Birefringence calculations in elliptical core optical fibers pdf

A simple first order perturbation approach to study the birefringence of highly elliptical core weakly guiding optical waveguides is presented. Versatile control of geometric birefringence in elliptical. Geometrical birefringence in circular and elliptical hole squarelattice holey optical fibers having a core consisting of a multiple defect is investigated. The compound to be detected is allowed to adsorb onto a decladded 5 cm length of the fibre. In this case, birefringence arises due to the perturbed elliptical core and also with the metamaterial used in the cladding which is anisotropic in nature. In this paper, we propose a highly birefringent bragg. Table salt, or sodium chloride, is also isotropic and is illustrated below in figure 1a. The optical path difference is a classical optical concept related to birefringence, and both are defined by the relative phase shift between the ordinary and extraordinary rays as they emerge from an anisotropic material. The subscripts l and 2 correspond to lpol and lpll modes, respectively. The theoretical analysis of the structure is performed using a finite difference method based on a vector potential formulation.

Accurate measurements of circular and residual linear. Rp photonics encyclopedia polarizationmaintaining fibers. Modal propagation properties of elliptical core optical fibers. High birefringence fibers hibi fiber or polarization maintaining fibers pmf have been widely. Polarization of light with applications in optical fibers. Fibers free fulltext a dual hollow core antiresonant. Optical fiber with the elliptical hollow core and an anisotropic metamaterial amm cladding is presented with an excellent experimental potentiality. Although, the theory is very useful in determining the impacts of pmd on optical communications systems, it does not help in determining the exact cause of the pmd of a specific optical fiber, i. Perturbation effects on mode propagation in highly elliptical. Birefringence and the phenomenon of polarization mode dispersion pmd in singlemode fibers are also covered. In addition to anisotropy in the electric polarizability electric susceptibility, anisotropy in the magnetic polarizability magnetic permeability can also cause birefringence. It is shown that in the useful singlemode region, the birefringence properties of ellipticalcore fibres match very well with those of a rectangularcore.

In these conventional optical fibers, the stressinduced birefringence exhibited dominant influence on total birefringence. Birefringence calculations in ellipticalcore optical fibres iet. Express 11 27938 8 hlubina p and ciprian d 2007 spectraldomain measurement of phase modal birefringence in polarizationmaintaining fiber opt. The effect of unidirectional extension of the core area on the birefringence of these holey fibers hfs is discussed. The birefringence induced by an elliptical core is. The results clearly show that it is possible to improve. High birefringence micro structured optical fibers mofs are a potential candidate for fiber sensor system, optical.

Polarizationmaintaining fibers are specialty optical fibers with strong builtin birefringence, preserving the properly oriented linear polarization of an input beam. Their task is to slightly increase and decrease the refractive. Circular birefringence can also be obtained by making the core of a fiber follows a. Birefringence analysis of multilayer leaky cladding optical bre. Elliptically infiltrated core nonlinear photonic crystal fiber. The modal birefringence and confinement loss are calculated by using finite. Birefringence of the elliptical fibers can be increased by increasing ellipticity of the core. Wanner department of mathematical sciences, george mason university, fairfax, virginia22030 b. We theoretically analyze the birefringence of the designed fiber over different. Fiber birefringence can also be calculated using this method. Pdf the polarization properties of singlemode optical fibers are theoretically modeled with use of the jones formalism. Multi core fibers mcfs have sparked a new paradigm in optical communications, as they can significantly increase the shannon capacity of optical networks based on single core fibers. It is shown that birefringence properties of a sidetunnel fiber match well those of the corresponding rectangular core waveguide.

Polarization decorrelation in optical fibers with randomly varying elliptical birefringence t. A common approach is the use an elliptical core, which introduces strong birefringence and also a polarization dependence of a cutoff wavelength, so that only light with one polarization direction is guided, whereas the fiber is a leaky waveguide for the other polarization. Extended interference formula for optical fiber characterization. Elliptical core fibers would be a typical example of shapeform birefringent fibers. The theoretical results reveal that the birefringence of embedded core hollow optical fibers can reach the order of 104. In addition to the high birefringence and polarizationmaintaining characteristics ofthese fibers,1,2 a number of properties. The optical birefringence and the first order polarization mode dispersion were studied based on a fullvector localized basis function. We investigate circular birefringence induced by spinning microstructured optical fibres during their fabrication to produce helicalshaped holes. This birefringence depends strongly on the frequency, or on the normalized frequency v, at which the fiber is being operated. A sidetunnel optical fiber is approximated by a rectangular core waveguide, the polarization characteristics of which can be obtained by a simple perturbation analysis.

One of the most important applications of the deliberately introduced birefringence in optical fibers is the development of highbirefringence hibi fibers, which are realized by introducing a permanent high birefringence into the fiber during the fabrication stage itself. Tension caused induces birefringence creating two different indices of refraction. Fabrication and study of microstructured optical fibers with. Measurements on variation of birefringence with depth of. Chow1 1department of mechanical engineering, university of hong kong, hong kong 2department of electronic engineering, city university of hong kong, hong kong 3department of physical electronics, school of electrical engineering. These optically anisotropic materials are said to be birefringent or birefractive. After removal of the variation common to both components of the electrical field vector of a signal, a, the. The early research on ellipticalcore fibers dealt with the computation of the. In conventional elliptical core fibers, the birefringence primarily comes from the core ellipticity and the.

The statistical correlations between the birefringence and the various parameters are obtained. Accurate measurements of circular and residual linear birefringences of spun fibers using binary polarization rotators zhexi xu, 1,3,4,5 x. One of the most important applications of the deliberately introduced birefringence in optical fibers is the development of high birefringence hibi fibers, which are realized by introducing a permanent high birefringence into the fiber during the fabrication stage itself. In this paper, we present results of a direct measurement of the birefringence of a polished elliptical core fiber as a function of depth of polishing using the prism coupling technique of ref. The fibre is polarization maintaining with an elliptical fibre core and a dshaped geometry. An analysis of birefringence properties of sidehole optical fibers has been presented in this work by using a finite element method.

Core and cladding have different refractive indices, with the core having a refractive index, n 1. Doublecladding rectangularlattice birefringence photonic. The exact calculation of bg in ellipticalcore fibers is quite difficult, as the. The core is flanked by areas of high expansion, borondoped glass, which shrink back more than the surrounding silica. Applications 173 the exact calculation of bg in ellipticalcore fibers is quite difficult, as the wave equation must be solved in the elliptical coordinates, and the eigenvalue equation so obtained is in the form of an infinite determinant.

Designs with an offset core which results in a helical path for the light and exhibit only circular birefringence and designs with a linearly birefringent core that result in elliptical birefringence are both investigated. The index profile is taken to be a rectangular waveguide for which exact scalar wave modes are known. The use of an optical fibre polarimeter as a chemical sensor is demonstrated. Thus to achieve higher contrast for better control ability, the core is being designed with various crystal with larger refractive index than silica. A circular birefringence tcf, where each core supports the right and leftcircularly polarized modes, is a special fiber that could be fabricated by making the two cores rotate around the central axis of the fiber rapidly e. Manipulating high birefringence in elliptical core meta fiber. Birefringence analysis of multilayer leaky cladding. The experimental results are compared with theoretical calculations using. The discussion of concepts is succinct, and the presentation of methods includes concrete examples, making the book an ideal text for students and a useful resource for engineers.

Broad spectral range measurements and modelling of. Performance of sagnac interferometer with loops made of. The birefringence is often quantified as the maximum difference between refractive indices exhibited by the material. High precision measurement technology for beat length of. We have then introduced the mlc to the elliptical core and have calculated the birefringence for d 3 m and 5 m for a given value of. Hlubina p 2003 dispersion of group and phase modal birefringence in ellipticalcore fiber measured by whitelight spectral interferometry opt. Generation and characterization of birefringence in optical. Birefringence in weakly guiding highly elliptical core fibers. Performance of sagnac interferometer with loops made of pcf. Birefringence calculations in sidetunnel optical fibers. Pdf high birefringence in elliptical hollow optical fiber. Design of high birefringence photonic crystal fiber with. Optical and acoustic birefringence in an imperfectly structured pcf the pcf used in the experiment is a commercially available pcf, which has inversion and sixfold rotation symmetry of the airhole lattice surrounding a silica core as shown in fig.

Pdf measurement of the elliptical birefringence of singlemode. Therefore, the opportunity arises to influence the stress induced birefringence in pm fibers after the fiber drawing process. The experimental results are compared with theoretical calculations using the rectangularcore waveguide model of ref. The numerical simulation is carried out by using the finite element method. Tuma, t andreas weisshaar, 2 jian li, 2 and glenn beheim t 1nasa lewis research center cleveland, oh 445 2oregon state university, department of electrical and computer engineering corvallis, or 97331 abstract. Also, for propagation properties, the results depend much on the approach of stress analysis. Manipulating high birefringence in elliptical core meta.

The birefringence that causes polarization mode dispersion in optical fibers may be linear, circular, or, in general, elliptical. Fabrication and study of microstructured optical fibers. Thus, the birefringence of an ellipticalcore fiber with major and minor axes as 2a and 2b, respectively, is approximately equal to that of a rectangularcore waveguide with major and minor axes given by. Many transparent solids, such as glass, are optically isotropic, which means that their index of refraction is equal in all directions throughout the crystalline lattice of the substance. The polarization properties of a new structure of high birefringence polarization maintaining photonic crystal fibers were explored, which were consisted of ellipticalholes and near elliptical core triangle lattice of hexangular structure based on polymer. The basic material used in the manufacture of optical. The core is a cylindrical structure, and the cladding is a cylinder without a core. Rp photonics encyclopedia singlepolarization fibers. The modal birefringence and confinement loss are calculated by.

