Dispersion techniques dispersion compensating fibers fiber bragg grating electronic dispersion compensation digital filters optical phase conjugation techniques 7. The dispersion compensating fiber dcf is tested for a single span, single channel. Several techniques, including dispersion compensating fiber or fiber bragg grating, can be used to compensate the accumulated dispersion in the fiber. Material dispersion occurs because the refractive index of cladding changes with the wavelength and waveguide dispersion due to light confinement problem in the fiber core, where the light is also propagated through the fiber cladding that travel at different velocities. Rp photonics encyclopedia dispersionshifted fibers. Pdf symmetrical dispersion compensation for high speed. Broadband dispersion compensation technology in high speed. Optimum fiber design and properties of different fiber combinations are treated. Regenerators, however, are not generally designed to compensate for chromatic dispersion, this is routinely achieved using dispersion compensating fiber dcf.
Fiber dispersion and optical dispersion an overview. Singlemode dispersion compensating fiber designs with absolute dispersion values of greater than 100 psnm km are described. Dispersioncompensating fiber an overview sciencedirect. Dwdm wavelengths 100ghz grid can be compensated on a fiber optic link.
The following shape was generated in the optical gaussian pulse generator with an initial 12. The dispersion of smf in the 1550nmwavelength is 17 20 ps with positive dispersion slope. Dispersion management using dcf dispersion compensation fiber. Pdf performance analysis of dispersion compensation in long. A simulation approach for dispersion compensation in optical. A twoconcentriccore structure is obtained by introducing two different sizes of capillaries for the airholes and exhibits very high negative chromatic dispersion 2200 psnm km at 1550 nm. Dcf3 fiber is a nonzero dispersionshifted fiber nzdsf with negative dispersion and low positive dispersion slope that is optimal for medium distances and wide band wdm systems. In fiber optic communication is transmitted pulses of light through an. The length of non linear fibre is 75km with dispersion of 0. Apr 21, 2018 historically, singlemode optical fiber was designed with the minimum chromatic dispersion point at the operating wavelength. Starting with the basic principle behind dcf, its need for upgrading the 10 nm optical fiber links is discussed. Use of dispersion compensating fiber in optical transmission. The extra dispersion used to encrypt and hide the stealth channel can be achieved by adding the extra length of standard single mode fiber ssmf, dispersion compensation fiber dcf, chirped fiber bragg grating 6, or photonic crystal fibers 7. Dispersion compensating fibers for raman applications.
Dispersion compensation was originally proposed to equalize pulse distortion. In view of optical properties for transmission system, production cost, and module assembly, for a long time slope compensating and dispersion compensating fiber scdcf has been the most advantageous and widely used method as dispersion compensation devices. This type of fiber is also called depressedinnercladding fiber and wprofile fiber from the fact that a symmetrical plot of its refractive index profile superficially resembles the letter w. Note how an open transmit eye from which correct decisions can easily be made, begins to close due to dispersion and noise, as the distance through the fiber increases. There are three main types of dispersion in a fiber. Dispersion compensation optical fiber modules for 40 gbps. The use of dispersion compensated fiber dcf is considered as the best method to mitigate harmful. Optical fiber for compensating the chromatic dispersion of an optical fiber having positive chromatic dispersion.
With the program optisystem, is simulated the dispersion compensating of a link of optical fiber communication system using dcf and cfbg with different apodizations. Standard single mode fiber or nonzero dispersion shifted fiber has been widely used in long haul systems. Dispersion compensation is an important issue for fiber optic links, i. Polarization mode dispersion compensation in wdm system. The idea of using dispersion compensation fiber for dispersion compensation was proposed as early as in 1980 but, until after the invention of optical. Singlemode optical fiber having multiple cladding regions for dispersion compensation. Research on dispersion compensation of 40 gbs optical duo. Low loss chromatic dispersion emulators and compensators available for lab use. Dispersion deployment and compensation for optical. Analysis of dispersion compensation using fiber bragg. Dispersioncompensating fiber an overview sciencedirect topics. Dispersion compensating fiber has a high negative dispersion 70 to 90 psnm. Each repeater span basically consists of two kinds of fibers.
