Structure and working of the optical fiber, optical fiber communication process, types of optical fibers. The diameter of core is about 10micrometers in case of single mode fiber and 50 to 200 micrometers in multi mode fiber. Almost all fibers currently used in optical communication systems are made of. Step index and graded index fiber free download as powerpoint presentation. The core in a step index fiber has a uniform refractive index throughout. This page contains optical fiber communication seminar and ppt with pdf report. The step index cable cross section is depicted in the figure2. A depressedclad fiber has the advantage of very low macrobending losses. Pdf file ac0128710200micronsimplex step index hcs fiber optic cableweb. The numerical aperture na is a dimensionless quantity used by fiber manufacturers to specify the acceptance angle of an optical fiber and is defined as.
The problem with step index fibres is multipath dispersion. The image to the right is a photograph of a step index fiber, shown next to the tip of a sewing needle. Therefore the socalled eigenmodes or normal modes are determined. The core is a cylindrical structure, and the cladding is a cylinder without a core. The simplest form of an optical waveguide consists of a lightconducting. Fiberguide industries manufactures over 500 different specialty optical fiber part numbers to meet the needs of our customers. Effect of helix pitch angle on the modal dispersion. My efforts and wholehearted cocorporation of each and everyone has ended on a successful note. Three basic types of fiber optic cable are used in communication systems. Basics of fiber optics mark curranbrian shirk fiber optics, which is the science of light transmission through very fine glass or plastic fibers, continues to be used in more and more applications due to its inherent advantages over copper conductors. For an optical fiber, a step index profile is a refractive index profile characterized by a uniform refractive index within the core and a sharp decrease in refractive index at the corecladding interface so that the cladding is of a lower refractive index. Fiber geometry an optical fiber is illustrated in fig.
Jul 16, 2016 step index multimode fiber was the first fiber design but is too slow for most uses, due to the dispersion caused by the different path lengths of the various modes. We specialize in optical fiber used for photonics applications, power delivery and sensing, and we also offer data communications fiber. Silvio abrate, roberto gaudino and guido perrone june th 20. Pdf the pluta polarizing interference microscope is used to measure the refractive index profile and material dispersion of step index optical.
Step index pmma fibers and their applications, current developments in optical fiber technology, sulaiman wadi harun and hamzah arof, intechopen, doi. This indicates that in step index, core and cladding have their own constant index of refractions n1 and n2 respectively. Types of optical fiber learning outcome epg pathshala. This results in the modes traveling down the fiber in a very jagged path see animation to the right. Fibers are typically made of silica with indexmodifying dopants such as geo2. In a step index fiber, the index of refraction changes abruptly from the core to the cladding. For simpler cases, the rp fiber calculator software is sufficient. Difference between step index fiber and graded index fiber. Optical fiber communication seminar and ppt with pdf report.
It is possible for light to take a number of different paths. I have made this report file on the topic optical fiber communication. In comparison to allsilica fiber, where the cladding is also made of silica giving a closer index of refraction match and thus a graded index profile. The ultimate diagnostic tool for optical fiber production. Stepindex fibers have a uniform core with one index of refraction, and a uniform cladding with a smaller index of refraction. Optical fiber communication seminar ppt with pdf report. How do i determine which type of dispersion is important for step index optical fiber if the group index of he11 group index core material. Apr 30, 2015 optical fiber communication seminar and ppt with pdf report. Pdf fiber optic systems are important telecommunication infrastructure for worldwide broadband networks. Optical communication pdf notes oc pdf notes smartzworld. Photon kinetics refractive index profiler for optical. Stepindex pmma fibers and their applications intechopen.
Optical fiber carries much more information than conventional copper wire and is in general not subject to electromagnetic interference. Stepindex multimode fiber was the first fiber design but is too slow for most uses, due to the dispersion caused by the different path lengths of the various modes. These fibers are singlemode and have a dual cladding. Introduction physical fundamentals of optical fiber transmission light is used in optoelectronics and optical fiber telecommunication for data. Electrodynamic analysis for gradientindex cylindrical fiber 1. Aug 25, 2017 description of step index fibers and their 2 types multimode and single mode step index fibers. Which refractive index, the core or cladding, is lower. V22, and a step index fiber becomes singlemode for a given wavelength. Step index optical fiber multi mode and single mode step. Photonics communications engineering, opti 500b, lectures 17 and 18. Multiple choice questions and answers on optical fiber. While in the beginning i have tried to give a general view about this topic. Figure 310 corresponds to singlemode propagation with a refractive index profile that is called dual step index.
