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METHODS OF REDUCING THE PROBABILITY OF SIGNAL LOSS ON OPTICAL FIBER COMMUNICATION LINES Iskandarov U.U.1, Khalilov M.M.2, Dalibekov L.R.3, Nabijonov R.M.4 Email: [email protected]
1Iskandarov Usmonali Umarovich - Senior Teacher; 2Khalilov Mukhammadmuso Mukhammadyunusovich - Senior Teacher; 3Dalibekov Lochinbek Rustambekovich - Assistant, TELECOMMUNICATION ENGINEERING DEPARTMENT;
4Nabijonov RavshanbekMukhammadjohn o'g'li - Student, DIRECTION: TELECOMMUNICATION TECHNOLOGIES, TELECOMMUNICATION TECHNOLOGIES AND PROFESSIONAL EDUCATION FACULTY,
FERGHANA BRANCH TASHKENT INFORMATION TECHNOLOGIES UNIVERSITY, FERGHANA, REPUBLIC OF UZBEKISTAN
Abstract: the article under discussion depicts methods of reducing the probability of signal loss on optical fiber communication lines. Today development of data transmission in optical fibers without loss signals areremains as an important task. Many of scientific works around the world are being carried out on this area. The authors of the article analyzed the ways to prevent the loss of optical signals and ways to reduce the probability of losses in the optical data transmission system. It also examines the factors that affect the reliability of the optical transmission system under study and draws appropriate conclusions.
Keywords: optical fiber, macro bend, micro bend, digital signals, timing diagram, window of transparency, extinction, DWDM (dense wavelength division multiplexing) device.
МЕТОДЫ СОКРАЩЕНИЯ ВЕРОЯТНОСТИ ПОТЕРИ СИГНАЛА НА
ЛИНИИ ОПТИЧЕСКОГО ВОЛОКНА Искандаров У.У.1, Халилов М.М.2, Далибеков Л.Р.3, Набижонов Р.М.4
1Искандаров Усмонали Умарович - старший преподаватель; 2Халилов Мухаммадмусо Мухаммадюнусович - старший преподаватель; 3Далибеков Лочинбек Рустамбекович - ассистент, кафедра телекоммуникационного инжиниринга; 4Набижонов Равшанбек Мухаммаджон угли - студент, направление: телекоммуникационные технологии, факультет телекоммуникационных технологий и профессионального образования,
Ферганский филиал Ташкентский университет информационных технологий, г. Фергана, Республика Узбекистан
Аннотация: в данной статье представлены методы снижения вероятности потери сигнала на оптоволоконных линиях связи. В настоящее время развитие передачи данных в оптическом волокне без потерь сигналов является важной задачей. В последнее время во всем мире ведутся многие научные работы в этой области. Авторы статьи проанализировали способы предотвращения потери оптических сигналов и способы снижения вероятности потерь в оптической системе передачи данных. В ней также рассмотрены факторы, влияющие на надежность исследуемой оптической системы передачи данных, и сделаны соответствующие выводы.
Ключевые слова: оптическое волокно, макроизгиб, микроизгиб, цифровые сигналы, временная диаграмма, окно прозрачности, исчезновение, устройство DWDM (плотное мультиплексирование с разделением длин волн).
UDC 004.08
Today using of information is leading to an increase in the demand for the protection. There are various methods of data protection in FL (fiber lines). There are many factors to loss in fiber optic. Many factors can be caused for signal loss. The signal transmitted across the FDTOL (fiber optic transmission line) system propagates according to the law of complete internal reflection, FDTOL (fiber optic transmission line) has a high degree of protection. However, OF (optic fiber) has attenuation, that occurs for a whole number of reasons: Fresnel reflection, specific absorption, absorption, radiation in micro and macro bends, and more.
Microscopy is a microscopic change in the geometry of the fiber core during this manufacturing process. Microbending is causes by the fact that the core is not located in the center of the gladding.[4]. Micro-bends increase cable signal losses. These losses can be different and in some cases can exceed 100 dB/km. The minimum allowable radius of bending of a fiber is 10 cm. In such bending, light pulses propagate with a less distortion. Decreasing the bending radius increases the scattering effect of optical pulses through the fiber sheath. The imperfection of the produced optical fiber, changes in fiber geometry lead to the fact that the fibers are not easily, quickly and efficiently welded. The reasons for losses in welding, fiber bonding are: the mismatch of fiber core sizes, differentiation of fiber refractive indices, the fibers do not intersect the longitudinal axes when connected, differentiation of angular apertures of fibers, formation of air bubbles due to non-tight bonding of fibers [3]. All of these factors increase the attenuation, loss of optical signals.