A multiclad fiber with a triangular refractiveindex profile in the core gives a dispersion of. Is also analysed the cfbg the apodized and nonapodized using the program optigrating. Analysis and simulation of dispersion compensation in fiber. Fiber bragg grating fbg is one of the most applicable components to compensate dispersion losses in optical communication system. This dispersion compensation fiber dcf is designed to compensate the accumulated dispersion in long haul optical fiber transmission systems in the c band. Ask rp photonics for finding the most suitable dispersionshifted fiber for your application definition. Compensation of dispersion with fiber bragg grating component. The ape femtocontrol is a compact motorized dispersion compensation unit for. Conventional dispersion compensating fibers have a high negative dispersion 80 psnm. We have used coupled mode equations to evaluate appropriate fbg profile for long distances. High performance dispersion and dispersion slope compensating. Dispersion limits the bandwidth or information carrying capacity of a fiber. We are living in the age of bandwidth hungry and high speed applications, for which optical networks form the most important part because of its high bandwidth.
There is an assumption for the proposed structure to keep the 1 st mode in a central core over the wide working spectrum of. A slopecompensating rate can be expressed by the following equation using rds. Dispersion compensating fiber and optical transmission system including the. The use of dispersion compensating fiber is an efficient way to upgrade installed links made of standard single mode fiber 2.
Dispersion compensating fiber and optical transmission system including the same. The rp photonics buyers guide contains 20 suppliers for dispersion compensation modules. Dual core dispersion compensating fibre with large negative dispersion parameter a concentric core dcf based on microstructured optical fibre is proposed 1. The ability to control chromatic dispersion is paramount in applications where the optical pulsewidth is critical, such as chirped pulse amplification and fiber optic communications other devices. The optimal operating condition of the dcm is obtained by considering dispersion management configurations for the symmetrical system i. The isi thus limits transmission of high speed data. Performance analysis of dispersion compensation in long haul optical fiber using dcf. Dispersioncompensating fiber in doubleclad fiber for dispersion compensation, the inner cladding layer has lower refractive index than the outer layer. First we will use dispersion compensating fibers dcfs. The dispersioncompensating fiber should be selected to match the dispersion of a regular sm or pm fiber, not only at a single wavelength, but over the whole spectral range of the optical pulse. Polarizationmaintaining dispersioncompensating optical fiber. Dispersion adjustment broad band dispersion compensating of dwdm network and extremely low residual dispersion 80120% slope compensation in cl band low insertion loss and high negative dispersion coefficient high figure of meritfom low pmd performances meet the criterion telcordia gr2854core reliability meets the criterion telcordia.
Certified that this project report titled analysis of dispersion compensation techniques and fiber nonlinear effects in dwdm optical networks is the bonafide work of sathya. The importance of matching not only the dispersion and dispersion slope but also the dispersion curvature has been demonstrated with a new dispersion compensating fiber for low slope nzdf with rds. Inverse design of dispersion compensating optical fiber. The dispersion arrangement, which considers both the second and third order dispersion characteristics is illustrated in the above figure. A slope compensating and dispersion compensating fiber scdcf utilizing a. Alternative methods for dispersion compensation which have been proposed include chirped bragg grating, etalons and ring resonators, to name a few. Optical fiber with highly negative dispersion at 1550nm to compensate for a buildup of positive dispersion in that region in conventional fiber. The chromatic dispersion of a fiber is expressed in psnmkm, representing the differential delay, or time spreading in ps, for a source with a spectral width of 1 nm traveling on 1 km of the fiber. Different dispersion compensation techniques in fiber.
