The numerical aperture of an optical fiber

1992 ◽  
Author(s):  
David F. Nall ◽  
Gregory M. Alman
Keyword(s):  
Optical Fiber ◽  
Numerical Aperture

Fabrication of Lensed Plastic Optical Fiber Array Using Electrostatic Force

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Yih-Tun Tseng ◽  
Jhong-Bin Huang ◽  
Che-Hsin Lin ◽  
Chin-Lung Chen ◽  
Wood-Hi Cheng
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Electrostatic Force ◽  
Coupling Efficiency ◽  
Numerical Aperture ◽  
Uv Curing ◽  
Power Budget ◽  
Fiber Array ◽  
Plastic Optical Fibers ◽  
Efficient Coupling

The GI (graded-index) POFs (Plastic optical fibers), which has been proven to reach distances as long as 1 km at 1.25 Gb/s has a relatively low numerical aperture . Therefore, the efficient coupling of GI POFs to the light source has become critical to the power budget in the system. Efficient coupling for a POFs system normally involves either a separate lens or the direct formation of the lens at the end of the fiber. Forming the lens-like structure directly on the fiber end is preferred for simplicity of fabrication and packaging, such as polishing and fusion, combine different fibers with the cascaded fiber method and hydroflouride (HF) chemical etching. These approaches are well established, but applicable only to glass. Optical assembly architecture for multichannel fibers and optical devices is critical to optical fiber interconnections. Multichannel fiber-pigtail laser diode (LD) modules have potential for supporting higher data throughput and longer transmission distances. However, to be of practical use, these modules must be more precise. This work proposes and manufactures lensed plastic optical fibers (LPOF) array. This novel manipulation can be utilized to fabricate an aspherical lens on a fiber array after the UV curing of the photo-sensitive polymer; the coupling efficiency (CE) is increased and exceeds 47% between the LD array and the fiber array.

scholarly journals Study of Optical Fiber Design Parameters in Fiber Optics Communications

2017 ◽  
Vol 2 (3) ◽  
pp. 302-308 ◽  
Author(s):  
Salim Qadir Mohammed ◽  
Asaad M. Asaad M. Al-Hindawi
Keyword(s):  
Optical Fiber ◽  
Fiber Optics ◽  
Numerical Aperture ◽  
Design Parameters ◽  
Light Sources ◽  
Long Distance ◽  
Graded Index ◽  
Large Bandwidth ◽  
Telecommunication Infrastructure ◽  
Distance Communication

Fiber optics is an important part in the telecommunication infrastructure. Large bandwidth and low attenuation are features for the fiber optics to provide gigabit transmission. Nowadays, fiber optics are used widely in long distance communication and networking to provide the required information traffic for multimedia applications. In this paper, the optical fiber structure and the operation mechanism for multimode and single modes are analyzed. The design parameters such as core radius, numerical aperture, attenuation, dispersion and information capacity for step index and graded index fibers are studied, calculated and compared for different light sources.

scholarly journals Insights and Aspects to the Modeling of the Molten Core Method for Optical Fiber Fabrication

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2898 ◽  
Author(s):  
Cavillon ◽  
Dragic ◽  
Faugas ◽  
Hawkins ◽  
Ballato
Keyword(s):  
Optical Fiber ◽  
Numerical Aperture ◽  
Effective Area ◽  
Refractive Index Profile ◽  
Aluminosilicate Glass ◽  
Core Diameter ◽  
Fiber Core ◽  
Core Method ◽  
Core Composition ◽  
Underlying Mechanisms

The molten core method (MCM) is a versatile technique to fabricate a wide variety of optical fiber core compositions ranging from novel glasses to crystalline semiconductors. One common feature of the MCM is an interaction between the molten core and softened glass cladding during the draw process, which often leads to compositional modification between the original preform and the drawn fiber. This causes the final fiber core diameter, core composition, and associated refractive index profile to vary over time and longitudinally along the fiber. Though not always detrimental to performance, these variations must, nonetheless, be anticipated and controlled as they directly impact fiber properties (e.g., numerical aperture, effective area). As an exemplar to better understand the underlying mechanisms, a silica-cladding, YAG-derived yttrium aluminosilicate glass optical fiber was fabricated and its properties (core diameter, silica concentration profile) were monitored as a function of draw time/length. It was found that diffusion-controlled dissolution of silica into the molten core agreed well with the observations. Following this, a set of first order kinetics equations and diffusion equation using Fick’s second law was employed as an initial effort to model the evolution of fiber core diameter and compositional profile with time. From these trends, further insights into other compositional systems and control schemes are provided.

Application of Optical Fiber Made of Various Materials with Composite Properties of Materials in Laser Medical Treatment

2012 ◽  
Vol 600 ◽  
pp. 222-225
Author(s):  
Zhen Zhang ◽  
Fang Liu
Keyword(s):  
Optical Fiber ◽  
Medical Treatment ◽  
Plastic Material ◽  
Numerical Aperture ◽  
Fiber Material ◽  
Spot Size ◽  
Light Transmittance ◽  
Core Diameter ◽  
Transmission Distance ◽  
Fiber Manufacturing

Though introducing the optical fiber in a laser medical treatment made ​​of different materials, contrast expounded integrated characteristic of the different materials in manufacturing an optical fiber material, summed four aspects need to be considered in the choice of the optical fiber manufacturing material. First, the laser parameters, such as maximum laser power, the wavelength, the transmission distance, the laser beam spot size and numerical aperture of the laser light source. Second, according to the optical fiber light transmittance curve, to identify the optimum transmittance of the application wavelength. Third, determining transmission optical slender core diameter, typically a core diameter is greater than the laser spot size of 2/3; decision sets of plastic material finally.

