A distributed feedback (DFB) quantum dot semiconductor laser structure is
provided. The DFB quantum dot semi-conductor laser structure includes: a
first clad layer formed on a lower electrode; an optical waveguide (WG)
formed on the first clad layer; a grating structure layer formed on the
optical WG and including a plurality of periodically disposed gratings; a
first separate confinement hetero (SCH) layer formed on the grating
structure layer; an active layer formed on the first SCH layer and
including at least a quantum dot; a second SCH layer formed on the active
layer; a second clad layer formed on the second SCH layer; an ohmic layer
formed on the second clad layer; and an upper electrode formed on the
ohmic layer. Accordingly, an optical WG is disposed on the opposite side
of the active layer from the grating structure layer, thereby increasing
single optical mode efficiency. And, an asymmetric multi-electrode
structure is used for applying current, thereby maximizing purity and
efficiency of the single mode semiconductor laser structure.