side surface that was subjected to anisotropic etching.