Step index means sharp step in the index of refraction between core and cladding interface. On the basis of refractive index profile, we can classify optical fibers into two types step index. Singlemode step index fiber has a central core that is sufficiently small so that there is essentially one path that light takes as it propagates down the cable multimode step index fiber similar to the singlestepsinglemode configuration except that the core is much larger. Depressedclad fiber is also known as doubly clad fiber. This type of optical fibre is called a stepindex fibre because the refractive index increases in a step from the air on the outside, to the much higher value of the cladding, to the even higher value of the core. The birth of optical fiber communication coincided with the. Figure 1b shows another type of optical fiber, graded index fiber, in which the. When plotted on a graph as a function of distance from the center of the fiber, the index of refraction resembles a stepfunction. The general characteristic equation, which is valid for any mode order. Optical fiber optical fiber or fiber optic refers to the medium and the technology associated with the transmission of information as light pulses along a glass or plastic strand or fiber.
Jan 09, 2020 multiple choice questions and answers on optical fiber communicationpart1 multiple choice questions and answers by sasmita january 9, 2020 1 in an optical fiber communication system, which among the following is not a typical transmitter function. It is especially advantageous for longdistance communications, because infrared light propagates through the fiber with much lower attenuation compared to electrical cables. In step index fibers with a large core multimode, the na can be calculated directly using this equation. Guide modes of step index and other fibers can be calculated and optimized with the rp fiber power software. Rp photonics encyclopedia stepindex fibers, optical fiber.
The refraction index of multimode step index fiber is uniformly throughout the core. The s14 refractive index profiler provides accurate, precise characterization of the refractive index profile of singlemode, multimode, and specialty fibers using the rnf refracted near field technique. Optical fiber is used as a medium for telecommunication and computer networking because it is flexible and can be bundled as cables. The first transatlantic telephone cable with optical fibre in 1988. Propagation modes fiberoptic technologies cisco press. Core and cladding have different refractive indices, with. Structure and working of the optical fiber, optical fiber communication process, types of. The step index profile corresponds to a powerlaw index profile with the profile. Shorthaul, limited bandwidth, lowcost applications typically use multimode step index fibers. Measurement of the numerical aperture na of multimode fibers and of the beam pro file of a singlemode fiber. The refractive index of the core is uniform throughout and undergoes on abrupt change at the core cladding boundary. In comparison to allsilica fiber, where the cladding is also made of silica giving a.
For an optical fiber, a stepindex profile is a refractive index profile characterized by a uniform refractive index within the core and a sharp decrease in refractive index at the corecladding interface so that the cladding is of a lower refractive index. I have tried my best to elucidate all the relevant detail to the topic to be included in the report. The purpose of this article is to provide the nontechnical reader with an overview of. Taking advantage of the durability and toughness of hcs optical fibers, these tightbuffer cables surround the fiber with highstrength aramid yarn and. Bandwidth of multimode stepindex optical fibre in dependence on. Optical fibers 3 lab periods objective stripping and cleaving of optical fibers for integration into optical devices. Some other variants exist but are not commonly used, so we will not ad. Step index fiber in step index fibers the refractive index of the core medium is uniform and undergoes an abrupt change at the interface of core and cladding as shown in figure. Description of step index fibers and their 2 types multimode and single mode step index fibers. Bandwidth of step index multimode optical fiber depends strongly on its length and numerical aperture.
Multimode step index fiber selection depends on system application and design. There is a sharp decrease in refractive index at the corecladding boundary where the cladding refractive index is lower than that of the core. An optical fiber is a thin, flexible, crystal clear fiber that acts as a waveguide, or light pipe, to convey light between the two ends of the fiber. The structure and physics of an optical fiber the optical. Jul 14, 2017 optical fiber in communication lecture on optical fiber includes. To help reduce modal dispersion, fiber manufacturers created gradedindex fiber. Three main types of fibers are multimode step index fiber, multimode grades index fiberand single mode fiber.
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