Balanced light detector

A method of generating a random number that includes one or more random bits of data, said method comprising:

• detecting light in a first light detector;
• outputting, from the first light detector, a first electrical signal that is representative of light intensity of the light detected by the first light detector;
• amplifying the first electrical signal to yield a first amplified electrical signal;
• detecting light in a second light detector;
• outputting from the second light detector, a second electrical signal that is representative of light intensity of the light detected by the second light detector;
• amplifying the second electrical signal to yield a second amplified electrical signal;
• applying a common offset to the first and second electrical signals, such that noise introduced by the common offset to the first and second electrical signals is common to the first and second electrical signals;
• generating a difference signal based on the first and second amplified electrical signals, wherein the difference signal is indicative of quantum noise;
• and
• providing the one or more random bits of data based on the difference signal.