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(IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 Improvement of the Performance of Advanced Local Area Optical Communication Networks by Reduction the Effects of the Propagation Problems * Mahmoud I. Abd-Alla Fatma M. Aref M. Houssien Electronics & Communication Department, Faculty of Engineering, Zagazig University, EGYPT Email: mabdalla@gmail.com, *E-mail: fatma_shahin2010@yahoo.com Abstract In the present paper, the improvement of transmission distance when the light traveling down a fiber optic cable and bit rates of Advanced Local Area Optical Communication “spreads out,” becomes longer in wavelength and Networks (ALAOCN) are investigated by reducing the effects eventually dissipates. Attenuation, a reduction in the of propagation problems over wide range of the affecting transmitted power, has long been a problem for the fiber parameters. Dispersion characteristics in high-speed optical transmission systems are deeply analyzed over a span of optics community. However, researchers have optical wavelengths from 1.2 μm up to 1.65 μm. Two different established three main sources of this loss: absorption, fiber structures for dispersion management are investigated. scattering, and dispersion [2, 3]. Fiber to the Home Two types of fabrication material link of single mode fiber (FTTH) technology is one of the main research made of Germania doped Silica and plastic fibers are objectives of the lasts years in optical fiber suggested. Two successive segments of single mode fiber communication. The increasing development of data made of Germania doped Silica are suggested to be employed communications and the emerging of applications periodically in the long-haul systems. The two successive demand a redesign of the access networks in order to segments are: i) of different chemical structures (x), or ii) of accomplish new bandwidth and latency requirements. different relative refractive index differences (Δn). As well as Wireless communications are a good alternative for the total spectral losses of both fabrication materials and total insertion losses of connectors and splices of these fabrication quick deployments and low cost implementations but materials are presented under the thermal effect of to be this technology cannot compete against optical processed to handle both transmission lengths and bit rates per communications in terms of available bandwidth, channel for cables of multi links over wide range of the latency and robustness. Since 1980, several techniques affecting parameters. Within soliton and maximum time have been proposed and applied to reduce such division multiplexing (MTDM) transmission techniques, both phenomenon which severely reduces the transmitted bit- the transmission bit rate and capacity-distance product per rate [4, 5]. The rapid increase of transmission capacity channels for both of silica doped and plastic fabrication need is requiring higher speed optical communication materials are estimated. The bit rates are studied within system. However, the upgrade of most installed system thermal sensitivity effects, loss and dispersion sensitivity effects of the refractive index of the fabrication core materials at third window to multi-Giga-bit rate is limited by the are taken into account to present the effects on the high linear chromatic dispersion of the optical standard performance of optical fiber cable links. Dispersion fiber deployed worldwide [6, 7]. To upgrade existing characteristics and dispersion management are deeply studied networks based on standard single-mode 1310 nm where two types of optical fiber cable core materials are used. optimized optical fibers, several all-optical dispersion A chromatic dispersion management technique in optical compensation techniques have been proposed [6].Recent single mode fiber is introduced which is suitable for progress in optical fiber amplifier technology makes (ALAOCN) to facilitate the design of the