Broadband photon-number squeezing in light-emitting diodes at low photon-flux levels

We have investigated the squeezing of intensity-fluctuation below the full-shot-noise level in light-emitting diodes (LEDs) at low-photon flux levels. By using a tailor-made LED, the squeezing over a wide frequency range, near-dc to 1.5 GHz was achieved at an injection-current level as low as 100 μA. As a result, the number of photons, which can be expected in the sub-Poissonian light, was reduced to the order of 105 per pulse, nearly three orders of magnitude smaller than those obtained in commercial LEDs.