  Pixelated Photon Detectors (PPDs) are the most promising semiconductor
photodetectors in recent years. One of the issues with the PPD is its high
noise rate. As well as random noise, PPD also exhibits so called after-pulsing
and optical crosstalk, and these limit the applicable range of its gain as well
as its size. By accurately measuring each of these causes of noises
independently, we quantitatively evaluated how the performance of the present
device is limited by multiplication effect of these noises. With this result
and the pulsing mechanism of PPD, we propose a new structure of PPD which could
have high gain with low noise.
