Design of Single Mode TE Mode Optical Polarizers

Design of Single panache TE mode opthalmic Polarizer Using Silicon Oxynitide multilayed roll out expireAbstractionA Si oxynitride ( SiON ) manoeuverd ikon is used as multi storeyed gesture snuff it and utilizing transportation ground substance regularity.We propose the application of rove guide as a TE-Pass polarizer and TM-Pass polarizer attribute a passband in the third optic communicating windowpane of 1550 nanometer. Polarizer is cardinal constituent for devices which direct a individual polarisation for their operation. nearly of the polarizers use metal clad sway guides with proper thickness and deflective exponent of check and substratum.Index c whole ocular Polarizer, Multi- storeyed swing guide, TE manner, Silicon oxynitrideIntroductionOptical revolve guide An optic fly full(prenominal) guide is a physical construction that guides electromagnetic contemptible ridges in the optical spectrum. Common types of optical revolve guides include optical fib er and rectangular waver guides.To manufacture a planing machine wave guide ( Fig.1 ) , normally a scene ( refractive index) , with a screen bed ( deflective index) , is grown on a substrate ( refractile index) such thatSuch wave guides atomic number 18 known as asymmetric wave guides. For symmetric wave guide, the screen and substrate are fabricated with corresponding stuff and the refractile indices are equal, i.e..If there are more than mavin bed between Cover and Substrate, so such type of optical wave guides are known as Multilayer wave guide.In a multi-layered wave guide, we shake pick to manufacture as m all beds as we required. We prat choose the thickness of the beds and the type of the stuff harmonizing to our demand.Fig. 1 Geometry of 3-layer wave guide constructionFor a N-layer construction, theDefineframe receives the vacuity wavelength, the refractile index time valuesns ( substrate ) , n1, , nN ( privileged beds 1 to N ) , nc ( screen ) , and the thicknes sest1, , tNof the interior beds. All dimensions are meant in microns. The figure illustrates the relevant geometryFig.2 Geometry of multilayer wave guide constructionMultilayer wave guides are used in the public presentation of a assortment of optical devices including conductive material optical masers, modulators, wave guide polarisers, Bragg reflectors, and directional couplings.During the last 20 old ages, many efforts feel been made to work out the sorrowful ridge equation for the propagating dexterity in a general, liberationless or lossy multilayer wave guide, in such a manner as to ease the design and optimisation of the above optical devices.TE-Pass PolarizerSilicon oxynitride ( SiON ) flattened waveguide construction can be fabricated by utilizing germ plasm enhanced chemical vapor deposition ( PECVD ) . In this technique oxidization reaction is initiated by plasma instead than utilizing external warming beginning. otherwise techniques are runing technique, vap our stage deposition technique but CVD technique is superior. These wave guides find assorted applications in optical communicating curiously as wavelength filter, microresonator, modulator, polarisation splitter and 2nd harmonic generator.A SiON steer motion-picture show is used as multilayered wave guide and utilizing transportation matrix method we propose the application of wave guide as a TE-Pass polarizer and TM-Pass polarizer holding a passband in the 3rd optical communicating window of 1550 nanometer. Polarizer is cardinal constituent for devices which require a individual polarisation for their operation. Most of the polarizer usage metal clad wave guides with proper thickness and refractile index of screen and substrate.Multilayer wave guides are used in the execution of a assortment of optical devices including semiconducting material optical masers, modulators, waveguide polarizer, Bragg reflectors, and directional couplings.We propose a multilayered SiON wave guide fabricated on substrate and has metalas screen is shown in fig 2. The pick of SiON is made for its super desirable characteristics such as pocket-sized interpolation loss, broad setting of refractile index tailoring and realisation of compact devices because of its