With the development of wavelength division multiplexing wdm techniques for large capacity optical communication systems, dispersion compensation technologies have been applied into the field. 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. From loss test to fiber certification fiber characterization today part i. Fiber bragg gratings for dispersion compensation in transmission. Singlemode dispersion compensating fiber designs with absolute dispersion values of greater than 100 psnm km are described. Dispersion flattened fibres and wideband fibres 23 some compensating fibres could work at short spectrum of. Dispersion compensation in optical fiber communication. Indeed, in a single mode fiber we can assume with a good approximation that the optical path of the rays is directed along the optical.
Dispersion can cause various penalties in signal transmission in optical communications systems. It consists of an optical fiber that has a special design such as providing a large negative dispersion coefficient while the. A wide variety of dispersion compensated fiber options are available to you, there are 187 suppliers who sells dispersion compensated fiber on, mainly located in asia. Thorlabs dispersion compensating bare fiber delivers high performance across a broad spectral range in the telecom region. Compensation of dispersion with fiber bragg grating component. Its coefficient is found to depend strongly on the dispersion slope. The design features of a tricladding index profile were described, and the properties of the obtained fibers were measured. Taking advantages of pcvd process, yofc is able to manufacture complex indexprofile shapes accuratelly, therefore,to get the optimized products. 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. After lh propagation, pmd gives rise to a differential delay. The physical idea behind this compensation is following. A multiclad fiber with a triangular refractiveindex profile in the core gives a dispersion of.
Chromatic dispersion compensation can be done when the type of fiber is known. Dispersion compensating fiber dcf is the predominant technology for dispersion compensation. The closer the dispersion compensating rate is to 100% the easier it is to realize a transmission link with zero dispersion over a wide range of wavelengths. Performance analysis of dispersion compensationof optical.
Here, strong dispersive broadening of modulated signals can occur in. Dispersion compensating fibers with improved splicing. Unfortunately, such dispersion compensation comes with additional attenuation, fig3 optical fiber. Calculating dispersion penalty dispersion in submarine systems. Dispersion compensating fibers dcf with improved splicing performance were designed and fabricated. Kazuhiko aikawa and kuniharu himeno slope compensating and dispersion compensating fibers scdcf for a dispersionshifted fiber dsf have been designed and fabricated. Conventional dispersion compensating fibers have a high negative dispersion 80 psnm. Dispersion compensation was originally proposed to equalize pulse distortion. In view of optical properties for transmission system, production cost.
Is also analysed the cfbg the apodized and nonapodized using the program optigrating. 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. Standard single mode fiber or nonzero dispersion shifted fiber has been widely used in long haul systems. Dispersion techniques dispersion compensating fibers fiber bragg grating electronic dispersion compensation digital filters optical phase conjugation techniques 7. Dispersion phenomena in optical fibers halina abramczyk. All fiber designs use only the fundamental lp01 mode for dispersion compensation and can account for first and. The use of dispersion compensated fiber dcf is considered as the best method to mitigate harmful results of dispersion and also to upgrade single mode fiber links which had already been installed. Thorlabs offers dispersion compensating bare fiber for custom solutions across a broad spectral range in the telecom region. In this white paper we discuss how the phase of the image on the lcos can be varied along the spectral axis to modulate the group delay across the spectrum, which results in a dispersion generating or compensating device.
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. Dispersion compensation is an important issue for fiberoptic links, i. Design optimization of dispersion compensating fibers and. The model for predicting attenuation of high index fibers presented in chapter 5 will be used for optimizing the fiber design and results on two manufactured dispersion compensating fibers with fom as high as 430 psnm.
These fibers have both high mechanical reliability and high optical stability. Fiber bragg gratings for dispersion compensation in. To reduce fiber dispersion, new types of fiber were invented, including dispersionshifted fibers itu g. The dispersioncompensating module can be ordered to match the fiber that has to be. A fiberoptic technique for compensating both first and secondorder groupvelocity dispersion in singlemode fiber spans is demonstrated by using the large waveguide dispersion that occurs for. Inverse design of dispersion compensating optical fiber using topology optimization. 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. Yofc dispersion compensating fibre is specially developed through proprietary pcvdbased technology.
