OPTICAL FIBERS AND PHOTONICS
The undergraduate course “Optical Fibers and Photonics” develops the problem of electromagnetic propagation in dielectric waveguides by studying all details of the symmetric slab waveguide. Moreover, it provides basic principles explaining the behavior of the most important optical and photonic components: coupled waveguide filters for waveguide division multiplexing, electro-optic phase modulators, LED diodes, optical amplifiers, LASERs and photodetectors.
The course provides the students with the basic notions related to the transmission of information in optical fibers. The propagation of guided waves together with the problems related to attenuation and dispersion are addressed in some details. In the second part of the course the principles of operation of the main optical and photonic components are presented. The students are involved in laboratory simulations related to the main topics of the course.
AIMS AND LEARNING OUTCOMES
The course provides the students with the basic notions related to propagation of electromagnetic fields in dielectric waveguides. The topics of attenuation and dispersion of the waves are addressed in some details. Some simplified models of coupled dielectric waveguides are shown and analyzed, in order to understand of filters for wavelength division multiplexing. Electro-optic phase modulators are presented together with the principles underlying the interaction of photons with matter, leading to the understanding of the way LED diodes, optical amplifiers, LASERs and photodetectors operate. The students are involved in laboratory simulations related to the main topics of the course.
Al the end of the course, the student will be able to describe the main concepts related to the topic of electromagnetic propagation in dielectric waveguides and to the topic of optical and photonic components. They will also be able to solve simple problems related to the most important practical applications.
All teaching activities are presented by the teacher.
1. Course organization, motivation and applications, course overview (2;2)
2. Introduction to optical transmission: history, applications, fundamental components and possible future developments (3;5)
3. Propagation in a slab waveguide:
3.1. Guided modes: field components, their graphical behavior, dispersion equation, graphical and numerical solution of the dispersion equation, cut-off frequencies, geometrical optics and numerical aperture (12;17)
3.2. Radiated and evanescent modes: cardinality of the set of radiated and evanescent modes, field components, properties of the modes (2;19)
3.3. Some comments on the orthogonality of modes and on the completeness of the set of modes: excitation of fields and their propagation in terms of modes (2;21)
3.4. Some comments on leaky modes (1;22)
3.5. Lab exercise using COMSOL Multiphysics: numerical analysis of a slab waveguide at different frequencies and using different excitations (3;25)
4. Features of the most important dielectric waveguides:
4.1. Step index optical fibers: fundamental mode, superior modes, cut-off frequencies, usual terminology, useful approximations (3;28)
4.2. Graded index optical fibers (1;29)
4.3. Holey fibers, photonic-crystal fibers and dielectric waveguides for integrated optics (1;30)
5. Attenuation in dielectric waveguides (1;31)
6. Dispersion in dielectric waveguides (4;35)
7. Lab exercise using COMSOL Multiphysics: numerical analysis of propagation in dispersive media (3;37)
8. Coupled slab waveguides in the presence of weak coupling and fundamental modes (4; 41)
9. Applications of coupled slab waveguides: power splitters, power combiners, directional couplers, switches (2; 43)
10. Lab exercise using COMSOL Multiphysics: numerical analysis of coupled slab waveguides (2; 45)
11. Fundamental ideas on electro-optics (2; 47)
12. Electro-optic modulators and switches (2; 49)
13. Basic ideas about the interaction of electrons and photons (2; 51)
14. Some comments on LED and semiconductor optical amplifiers (3; 54)
15. Principles of laser diodes (2; 56)
16. Basic ideas behind Erbium Doped Fiber Amplifiers (1; 57)
17. Some comments on photodetectors: photoelectric detectors; vacuum photodiodes; photomultiplier tube; photoconductive detectors; photodiodes detectors; avalanche photodiodes (2; 59)
18. Basic introduction to Rayleigh, Raman and Brillouin scattering; Raman Fiber Amplifiers by stimulated Raman scattering (1; 60)
- D. Marcuse, Light transmission optics, Van Nostrand Reinhold Company, 1972, New York, USA
- D. Marcuse, Theory of dielectric optical waveguides, Academic Press Company, 1974, New York, USA
- G. P. Agrawal, Fiber-optic communication systems, Wiley interscience, 2002, New York, USA
- B. E. A. Saleh and M. C. Teich, Fundamentals of Photonics, Wiley, 2007, New York, USA
The teacher has written the lecture notes for this course. They are available for all students.
Ricevimento: Monday, from 5 to 6 p. m., third floor, Via Opera Pia 11a, or by appointment.
MIRCO RAFFETTO (President)
GIAN LUIGI GRAGNANI
All teaching activities are presented by the teacher.
L'orario di tutti gli insegnamenti è consultabile su EasyAcademy.
The final exam is oral. All students will be asked three questions, of which at least one theoretical and one presented as an exercise.
At the end of the course the student should show to have understood the basic principle of guided wave propagation and the basic ideas explaining the way the most important optical and photonic components operate.