Reduction of optical shot noise from light emitting diodes

The mechanism responsible for the reduction of optical shot noise from high impedance driven light-emitting diodes is addressed. It is shown that the electronic feedback mechanism is the same as that for laser diodes with spontaneous recombination. Quantum noise reduction below the optical shot noise level is due to the effect of negative feedback on the recombination rate that occurs when the junction voltage and carrier number are permitted to respond to the underlying (Poisson) stochastic recombination process as in a light-emitting diode or laser diode driven by a high impedance source. Extensive measurements on light-emitting diodes confirm the magnitude of the noise suppression predicted from semiclassical theory.<
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