Photo-detecting apparatus

A photo-detecting apparatus, comprising:

• two adjacent pixels each comprising an absorption region configured to receive an optical signal and to generate photo-carriers in response to the optical signal, wherein the absorption region includes a first material, wherein the first material comprises germanium;
• a substrate supporting the two adjacent pixels, wherein the substrate includes a second material different from the first material, wherein the second material comprises silicon;
• a light shield comprising two optical windows;
• one or more density compensation structures comprising a third material and arranged to provide a predetermined density distribution of the first material and the third material, wherein the third material comprises germanium;
• and
• two isolation regions each surrounding a respective absorption region of the absorption regions of the two adjacent pixels,
• wherein each of the two optical windows is arranged over a respective absorption region of the two adjacent pixels such that the respective absorption region receives the optical signal through the optical window, and wherein the light shield is arranged over the one or more density compensation structures to block light from entering the one or more density compensation structures.

A system, comprising:

• a transmitter;
• a receiver;
• a signal processor in electrical communication with the receiver;
• and
• a controller in electrical communication with the signal processor and the transmitter;
• wherein the receiver includes one or more photo-detecting apparatus, each of the one or more photo-detecting apparatus comprising:
• a pixel comprising an absorption region configured to receive an optical signal and to generate photo-carriers in response to the optical signal, wherein the absorption region includes a first material, wherein the first material comprises germanium;
• a substrate supporting the absorption region, wherein the substrate includes a second material different from the first material, wherein the second material comprises silicon;
• a light shield comprising an optical window;
• and
• one or more density compensation structures comprising a third material and arranged to provide a predetermined density distribution of the first material and the third material, wherein the third material comprises germanium,
• wherein the optical window is arranged over the absorption region such that the absorption region receives the optical signal through the optical window,
• wherein the light shield is arranged over the one or more density compensation structures to block light from entering the one or more density compensation structures, and
• wherein a total area of the absorption region and the one or more density compensation structures is at least 20% of an area of the pixel.