Optical communications
Objectives and Contextualisation
1. To Acquire an advanced level of knowledge of the main blocks that constitute an optical communications link, the integral components (optical fibers, light emitters, photodetectors and other photonic devices), and the basic principles of the digital transmission of optical signals.
2. Skills: the ability to calculate the most important parameters in the context of digital optical links, to use high-performance optical device and system simulation software (VPI TransmissionMaker), solve problems and write reports, work in small groups of two people.
3. Competences: To have the mathematical and physical foundations necessary to interpret, select, evaluate, and possibly propose concepts, theories, use the technological developments related to optical communications and their application. Ability to analyze photonic devices, and understand their use in optical telecommunications.
Competences
Analyse components and specifications for communication systems that are guided or non-guided by electromagnetic, radiofrequency or optical means.
Apply the necessary legislation in the exercise of the telecommunications engineer's profession and use the compulsory specifications, regulations and standards.
Communication
Develop personal attitude.
Develop personal work habits.
Develop thinking habits.
Learn new methods and technologies, building on basic technological knowledge, to be able to adapt to new situations.
Select and devise communication circuits, subsystems and systems that are guided or non-guided by electromagnetic, radiofrequency or optical means to fulfil certain specifications.
Work in a team.
Learning Outcomes
Analyse components and specifications of optical communication systems.
Apply the national and international regulations and standards to the field of optical communications.
Apply the techniques on which, in the field of optical communications and from the point of view of transmission systems, networks, services and applications are based.
Communicate efficiently, orally and in writing, knowledge, results and skills, both professionally and to non-expert audiences.
Develop curiosity and creativity.
Develop scientific thinking.
Develop systemic thinking.
Efficiently use ICT for the communication and transmission of ideas and results.
Evaluate the advantages and disadvantages of different technological options for the deployment or implementation of optical communication systems.
Make one's own decisions.
Manage available time and resources.
Prevent and solve problems.
Select transmission equipment and systems by optical means.
Use computer applications to support the development and exploitation of networks, services and applications based on optical communications.
Work cooperatively.
Content
Content
(T: theory, S: problems or seminars, PS: preparation of problems or seminars, L: laboratories, PP: lab work preparation, E: study, AA: other activities, all these activities have required times specified in hours.)
1. Optical fibers
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S
PS
L
E
PP
AA
Total
9
3
3
6
9
6
36
General introduction. Basic concepts of Optics. Guided optical radiation. Singlemode and multimode fibers. Step index fibers and graded index fibers. The optical properties of fibers. Fiber losses, the scattering of Rayleigh, Mie, Brillouin and Raman. Chromatic dispersion, modal dispersion. Transmission characteristics. Special fibers: zero dispersion, displaced dispersion, flattened dispersion. Modelling parameters.
2. Optical Emitters
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S
PS
L
E
PP
AA
Total
9
3
3
6
9
6
36
The basis of light emission. Emission of light in semiconductors. Double heterojunction structure. LED rate equation. Characteristics: spectral line width, step response, modulation response, bandwidth. Fabry-Perot Resonator. Bragg reflectors. Semiconductor laser, types and properties. Laser rate equations, threshold current, step response, modulation response, bandwidth dependence with current. Modeling parameters with rate equations, life time carriers and photons, coefficient of damping, confinement factor.
3. Optical receivers
T
S
PS
L
E
PP
AA
Total
9
3
3
6
9
6
36
Light detection in p-n junctions. PIN and APD diodes. Equivalent circuit, transimpedance amplifier. Responsivity, dark current. Thermal noise, shot noise, avalanche factor. Consequences of converting optical power to electric current: electrical beat noise S-ASE and ASE-ASE. Bandwidth in actual devices. Modeling parameters: noise spectral density, M, k.
4. Optical Amplifiers
T
S
PS
L
E
PP
AA
Total
9
3
3
6
9
6
36
Importancein WDM systems. Optical semiconductor amplifiers, two-level system, electric pumping. Introduction to rate equations. Small signal gain, saturation power, noise dependence with gain. ASE noise, dependence with gain. Fiber amplifiers, three-level system, photonic pumping, EDFA doped fiber amplifiers, RAMAN fiber amplifiers with high bandwidth. Modeling parameters.
5. Optical communications digital links
9
T
S
PS
L
E
PP
AA
Total
9
3
3
6
6
36
Transmission of digital signals, IIDD intensity modulation, direct detection. Parameter Q, BER. Thermal noise, "shot" noise. ASE optical noise influence: electric beating noise, S-ASE, ASE-ASE. Interference between symbols (ISI), dispersion. Passive components: isolator, MZ modulator, optical filters. Balance of power and time. Impulse response of the link.
Presential
TRUE
Optical communications
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or HaDEA. Neither the European Union nor the granting authority can be held responsible for them. The statements made herein do not necessarily have the consent or agreement of the ASTRAIOS Consortium. These represent the opinion and findings of the author(s).
