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Author
Date
2023Type
- Doctoral Thesis
ETH Bibliography
yes
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Abstract
Contemporary society is in constant demand for faster and more reliable
communications. This leads to an exponential increase in the load upon the
communications infrastructure, which starts to suffer from physical limitations
imposed by the supporting medium. Optical fibers, which have so far been able
to sustain the growing demand, are in fact reaching their theoretical maximum
capacity. These new challenges require innovative solutions and different
approaches.
In this dissertation, we propose the use of coherence as information carrier.
The standard encoding scheme achieved by modulating amplitude and phase of
the single electric field is replaced by the encoding of information in the mutual
coherence of each pair of a set of fields, thus generating a number of signals
that scales quadratically with the number of transmitted beams. We provide a
description of the resulting communication system, followed by the analysis
of the dependence of the figures of merit (signal-to-noise ratio, maximum bitrate,
and spectral efficiency) on the number of transmitted fields. In addition
to a potential advantage in terms of transmission capacity, we discuss how a
coherence-based communication system can find application in cryptography.
The system relies on the ability to independently control the coherence
between each pair of fields. To this end, we demonstrate experimentally
that this control can be achieved by implementing a linear port combining
several mutually incoherent fields. The experimental setup is based on a system
consisting of a spatial light modulator and an optical complex medium.
In conclusion, the present work offers for the first time a method, and
its experimental realization, to simultaneously control the coherence between
several pairs of fields. It also demonstrates how such control can be effectively
exploited to provide a new solution to the challenges present in optical
communication. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000615111Publication status
publishedExternal links
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Publisher
ETH ZurichSubject
complex media; optical communications; coherence (optics); beam shapingOrganisational unit
03944 - Novotny, Lukas / Novotny, Lukas
Funding
ETH-41 19-1 - Spatial Correlation Coding (ETHZ)
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ETH Bibliography
yes
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