Practical uses of step-index plastic optical fibres often involve layouts with complex three-dime... more Practical uses of step-index plastic optical fibres often involve layouts with complex three-dimensional bends, especially in short-distance applications with small spaces available (automotive industry, robotics, etc.). Therefore, the simulation of optical links with arbitrary non-planar geometries becomes of great interest. This paper employs a new computer program capable of simulating light propagation in such configurations to draw some conclusions in situations of practical interest. 1 Introduction Many practical uses of step-index plastic optical fibres (SI POFs) involve layouts in which complex three-dimensional bends are needed (e.g. automotive industry, robotics, some LANs and sensors, etc.) [1]. Although quite precise computational simulations of light propagation in straight and circular POF sections have already been carried out [2,3], planar bends often have a variable curvature (e.g. in the form of a sine, or even shapes that cannot be expressed with an analytical exp...
This paper describes an efficient implementation of numerical algorithms that allows the ray-trac... more This paper describes an efficient implementation of numerical algorithms that allows the ray-tracing method to simulate light propagation in step-index plastic optical fibres (POFs) of arbitrary three-dimensional fibre-axis and cross-section geometries. The flexibility provided by this new technique can be very useful for calculating the transmission properties of bent POFs in many complex configurations common in the automotive industry, LANs, sensors, etc. Implementation details of the algorithms are given, followed by a few results to show the agreement with experimental measurements.
Proceedings of SPIE - The International Society for Optical Engineering
In this work we perform a detailed experimental and theoretical analysis of the properties of amp... more In this work we perform a detailed experimental and theoretical analysis of the properties of amplified spontaneous emission (ASE) in a rhodamine-6G-doped graded-index polymer optical fiber when the fiber is pumped either longitudinally or transversally with respect to the fiber axis. The dependence of the ASE threshold and efficiency on fiber length has been compared for both schemes of excitation. A theoretical model for longitudinal excitation has been carried out by means of the laser rate equations as functions of time, distance traveled by light and wavelength. The analysis takes into account that the fiber is a typical graded-index POF in which the radial distributions of light power density and dye concentration are not uniform. The theoretical calculations agree satisfactorily with the experimental results. The photodegradation of the ASE intensity has also been measured for both pumping schemes.
Proceedings of SPIE - The International Society for Optical Engineering
The aim of this work is to analyze the propagation of the emitted light in fluorescent POFs by us... more The aim of this work is to analyze the propagation of the emitted light in fluorescent POFs by using the side-illumination technique. In particular, we have studied the angular distribution of the emitted light as a function of the launching angle and of the height of the incident beam. A theoretical model has been developed in order to explain the experimental measurements. A good agreement between the theoretical and the experimental results has been obtained both qualitatively and quantitatively. It is shown that both the theoretical and the experimental critical angles are appreciably higher than the meridional one corresponding to the maximum acceptance angle for a single source placed at the fiber axis. This increase changes the value of several important parameters in the performance of active fibers. The analysis has been performed in polymer optical fibers doped with a conjugated polymer.
In this work we analyze experimentally and theoretically the properties of amplified spontaneous ... more In this work we analyze experimentally and theoretically the properties of amplified spontaneous emission (ASE) in a rhodamine-6G-doped graded-index polymer optical fiber. A theoretical model based on the laser rate equations describes the ASE features successfully. The dependence of the ASE threshold and efficiency on fiber length is analyzed in detail.
In this work we have analyzed theoretically and experimentally the critical angle for the emissio... more In this work we have analyzed theoretically and experimentally the critical angle for the emission generated in doped polymer optical fibers as a function of different launching conditions by using the side-illumination fluorescence technique. A theoretical model has been developed in order to explain the experimental measurements. It is shown that both the theoretical and experimental critical angles are appreciably higher than the meridional critical angle corresponding to the maximum acceptance angle for a single source placed at the fiber axis. This increase changes the value of several important parameters in the performance of active fibers. The analysis has been performed in polymer optical fibers doped with a conjugated polymer.