highest and the best fiber dispersion the ultimate limiting factor for high- transmission performance of bit rates in optical networks. speed long-distance optical fiber transmission. Low- Keywords: Propagation problems, Single mode fiber (SMF), chirp, high-speed optical sources are indispensable for Fiber losses, Dispersion types, Dispersion management, long-haul multi Giga bit-per-second optical Soliton Bit rate thermal sensitivity, optical link design, communication systems [7].Traffic demand has been Thermal effects, Advanced-optical networks. increasing steadily in the last few years. In order to support this increasing traffic demand the optical links 1. Introduction between the main cities, which are typically terrestrial links with hundreds of kilometers operating at 10 Fiber optic transmission and communication Gbit/sec per channel, have to be upgraded. A solution are technologies that are constantly growing and for the upgrading of these links is to increase the bit rate becoming more modernized and increasingly being used per channel to 40, 80 or even to 160 Gbit/s. Access in the modern day industries [1]. Dispersion occurs optical networks are capable of solving those 21 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 requirements for present and future applications. The α S ≡ Rayleigh scattering ⎛ 0 . 75 + 66 Δ n ⎞ ⎛ T =⎜ ⎟ ⎜ ⎞ ⎟ dB/km (3) ⎜ ⎟ ⎜T ⎟ recent explosive growth of the internet has triggered the ⎝ λ4 ⎠ ⎝ 0 ⎠ introduction of broadband access network based on Where we have assumed that the scattering loss is FTTH. To deal with various demands [6], access and linearity is related to the ambient temperature (Τ) and metro networks require scalability in terms of capacity (T0) is a reference temperature (300 °K), (Δn) and (λ) and accommodation and flexibility with regard to are the relative refractive index difference and optical physical topology [7]. Therefore, new specific signal wavelength respectively. The absorption losses (α components are required. The advanced high speed UV: Ultra-violet losses) and (α IR: Infra-red losses) are technology of core networks is expected to provide cost given as in reference [14]: effective migration of the component solutions towards αUV = 1.1×10−4 ω ge 0 0 e 4.9λ dB/km (4) access applications; however, improvements in terms of 2 ⎛ − 24 ⎞ the integration of functions and low cost packaging have α IR = ⎜ 7 × 10−5 e λ⎟ dB/km (5) ⎜ ⎟ ⎝ ⎠ to be made. Dense wavelength division multiplexing (DWDM) is widely becoming accepted as a technology Where (ωge %) is the weight percentage of Germania, for meeting growing bandwidth, and WDM systems GeO2 added to optical silica fibers to improve its optical beginning to be deployed in undersea transmission characteristics. telecommunications links [8, 9]. 2.1.2. Plastic fibers attenuation model As complexity of optical dense wavelength Plastics PMMA Polymethyl Methacrylate, as all division multiplexing (DWDM) networks increases due any organic materials, absorb light in the ultraviolet to the large number of channels involved, managing the spectrum region. The mechanism for the absorption large spectral variations in the dispersion and gain depends on the electronic transitions between energy becomes more difficult as the desired spectral bandwidth levels in molecular bonds of the material. Generally the increases. Dispersion managed soliton, now being electronic transition absorption peaks appear at developed by a number of different groups, can resolve wavelengths in the ultraviolet region, and their the technical problems that in the past have prevented absorption tails have an influence on the plastic optical the use of the soliton transmission format in optical fiber fiber (POF) transmission loss [15]. According to communication systems [10-12]. Optical solitons are urbach’s rule, the attenuation coefficient αe due to stable nonlinear pulses formed in optical fibers when the electronic transitions in POF is given by the following nonlinearity