High birefringence and polarizationholding ability in. Microstructured optical fibers mofs with elliptical holes have received significant theoretical analysis because of their polarizationdependent interaction with guided electromagnetic waves. Pdf birefringence properties of sidehole optical fibers. Birefringence calculations in ellipticalcore optical fibres, birefringence in singlemode optical fiber due to elliptical core deformation and stress anisotropy. The birefringence of our structure the fiber core region for making the asymmetry. One of the recently advancing concepts is that of dual hollowcore antiresonant fibers, which have the potential to be used as optical fiber couplers. Combined effects of optical and acoustic birefringence on. The mentioned problem can be fixed by using a polarizationmaintaining fiber, which is not a fiber without birefringence, but on the contrary a specialty fiber with a strong built in birefringence high birefringence fiber or hibi fiber, pm fiber.

In the stress birefringent fibers, the birefringence is created as a consequence of the addition of two stress applying parts saps at opposite sides of the core in the cladding of the fiber. Calculated coupling efficiency between an ellipticalcore. In order to understand the nature of polarization mode dispersion and to control or reduce it, one must know how the various types of birefringent media affect the polarization state of the guided light while. Furthermore, environmental factors such as bend, twist. As a result, the two modes propagate with slightly different phase and group velocities. Generation and characterization of birefringence in. Calculated coupling efficiency between an elliptical core optical fiber and an optical waveguide over temperature margaret l. In an ideal circularcore fiber, these two modes will propagate with the same phase velocity. A novel microstructured optical fiber with high birefringence. Birefringence assessment of singlemode optical fibers. High birefringence in elliptical hollow optical fiber osa. Provided that the polarization of light launched into the fiber is aligned with one of the. Fabrication and study of microstructured optical fibers with elliptical holes nader a. It is shown that birefringence properties of a sidetunnel fiber match well those of the corresponding rectangularcore waveguide.

We extend their results to the case of elliptical birefringence. A sidetunnel optical fiber is approximated by a rectangularcore waveguide, the polarization characteristics of which can be obtained by a simple perturbation analysis. Polarization decorrelation in optical fibers with randomly. Analysis of high birefringence of four types of photonic. Feasibility of coupling between a singlemode ellipticalcore fiber. Therefore, the opportunity arises to influence the stress induced birefringence in pmfibers after the fiber drawing process. In general, the optical path difference is computed by multiplying the specimen thickness by the refractive index, but only. The mechanical stress states of panda fibers after their fabrication and the state after the additional high temperature annealing step are compared. Perturbation effects on mode propagation in highly. With the growing interest in hollowcore antiresonant fibers hcarf, attributed to the development of their fabrication technology, the appearance of more sophisticated structures is understandable. Due to high ellipticity in the hollow ring core, the fiber provides an extremely high group birefringence of 2.

Modes in highly elliptical core twomode fiber a highly elliptical core twomode fiber guides four non degenerate eigenmodes with propagation constants, pi r, pi. Propagation characteristics of optical fibers with an. Keywordsbirefringence, dispersion, elliptical core fiber, optical mode. Calculated coupling efficiency between an ellipticalcore optical fiber and an optical waveguide over temperature margaret l. The noncirculatory or ellipticity of the core is defined by the parameter where a and b are respectively the minor and major axis of the elliptical core. It has been seen that higher ellipticity of the core results much higher thermal stress in the fiber core, which in turn produces higher birefringence to produce nondegenerate modes in the fiber. A more recent example is the proposed new type of polarizationholding fibers with claddings of photonic crystal structure 18, 19, in which the elliptical core surrounded by microstructured claddings mainly enhances. Birefringence is intentionally introduced for instance, by making the crosssection elliptical in order to produce polarizationmaintaining optical fibers. Simulation results show that the elliptical air hole in the core can enhance the performance of mode birefringence and control the properties of chromatic dispersion at the same time. Zweck department of computer science and electrical engineering, university of maryland, baltimore county, baltimore. Sammut, analytical method for calculation of stresses and.

Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. Elliptical core optical fibers have attracted much attention in research and industrial applications for a long time due to their improved birefringent properties over the circular core. Multicore fibers mcfs have sparked a new paradigm in optical communications, as they can significantly increase the shannon capacity of optical networks based on singlecore fibers. The central elliptical portion of the core is filled with a sf57 glass rod. Zero polarization mode dispersion and high birefringence can be obtained by an elliptical depressed inner core singlemode fiber 1719. Modulation instabilities in birefringent twocore optical. Gardiol summary a new type of optical fiber with a twincore is proposed exhibiting good birefringence properties. The theoretical results reveal that the birefringence of embeddedcore hollow optical fibers can reach the order of 104. Modulation instabilities in birefringent twocore optical fibers. The validity of the calculations are checked for circular fibers with circular or elliptical core by comparing with the existing results. An optical ray is guided by total internal reflections within the fiber core if its angle of incidence on the corecladding boundary is greater than the critical angle 8, sin.