The method yields detailed information about the spatial and angular properties of the propagating. Graded index fiber is of only of one type that is multi mode fiber. The bandwidth of the fiber lies in between 200 mhz km to 600 mhz km even though theoretically it has an infinite. The profile shows a sharp step at the junction of the core and cladding. If this were a multimode stepindex fiber with the same n1 and n2, then the full dispersion total spread would roughly be 6. Step index graded index the step index fiber has a core with uniform index throughout. It is important to note that, step index fiber is found in two types, that is mono mode fiber and multi mode fiber. For those interested in the evolution of optical communica. Attenuation is very less in graded index fibers numerical aperture is less in graded index fibers. Explain the terms refractive index profile, relative refractive index difference, and profile parameter. It is found out that optimization method for precise tuning of the zerodispersion wavelength as well as the small dispersion slope requires larger value for the index of refraction difference.
Difference between step index fiber and graded index fiber brainkart. Genetic approach based design of dispersionfree optical fiber. The fiber properties are exhibited in order to check if perfluorinated graded index plastic optical fiber pfgipof is suitable to support a multiplexing transmission. The most common refractive index profile for a gradedindex. The refractive index of the core is uniform throughout and undergoes on abrupt change at the core cladding boundary. Characteristics comparison of the zdsfs based on the. Step index optical fiber multi mode and single mode step index fibers hd duration. I think its confusing due to historical nomenclature.
Stepindex fiber is a fiber with a uniform refractive index in its core that is a step below the refractive index of the cladding. Gradedindex fibers simulations on gradedindex fibers. Refer single mode fiber vs multimode fiber which mentions difference between both modes of fiber. Step index fiber and graded index fiber, step graded index. For a short fiber, the gradedindex fiber has a larger splicing tolerance to misalignment than the stepindex fiber. Types of optical fiber learning outcome epg pathshala. 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. Fibers that carry more than one mode are called multimode fibers.
The index is highest at the center and gradually decreases until it matches with that of the cladding. Our highpower multimode fiber patch cables use connectors with this design feature. Optical fiber forms a dielectric wave guide and free from electromagnetic. The refractive index of core is nonuniform, the refractive index of core decreases parabolically from the axis of the fibre to its surface. Gradedindex fiber article about gradedindex fiber by. Another type of fibre, known as singlemode sm fibre, eliminates multimode dispersion by reducing the diameter of the core. Air serves as the cladding in the simple glass tube example. Rp photonics encyclopedia gradedindex fibers, parabolic. Dictionary, thesaurus, medical, financial, wikipedia. The software rp fiber power can be used for calculations and simulations on gradedindex fibers, e.
Signal distortion is more in case of highangle rays in. Identify the two basic types of single mode stepindex fibers. Thorlabs gradedindex grin multimode fiber provides lower modal dispersion and less bend loss than traditional multimode stepindex fiber, with a broad operating wavelength range from 800 1600 nm see the graphs tab for attenuation plots over this range. Suitable for light wave communication links and local area networks carrying voice, video and data. Stepindex optical fiber in stepindex optical fiber, the diameter of the core is high therefore more number of modes of propagation of light can. In graded index fibers, the refractive index of the core medium is varying in the parabolic manner such that the maximum refractive index is present at the center of the core. Differentiate between step index and graded index optical.
Multimode fiber and multimode fiber optic cable tutorial. Gradedindex grin multimode fiber optic patch cables. When plotted on a graph as a function of distance from the center of the fiber, the index of refraction resembles a stepfunction. According to the high bandwidth length of plastic fibers, both. Graded index multimode fiber makes use of variations in the composition of the glass in the core to compensate for the. The refractive index of the core is uniform and step or abrupt change in refractive index takes place at the interface of core and cladding in step index fibres. Gradedindex multimode optical fibers, optimized for signal transmission at 850 and 0 nm, are available with 50125, 62. If we look at the profile drawn from the measured data of a step index fiber, it looks like a step up and step down on a staircase as shown below.
