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RESEARCH OF THE FEATURES OF MANDELSTAM — BRILLOUIN BACKSCATTERING IN OPTICAL FIDERS OF VARIOUS TYPES
Igor V. Bogachkov, Omsk State Technical University (OmSTU), Omsk, Russia, bogachkov@mail.ru
Abstract
Investigation results of capabilities of the Mandelstam – Brillouin scatter in various types of optical fibers (OFs) by using Brillouin traces are demonstrated in this article. At present many various types of optical fibers (OFs) have been developed, each of which is optimized to solve certain problems. A dispersion-shifted single mode fiber (DSF) is applied in long-range fiber optical communication lines (FOCL). A frequency behavior of the DSF dispersion is shifted so that the minimum («zero») dispersion is observed near wavelength (l) 1.55 µm. (A single-mode OF- G.652 has the minimum dispersion around l = 1.31 µm). DSF have proven themselves both in attenuation rate and transmission capacity. However, it is known that the use of these OFs in fiber optical communication lines with wavelength division multiplexing (WDM) has been subjected to nonlinear effects. This led to the appearance of non-zero dispersion-shifted fiber (NZDSF) optimized particularly for long-range WDM systems. The «zero»-dispersion point is located before the fiber transparency «window» l = 1.55 µm in the NZDSF, but there are types with negative dispersion, where this point is placed behind the fiber transparency «window» l = 1.55 µm. A timely location of mechanically stressed sections in the OF laid in the optical cables (OC) is a major objective in an early OF diagnostics. To identify the fiber sections with enhanced strain and changed temperature is applied the Brillouin reflectometry method, which is taken as a basis for Brillouin optical time domain reflectometer (BOTDR). BOTDR supply accurate information on a distribution of a strain degree along OF length, and then allow the degradation of the OF to be forecast. The Brillouin traces for optical fibers with heated and cooled light-guide segments are given. The changes in the capabilities of the optical fibers under test are evaluated. The OFs of various manufacturers with similar optical capabilities have a different shape of the MBBS profile. The database of MBBS profiles of OFs of various types and manufacturers enables the OFs in the FOCL to be classified, as well as the «problem» segments to be identified.
The work was performed with the financial support of the Ministry of Education and Science of the Russian Federation within the scope of the base part of a State Assignment within the sphere of scientific activity (Project No. 8.9334.2017/8.9).
Keywords: optical fiber, strain, Mandelstam – Brillouin backscatter, spectrum profile, Brillouin reflectometry.
References
1. Bogachkov I.V. (2015). Research of influence of the optical fi-bers strain degree on the Brillouin backscattering characteristics. Inter-national Siberian Conference on Control and Communications (SIB-CON-2015), Omsk, pp. 1-6.
2. Bogachkov I.V. (2017). Temperature Dependences of Mandel-stam – Brillouin Backscatter Spectrum in Optical Fibers of Various Types. Systems of Signal Synchronization, Generating and Processing in Telecommunications (SINKHROINFO-2017). Proceedings, Kazan, pр. 1-6.
3. Bogachkov I.V., Gorlov N.I. (2016). Researches of Strain Characteristics of Dispersion-Shifted Optical Fibers. 13th International Conference on Actual Problems of Electronic Instrument Engineering Proceedings(APEIE–2016). Proceedings, Novosibirsk, vol. 1, p. 1,
pp. 169-174.
4. Bogachkov I.V. (2016). Experimental Researches of Brillouin Backscatter Spectrum in Non Zero Dispersion-Shifted Optical Fibers at Longitudinal Stretching Forces. Dynamics of Systems, Mechanisms and Machines (Dynamics–2016). Proceedings, Omsk, pp. 1-5.
5. BOTDR Measurement Techniques and Brillouin Backscatter Characteristics of Corning Single-Mode Optical Fibers. http://www.corning.com/media/worldwide/coc/documents/Fiber/RC-%20White%20Papers/WP-General/WP4259_01-15.pdf.
6. Koyamada Y., Sato S., Nakamura S., Sotobayashi H., Chujo W. (2004). Simulating and designing Brillouin gain spectrum in single-mode fibers. Lightwave Technol., vol. 22, pp. 631-639.
7. Liu X. (2011). Characterization of Brillouin Scattering Spectrum in LEAF fiber. University of Ottawa. 102 p.
8. Bao X., Chen L. (2011). Recent Progress in Brillouin Scattering Based Fiber Sensors. Sensors, vol. 11, pp. 4152-4187.
9. Bogachkov I.V. (2016). Experimental Researches of Temperature Dependences of Brillouin Backscatter Spectrum in Optical Fibers of Various Types. Dynamics of Systems, Mechanisms and Machines
(Dynamics–2016). Proceedings, Omsk, pp. 1-7.
10. Horiguchi T., Kurashima T., Koyamada Y. (1992). Measurement of temperature and strain distribution by Brillouin frequency shift in silica optical fibers. Distributed and Multiplexed Fiber Optic Sensors, vol. 1797, pp. 2-13.
11. Bogachkov I.V., Gorlov N.I. (2016). Researches of the influence of temperature changes in optical fibers on the Brillouin backscattering spectrum. 13th International Conference on Actual Problems of Elec-tronic Instrument Engineering (APEIE–2016). Proceedings, Novosibirsk, vol. 1, pp. 157-161.
12. Parker T., Farhadiroushan M., Handerek V., Rogers A. (1997). Temperature and strain dependence of the power level and frequency of spontaneous Brillouin scattering in optical fibers. Optics letters, vol. 26, N. 11, pp. 787-789.
13. Belal M., Newson T.P. (2012). Experimental Examination of the Variation of the Spontaneous Brillouin Power and Frequency Coefficients Under the Combined Influence of Temperature and Strain. Journal of Lightwave Technology, vol. 30, N. 8, pp. 1250-1255.
14. Bogachkov I.V. (2018). A Classification of Optical Fibers Types on the Characteristics of the Mandelstam – Brillouin Backscatter Spec-trum. IEEE Ural Symposium on Biomedical Engineering, Radioelec-tronics and Information Technology (USBEREIT-2018) – Proceedings, Ekaterinburg, pp. 308-312.
15. Bogachkov I.V. (2018). Detection of initial level of Brillouin frequency shift in optical fibres of different types. Journal of Physics: Conference Series, vol. 1015 (2018), pp. 1-6.
Information about author:
Igor V. Bogachkov, Associate professor (docent) of «Communication means and information security» department of Omsk State Technical University (OmSTU), Omsk, Russia