Step index fiber and graded index fiber pdf download

Optical fibers are classified into two types based on the refractive index profile of core. Refractive index of the core and that of the cladding are constants. In fiber optics, a graded index is an optical fiber whose core has a refractive index that. Step index and graded index fibre comparison between step index and graded index fibre optical fiber cable here is the comparison between step index and graded index fibres on the basis of various parameters like basic structure, working principle, types, refractive index profile, propagation of light inside fibers, dispersion in optical. The light rays,propagate in the form of skew rays or helical rays. Multi mode fiber based on the material used, optical fibers are may broadly classified into four categories i. This particular fiber is fairly large by modern standards, but it provides a nice example of the different layers in an optical fiber. Step index and graded index fiber optical fiber refractive index. You can see the image shown above, how a single mode of light is propagating through the core of the optical fiber. Difference between step index fiber and graded index fiber with. If you recall, there are two types of multimode fiber. Stepindex and gradedindex fiber fde lumerical support. In this video lecture, you will learn about the difference between the two.

Graded index fiber is of only one type,that is multi mode fiber. Suitable for light wave communication links and local area networks carrying voice, video and data. The refractive index of the core of step index fiber is constant throughout the core. What is the difference between step index and graded index. However, misalignments result in the excitation of leaky. Step index and graded index fiber mode of the fiber. Graded index fiber is a type of optical fiber where the refractive index of the core is uniform at the center core and then it decreases towards corecladding interface. A second mode travels at a steep angle and bounces back and forth by total. The step is the shift between the core and the cladding, which has a lower refractive index. Probability that a given stokes mode of a multimode fiber has the greatest raman gain given random pump launching conditions. Advantages disadvantages of step index,graded index fiber. The app can be used for analyzing both stepindex fibers and gradedindex fibers.

Within the multimode fiber choices, the degree of refraction change between the core and the cladding varies between graded index and step index. Differentiate between step index and graded index fibre. In 1966, the first plastic opticalfiber pof product with a polymethyl methacrylate or acrylic core was introduced by dupont under the brand name crofon. In a gradedindex fiber the velocity increases with distance from the core axis since the refractive index decreases. Multimode fiber is rarely available longer than couple km and is used to connect server to a network backbone. A multimode stepindex fiber has a core of radius a and a constant refractive index n1. One mode travels straight down the center of the core. Standard gradedindex fibers typically have a core diameter of 50 or 62. A multimode or singlemode optical fiber with a uniform refractive index throughout the core. It compares both step index and graded index fibers. The path followed by the light in a fiber is called the mode of the fiber. What is multimode stepindex fiber in data communication.

The plot of refractive index transversely across the fibre is a simple step up and down. It bends the rays inward and also allows them to travel faster in the. Graded index or step index multimode fiber fiber optic. The step index fiber was tested at a wavelength of 1. Since it is a type of step index fiber, therefore the refractive index of this optical fiber makes step sudden change at the core cladding interface. Stepindex fibers obtain their name from this abrupt change called the step change in refractive index. It has a cylindrical core which is surrounded by a cladding of lower refractive index. What is single mode and multimode fiber slideshare.

Difference between step index fiber and graded index fiber brainkart. Step index fibre is the simplest form of optical guide. As noted before, multimode fiber may be divided into stepindex and gradedindex fiber. Stepindex multimode fiber was the first fiber design but is too slow for most uses, due to. Difference between step index fiber and graded index fiber. Step index and graded index fiber step index vs graded.

The refractive index of the core is uniform and step or abrupt change selection from engineering physics book. Single mode graded index fiber not a commonly used standard type of fibers. A cladding of slightly lower refractive index n2 surrounds the core. In optical fiber, a step index fiber is a fiber characterized by a uniform refractive index within the core and a sharp decrease in refractive index at. 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. Instead of a sharp step down from the core refractive index to the cladding as in stepindex fiber, in gradedindex fiber, fiber core has the highest refractive index at the center, and then refractive index gradually decreases until it is the same as the cladding at the edge of the core. Step index and graded index fiber free download as powerpoint presentation. Difference between step index and graded index fiber. Graded index fiber is a type of fiber where the refractive index of the core is lower toward the outside of the fiber. Osa an explanation of srs beam cleanup in gradedindex. Us5729645a us08696,369 us69636996a us5729645a us 5729645 a us5729645 a us 5729645a us 69636996 a us69636996 a us 69636996a us 5729645 a us5729645 a us 5729645a authority us unite. In a stepindex fiber, the lp 01 mode is not dominant.

For a gradedindex fiber, if we draw the refractive index from the cladding region to the core. Therefore this type of step index fiber is known as single mode step index fiber. Pdf an approach to calculate the waveguide dispersion, and consequently the chromatic dispersion, for graded index optical fibers is. Guide modes of stepindex and other fibers can be calculated and optimized with the rp fiber power software. The refractive index of the core is uniform throughout and undergoes on abrupt change at the core cladding boundary. Gradedindex multimode optical fibers, optimized for signal transmission at 850 and 0 nm, are available with 50125, 62. As we have discussed in the earlier article about the light propagation through an optical fiber after total internal reflection. Figure 32 shows the refractive index profile nr for this type of fiber.

Stepindex, gradedindex become focus for plastic opticalfiber applications. There are two methods to classify fiber optic cables. 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. Here you will know the list of differences between step index fiber and graded index fiber. 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. The step index fiber was created using two overlapping circle structures of silica n1. For simpler cases, the rp fiber calculator software is sufficient definition.

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. Difference between step index and graded index fibers in. Graded index fiber is another type of optical fiber in which the refractive index of the core is nonuniform. The basic material used in the manufacture of optical fibers is vitreous silica dioxide sio2, but to achieve the properties required from a fiber. Types of optical fiber learning outcome epg pathshala. Based on number of modes, they are categorized into single mode and multimode. Graded index fiber based on the number of modes of transmission, optical fibers are classified into two categories i. Consider a 30km long optical fibre that has an attenuation of 0. The uniformity is present because the refractive index is higher at the axis of the core and continuously reduces with the radial movement away from the axis. Take oreilly online learning with you and learn anywhere, anytime on your phone or tablet. Bandwidths of singlemode and multimode optical fibre. Pdf chromatic dispersion in gradedindex singlemode optical fibers.