Knox, W. H., J. M. Roth, and C. Xu.
Dynamic Measurement of and Compensation for Impairments to Optical Data Communication Pulses Using Photon-Counting Silicon Avalanche Photodiode” US Patent 7,024,111. (April 4, 2006)  >>> Link

Dynamic Measurement of and Compensation for Impairments to Optical Data Communication Pulses Using Photon-Counting Silicon Avalanche Photodiode