ABSTRACT Polymer optical fibers doped with organic dyes can be used as efficient optical amplifie... more ABSTRACT Polymer optical fibers doped with organic dyes can be used as efficient optical amplifiers and lasers in the visible region. We computationally study the spectral evolution with distance of the pulses propagating along such fibers. The main goal is to analyze the lasing threshold and the slope efficiency as functions of the fraction of spontaneous emission that contributes to laser emission. The discussion focuses on rhodamine-6G doped fibers.
ABSTRACT In this paper, the two-photon-excited emission spectra of polymer optical fibers doped w... more ABSTRACT In this paper, the two-photon-excited emission spectra of polymer optical fibers doped with the conjugated polymer Poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) have been measured pumping the fibers transversely to their symmetry axis. Measurements include evolutions of the emission spectra with excitation wavelength and with propagation distance, together with an analysis of emission photostability. Comparisons with results for one-photon-excited emission are also presented and discussed.
ABSTRACT Mirrorless graded-index polymer optical fibers doped with the organic dye rhodamine 6G r... more ABSTRACT Mirrorless graded-index polymer optical fibers doped with the organic dye rhodamine 6G result in very compact broadband fiber lasers in the visible region when pumped from the side. The emission spectrum, threshold, and efficiency obtained on both fiber ends depend on the lengths of the directly illuminated region and of the non-excited ones. The paper analyzes such parameters both experimentally and theoretically for the first time.
Abstract This paper reviews the theoretical analysis of light propagation we have carried out on ... more Abstract This paper reviews the theoretical analysis of light propagation we have carried out on multimode multi-step index (MSI) optical fibres. Starting from the Eikonal equation, we derive the analytical expressions that allow calculating the ray trajectories inside these ...
ABSTRACT The characterization of the spectral emission and of the photostability of polymer optic... more ABSTRACT The characterization of the spectral emission and of the photostability of polymer optical fibers (POFs) doped with conjugated polymers has been carried out taking into account the distribution of the dopant in the fiber core. Four different conjugated polymers embedded in the matrix of the typical POF material have been analyzed. Measurements include, among others, evolutions of the emission with excitation wavelength and time, spectral changes for different excitation irradiances, and the influence of the propagation distance along the fiber.
Three new general properties of conic sections are established, namely: (1) By offsetting from a
... more Three new general properties of conic sections are established, namely: (1) By offsetting from a given conic (ellipse, parabola or hyperbola) perpendicularly to it by a distance proportional to the cube root of its radius of curvature, another conic of the same kind is generated; (2) The cube root (or proportional to it) is the only function for with such a property can be stated; (3) The cube root of the radius of curvature at any point is proportional to its distance to any one of the principal axes of the conic, taken perpendicularly to it. Starting from any particular conic, and taking the proportionality constant k as a parameter, a family of conics of its kind is generated. Piling these conics up in the 3D space, different surfaces can be defined. If one of the Cartesian coordinates is made to be proportional to k, these surfaces are ruled, which greatly facilitates their constructive applications. We derive the parametric equations of these surfaces and represent them graphically, choosing viewpoints for a good visualization. Some ideas of applications are proposed for further development. Ó 1999 Elsevier Science B.V. All rights reserved.
Practical uses of step-index plastic optical fibres often involve layouts with complex three-dime... more Practical uses of step-index plastic optical fibres often involve layouts with complex three-dimensional bends, especially in short-distance applications with small spaces available (automotive industry, robotics, etc.). Therefore, the simulation of optical links with arbitrary non-planar geometries becomes of great interest. This paper employs a new computer program capable of simulating light propagation in such configurations to draw some conclusions in situations of practical interest. 1 Introduction Many practical uses of step-index plastic optical fibres (SI POFs) involve layouts in which complex three-dimensional bends are needed (e.g. automotive industry, robotics, some LANs and sensors, etc.) [1]. Although quite precise computational simulations of light propagation in straight and circular POF sections have already been carried out [2,3], planar bends often have a variable curvature (e.g. in the form of a sine, or even shapes that cannot be expressed with an analytical exp...
