Lecture

Multiwavelength Effects: Coupled NLSE and Degenerate FWM

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In course

PHYS-607: Nonlinear fibre optics

Presentation of the different sources of optical nonlinearities in an optical fibre ...

Description

This lecture delves into the details of Four-Wave Mixing (FWM) using the coupled Nonlinear Schrödinger Equation (NLSE) and explores the case of non-depleted degenerate FWM. Starting with the simplifications of the coupled wave equations, the instructor explains the assumptions made for intense and un-depleted pump waves, identical transverse modes, and nonlinear coefficients. The lecture progresses to solving the coupled NLSE equations and discussing the implications of phase matching for maximizing the FWM process. Illustrations with degenerate cases and considerations for mismatch due to material dispersion are provided, along with an experimental illustration of FWM. The session concludes with a quiz on determining the pump power for phase matching in degenerate FWM.

Instructors (2)

Luc Thévenaz

Luc Thévenaz received in 1982 the M.Sc. degree in astrophysics from the Observatory of Geneva, Switzerland, and in 1988 the Ph.D. degree in physics from the University of Geneva, Switzerland. He developed at this moment his field of expertise, i.e. fibre optics. In 1988 he joined the Swiss Federal Institute of Technology of Lausanne (EPFL) where he currently leads a research group involved in photonics, namely fibre optics and optical sensing. Research topics include Brillouin-scattering fibre sensors, nonlinear fibre optics, slow & fast light and laser spectroscopy in gases. His main achievements are: - the invention of a novel configuration for distributed Brillouin fibre sensing based on a single laser source, resulting in a high intrinsic stability making for the first time field measurements possible, - the development of a photoacoustic gas trace sensor using a near infra-red semiconductor laser, detecting a gas concentration at the ppb level, - the first experimental demonstration of optically-controlled slow & fast light in optical fibres, realized at ambient temperature and operating at any wavelength since based on stimulated Brillouin scattering. The first negative group velocity of light was also realized in optical fibres using this approach. In 1991, he visited the PUC University in Rio de Janeiro, Brazil where he worked on the generation of picosecond pulses in semiconductor lasers. In 1991-1992 he stayed at Stanford University, USA, where he participated in the development of a Brillouin laser gyroscope. He joined in 1998 the company Orbisphere Laboratories SA in Neuchâtel, Switzerland, as Expert Scientist to develop gas trace sensors based on photoacoustic laser spectroscopy. In 1998 and 1999 he visited the Korea Advanced Institute of Science and Technology (KAIST) in Daejon, South Korea, where he worked on fibre laser current sensors. In 2000 he co-founded the spin-off company Omnisens that is developing and commercializing advanced photonic instrumentation. In 2007 he visited Tel Aviv University where he studied the all-optical control of polarization in optical fibres. During winter 2010 he stayed at the University of Sydney where he studied applications of stimulated Brillouin scattering in chalcogenide waveguides. In 2014 he stayed at the Polytechnic University of Valencia where he worked on microwave applications of stimulated Brillouin scattering. He was member of the Consortium in the FP7 European Project GOSPEL "Governing the speed of light", was Chairman of the European COST Action 299 "FIDES: Optical Fibres for New Challenges Facing the Information Society" and is author or co-author of some 480 publications and 12 patents. He is now Coordinator of the H2020 Marie Skłodowska-Curie Innovative Training Networks FINESSE (FIbre NErve Systems for Sensing). He is co-Executive Editor-in-Chief of the journal "Nature Light: Science & Applications" and is Member of the Editorial Board (Associate Editor) for the journal "APL Photonics" & "Laser & Photonics Reviews". He is also Fellow of both the IEEE and the Optical Society (OSA).

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Related concepts (23)

Schrödinger equation

The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. Its discovery was a significant landmark in the development of quantum mechanics. The equation is named after Erwin Schrödinger, who postulated the equation in 1925 and published it in 1926, forming the basis for the work that resulted in his Nobel Prize in Physics in 1933. Conceptually, the Schrödinger equation is the quantum counterpart of Newton's second law in classical mechanics.

Double-clad fiber

Double-clad fiber (DCF) is a class of optical fiber with a structure consisting of three layers of optical material instead of the usual two. The inner-most layer is called the core. It is surrounded by the inner cladding, which is surrounded by the outer cladding. The three layers are made of materials with different refractive indices. There are two different kinds of double-clad fibers. The first was developed early in optical fiber history with the purpose of engineering the dispersion of optical fibers.

Relativistic wave equations

In physics, specifically relativistic quantum mechanics (RQM) and its applications to particle physics, relativistic wave equations predict the behavior of particles at high energies and velocities comparable to the speed of light. In the context of quantum field theory (QFT), the equations determine the dynamics of quantum fields. The solutions to the equations, universally denoted as ψ or Ψ (Greek psi), are referred to as "wave functions" in the context of RQM, and "fields" in the context of QFT.

Transverse mode

A transverse mode of electromagnetic radiation is a particular electromagnetic field pattern of the radiation in the plane perpendicular (i.e., transverse) to the radiation's propagation direction. Transverse modes occur in radio waves and microwaves confined to a waveguide, and also in light waves in an optical fiber and in a laser's optical resonator. Transverse modes occur because of boundary conditions imposed on the wave by the waveguide.

Optical fiber

An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber and find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables.

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