Post dispersion compensation scheme is employed for dispersion. Dispersioncompensating fiber dcf provides an optical medium with a relatively large negative chromatic dispersion factor d. Mar 08, 2019 intramodal dispersion in optical fiber pdf admin march 8, 2019 march 8, 2019 no comments on intramodal dispersion in optical fiber pdf due to dispersion when the optical pulses travel along the fiber they broaden as shown in 1 intramodal or chromatic dispersion present in single mode an. The overall dispersion of these fibers is opposite in sign and much larger in magnitude than that of standard fiber, so they can be used to cancel out or. Dispersion management is the process to design the fiber and compensating elements in the transmission path to keep the total dispersion to a small number. In this paper, dispersion compensating fibers dcf are used to compensate the positive dispersion accumulated over the length of the fiber at. A simulation approach for dispersion compensation in. Single mode dispersion compensating fiber aitc group. Dcf modules inserted into transmission line at regular interval. Typically, devices used to generate large amounts 100 psnm of chromatic dispersion are based on diffraction gratings, chirped fiber bragg gratings, or dispersion compensating fiber. Dispersion compensation techniques for optical fiber. Fiber dispersion and optical dispersion an overview fosco.
Using these dispersion compensation modules, the transmission distances in fiber can be increased significantly without regenerating the signals. Dispersion compensating optical fiber for smf and transmission link including same. This is largely because groupvelocity dispersion gvd, or socalled chromatic dispersion cd, in optical fibers i. Design and simulate a fiber optic system using dispersioncompensating fiber to reduce chromatic dispersion.
Dispersion compensation schemes a system perspective. Dispersion compensating fiber dcf provides an optical medium with a relatively large negative chromatic dispersion factor d. Dcf can minimize the overall dispersion to optimize the system for high bit rate. Performance analysis of dispersion compensation in long. The amount of light dispersed by a normal fiber in reduced or even nullified by using a dispersion compensating fiber having a very large value of dispersion of opposite sign as.
The splice loss between dcf and standard fibers is shown to be reducible by use of a special intermediate fiber. Static and tunable dispersion compensation modules for access, dci and legacy communication systems. In view of optical properties for transmission system, production cost. Pulse spreading due to the dispersion causes the overlapping of the transmitted pulses at the receiver end known as inter symbol interference isi. A photonic crystal fiber based on a particular periodic arrangement of airholes and pure silica is designed for chromatic dispersion compensation. Thorlabs offers dispersion compensating bare fiber for custom solutions across a broad spectral range in the telecom region.
Thus, dispersion management is a very important part of designing a fiber optic transmission system. Dispersion phenomena in optical fibers halina abramczyk. Fiberbased dispersion compensation is an attractive technology for upgrading wdm communication. Dispersioncompensating fiber how is dispersioncompensating fiber abbreviated. Dispersion compensation fiber dcf, with its large negative cd coefficient, can be inserted into the link at regular intervals to minimize its global chromatic dispersion.
In this technique, the designed wdm system is compensated with dispersion compensating post compensation method in which dcf is used after the non linear fibre. If a transmission fiber of length l tf is connected in series with a dcf of length. Compensation of dispersion at a wavelength around 1550nm in a 10nm optimized single mode fiber can be achieved by specially designed fibers whose. Osa design of dispersioncompensating fibers based on a.
Dispersion compensating optical fiber, and wavelength division multiplexing transmission line using a dispersion compensating optical fiber. Dispersion managed fiber dmf designs were introduced where the dispersion slope was also compensated. As a consequence of its optical characteristics, the chromatic dispersion of a fiber can be changed by acting on the physical properties of the material. Negativedispersion optical fiber and optical transmission line incorporating the same. A dispersion compensating module or dcm is used to compensate the cumulative dispersion in a single mode fiber and a dispersion coefficient is used to characterize the dispersion value.