This paper describes an efficient implementation of numerical algorithms that allows the ray-trac... more This paper describes an efficient implementation of numerical algorithms that allows the ray-tracing method to simulate light propagation in step-index plastic optical fibres (POFs) of arbitrary three-dimensional fibre-axis and cross-section geometries. The flexibility provided by this new technique can be very useful for calculating the transmission properties of bent POFs in many complex configurations common in the automotive industry, LANs, sensors, etc. Implementation details of the algorithms are given, followed by a few results to show the agreement with experimental measurements.
Proceedings of SPIE - The International Society for Optical Engineering
In this work we perform a detailed experimental and theoretical analysis of the properties of amp... more In this work we perform a detailed experimental and theoretical analysis of the properties of amplified spontaneous emission (ASE) in a rhodamine-6G-doped graded-index polymer optical fiber when the fiber is pumped either longitudinally or transversally with respect to the fiber axis. The dependence of the ASE threshold and efficiency on fiber length has been compared for both schemes of excitation. A theoretical model for longitudinal excitation has been carried out by means of the laser rate equations as functions of time, distance traveled by light and wavelength. The analysis takes into account that the fiber is a typical graded-index POF in which the radial distributions of light power density and dye concentration are not uniform. The theoretical calculations agree satisfactorily with the experimental results. The photodegradation of the ASE intensity has also been measured for both pumping schemes.
Proceedings of SPIE - The International Society for Optical Engineering
The aim of this work is to analyze the propagation of the emitted light in fluorescent POFs by us... more The aim of this work is to analyze the propagation of the emitted light in fluorescent POFs by using the side-illumination technique. In particular, we have studied the angular distribution of the emitted light as a function of the launching angle and of the height of the incident beam. A theoretical model has been developed in order to explain the experimental measurements. A good agreement between the theoretical and the experimental results has been obtained both qualitatively and quantitatively. It is shown that both the theoretical and the experimental critical angles are appreciably higher than the meridional one corresponding to the maximum acceptance angle for a single source placed at the fiber axis. This increase changes the value of several important parameters in the performance of active fibers. The analysis has been performed in polymer optical fibers doped with a conjugated polymer.
In this work we analyze experimentally and theoretically the properties of amplified spontaneous ... more In this work we analyze experimentally and theoretically the properties of amplified spontaneous emission (ASE) in a rhodamine-6G-doped graded-index polymer optical fiber. A theoretical model based on the laser rate equations describes the ASE features successfully. The dependence of the ASE threshold and efficiency on fiber length is analyzed in detail.
In this work we have analyzed theoretically and experimentally the critical angle for the emissio... more In this work we have analyzed theoretically and experimentally the critical angle for the emission generated in doped polymer optical fibers as a function of different launching conditions by using the side-illumination fluorescence technique. A theoretical model has been developed in order to explain the experimental measurements. It is shown that both the theoretical and experimental critical angles are appreciably higher than the meridional critical angle corresponding to the maximum acceptance angle for a single source placed at the fiber axis. This increase changes the value of several important parameters in the performance of active fibers. The analysis has been performed in polymer optical fibers doped with a conjugated polymer.
ABSTRACT Polymer optical fibers doped with organic dyes can be used as efficient optical amplifie... more ABSTRACT Polymer optical fibers doped with organic dyes can be used as efficient optical amplifiers and lasers in the visible region. We computationally study the spectral evolution with distance of the pulses propagating along such fibers. The main goal is to analyze the lasing threshold and the slope efficiency as functions of the fraction of spontaneous emission that contributes to laser emission. The discussion focuses on rhodamine-6G doped fibers.
ABSTRACT In this paper, the two-photon-excited emission spectra of polymer optical fibers doped w... more ABSTRACT In this paper, the two-photon-excited emission spectra of polymer optical fibers doped with the conjugated polymer Poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) have been measured pumping the fibers transversely to their symmetry axis. Measurements include evolutions of the emission spectra with excitation wavelength and with propagation distance, together with an analysis of emission photostability. Comparisons with results for one-photon-excited emission are also presented and discussed.
