|SCIENTIFIC DISCIPLINARY SECTOR||ING-INF/02|
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 expertise on the most important optical, optoelectronic 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.
The course provides the students with the fundamental notions related to the propagation of electromagnetic fields in dielectric waveguides of practical interest. The topics of attenuation and dispersion of the waves are addressed in some details. The second and last part of the course deals with the most important optical or optoelectronic components, like "power splitters", "power combiners", "mux" and "demux" for WDM, electro-optical modulators, LED diodes, LASERs, optical amplifiers and photodetectors. The main topics of the course are presented with the help of numerical simulators. The goal is to provide the essential tools to understand the principles of operation and to evaluate the perfomances of the most important optical, optoelectronic, photonic components or systems.
At the end of the course, the students will be able to:
1. explain the most important aspects of propagation in dielectric waveguides
2. explain the fundamental concepts underlying the operation of optical or photonic components
3. solve simple problems in dielectric waveguides
4. solve simple problems concerning the operation of optical or photonic components
5. analyze the solutions of problems or the results obtained by means of numerical simulators
6. evaluate the performance of dielectric waveguides and optical or photonic components
7. improve the performance of dielectric waveguides and optical or photonic components.
Lectures and exercises are presented in the classroom by the teacher. All lab experiences are explained by the teacher but the students have to manage the simulations and understand and explain the results.
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)
The teacher has written the lecture notes for this course. They are available for all students.
Office hours: Monday, from 5 to 6 p. m., third floor, Via Opera Pia 11a, or by appointment.
All class schedules are posted on the EasyAcademy portal.
The exam is oral and consists of three questions, for a total duration of three quarters of a hour. One of the questions will be theoretical. The other two will be focused on the resolution of an exercise and on the analysis, discussion and evaluation of results of numerical simulations.
The theoretical question will allow to evaluate the ability to explain the most relevant aspects of guided electromagnetic propagation and the fundamental concepts that underlie the operation of the most important optical or optoelectronic components. The other two questions, formulated as problems to be solved or in terms of simulations to be managed or simulation results to be interpreted, will allow, on the one hand, to evaluate the ability to solve simple problems and, on the other hand, to estimate the ability to analyze, evaluate, interpret and summarize the results.