Learning outcomes of the course unit
The main objective of the course is to let the students understand the importance of conventional optical fibers as basic component for optic and photonic devices with great impact on the market at present, such as optical fiber sensors and lasers, and of photonic crystal fiber, which is still an exciting research subject all over the world, for next generation devices.
Moreover, the course has the aim to give the students a detailed knowledge of advanced numerical methods for the simulations of the properties of optical fibers and components, in order to make them develop the skill to analyze and design complex optic and photonic devices.
Course contents summary
The first part of the course will be devoted to a thorough study of point and distributed optical fiber sensors, with particular attention to working principles, practical applications, products already available on the market or still subject of intense research worldwide.
Optical fiber lasers will be the subject of the lessons in the second part of the course. Most common configurations, main parameters to characterize the performances and most important present and future applications will be presented in detail.
During the last part of the course photonic crystal fibers will be illustrated, with a detailed description of their distinguishing characteristics with respect to conventional optical fibers, in particular of the different light guiding mechanisms, which make them particularly suitable for important applications.
Some lessons of the course, devoted to experimental and simulation activities, will take place in laboratory.
Present and future importance of optic and photonic technologies
Main characteristics of conventional optical fibers (guided modes, propagation constant, numerical aperture, single-mode and multi-mode regime, attenuation, etc.)
Point and distributed optical fiber sensors:
Main properties, working principles, advantages and disadvantages
Sensor classifications, according to sensing zone, light modulation mechanism and spatial sensing distribution
Sensors for bio-medical applications
Optical components and instruments used for optical fibers sensor and biosensor realization and characterization (laboratory activity)
Optical fiber lasers:
Configurations and pumping schemes (optical components, active and passive fibers)
Performance evaluation parameters (efficiency, beam quality) and parasitic effects (nonlinear effects, photodarkening, thermal effects)
Main applications, devoting particular attention to high-power fiber lasers
Photonic crystal fibers:
Main characteristics, fabrication techniques, most important applications
Light guiding mechanisms based on modified total internal reflection or photonic bandgap, with reference to photonic crystals
Examples of photonic crystal fibers suitable for applications in the sensing field and for high-power sources
Presentation of the main characteristics of the COMSOL Multiphysics software
Introduction to the Finite Element Method (FEM)
Simulation activity (in laboratory) to analyze the properties of special optical fibers and optical components necessary for design and realization of sensors and lasers (step-index fiber, photonic crystal fiber, optical fiber with bending loss, beam splitter, directional coupler, Fabry-Perot cavity, etc.).
S. Selleri, L. Vincetti, A. Cucinotta, “Componenti ottici e fotonici”, Esculapio, 2012
R. Paschotta, “Encyclopedia of laser physics and technology”, Wiley, 2008
E. Udd, “Fiber optic sensors : an introduction for engineers and scientists”, Wiley, 1991
F. Poli, A. Cucinotta, S. Selleri, “Photonic crystal fibers: properties and applications”, Springer, 2007
Scientific papers suggested during the course
Frontal lessons carried out in a lecture room, using blackboard and/or pc/projector to show multimedia presentations, videos/images, web pages, software applications (28 hours).
Experimental and simulation activity carried out in laboratory, using the commercial software COMSOL Multiphysics for the analysis of electromagnetic waves at optical frequency propagating in linear and nonlinear media (~14 hours).
Assessment methods and criteria
Individual report on an assigned project to be developed through numerical simulations made with COMSOL Multiphysics, evaluated according to accuracy, completeness and clarity.
Oral exam to verify student’s learning, analytical capacity and speaking ability on the topics explained during the course.
Project report and oral exam with the same importance on the final mark.