induced by the optical intensity is sufficient expression [15]: α e (PMMA) = 1.10 × 10 − 5 exp⎜ ⎟ dB/km (6) ⎛8⎞ to balance the dispersion of the fiber. In an ideal lossless ⎜ ⎟ ⎝λ⎠ fiber, solitons would not distort in either the time or Where: (λ) is the optical signal wavelength of light in frequency domains, regardless of the distance over (μm). In addition, there is another type of intrinsic loss, which they propagated. A dispersion managed fiber is caused by fluctuations in the density, and composition made by alternating sections of positive and negative of the material, which is known as Rayleigh scattering. dispersion fiber to create a transmission line with high This phenomenon gives the rise to scattering coefficient local dispersion and low total dispersion [13]. (αR) that is inversely proportional to the fourth power of 2. Modeling Basics and Analysis the wavelength, i.e., the shorter is (λ) the higher the Special emphasis is given to the propagation losses are. For POF, it is shown that (αR) is [16]: problems in silica-doped and plastic fibers as promise ⎛ 0.633 ⎞ α R (PMMA) = 13 ⎜ ⎟ 4 dB/km (7) ⎝ λ ⎠ links in long and short–distance advanced optical Then the total losses of plastic optical fibers are given: communication networks. Silica-doped and plastic fibers 4 ⎛8⎞ ⎛ 0 .633 ⎞ characteristics (spectral loss and chromatic dispersion) α total (PMMA ) = 1 .10 × 10 − 5 exp ⎜ ⎟ + 13 ⎜ ⎟ dB/km are thermal dependent, thus, these two variables must be ⎝ λ⎠ ⎝ λ ⎠ taken into account when studying the transmission (8) capacity of the fibers. The processed propagation 2.1.3. Connector and splice attenuation model problems in this study will deeply defined, analyzed, There are many types of connectors developed for investigated parametrically and treated over wide range fiber cable. A connector is used to join a fiber cable to a of the affecting parameters. transmitter or receiver, or is used to join together strands 2.1. Simplified attenuation model of fiber. A connector for fiber is similar in concept to a 2.1.1. Silica-doped fibers attenuation model traditional electrical connector, but the fiber connector is Based on the models are given in reference [14], the actually more delicate, as it must precisely align the spectral losses of silica-doped fibers are cast as: internal fibers to insure a proper flow of data through the α = α I + α S + α UV + α IR dB/km (1) cables. Before connecting one fiber with the other fiber Where α I ≡ the intrinsic loss ≅ 0.003 dB/km, and (2) in the fiber optic communication link, one must decide whether the joint should be permanent or demountable. 22 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 Based on this, two types of joints are presented. A pulse spreading) arises from the use of sources with a permanent joint is done by splice and a demountable finite spectral spread, since signals impressed on a fiber joint is done by connector. The insertion loss of any at different wavelengths will have different group connector can be expressed as given by [17]: velocities. The transit time τ(λ) of a mode at a ⎛ P ⎞ dB/km (9) wavelength (λ) may be related to that at the mean source IL( Insertion Loss) = 10 log ⎜ i ⎟ ⎜P ⎟ ⎝ t⎠ wavelength (λo) by expanding as a Taylor series about Where (Pi) is the incident power in (mWatt) and (Pt) is (λo) as given in [19-21]: the transmitted power in (mwatt). For single mode fibers (SMF), the Fresnel reflection loss caused by the dτ 1 d 2τ τ (λ ) = τ (λo ) + (λ − λo ) + (λ − λo ) 2 differences between the refractive indices of the silica- dλ λ 2 dλ2 λ o o doped, (n=n1) and plastic fibers, (n=n2) and the material separation are given as the following [18]: 1 d 3τ + (λ − λo )3 (23) ⎛ 4n n ⎞ 6 dλ3 λo Loss = 20 log ⎜ 1 clad ⎟ dB/km (10) ⎝ 1 clad ) ⎠ ⎜ (n + n 2⎟ dτ 1 d 2τ 1 d 3τ ⎛ 4n n ⎞ Δτ = Δλ + (Δλ ) 2 + (Δλ )3 (24) Loss = 20 log ⎜ 2 clad ⎟ dB/km (11) dλ λ 2 dλ2 6 dλ3 ⎜ (n + n )2 ⎟ o λo λo ⎝ 2 clad ⎠ Lm Where (n1) is the refractive-index of silica-doped core Noting that: τ = (25) C material, and (n2) is the refractive-index of plastic core material. The cladding refractive-index can be expressed Where (L), (C), and (m) are the fiber length, the velocity as a function of both silica-doped and plastic core of light in vacuum, and the group index for the mode refractive-indices and relative refractive-index respectively, (m) is given by assuming good dn1 difference as the following: confinement in [20]: m = n1 − λ (26) dλ nclad = (1 − Δn ) n1 (12) We can deduce that nclad = (1 − Δn ) n2 (13) L ⎡ dn1 ⎤ Then by substituting with equations (12, 13) into τ= ⎢n1 − λ dλ ⎥ (27) C ⎣ ⎦ equations (10, 11), we can obtain: The use of Eq. (27) into Eq. (24) yields per unit length: ⎛ 4 (1 − Δn ) n 2 ⎞ Loss (silica − doped ) = 20 log ⎜ 1 ⎟ dB/km (14) ⎡ d 3n ⎤ ⎜ (2 n − Δn ⋅ n )2 ⎟ Δλ d 2 n1 (Δλ ) 2 ⎢λ 2 1 + d n1 ⎥ ⎝ 1 1 ⎠ Δτ = .λ − ⎛ 4 (1 − Δn ) n 2 ⎞ C dλ2 2C ⎢ dλ3 ⎣ dλ2 ⎥ ⎦ λo dB/km (15) λo Loss ( plastic ) = 20 log ⎜ 2 ⎟ ⎜ (2 n − Δn ⋅ n )2 ⎟ ⎝ 2 2 ⎠ 2.2. Simplified dispersion model analysis (Δλ )3 ⎡ d 4 n1 ⎢λ d 3n1 ⎤ ⎥ (28) − +2 2.2.1. Silica-doped fiber dispersion model 6C ⎢ dλ 4 dλ3 ⎥ ⎣ ⎦ λo We have employed Germania-doped Silica fiber as a communication channel, where (x) is the mole fraction Where higher-order dispersion modes are considered, of Germania added to silica material. The refractive following the same spirit of Refs. [20, 21], in separating index of silica-doped material may be evaluated the various contributions to the total chromatic following the three terms Sellmeier equation [19]: dispersion in single mode fibers of radius (a), we have: 2 3 Ai λ2 (Δτch/Δλ.L) = Dt = total chromatic dispersion n1 = 1 + ∑ (16) 2 i =1 λ − λi 2 coefficient= (Mmd + Mwd + Mpd), (29) Where: Mmd = material dispersion coefficient Where (n1), (λ), (Ai), and (λi) are the core refractive ⎡ ⎤ index, the oscillator strength and the oscillator wave λ d 2 n1 Δλ ⎢ d 3n1 d 2 n1 ⎥ = + λ + length respectively. For GeO2-SiO2 fibers of x % GeO2 C dλ2 2C ⎢ dλ3 dλ2 λ ⎥ ⎥ λo ⎢ ⎣ o⎦ (mole), the two sets (Ai) and (λi) are given [19]: A1 = (0.6961663 + 0.11070010 x) fT 1 , (17) ⎡ ⎤ (Δλ ) 2 ⎢ d 4 n1 d 3n1 ⎥ A2 = (0.4079426 + 0.31021588 x) f T 1 , (18) − λ +2 (30) 6C ⎢ dλ4 dλ3 ⎥ ⎢ ⎣ λo ⎥ ⎦ A3 = (0.8974794 − 0.04331091x) f T 1 , (19) Mwd = waveguide dispersion coefficient λ1 = (0.0684043 + 0.00568306 x) f T 2 , (20) 2 λ 2 = (0.1162414 + 0.03772465x) f T 2 , (21) n Δn ⎛ m ⎞ = 1. ⎜ ⎟ M (V ) (31) C λ ⎜ n1 ⎟ ⎝ ⎠ And λ3 = (9.896161 + 1.94577 x) f T 2 . (22) Where fT1=0.93721+2.0857x10-4T, fT2=T0/T, (T0) is a Mpd = profile dispersion coefficient reference temperature and T is the medium (fiber n Δn \ ⎛ λ Δn \ m ⎞ = 1 ⎜ − ⎟ M (V ) (32) temperature) [19-21]. Chromatic dispersion (a cause of C ⎜ 4 Δn n1 ⎟ ⎝ ⎠ 23 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 (n1 − nclad ) 1 Δn = (33) ⎛ ⎛ N Δn ⎞2 ⎛ α − 2 − ε ⎞ 2 2α ⎞ 2 n1 P = ⎜⎜ 1 ⎟ ⎜ ⎟ × ⎟ (46) ⎜ ⎝ cλ ⎠ ⎝ α + 2 ⎠ 3α + 2 ⎟ \dΔn ⎝ ⎠ Δn = (34) dλ Where the group index for the mode is given by: dn2 V = 2π 2 a n12 − nclad / λ , and (35) N1 = n2 − λ (47) dλ 2 Where: (Δτ) is the total pulse spreading due to chromatic M (V ) = 0.08 + 0.549(2.834 − V ) (36) dispersion in nsec, (Wmd) is the material dispersion Equation (30), in our suggested basic model, accounts coefficient in nsec/nm.km, (P) is the profile dispersion for the material dispersion (the first, the second, and the coefficient in nsec/nm.km, and (Δn) is the relative third -order dispersion effects simultaneously). Then the refractive index difference defined as: use of Eq. (16) yields: n2 − ncladding 2 2 (48) 2 3 − Ai λi λ Δn = n1n1\ = ∑ (37) 2 2 n2 ( i =1 λ2 − λ2 2 i ) Where (n2) is the cable core refractive index, (ncladding) is 3 A λ2 (3λ3 + λi ) 2 the core cladding refractive index, and (C1) is a constant n1n1\ \ + n1\ 2 = ∑ i i , and (38) i =1 ( λ2 − λi2 3 ) and is given by the following expression: α − 2−ε C1 = (49) 2 2 3 − 12 Ai λi λ (λ2 + λi ) n1n1\ \ \ + 3n1\ n1\ \ = ∑ (39) α +2 i =1 ( λ2 − λi2 4 ) Where (α) is the index exponent, (ε) is the