Lectures
Introduction to telecommunications and optical fibers - Telecommunications, basic ideas, connection point to point, networks, information capacity of optical fibers, transition from analog to digital transmission systems, place and role of the optical communication systems, history and development of the transmission properties and parameters of optical fibers, fiber optical communications systems, basic block diagram of optical transmission, nowaday stage in optical systems, future development trends
Basics of optical fibers 1 - Light guidance in optical fibers, step index fibers as a basic optical communication structure, total reflection on the core-cladding boundary, refractive index of core and cladding, critical angle on the core-cladding boundary and critical angle of transmission, light launching into optical fiber, acceptance angle, numerical aperture, attenuation on optical fibers, bending losses, microbending losses, light scattering, basic mechanism of absorption, transparent windows for fibers made of SiO2, calculation of total attenuation of optical line, direct method of attenuation measurement
Basics of optical fibers 2 - Intermodal and chromatic dispersion, description of modes, number of modes, physical meaning of modes, modal dispersion, mechanismus of pulse spreading and its calculations, resctriction of the bite rate due to modal dispersion in optical line, first solution to modal dispersion - grade-index fibers, basic ideas of graded-index fibers, reduction of the modal dispersion due to graded-index fibers, second and principal solution of the modal dispersion - singlemode fibers, structire of singlemode fiber, comparison of the modal dispersion in three types of optical fibers
Basics of optical fibers 3 - Chromatic dispersion, mechanismus of chromatic dispersion creation, calculating pulse spreading caused by chromatic dispersion, definition of bit rate and bandwidth, relationship between bit rate and bandwidth, elektrical and optical bandwidth, total dispersion and bit rate, bit rate calculation, specification of bit rate and bandwidth by optical fibers producers
Basics of optical fibers 4 - Reading a data sheet of optical fibers, general parameters, optical characteristics, geometrical characteristcs of optical fibers, environmental specifications of optical fibers, mechanical specifications, other characteristics
Basics of singlemode fibers (SM fibers) 1 - Principle of action, Gaussian beam, influence of core and cladding to mode field diameter (MFD), cutoff wavelength of SM fiber, attenuation in SM fibers, macrobending loss, microbending loss, absorption of light and light scattering of SM fibers, dispersion and bandwidth, chromatic dispersion, material dispersion,
Basics of single mode fibers 2 - waveguide dispersion, coventional fibers, shifted fibers, dispersion flattened fibers, polarization mode dispersion (PMD), bandwidth and bit rate of SM fibers, reading of datasheets, general characteristics, transmission parameters, MFD and cutoff wavelength, geometric characteristics, mechanical properties of SM fibers
Basics of sources for optical communications - lasers 1 Basic properties of lasers, spontaneous and stimulated radiation, population inversion, positive feedback, material loss, laser activity and conversion laser characteristics, characteristics and laser light properties,
Basics of sources for optical communications - lasers 2 diode lasers, basic structures of laser diodes, DH, BH, stripe lasers, QW lasers, VCSEL, optical resonators, restriction of the bandwidth, DFB and DBR lasers, laser diodes with and without active cooler, datasheets parameters of laser diodes
Basics of sources for optical communications -LEDs Advantages and disadvantages of LEDs to laser dodes, creation of photons in semiconductors, light radiation from pn junction, basic description and LED characteristics, homostructure LEDs, heterostructure LEDs, surface radiating LEDs(SLED), edge radiating LEDs(ELED), light coupling into optical fiber, technology improving coupling of optical fiber to LEDs, datasheets parameters of LEDs, modulating bandwidth
Tests and measurements of otical fibers and cables- 1 Kinds of measurements, measurement at SM and MM optical cables, attenuation measurement, conditions for correct attenuation measurement, cut off method, direct method of attenuation measurement, OTDR-metr, basic parts of OTDR-metr, dead zones
Basics of detectors and receivers for optical communications -
Basic requirements on optical detectors, basic principles and fotodetector structures, pfotidiode with PN junction, photovoltaic and photoconductive modes of operation, responsivity of photodiode, responsivity versus wavelength, short and long cutoff wavelength of photodiode, sensitivity of photodiode, photodiode bandwidth, equivalent circuit of a PN photodiode, bandwidth and photodiode digest, PIN photodiode, avalanche photodiodeAPD), MSM detectors
Fiber optic networks
Telephone networks, data networks, access networks, transport networks, multiplexing hierarchy in telecommunication networks, metropolitan networks, synchronous and asynchronous network, modulation and optical network multiplex, cable TV networks, place of optical networks in OSI model, coherent communication systems
Exercises
Safety rules for manipulation with laser light, laser light properties
Calculation of fiber lines attenuation
Calculation of power levels of optical routes
Calculation of modal dispersion
Calculation of modal dispersion for gradded index fibers
Calculation of material dispersion
Test No.1
Attenuation measurement of optical cabels and fibers
Attenuation measurement of optomechanical splices and connectors
Measurement of current/voltage characteristics of LEDs and LDs
Mesurement od power/current characteristics of LEDs and LDs
Attenuation measurement of optical fibers and cables with OTDR
Measurement of bending radii to attenuation of MM fibers
Test No.2 |