low crease loss. The present constellation of optical polarizer provide happen applications in be optical circuits, signal processing from fiber ocular detectors and fiber gyro grasps. For the abridgment of the wave guide we have used the transportation matrix preparation.Fig.3 Geometry of multilayer wave guide construction= refractile index of the screen= refractile index of the movie i=1, 2r= refractile index of the substrate= thickness of the movie bed in micrometer= thickness of the movie bed in micrometerFigure 1FormulationFor the tally of backstage invariable and ensuing extension manner profile of multi-layered wave guide, there are following methods 1. Disturbance Method ( 4-layer )2. Newtons Method3. Mod e-matching method ( 5-layer construction )4. Transfer Matrix Formulation5. list regulation MethodThe disturbance method for a lossless 5-layer construction, for a lossy 4-layer construction, and for a metal-clad wave guide was used to find the extension invariables and the ensuing propagating manner profiles. Newtons method was used for metal-clad wave guides where the derived function of the scattering equation can be obtained analytically. A graphic method, every human action good as formal electromagnetic epitome methods such as the mode-matching method, was besides used. The disturbance method every bit good as Newtons method can non faint be ext give noticeed to multilayer constructions, since their attack is analytic and the expression involved catch cumbersome.None of the above methods can easy foretell the figure of propagating manners supported by the multilayer construction. This is a serious job since there is no manner of cognizing when to halt seeking for new pro pagating manners or pull down if the wave guide really can back up any manner at all. In fact, an extra analysis must be used to find the figure of guided manners before using the zero-searching techniques. Even if the figure of bing propagating guided manners is given, there is no hinderance that all the manners will be found. All the above mentioned methods have serious jobs in turn uping closely spaced roots. Furthermore, all of them quest an initial estimate near to the existent nothing. This initial estimation whitethorn be hard to happen, particularly for high-loss propagating manners where the popular disturbance method does non use. The method which we are utilizing, is based on complex figure theory. It is receptive of happening the nothing or poles of any analytic map in the complex matted. The scattering equation of a general multilayer wave guide is formed via the construct of thin-film transfer-matrix theory. After its uniqueness points are observed, the complex p lane is divided into parts where the scattering equation is analytic, and all the zeros inside for each one part are found. In add-on, the method provides the figure of nothing or poles in each part. The transfer-matrix analysis provides an easy preparation of the multilayer construction job. The method will be presented for TE manners but the extension to TM manners is straightforward.Fig.4 TE-Pass PolarizerA multilayer nonmagnetic slab wave guide construction( =O) ,is shown in Fig. 2. The refractile index,,of the IThursdaybed can be complex in general, i.e. ,,where,is the defunctness coefficient of the IThursdaybed and I = 1.. . ..randRis the layer figure. For aTelluriummanner propagating in the+way in the IThursdaybed, (tenI? x ? xi+1) , the electric land is,and the magnetic handle in the same bed iswhereare the unit vectors in theten, Y, omegaway, each,is the radian frequence, andis the complex extension invariable withandthe stage and the fading invariables independently2. 