profile 2 2 2 2 3 12 AiT λiT (5λ4 + 10λiT λ2 + λiT ) dispersion parameter, and is given by the following: n1n1\ \ \ \ + 4n1\ n1\ \ \ + 3n1\ \ = ∑ 2 n λ dΔn i =1 λ2 − λiT 2 ( 5 ) ε =− 2 N1 Δn dλ (50) (40) 2.2.2. Plastic fiber dispersion model 3. Transmission Techniques for Reducing The plastic cable core material which the Propagation Problems investigation of the spectral variations of the refractive- The need of communication is an all time need index (n2) requires Sellemeier equation given in [22]: of human beings. For communication some channel is needed. Fiber is one channel among many other 2 3 Bi λ2 n2 = 1 + ∑ (41) channels for communication. The dispersion 2 i =1 λ − λi 2 phenomenon is a problem for high bit rate and long haul For the plastic fiber material, the coefficients of the optical communication systems. An easy solution of this Sellmeier equation and refractive-index variation with problem is optical solitons pulses that preserve their ambient temperature are [22]: B1= 0.4963, λ1= 0.6965 shape over long distances. Soliton based optical (T/T0), B2= 0.3223, λ2= 0.718 (T/T0), B3= 0.1174, and communication systems can be used over distances of λ3= 9.237. Then the first and second differentiation of several thousands of kilometers with huge information Eq. (41) with respect to (λ) yields: carrying capacity by using optical amplifiers. Soliton 2 communication systems are a leading candidate for 3 − Bi λi λ n2 n2 \ = ∑ (42) long-haul light wave transmission links because they i =1 (λ2 − λi2 )2 offer the possibility of dynamic balance between group 3 Bi λi (3λ3 + λi ) 2 2 velocity dispersion (GVD) and self-phase modulation n2 n2 \ \ + n2 \ 2 = ∑ (43) i =1 (λ2 − λi23 ) (SPM), the two effects that severely limit the performance of non soliton systems. Most system The total chromatic dispersion ( Dt ) of the output pulse experiments employ the technique of lumped width in single mode fibers of (POF) is given by [22]: amplification and place fiber amplifiers periodically Δτ along the transmission line for compensating the fiber Dt = = ( W md + P ) nsec/nm.km (44) loss. However, lumped amplification introduces large Δλ ⋅ L peak-power variations, which limit the amplifier spacing The output pulse width from single mode plastic optical to a fraction of the dispersion length. Soliton fiber (POF) was taken into account both material and propagation is employed where the controlling profile dispersions, and thus modal dispersion is equal to parameters lead to a balance between the pulse zero for single mode fibers [23]: spreading due to dispersion and the pulse shrinking due 1 ⎛ λ3 dn 2λ ⎛ d 2 n2 ⎞ ⎞ 2 to nonlinearity. The balance between the non-linearity Wmd = ⎜ − 2 ⎜ ⎟ (N Δn ) × C ⎛ 2α ⎞ ⎟ ⎜ c dλ − c ⎜ ⎜ 2 ⎟ 1 1⎜ ⎟⎟ ⎝ α + 2 ⎠⎟ effects from one side and the dispersion effects from the ⎝ ⎝ dλ ⎠ ⎠ other side creates a solitary wave [24]. The dispersion of (45) a medium (in the absence of non-linearity) makes the 24 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 various frequency components propagate at different Where: (nnl) is the nonlinear Kerr coefficient in m2/watt, velocities; while the non-linearity (in the absence of (Aeff) is the effective area in µm2/Watt, dispersion) causes the pulse energy to be continually (Pso) is the optical signal power in Watt, injected, via harmonic generation, into higher frequency (λs) is the optical signal wavelength in µm, modes. That is to say, the dispersion effect results in and (Dt) is the total chromatic dispersion coefficient in broadening the pulse while the non-linearity tends to nsec/nm.km. Ref. [27] derived the condition for MTDM sharpen it. Analysis given in references [25, 26], the where the bit rate Brm is given by: soliton bit rate per channel (Brs) is given by: 0.25 Brm = Gbit / sec (52) − − λ Aeff 3.2 x10 −20 τ min Brs2 = 59.7 Pso1( s )( )( ) Dt x106 (51) 1.54 20 nnl Where: (τmin) is the minimum pulse broadening in nsec. B S Drm = D dBrm . . = . 