Optical communications

Subject description

Properties and limitations of metal transmission lines: twisted pair, coaxial cable and metal wave-guide, bandwidth and attenuation of coaxial cable. Reflection and refraction of electromagnetic waves on the boundary of two different dielectrics, implementation of a planar wave-guide, group delay, dispersion equation, and number of modes in a planar dielectric wave-guide. Multi-mode and single-mode optical fibers, raw materials and methods of fabrication, multi-mode, chromatic and polarization-mode dispersion, non-linear effects in optical fibers. Optical-network components: splitters, combiners, filters, diffraction gratings, wavelength multiplexers, light-wave isolators and circulators. Optical-source properties, longitudinal and transversal coherence, source modulation, source types: filament bulbs, gas-discharge bulbs, light-emitting diodes, gas and solid-state lasers and their properties. Light-wave modulators, electro-optical phase modulator, electro-optical amplitude modulator, electro-absorption modulator. Lightwave receivers: thermal, photo-resistors and photo-diodes, quantum efficiency, photo-resistor and photo-voltaic regimes, quantum and thermal noise of an optical receiver, implementations of different receivers, clock recovery, clock jitter. Optical amplifiers, fiber and solid-state amplifiers, Brillouin and Raman effects.

The subject is taught in programs

Objectives and competences

Learning the fundamentals of guided-wave (wired) communications. Reasons to use optical fibers. Learning optical fibers and other components of optical networks: optical transmitters, optical modulators, optical receivers and optical amplifiers.

Teaching and learning methods

Lectures to explain the theoretical background and laboratory experiments to practically confirm the theory in the spirit of team work.

Expected study results

After successful completion of the course, students should be able to:

–  calculate the insertion loss and bandwidth of an optical link

– estimate the basic nonlinear effects in an optical fiber

– select the most appropriate optical transmitter and receivers

– use test equipment for fiber-optic links

– correct cleaning and mating of optical connectors

– troubleshoot an optical link

– check the correct operation of an optical link and measure its margin

Basic sources and literature

  1. J. Budin, Optične komunikacije, FE, Ljubljana, 1993.
  2. B. Batagelj, M. Vidmar, Optične komunikacije, Laboratorijske vaje, FE, Ljubljana, 2003.
  3. J. Budin, Sisitemi optičnih komunikacij, FE, Ljubljana, 1995.
  4. http://antena.fe.uni-lj.si/literatura/

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