Noise characteristics of avalanche photodiode arrays of the bevel-edge type

A calculation of the noise characteristics beveled-edge avalanche photodiode arrays is presented. It describes well the observed results from 61-element arrays with 1.2/spl times/1.2 mm/sup 2/ and 0.45/spl times/0.45 mm/sup 2/ pixel size. The main source of noise at low gain is Johnson noise from the interpixel resistance. At high gain, the shot noise from the bulk dark current dominates. There is an intermediate narrow gain region (M=10-25) where the noise current decreases to 0.1 pA//spl radic/Hz in both arrays and the performance of the pixels is optimized. A comparison between the model and experimental data shows that the bulk dark current per unit area is higher in the array than a single element APD. This increase is most probably due to the grooving process, which create defects that generate high bulk dark current.