Patent ID: 7580435

Claim:
A laser diode comprising: a first cladding layer of a first conductive type formed on a substrate; an active layer formed on said first cladding layer; a second cladding layer of a second conductive type formed over a top layer of said active layer, said second cladding layer having a ridge shape in cross section; a first optical guide layer within said first cladding layer; and a second optical guide layer within said second cladding layer, wherein, said first and second optical guide layers each have a higher refractive index than those of said first cladding layer and said second cladding layer, respectively, said first and second optical guide layers broaden a beam waist in a waveguide, said first and second optical guide layers are sandwiched between portions of said first cladding layer and said second cladding layer, respectively, and the active layer includes a quantum well structure, a barrier layer and SCH optical guide layer.