Characteristics dcf fbg bandwidth 20 nm wide band, 0. In this paper, the use of chirped fbg has been studied as a dispersion compensator in an optical communication system. Fiber brag grating fbg and dispersion compensating fiber dcf are two mostly used techniques in long haul communication. In proposed work we have provided a fbg system to transmit lossless data up to 80 kilometer. This means that the dcf should match not only the dispersion, d, but the dispersion slope, dd fiber d. The bitrates must be low enough to ensure that pulses are farther apart and therefore the greater dispersion can be tolerated. Performance analysis of dispersion compensation in long haul. How does a dispersion compensating fiber reduce chromatic. Rp photonics encyclopedia dispersion compensation, pulse. In order to achieve high speed, large capacity and long distance communication, it is necessary to use dcf in the optical fiber 7, thus the total dispersion of the whole optical fiber line is approximately zero 8. Dispersion compensating fibers dcfs are quite attractive fiberbased. For instance, if smf has positive dispersion over a specific range of wavelengths, dcf has negative dispersion over the same. Pdf dispersion compensation using only fiber bragg gratings. Dispersion compensating fiber module semantic scholar.
Dispersion compensation with dispersion compensating fibers. The key optical properties of scdcf are chromatic dispersion, rds, figure of merit fom, bending loss, cutoff wavelength, and effective area aeff. To reduce fiber dispersion, new types of fiber were invented, including dispersionshifted fibers itu g. The first type spliced to the repeater output is a large effective area fiber with positive dispersion. With the development of wavelength division multiplexing wdm techniques for large capacity optical communication systems, dispersion compensation technologies have been applied into the field.
Project layout for dispersion compensation with fiber bragg grating component in optisystem the following shape was generated in the optical gaussian pulse generator with an initial 12. Then, the total dispersion equation can be rewrite as 3 2. Since dispersion is inevitable in optical fibers, dispersioncompensating fibers, such as those sold on this page, can be incorporated into optical systems. Here, strong dispersive broadening of modulated signals can occur in cases with high data rates. All fiber designs use only the fundamental lp01 mode for dispersion compensation and can account for first and. Analysis and simulation of dispersion compensation in. When shining a beam of white light into a prism, you see the light is composed of a rainbow band.
Project layout for dispersion compensation with fiber bragg grating component in optisystem. Dispersion compensation using only fiber bragg gratings article pdf available in ieee journal of selected topics in quantum electronics 55. Ajout dun anneau externe au profil dindice dune fibre optique monomode a dispersion decalee. In this paper, the performance of high speed optical fiber based network is analysed by using dispersion compensating module dcm. So far, several dispersion compensation techniques have been proposed. In the following example we will show three different schemes, pre, post, and symmetrical compensation, to compensate the fiber dispersion. Dcf3 fiber is a nonzero dispersion shifted fiber nzdsf with negative dispersion and low positive dispersion slope that is optimal for medium distances and wide band wdm systems. Inverse design of dispersion compensating optical fiber using. Dispersion can cause various penalties in signal transmission in optical communications systems. Smf have positive dispersion and dcf have negative dispersion so overall dispersion is zero. Dispersion compensating fiber dcf, chirped fiber bragg grating cfbg, optigrating, optisystem, dispersion compensating, apodization. It depends on the fiber type, and it limits the bit rate or the transmission distance for a good quality of service. According to the relative positions of dcf and single mode fiber the three dispersion compensation schemes predcf, postdcf and symmetrical mixdcf are proposed.
Dispersion compensating fiber dcf in dispersion compensating fiber technique we use a fiber having a large negative dispersion along with a standard fiber. A dcf is a fiber that causes dispersion opposite to conventional singlemode fibers. Design and simulate a fiber optic system using dispersion compensating fiber to reduce chromatic dispersion. Typically, dispersion compensating elements are placed every 100 km or so. Introduction in a communications system the transmitter sends a message to the receiver through a communication medium. Pdf dispersion compensation in an optical fiber by using chirp gratings esat journals academia. Dispersion compensation in optical fiber communication.
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