2 ( 2 2 3 4 3 3 2 D 14.7 λs Aeff B1 A1 λs + T B2 A1 λs )2 The spectral and thermal sensitivities are the guide of Brm dD Brm ( nnl Pso T B1 A2 λs − A2 B1 λ4 2 3 2 2 4 )3 the measurement the relative variations of the outputs s and the relative variations of the inputs. The soliton and (58) MTDM bit rate within thermal, loss, dispersion Using the series of the set of equations analysis sensitivity coefficients, and parameters as ( ST ), Brs from Eq. (1) to Eq. (59), the transmission bit rates per ( Sα ), ( S D ), ( ST ), ( Sα ), and ( S D ) are taken Brs Brs Brm Brm Brm channel for both silica-doped and plastic materials are investigated under wide optical ranges which give the into account as criteria of a complete comparison minimum values of both total losses and total between silica doped and plastic materials and are given: dispersion. The calculations are based on the values: T dBrs T A1 B1 3λ3 B1 + Dt λ1 2 2 ( 2 ) (53) Central optical signal wavelength (λ0) is selected to be ( ) B ST rs = . = . Brs dT Brs λ3 − A2 B 2 + Dt2λ2 A2 B 3 (1.2 μm ≤ λ0 ≤ 1.65μm), relative refractive index 1 2 2 B Sα rs = α . dBrs = α 0.633 B1 α t 2λs A1B3 T + λs A2 B1 T . 2 2 ( 2 2 4 3 4 3 ) 2 (54) difference for silica-doped material (Δn) is chosen to be Brs dα Brs 2 ( 3 3 2 33 A1 λs T + α t B2 λs ) ( 0.006 ≤ Δn ≤ 0.008 ), source spectral line width (Δλ) is selected to be (0.1 nm ≤ Δλ ≤ 0.5 nm), GeO2 mole B S Drs = D dBrs . = . 2 2 2 3 3 (3 3 2 D 14.7 λs Aeff A1 B1 T λs + A2 B1 λs ) 3 (55) fraction (x) is chosen to be ( 0.0 ≤ x ≤ 0.2 ), relative Brs dD Brs 3 2 (2 2 4 42 nnl Pso A1B2 λs − T B2 A1 λs ) refractive index difference for plastic material (Δn) is determined where ( 0.05 ≤ Δn ≤ 0.07 ), and fiber B ST rm = T dBrm . = 2 2 3 2 3 3 T B1 A2 4 λ A1 + Dt λ1 A2 B2 . ( ) (56) temperature (T) is chosen to be (290°K ≤ T ≤ 330°K). Brm dT Brm 2 2 2 (3 2 4 2 λ + B2 A3 − Dt λB2 A2 ) B Sα rm = α . dBrm = α 2 s ( 0.633 A1 α t 2λ2 B1 A3 T 5 + λ4 B2 A1 2 s 3 4 )2 dα . Brm Brm (2 2 3 B1 λs α t5 + T 2 A2 λ3 s ) (57) 4. Results and Discussions We have analyzed the propagation problems of ambient temperature (T0 ), and relative refractive-index these materials in the interval of 1.2 µm to 1.65 µm difference (Δn)}, both the effective performance of under the set of affecting parameters at temperature plastic, and Germania-doped silica fibers are processed range varies from 290 °K to 330 °K. The following based on the transmission bit rate or capacity-distance numerical sets of data are used to obtain transmission bit product per channel: Transmitted bit-rate x transmission rate and capacity-distance product per channel as distance (L) is given by: follows: (1.2 μm ≤ λ0 ≤ 1.65 μm); (λ0): central optical Pr = B r × L , Gbit.km/sec (59) signal wavelength, (0.1 nm ≤ Δλ ≤ 0.5 nm); (Δλ): The transmitted bit-rate per optical channel is also a spectral line width of the optical source, effective area; special criterion for comparison for different fiber cable Aefff= 85 µm2, (2 Km ≤ L ≤ 10 Km); (L): transmission materials of plastic and silica-doped fibers. Based on the distance, (0.0 ≤ x ≤ 0.2); (x): percentage of Germania clarified variations in figures (1- 20), the facts are doped in silica fibers, (0.05 ≤ ΔnPMMA ≤ 0.07); assured: (ΔnPMMA): relative refractive-index difference, (0.006 ≤ Δnsilica-doped ≤ 0.008), (Δnsilica-doped): relative refractive- index difference for silica-doped, (4 mwatt ≤ Ps ≤ 30 mwatt); (Ps): optical signal power. At the set of affecting parameters {optical signal wavelength ( λs), 25 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 26 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 27 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 28 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 i- Figs. (1, 2) prove that as λ0 increases, the total spectral T increases, total dispersion coefficient also increases losses decrease at constant both T, and Δn for silica- at constant λ0. doped fibers. But as Δn, and T increase, the total vi- Figs. (11, 12) indicate that as the Pt