Slitless Optical-Fiber Laser-Raman Spectrometer Employing a Concave Holographic Grating

1977 ◽  
Vol 31 (4) ◽  
pp. 295-298 ◽  
Author(s):  
George E. Walrafen
Keyword(s):  
Optical Fiber ◽  
Fiber Laser ◽  
Numerical Aperture ◽  
Fused Silica ◽  
Holographic Grating ◽  
Photomultiplier Tube ◽  
Solid Core ◽  
Raman Spectrometer ◽  
Focal Line ◽  
Laser Raman

A slitless optical-fiber laser-Raman spectrometer has been developed that employs a single f/3 concave holographic diffraction grating. The exit end of an optical fiber is positioned at the grating focus, and the divergent excitation and Raman radiation are then dispersed and refocussed. Detection is accomplished by translating an exit slit and photomultiplier tube along the focal line. A moveable solid-core optical fiber that transmits light to a fixed photomultiplier tube may also be used. The holographic grating produces a straight focal line, instead of a curve, resulting in accurate focussing from 480 to 650 nm, with linear scanning. The low f-number grating was used to accommodate high numerical aperture optical fibers without loss of light. A comparison between the present spectrometer with a 55 m fused silica fiber and a Jarrell-Ash Czerny-Turner single monochromator using a 1-cm bulk sample indicates a signal/noise improvement by a factor of 137 for the very weak two-phonon band from fused silica near 1600 cm−1.

scholarly journals Исследование оптических свойств многомодового кварцевого оптического волокна с отражающей оболочкой из фторированного термопластичного полимера

2019 ◽  
Vol 127 (9) ◽  
pp. 477
Author(s):  
А.А. Маковецкий ◽  
А.А. Замятин ◽  
Д.В. Ряховский
Keyword(s):  
Optical Properties ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Scattered Radiation ◽  
Fiber Length ◽  
Numerical Aperture ◽  
Optical Losses ◽  
Laser Medicine ◽  
Propagation Of Light ◽  
Absorption Of Light

Optical properties silica - polymeric optical fiber with a core with a diameter of 430 microns and the reflecting cover 70 microns thick from thermoplastic copolymer of a tetraftoretilen with ethylene (Tefzel brand) are experimentally investigated. The polymeric cover is applied on silica fiber with applicator from polimer melt directly on drowing tower. Optical losses of the fiber, a numerical aperture and its dependence on fiber length are measured. It is established that at propagation of light in fiber its noticeable scattering is observed. It is connected with crystallinity of polymeric cover. Distribution of intensity of scattered radiation along an axis of fiber and an indicatrix of dispersion of radiation by a coating are measured. Relative deposits of dispersion and absorption of light in a cover at the general optical losses of fiber are estimated. The possibility of use of optical fibers of this structure in laser medicine is considered.

Study of the optical parameters of a silica-polymeric optical fiber with a reflective coating made of a thermoplastic fluoropolymer

2020 ◽  
Vol 86 (7) ◽  
pp. 27-32
Author(s):  
A. A. Zamyatin ◽  
A. A. Makovetskii ◽  
I. P. Shilov ◽  
D. V. Lapshin
Keyword(s):  
Laser Radiation ◽  
Optical Fiber ◽  
Numerical Aperture ◽  
Optical Loss ◽  
Fiber Surface ◽  
Optical Parameters ◽  
Core Diameter ◽  
Protective Function ◽  
Reflective Coating ◽  
Rough Turning

Silica optical fibers (OF) having a core diameter of 400 – 800 μm made of biocompatible materials are widely used in laser medicine. The results of studying the optical parameters of novel silica-polymeric optical fiber with a reflective thermoplastic copolymer coating (tetrafluoroethylene – ethylene) and the influence of coating conditions on these optical parameters are presented. Coatings from polymer melt were applied to the silica fiber surface by orifice drawing. The numerical aperture of the drawn OF was measured by distribution of the laser radiation emerging from OF in the far field. The optical losses were determined by the distribution of the radiation scattered by the reflective coating along the OF length. The scattering parameters of the laser radiation transmitted through OF were estimated by the intensity and indicatrix of scattering. We studied OF samples up to 50 m in length with a silica core of about 400 μm in diameter and reflective coating with a thickness of 70 – 90 μm, the reflective coating also performed a protective function. The quality of applied coating and optical parameters of the OF samples depended on the speed of fiber drawing (coating speed) Vd. A smooth coating was obtained at Vd ≤ 2 m/min. When Vd > 2 m/min the coating became rough, turning into the so-called «shark skin» at Vd = 6 m/min. Observed scattering of radiation passing through the studied OF samples was attributed to the polymer structure which contained both crystalline and amorphous phases with different values of the refractive index. The smallest scattering was observed in a smooth-coated OF. The total optical loss at a wavelength λ = 532 nm amounted to 300 – 720 dB/km (a nominal numerical aperture was 0.44). Short (1.5 – 3 m) OF samples were shown to provide a transmission of 80 – 93% of the input power.

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