Noise effects in avalanche photodiodes

The usual formula for the excess noise produced in a simple avalanche photo diode may be introduced in a particularly simple manner by taking advantage of the Fact that the ionization coefficients usually encountered in practi ce are often regarded as constant throughout the device For any specific ap plied bias voltage. An analytic expression for the hole current as a functi on of position, along with a novel interpretation of the minimum-noise cond ition, are also given.