CQuIC Seminars
Optical communication in the low-power limit
Presented by Konrad Banaszek, Centre of New Technologies, University of Warsaw, Poland
We discuss noise effects in strategies to attain the maximum transmission rate of a lossy narrowband optical channel under the constraint of a low mean photon number per time bin. When direct detection is used at the output, the ultimate capacity can be approached by optimizing pulse position modulation (PPM) with respect to encoding parameters. We present an approximate analytical formula for the PPM transmission rate, which quantifies the effects of photon statistics in terms of the g(2) normalized second-order intensity correlation function of the light source, and analyse effects of dark counts. The highly imbalanced instantaneous power distribution for PPM encoding can be remedied by the use of binary phase shift keying (BPSK) with a joint detection receiver based e.g. on quantum memories. We show that for this scheme, the transmission rate in the presence of phase noise is equivalent to that of PPM with super-Poissonian light statistics and dark counts, retaining the enhancement compared to individual detection.
3:30 pm, Thursday, April 6, 2017
PAIS-2540, PAIS
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