Photon statistics of a single mode of spontaneous Raman scattering in a distributed Raman amplifier
Experimental measurement of spontaneous noise statistics from a distributed Raman amplifier has been achieved with single-mode and single-photon resolution. The results agree with quantum theoretical predictions of a Bose-Einstein probability distribution. Distributed Raman amplification is becoming increasingly important in today's optical communication systems. It improves the optical signal-to-noise ratio by providing optical gain inside the transmission fiber.
Temporal correlation of photons following frequency up-conversion.
We demonstrate an approach to measure temporal correlations of photons in the near infrared range using frequency up-conversion. In this approach, the near infrared signal photons are converted into the visible range, in which highly efficient silicon avalanche photodiodes are used to perform the temporal correlation measurements. A coherent light source and a pseudo-thermal light source were used in the experiment. The results are in agreement with theoretical values and those obtained from measurements directly made using superconducting nanowire single photon detectors. We conclude that the temporal correlation (up to 4th order) of photons was preserved in the frequency up-conversion process. We further theoretically and experimentally studied the influence of the dark counts on the measurement. The setup uses commercially available components and achieves high total detection efficiency (~26%).
A master equation approach to the Raman effect
A quantum-mechanical model of Raman scattering from a phonon bath is formulated. A master equation is derived for the density operator of the light fields alone. This model correctly describes the stochastic coupling of Stokes and anti-Stokes radiation through the phonon bath. Since quantum fluctuations are included, this treatment contains the spontaneous and stimulated Raman effects in one self-consistent formalism. The photon statistics of the light fields are obtained by the solution of a Fokker-Planck equation.