Optical Communication Systems

Course Description

The course gives detailed account of the phenomena related to the transmission of an optical electromagnetic wave. The restrictions imposed by particular components in the communication chain are considered (optical fibers, photo-detectors, optical amplifiers, laser sources). Examples of design of optical communication systems are given.

General Competencies

The emphasis in this course is on understanding the phenomena and the restrictions related to the transmission of information with an optical signal and by using opto-electrical transformation. Students will be able to apply this knowledge, together with the knowledge of modulation and multiplexing techniques, to better understand the principles of operation of optical communication systems. They will also be capable of designing high-speed point-to-point optical communication systems and solving speed increase-related problems in existing systems.

Learning Outcomes

  1. describe the physical method of wave propagation inside the fiber, describe the limitations of fiber data transmission
  2. describe the working principle of lasers, optical amplifiers and photodetectors
  3. select the communication window, laser type, fiber type and photodetector type, for realization of considered optical link
  4. select the modulation method and multiplexing method suitable for considered communication system
  5. estimate limitation on link length, determine the type and number of needed optical amplifiers and dispersion compensators
  6. design optical communication systems

Forms of Teaching

Lectures

Lectrures are given with the use of powerpoint presentations published on the web pages.

Exams

Continuous examination: two home exercises.

Exercises

Solving problems takes place when necessary (according to the treated subjects). Exercises are held by teaching assistant.

Laboratory Work

Laboratory excercises take place within subject "Laboratory".

Grading Method

Continuous Assessment Exam
Type Threshold Percent of Grade Comment: Percent of Grade
Homeworks 0 % 10 % 0 % 0 %
Mid Term Exam: Written 0 % 25 % 0 %
Final Exam: Written 0 % 25 %
Final Exam: Oral 40 %
Exam: Written 0 % 50 %
Exam: Oral 50 %
Comment:

Week by Week Schedule

  1. Overview of demands and restrictions in the design of optical communication systems
  2. Absorption, spontaneous emission, stimulated emission, Einstein's coefficients, laser working principle, Types of laser diodes: Fabry-Perot laser diodes, single-mode lasers (DFB, DBR), tunable lasers, vertical-cavity surface-emitting laser (VCSEL)
  3. Multiplexing in optical communication systems, WDM systems, properties of DWDM and CWDM systems; modulation principles in optical systems, direct and indirect type of modulation
  4. Semiconductor photodetectors, PIN and avalanche photodiodes
  5. Noise in photodetectors, Bit Error Rate (BER) and receiver sensitivity, optical systems with predominant quantum noise, optical systems with predominant thermal noise
  6. Optical amplifiers, gain saturation, ASE noise in optical amplifiers, problem of noise in cascaded optical amplifiers, erbium-doped fiber amplifier (EDFA), semiconductor optical amplifier (SOA), Raman fiber amplifier determine limitation on link length, determine the type and number of needed optical amplifiers and dispersion
  7. Principle of operation of fibers, types of fibers, fiber analysis by Geometrical Optics, modes in a multi-mode fiber, numerical aperture, intermodal dispersion
  8. Planar fibers, rigorous method of analysis of planar fibers, rigorous method of analysis of a cylindrical fiber, modes inside a fiber, dependence of the propagation constant on frequency, dependence of the number of modes on frequency
  9. Mid-term exam
  10. Losses in fibers, infrared absorbtion, ultraviolet absorbtion, Rayleigh scattering, technological losses, bending losses, photonic crystal fibers (PCF)
  11. Chromatic dispersion, determining the parameters of chromatic dispersion, material dispersion, waveguide dispersion, polarization dispersion, chromatic dispersion and polarization dispersion compensation
  12. Nonlinear effects: four-wave mixing, self-phase modulation, cross-phase modulation, stimulated Raman scattering, stimulated Brillouin scattering
  13. Performance measurement and monitoring, basic test equipment
  14. Optical link design - power budget and response time calculation, optical link design - power loss method
  15. Optical signal multiplexing - TDM, WDM, and OTDM systems, TDM systems - PDH and SDH systems, WDM systems, WDM system components

Study Programmes

Electronics -> Electrical Engineering and Information Technology (Profile)

Wireless Technologies -> Information and Communication Technology (Profile)

Literature

G. Keiser (2011.), Optical Fiber Communications, Mcgraw Hill
G.P. Agrawal (2005.), Lightwave technology - telecommunication systems, John Wiley
R. Ramaswami, K.N. Sivarajan (2010.), Optical Networks, Morgan Kaufmann Publishers

Grading System

5 ECTS
L1 English Level
L1 e-Learning
37 Lecturers
8 Exercises
0 Laboratory exercises

Grading

89 Excellent
76 Very Good
63 Good
50 Acceptable