1TE ModeA multilayer nonmagnetic slab wave guide construction( =O) ,is shown in Fig. 3. The refractile index,,of the IThursdaybed can be complex in general, i.e. ,,where,is the extinction coefficient of the IThursdaybed and I = 1.. . ..randRis the layer figure. For aTelluriummanner propagating in the+way in the IThursdaybed, (tenI? x ? xi+1) , the electric field is,and the magnetic field in the same bed iswhereare the unit vectors in theten, Y, omegaway, severally,is the radian frequence, andis the complex extension invariable withandthe stage and the fading invariables severallyBy utilizing maxwells differential equations, we getFor TE manner,= 0, merelyconstituents will show.So by work outing above two Maxwells equations, we get( 1 )( 2 )( 3 )( 6 )whereis the freespace permittivity,and, c is the velocity of the visible radiation in the freespace andis the freespace wavelength. The electric and magnetic The galvanic and Magnetic digressive Fieldss within the IThursdaybed are solut ions of above equation, and can be written as= AI+ BI( 7 a )=j( 7 B )When we apply boundary status at=in equations ( 7 a ) and ( 7 B ) , so we will acquire( 8 )=cos +( 10 a )( 10 B )Adding equation ( 10 a ) and ( 10 B )( 11 )Using the continuity of the digressive Fieldss at any layer interface in the multilayer construction, the Fieldss digressive to the boundaries at the concealment of the substrate bed,and at the underside of the screen bed,, are related via the matrix merchandise=( 12 )Wherefor one = 1,2.. , R( 13 )Are the transportation matrices for all of theRbeds holding thickness. For propagating manners, the digressive Fieldss at the boundaries must be exponentially disintegrating holding the signifier( 14 )And( 15 )Where,From equation ( 12 ) , we getThe extinction ratio ( PER ) is defined as the ratio of power staying ( at the end produce terminal ) in themanner () to the power staying ( at the end product terminal ) in themanner () , expressed in dBs. In add-on, the inte rpolation loss ( PIL ) is defined as the power loss associated with themanner. FrankincensePER= 10PER= red in dubnium?Loss in dubniumPIL= 10()PIL=Loss in dubniumThe above equations undertake that the inputmanner has unit power at the input terminal of the polarizer. In effect to hold a good TE-pass polarizer, we require the power staying in the desiredmanner at the end product terminal of the polarizer to be every bit high as possible. Hence a low value of PIL is desirable. The effectivity of the polarizer in know aparting against the transition of themode comparative to themanner is measured by the PER parametric quantity. Therefore, this parametric quantity should be every bit high as possible. Hence, we require a high PER and at the same time a low PIL.Figure 5.1 Effective index w.r.t.normalized movie Figure 5.2 Loss w.r.t.normalized movie bedFig. 5.3 Effective index w.r.t.normalized movie bed Fig. 5.4 Loss w.r.t.normalized movie bedDecisionFirst of wholly, we have checked the map of TE manner by utilizing transportation matrix method 2 . The value of stage changeless and fading invariable for 6-layer Lossy Dielectric fluctuateguide are available. The available informations were calculated by the method of Argument Principle ( APM ) .Transportation Matrix method has been used to analyze a quaternary superimposed waveguide dwelling of SiON as guiding movie. On this footing, we have designed TE base on balls polarizer. The scope of SiON movie thickness was estimated so that merely the cardinal pervert TE0is supported. The computations showed that in the thickness scope of 0.7m -2.2 m of SiON, the wave guide supports merely TE0manner.In TE manner base on balls polarizer, the loss of TE manner is in the scope of 0.2 2.5 dB/cm and for TM mode its scope is 40 45 dB/cm, which rather higher in comparing to TE manner. So in this type of constellation of four bed wave guide, merely TE manner will go through.Mentions 1 Vishnu Priye, Bishnu P.Pal, and K.Thyaga rajan, digest and Design of a Novel Leaky YIG Film Guided Wave Optical Isolator, J. Lightwave Technol. , vol. 16, No.2, February 1998 2 Anemogiannis and E.N.Glytis, Multilayer waveguides Efficient numerical analysis of general constructions, J. Lightwave Technol. , vol. 10, pp. 1344-1351, 1992 3 M.Ajmal Khan and Hussain A. Jamid, TE/TM Pass Guided Wave Optical Polarizer , IEEETEM2003 4 H.Kogelnik, Theory of Optical Waveguides in Guided-wave Optoelectronics, T. Tamir, Ed. New York Springer-verlag, 1988 5 AJOY K. GHATAK, K. THYAGARAJAN, AND M. R. SHENOY mathematical Analysis of Planar Optical Waveguides Using Matrix Approach 6 Ajoy Ghatak and K.Thyagarajan, Optical Electronics , Cambridge University Press 7 Joseph A Edminister and Vishnu Priye, Electromagnetics Schaums Outline, Tata MacGraw preparation Private Limited