A random number generator, RNG, a method of fabricating the same, and a method of generating a random number. The RNG, comprises at least one first avalanche photodiode, APD, configured for producing “1” events based on dark electron initiated avalanches in the first APD; at least one second avalanche photodiode, APD, configured for producing “0” events based on dark electron initiated avalanches in the second APD; and a feedback circuit configured for substantially evening out the respective numbers of generated avalanches in the first and second APDs by independently controlling respective dynamic bias voltages of the first and second APDs.