ABSTRACT Mirrorless graded-index polymer optical fibers doped with the organic dye rhodamine 6G r... more ABSTRACT Mirrorless graded-index polymer optical fibers doped with the organic dye rhodamine 6G result in very compact broadband fiber lasers in the visible region when pumped from the side. The emission spectrum, threshold, and efficiency obtained on both fiber ends depend on the lengths of the directly illuminated region and of the non-excited ones. The paper analyzes such parameters both experimentally and theoretically for the first time.
Abstract This paper reviews the theoretical analysis of light propagation we have carried out on ... more Abstract This paper reviews the theoretical analysis of light propagation we have carried out on multimode multi-step index (MSI) optical fibres. Starting from the Eikonal equation, we derive the analytical expressions that allow calculating the ray trajectories inside these ...
ABSTRACT The characterization of the spectral emission and of the photostability of polymer optic... more ABSTRACT The characterization of the spectral emission and of the photostability of polymer optical fibers (POFs) doped with conjugated polymers has been carried out taking into account the distribution of the dopant in the fiber core. Four different conjugated polymers embedded in the matrix of the typical POF material have been analyzed. Measurements include, among others, evolutions of the emission with excitation wavelength and time, spectral changes for different excitation irradiances, and the influence of the propagation distance along the fiber.
Three new general properties of conic sections are established, namely: (1) By offsetting from a
... more Three new general properties of conic sections are established, namely: (1) By offsetting from a given conic (ellipse, parabola or hyperbola) perpendicularly to it by a distance proportional to the cube root of its radius of curvature, another conic of the same kind is generated; (2) The cube root (or proportional to it) is the only function for with such a property can be stated; (3) The cube root of the radius of curvature at any point is proportional to its distance to any one of the principal axes of the conic, taken perpendicularly to it. Starting from any particular conic, and taking the proportionality constant k as a parameter, a family of conics of its kind is generated. Piling these conics up in the 3D space, different surfaces can be defined. If one of the Cartesian coordinates is made to be proportional to k, these surfaces are ruled, which greatly facilitates their constructive applications. We derive the parametric equations of these surfaces and represent them graphically, choosing viewpoints for a good visualization. Some ideas of applications are proposed for further development. Ó 1999 Elsevier Science B.V. All rights reserved.
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given conic (ellipse, parabola or hyperbola) perpendicularly to it by a distance proportional to the
cube root of its radius of curvature, another conic of the same kind is generated; (2) The cube root
(or proportional to it) is the only function for with such a property can be stated; (3) The cube root
of the radius of curvature at any point is proportional to its distance to any one of the principal axes
of the conic, taken perpendicularly to it.
Starting from any particular conic, and taking the proportionality constant k as a parameter, a
family of conics of its kind is generated. Piling these conics up in the 3D space, different surfaces
can be defined. If one of the Cartesian coordinates is made to be proportional to k, these surfaces are
ruled, which greatly facilitates their constructive applications. We derive the parametric equations of
these surfaces and represent them graphically, choosing viewpoints for a good visualization. Some
ideas of applications are proposed for further development. Ó 1999 Elsevier Science B.V. All rights
reserved.
given conic (ellipse, parabola or hyperbola) perpendicularly to it by a distance proportional to the
cube root of its radius of curvature, another conic of the same kind is generated; (2) The cube root
(or proportional to it) is the only function for with such a property can be stated; (3) The cube root
of the radius of curvature at any point is proportional to its distance to any one of the principal axes
of the conic, taken perpendicularly to it.
Starting from any particular conic, and taking the proportionality constant k as a parameter, a
family of conics of its kind is generated. Piling these conics up in the 3D space, different surfaces
can be defined. If one of the Cartesian coordinates is made to be proportional to k, these surfaces are
ruled, which greatly facilitates their constructive applications. We derive the parametric equations of
these surfaces and represent them graphically, choosing viewpoints for a good visualization. Some
ideas of applications are proposed for further development. Ó 1999 Elsevier Science B.V. All rights
reserved.