Difference between step index fiber and graded index fiber. Schematic of the wave number in radial direction kr and the turning radius r1 and r2 thus, the. Gradedindex multimode fiber article about gradedindex. An accurate numerical method is described for solving the helmholtz equation for a general class of optical fibers. I think this is confusing because early multimode communication fibers were step index.
A stepindex fiber is a cylindrical dielectric waveguide specified by its core and cladding. Multimode optical fiber can be built with either graded index or step index. Other articles where gradedindex fiber is discussed. On the basis of this, the fiber is divided into two types. Stepindex fibers have a uniform core with one index of refraction, and a uniform cladding with a smaller index of refraction. Advantages of single step index fiber over multimode step. Processes for the preparation of optical fibers are also disclosed. The stepindex profile corresponds to a powerlaw index profile with the profile parameter approaching infinity. The study reported here deals with the exploitation of perfluorinated graded index polymer optical fiber bandwidth to add further services in a homeoffice network. Describe multimode and single mode stepindex and gradedindex fibers. In fiber optics, a graded index is an optical fiber whose core has a refractive index that decreases with increasing radial distance from the optical axis of the fiber because parts of the core closer to the fiber axis have a higher refractive index than the parts near the cladding, light rays follow sinusoidal paths down the fiber. To minimize the risk of burning the epoxy, fiber connectors can be constructed to have an epoxyfree air gap between the optical fiber and ferrule near the fiber end face. The light can pass through one path that is mono mode or single mode fiber or more than one path that is called multi mode fiber. D fiber which has a stepindex refractive index profile.
The core and cladding of an optical fiber are made from the same materiala type of glass. Pdf comparative investigation of graded index optical fiber. The main difference between multimode and single mode fiber is that the former has much larger core diameter, typically has a core diameter of 50 or 62. It compares both step index and graded index fibers. The calculated optical and geometrical parameters are listed in table 1.
In contrast, the graded index has a nonuniform core. Single mode or monomode step index fiber allows the propagation of only. Here you will know the list of differences between step index fiber and graded index fiber. What is the difference between step index fiber and graded index fiber. Step index fiber is rare only pof makes use of a step index design today. This page describes single mode step index fiber and multimode graded index fiber. This article will compare gradedindex multimode fiber with. Pdf influence of different materials on graded index optical fiber systems was studied. This video also covers the basic concepts, structure and.
Step index fiber is a fiber in which the core is of a uniform refractive index and there is a sharp decrease in the index of refraction at the cladding graded index fiber is a type of fiber where the refractive index of the core is lower toward the outside of the fiber. A multimode optical fiber in which the refractive index of the core declines from its highest value at the center of the core to a value at the edge of the core that equals the refractive index of the cladding. Whats difference between single mode optical fiber and multimode. Optical fibers having novel refractive index profiles are disclosed. The different refractive indexes can be achieved by doping silica with different. There are two methods to classify fiber optic cables. In fiber optics, a gradedindex or gradientindex fiber is an optical fiber whose core has a refractive index that decreases with increasing radial distance from the fiber axis the imaginary central axis running down the length of the fiber. Optical fibers in accordance with the invention are especially useful for application in telecommunication applications such as networks. What is the difference between step index and graded index.
Gradedindex gi fibre reduces multimode dispersion by grading the refractive index of the core so that it smoothly tapers between the core centre and the cladding. In a gradedindex fiber the velocity increases with distance from the core axis since the refractive index decreases. The following illustration shows the differences between these two. Difference between step index fiber and graded index fiber with. For a gradedindex fiber, if we draw the refractive index from the cladding region to the core. That means the cladding had a low value and the core had a higher value for r. In fiber optics, a graded index is an optical fiber whose core has a refractive index that. The main characteristics of step index single mode optical fibers are as follows. Upon completion of this chapter, you should be able to do the following. Stepindex fibers obtain their name from this abrupt change called the step change in refractive index.