Semiconductor photodetector

A semiconductor photodetector comprising:

• a pair of a p-electrode and an n-electrode;
• a substrate;
• and
• an optical waveguide structure electrically connected between said p-electrode and said n-electrode and provided over said substrate,
• wherein said optical waveguide structure comprises plural periods of a multi-layered structure which comprises an InGaAs optical absorption layer of a first conductivity type, a pair of first and second InGaAsP cladding layers of said first conductivity type sandwiching said InGaAs optical absorption layer, and a pair of a first InP layer of said first conductivity type and a second InP layer of a second conductivity type, and said first and second InP layers sandwiching said first and second InGaAsP cladding layers.