increases, the spectral losses also increase at constant λ0. total insertion loss decreases for both silica-doped and ii- Figs. (3-4) indicate that as L increases, the plastic fibers at constant Δn. As well as Δn increases, transmission bit rate per channel decreases for both the total insertion loss also increases at constant Pt. silica-doped and plastic fibers at constant T. As well vii- Figs. (13, 14) demonstrate that as L increases, the as T increases, the transmission bit rate per channel transmission bit rate per channel decreases for both decreases at the constant L. silica-doped and plastic fibers at constant Δn. But iii- Figs. (5-6) assure that as T increases, the capacity- as Δn increases, the transmission bit rate per distance product per channel decreases for both channel decreases at constant L. silica-doped and plastic fibers at constant L. viii- Figs. (15, 16) assure that as Dt increases, the soliton Moreover as L increases, the capacity-distance and MTDM bit rates decrease for both silica-doped product per channel also increases at constant both and plastic materials, but with silica-doped presents T. higher bit rates than plastic materials at minimum iv- Figs. (7, 8) demonstrate that as λ0 increases, total losses. dispersion coefficient also increases for both silica- x- Figs. (17, 18) indicate that as T increases, Soliton doped and plastic fibers at the constant Δn. As well as bit rate thermal sensitivity also increases at constant Δn increases, total dispersion coefficient also Dt, but with increasing Dt, we have observed that increases at constant λ0. soliton bit rate thermal sensitivity deceases at v- Figs. (9, 10) prove that as λ0 increases, total constant T for both silica-doped and plastic dispersion coefficient also increases for both silica- materials. doped and plastic fibers at the constant T. As well as 29 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 8, No. 4, July 2010 xi- Figs. (19, 20) prove that as T increases, MTDM bit technique and offers the best conditions for the rate thermal sensitivity also increases at constant Dt, performance of transmission bit rates and capacity- but with increasing Dt, we have observed that distance products of silica-doped and plastic materials MTDM bit rate thermal sensitivity increases at for different transmission distances in advanced local constant T for both silica-doped and plastic area optical communication networks for suitable materials. operating conditions as shown in Table 1. Therefore we can summarize reduction of the propagation problems within soliton transmission Table 1: Transmission bit rates and capacity-distance product for both silica-doped and plastic core materials. Fiber cable core materials Silica-doped material Plastic material Best conditions of operation Best conditions of operation Transmission at Δn = 0.006 and T = 290 ºK at Δn = 0.05 and T = 290 ºK Distance Capacity-distance Capacity-distance Transmission bit product/channel Transmission bit product/channel rate/channel (Gbit/sec) (Gbit.km/sec) rate/channel (Gbit/sec) (Gbit.km/sec) L = 2 Km 8 Gbit/sec 30 Gbit.km/sec 0.5 Gbit/sec 1.5 Gbit.km/sec L = 5 Km 5 Gbit/sec 45 Gbit.km/sec 0.3 Gbit/sec 2 Gbit.km/sec L = 8 Km 2 Gbit/sec 60 Gbit.km/sec 0.1 Gbit/sec 2.5 Gbit.km/sec 5. Conclusions fibers will be increased. Therefore we can say that the The characteristics of both of silica doped and lowest total dispersion and total losses of silica-doped plastic fibers are investigated under the different fibers make these fibers as the best candidate media for affecting parameters. soliton and MTDM high long haul optical transmission in advanced optical transmission techniques are employed for reducing the communication networks. propagation problems as limiting factors such as total losses and dispersion across silica-doped and plastic References materials in (ALAOCN) within suitable affecting [1] M. Hossen, M. Asaduzzaman, and G. C. Sarkar, parameters. 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