Lecturer: Konrad Banaszek
Centre of New Technologies, University of Warsaw, Poland
Abstract:
Quantum theory of electromagnetic radiation defines fundamental
limits on the capacity of optical communication channels. Analysing
the quantum limits requires a change of paradigm from measuring
quantities well defined in classical systems, such as the amplitude
or the phase, to exploring quantum state distinguishability. This
approach is discussed in the context of deep-space optical
communication, in particular transmission of data collected by
space missions beyond the near-Earth region. We review the
efficiency of pulse position modulation (PPM) as the coding
standard in this regime. An inherent feature of the PPM standard is
the high ratio of the peak-to-average signal power, which may limit
the electrical-to-optical conversion efficiency of the transmitter.
We describe a possible solution to this problem in the form of
structured optical receivers which exploit the quantum mechanical
phenomenon of superadditivity of accessible information.