Gain-coupling distributed feedback semiconductor and method of producing the same

A gain-coupling distributed feedback semiconductor laser comprising:

• a waveguide including an active layer;
• and
• a current restraint layer formed along said waveguide, said current restraint layer including p- and n-type semiconductor portions which are periodically and alternatively arranged along a light propagation direction;
• wherein said p- and n-type semiconductor portions are respectively amphi-conductivity impurity doped semiconductor layers grown on a periodic uneven surface.

A method of fabricating a gain-coupling distributed feedback semiconductor laser, said method comprising the steps of:

• forming a periodic uneven surface having a plurality of kinds of surfaces with different surface indices;
• and
• forming a current restraint layer on the uneven surface by simultaneously forming p- and n-type semiconductor portions on the uneven surface using a gas-phase crystal growth method;
• wherein a pitch of carrier density of current injected by said current restraint layer is equal to one half of a pitch of the periodic uneven surface.