Patent ID: 7573925

Claim:
A DFB laser, comprising: a substrate; a mode modifier layer positioned above the substrate; a buffer layer positioned above the mode modifier layer; a first confinement layer positioned above the buffer layer; a second confinement layer positioned above the first confinement layer; a doped active region positioned above the second confinement layer, the doped active region comprising: a plurality of quantum wells separated by a plurality of barrier layers, wherein the quantum wells and the barrier layers are doped with a doping material with a concentration between about 1*10^16/cm 3 to about 1*10^17/cm 3 ; a third confinement layer positioned above the doped active region; a fourth confinement layer positioned above the third confinement layer; a first spacer layer positioned above the fourth confinement layer; an etch stop layer positioned above the first spacer layer; a second spacer layer positioned above the etch stop layer; a grating layer positioned above the second spacer layer; and a top layer positioned above the grating layer.