Linear-mode avalanche photo-diode detectors with a quasi-deterministic gain component: statistical model studies

Abstract

The optoelectronic gain of a linear mode avalanche photo-diode (APD) results from the cascade of electron and hole impact ionizations that take place in the high-field intrinsic multiplication layer of the APD. Due to the uncertainty associated with the stochastic nature of the APD's gain, the shot noise present in the resulting photo-generated electrical signal is accentuated and degrades the detection of single photon initiated avalanche signals. Recent advances in linearmode InGaAs APD detectors have been demonstrated that have reduced excess noise, along with the high gain necessary for detecting single photons. In these devices the avalanche buildup is characterized with a temporally varying noise. At low incident photon / photo-electron levels, the stochastic nature of the impulse response function of these APDs offers the potential of increased probability that the output exceeds a threshold level resulting in a "detection" and, hence, a better receiver-operating-characteristic (ROC). In this paper we examine the ROC (P_detection vs P_FalseAlarm) statistics of these single photon APDs as a function of the quasi-deterministic mean gain and standard deviation for an rms ROIC (readout integrated circuit) noise level of 25e^-. Single photo-electron and multiple photo-electron detection statistics are also examined for predicting a ROC. Measured linear-mode APD data are also presented.