Photodetector

A photodetector comprising

• germanium photoreceivers including:
• a silicon substrate;
• a lower clad layer formed on the silicon substrate;
• a silicon core layer formed on the lower clad layer and including a silicon region doped with a first conductivity-type impurity;
• a silicon waveguide layer connected to the silicon core layer;
• a germanium layer formed on the silicon core layer and including a germanium region doped with a second conductivity-type impurity;
• an upper clad layer formed on the silicon core layer and the germanium layer;
• and
• electrodes connected to the silicon region and the germanium region, respectively, wherein
• two or more germanium photoreceivers are arranged adjacent to each other on the silicon substrate,
• the photodetector includes resistors formed by doping an impurity into the silicon core layer to surround respective germanium layers of the two or more germanium photoreceivers arranged adjacent to each other, and
• the resistors are provided as many as the number of germanium photoreceivers, the resistors are arranged on a straight line, the resistors are connected to each other by a metal electrode, and the respective resistors share a power source.

A photodetector comprising

• germanium photoreceivers including:
• a silicon substrate;
• a lower clad layer formed on the silicon substrate;
• a silicon core layer formed on the lower clad layer and including a silicon region doped with a first conductivity-type impurity;
• a silicon waveguide layer connected to the silicon core layer;
• a germanium layer formed on the silicon core layer and including a germanium region doped with a second conductivity-type impurity;
• an upper clad layer formed on the silicon core layer and the germanium layer;
• and
• electrodes connected to the silicon region and the germanium region, respectively, wherein
• two or more germanium photoreceivers are arranged adjacent to each other on the silicon substrate,
• the photodetector includes resistors embedded in the upper clad layer to cover respective germanium layers of the two or more germanium photoreceivers arranged adjacent to each other, the resistors being made of a metal or a metal compound,
• the resistors are provided as many as the number of germanium photoreceivers, the resistors are arranged on a straight line, the resistors are connected to each other by a metal electrode, and the respective resistors share a power source, and
• an input optical waveguide of each of the germanium photoreceivers includes a bent portion, and optical axes of the germanium photoreceivers are arranged to be placed on a straight line.