Optical pulses, which appear as a flash of light, are used to transmit information in high speed optical fibers, and are increasingly used in Light Detection And Ranging (LIDAR) for 3-dimensional imaging. Both of these applications demand light sensors or photodiodes that are capable of detecting very low levels of light intensity down to a few photons, where a single photon is the quantized energy unit of light.
Click here for original story, New photodiode with extremely low excess noise for optical communication and long range LIDAR
Source: Phys.org