So far, several dispersion compensation techniques have been proposed. Polarization mode dispersion compensation in wdm system. By using this technique, the total accumulated dispersion will become zero after some distance, but the absolute dispersion per length is nonzero at all points along the fiber. With the program optisystem, is simulated the dispersion compensating of a link of optical fiber communication system using dcf and cfbg with different apodizations. To neutralize this phenomenon, design of dispersion compensating fiber dcf with negative dispersion seems to be an essential task 30, 31. According to the relative positions of dcf and single mode fiber the three dispersion compensation schemes predcf, postdcf and symmetrical mixdcf are proposed. Fiber also suffers from dispersion due to fiber material,so dispersion has to be minimized by some methods but installing the dcfdispersion compensating. Chromatic dispersion components of chromatic dispersion chromatic dispersion compensation dispersioncompensating fiber and modules chromatic dispersion measurement spectral group delay in the time domain interferometry method.
Dispersion compensating fiber dcf in dispersion compensating fiber technique we use a fiber having a large negative dispersion along with a standard fiber. Thus, dispersion management is a very important part of designing a fiber optic transmission system. Smf have positive dispersion and dcf have negative dispersion so overall dispersion is zero. You may also load your own data files for any parameter into the component. Optical performances of the dcf modules are mainly limited by the macro, microbending loss and the polarization mode dispersion that strongly depend on the module structure. Unit 3 welcome to department of ecewe born to invent.
Analysis and simulation of dispersion compensation in. Alternative methods for dispersion compensation which have been proposed include chirped bragg grating, etalons and ring resonators, to name a few. Multilayer fiber for dispersion compensating and wide. We show that very large negative dispersion value can be obtained, depending on the geometrical parameters.
This lesson demonstrates the possibility for dispersion compensation with the help of fiber bragg grating created with the fiber grating component. The success of high bit rate transmission through a standard fiber over a long distance depends on various dispersioncompensating schemes. We present the designs of a small residual dispersion fiber srdf and a corresponding dispersioncompensating fiber dcf, where the dispersion slopes of these fibers are so adjusted that a small. Symmetrical dispersion compensation for high speed. Design optimization of dispersion compensating fibers dcfs based on the fundamental mode is described considering the packaging technique.
Typically, dispersion compensating elements are placed every 100 km or so. Fiberbased dispersion compensation is an attractive technology for upgrading wdm communication. Patterson, member, ieee abstract we propose a transmissionbased dispersion compensator employing an apodized, unchirped. Dispersion compensation techniques for optical fiber.
The more the transmission distance, higher will be the dispersion effects on the transmitted pulses. Dispersion compensation fiber has a high value of negative dispersion. Electronic dispersion compensation university of illinois. Since the dispersion compensating rate is 100% only if the dps of the dispersionmanaged transmission lines with reversedispersion fiber. Dispersion compensation optical fiber modules for 40 gbps. Dcf modules inserted into transmission line at regular interval. Single mode dispersion compensating fiber aitc group. Osa temperature dependence of chromatic dispersion in. Regenerators, however, are not generally designed to compensate for chromatic dispersion, this is routinely achieved using dispersion compensating fiber dcf.
Theoretical model and design criteria for nearly ideal pulse recompression natalia m. Different dispersion compensation techniques in fiber. The top countries of suppliers are india, china, from which the percentage of dispersion compensated fiber supply is. Since dispersion is inevitable in optical fibers, dispersioncompensating fibers, such as those sold on this page, can be incorporated into optical systems. In this report we discuss about the optical fiber and its advantages, theory and principles of the fiber optics, fiber geometry, types of optical fiber, different parameters and. 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. You can use the regular fiber components located in the defaultoptical fibers library for any type of fiber as long as you know its parameters. This component allows design of apodized and chirped fiber gratings that are able to provide dispersion compensation in optical system. Fiber dispersion and optical dispersion an overview. This paper investigates the dispersion compensating performance in multilayer fiber. Dispersion compensating fiber has a high negative dispersion 70 to 90 psnm. Analysis on dispersion compensation using post fbg with edfa. This is largely because groupvelocity dispersion gvd, or socalled chromatic dispersion cd, in optical fibers i. 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.
Abstract the intended application of our different types of dispersions in an optical fiber. Journal of the optical society of america b optical physics, 251, 8897. The thermal coefficient of chromatic dispersion of scdcf for dsf is twice as large as that of scdcf for large effective area nzdsf. Dispersion compensating fiber modules for dispersion. Analysis of dispersion compensation using fiber bragg. The temperature dependence of chromatic dispersion is examined for various types of fiber. Dispersionflattened fiber has a significantly low coefficient of 0. 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. Inverse design of dispersion compensating optical fiber. Fiber characterization fiber optic training, fiber. Rp photonics encyclopedia dispersion compensation, pulse.