Fig. 1. Factors that cause signal loss in optical fibers
The concept of fiber optic transmission line (FDTOL) is a collector. It includes fiber optic cables, receivers, optical signal transmitters, regenerators and other devices. Each of the components can be a source of unauthorized access.[3]. In the transmission of information in optical fibers, the method of intensity of optical modulation is used. In this case, 0 and 1 digit signals are transmitted based on the change in the optical power of the laser. If the optical signal transmitted from the optical fiber is lost for some reason, it is practically impossible to restore signal.As can be seen from the figure above, optical signals are transmitted in a series digital signals.In modern communication systems, signals are transmitted by bidirectional (two-way) single over the fiber.
Fig. 2. Single direction optical transmition network
Fig. 3. Transmission of two-way signals via a single fiber
Preventing the loss of optical signals due to the above losses is one of the important issues. For this case, the principle of into 2 splitting digital signals or 2 fiber using.
Fig. 4. Schematic diagram of the transmission of digital signals by 2 optical fibers
The digital zero and 1 signals coming from the digital device are separated using a splitter, and the 1 signals are fed to the optical laser l2, and the 0 signals are passed through the inverter and converted to logical 1 signals, then the optical laser l1 converts it into optical signals. Optical signals come to the input optical fiber using a multiplexer device. The reverse process perform the receiving part. Our main goal is to be able to recover transmitted optical signals relative to each other.
A is digital signals transmitted on a coordinate axis (x). B is the signals after the inverter for the 0's of the digital signals transmitted on the B coordinate axis, the logical "1" signals are given in the C coordinate. In the receiving system, the adder checks the accuracy of the incoming signals. For example, if the signals from the optical laser l2 are lost, it restored based on the optical laser l1 signals. In addition, when optical signals go over long distances, noise signals generated in the optical fiber and distortion of the optical signals under the influence of dispersion occur. As a result, of synchronization of signals, it will be possible to distinguish useful signals from them by distinguishing them from each other [2]. But this method can also ensure information security in optical fibers. To do this, you can create a table on the following logic table 1.
Table 1. Logic table
Xi X2 Y
0 0 0
0 1 1
1 0 1
1 1 0
Fig. 5. Timing diagram of optical signal separation
Digital signals 0 and 1 are generated and transmitted based on the table above. In the receiving system, this logic amount restored based on the table too [1].
DWDM (dense wavelength division multiplexing) is widely uses of modern optical networks. The DWDM (dense wavelength division multiplexing) device multiplexes up to 40 optical signals along the wavelength. Through these channel we will be able to create 20 channels. In DWDM (dense wavelength division multiplexing), we are able to hide useful signals by randomly assigning channel pairs.
Fig. 6. Time diagram of optical fiber information security
Fig. 7. Time diagram of optical fiber information security References / Список литературы
1. Sklyarov O.K. Modern fiber-optic systems of transmission. Hardware and elements. M.: Solon-R, 2001. P. 237.
2. UbaydullaevR.R. Fiber-optic sets. M.: EKO-TRENDZ, 1998. P. 267.
3. Mirazimova G.X. "Fundamentals of Optical Communication", TUIT. Tashkent, 2006. P. 118.
4. Voronin V.E., Naniy A.N., Turkin V.I., Khlystov V.A., Kamynin A. Integral poteri v elementax volokonno-opticheskix liniy svyazi. M., 2012. P. 51.
5. Gagliardi RM, Karp Sh. Optical communication: Translated from English by S. M. Babia, ed. by A.T. Sheremetiev. Moscow: Svyaz, 1978. P. 67.
6. Optical transmission systems: Textbook for universities / B.V. Skvortsov, V.I. Ivanov, V.V.Krukhmalev et al.; edited by V. I. Ivanov. M.: Radio and communications, 1994. P. 98.
7. Digital and analog transmission systems: Textbook for universities/ V.I. Ivanov, V.N.Gordienko, G.N. Popov et al.; ed. 2nd ed. M.: Hotline-Telecom, 2003. P. 45.
