Learning outcomes of the course unit
Knowledge and understanding
At the end of the course the student will acquire the basic knowledge relating electromagnetic propagation at optical frequencies in dielectric guiding structures, such as guides and optical fibers. These knowledge is necessary in order to understand the operation principles of telecommunication systems. The student has to acquire the knowledge of operation principles of fundamental devices, such as lasers, optical amplifiers, optical couplers and gratings. New approaches and analysis tools will be provided as long as important novelty in the field of photonics and optoelectronics.Applying knowledge and understanding
-analysis and description of the architecture of an optical fiber telecommunication system;- evaluate the main characteristics and specifications of the main photonic devices;- find the solutions for the project of optical fibers and photonic devices for several applicationsMaking judgements
On passing the exam the student will develop the ability to critically evaluate the properties of several devices. The skill of analyzing data sheets of optical devices, also very complex ones, in order to predict their behavior and design their utilization.Communication skills
On passing the exam the student should acquire good language property, in particular as regards the technical terminology specific of the course.Learning skills
Students who take the course will be able to deepen their knowledge in the field of photonic devices by consulting on their own specialized texts or dissemination journals, even outside of the topics covered closely in class.
Course contents summary
The course gives the knowledge necessary to study the electromagnetic propagation at optical frequencies in guiding dielectric structures, as guides and optical fibers. The transmission properties of optical fiber are deeply coverd. The main devices such as lasers, optical amplifiers, and optical couplers will be deeply analyzed. New approaches and analysis tools will be provided as long as important novelty in the field of photonics and optoelectronics.
Introduction. Simmetric slab.
Optical fiber. Numerical aperture. V-number. Fractional refractive index difference.
Step-index fiber. TE, TM, EH e HE guided modes.
Weakly guiding fiber. LP guided modes.
Power confinement factor and its dependence on V-number.
Gaussian approximation: spot size and mode field diameter.
Graded index fibers.
Fiber trasmissive properties: attenuation. Intrinsic and extrinsic attenuation causes. Rayleigh scattering. Ultra violet and infra-red absorption.
Macro and micro-bending losses. Data sheets of commercial fiber types.
Fiber trasmissive properties: intermodal and intramodal dispersion,chromatic dispersion. Dispersion Shifted Fibers (DSFs), Non-Zero Dispersion Shifted Fibers (NZDSFs).
Dispersion Compensating Fibers (DCFs). Example of a DCF design.
Plastic optical fibers: material, attenuation, core and cladding dimensions.
Optical amplification principles.
Population rate equations. Four, three and two levels systems.
Propagation rate equations. Absorption and gain coefficient.
Rare earth doped fiber amplifies. Design, schemes, forward and backward pumping, gain, noise figure. Evolution of signals, pumps and ASE powers a long the fiber. C, L, and S band optical amplification.
Silicate, tellurite and florurate fibers.
Semiconductor optical amplifiers. Light emitting diodes (LEDs) and Lasers. Designs and physical operation principles.
Single longitudinal mode lasers. DFB e DBR. Tunable lasers.
Receivers. Photodetectors. Photodiodes.
PIN, Avalanches photodiodes. Noise sources.
Passive Components. Couplers/splitters.
Wavelength Division Multiplexers and Demultiplexers (WDM MUXs/DEMUXs).
Isolators, Circulators and Attenuators.
Mach-Zehnder interferometer filters.
Splitters and star-couplers, multiplexer and demultiplexer.
S. Selleri, L. Vincetti, A. Cucinotta, Optical and Photonic Components, Società editrice Esculapio, 2015, ISBN: 978-88-7488-924-2
Classroom lectures with the aid of Power Point.Lab experiments.
Assessment methods and criteria
The summative learning assessment is carried out in three stage: a presentation prepared by the student on a topic strictly related to the course and decided in agreement with the professor. In the presentation, the student should demonstrate the understanding of the topic principles, the knowledge of the definition and units of measure of all the quantities that are introduced, and to be able to identify the possible applications.a written exam in order to verify the ability to calculate the main quantities of interest for an optical fiber or a photonic device2) a final oral exam in order to verify the capacity of correlate the basic knowledge in order to understand the properties and the characteristic of the different photonic devices considered in the lectures.
It's strongly advised to attend the course.