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Study Of Multiwavelength Fiber Laser And Light Transfer Characteristic Based On Stimulated Brillouin Scattering In Optical Fiber

Posted on:2012-01-20Degree:MasterType:Thesis
Country:ChinaCandidate:B YaoFull Text:PDF
GTID:2218330338451834Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
Stimulated Brillouin scattering (SBS) is the major nonlinear optical phenomena in optical fibers because the threshold powers are much lower than those needed for stimulated Raman scattering (SRS). SBS is a nonlinear interaction between the pump and Stokes fields through an acoustic wave. Nowadays SBS has wide applications in distributed fiber-optic sensor(DFS),fiber optic gyro(FOG),fiber phase conjugating mirror, controllable slow light,microwave photonics,fiber lasers,and so on.Tunable multiwavelength Brillouin erbium-doped fiber laser (MWBEFL) takes the advantages of Brillouin amplification in optical fibers and high gain from the erbium-doped fibers amplifier (EDFA). It has the advantages of narrow linewidth , equal-wavelength spacing and high output uniformity over the channels. Therefore, BEFL as the light source will play a significant role in the field of ultra-dense wavelength division multiplexing. Slow light based on SBS has a lot of advantages such as large group velocity, tunable wavelength, low Brillouin threshold power and it is easy to be implemented in present telecommunications networks ,so it has already becomes a hot topic in the research of slow light.With the subjects supported by the Tianjin Natural Science Foundation (Grant No. 08JCYBJC14400), the main contents of this paper are as following:1.The researchs on controllable slow light and multiwavelength erbium-doped fiber lasers based on SBS are introduced systemically. First the physical principle of SBS in optical fibers is presented. And the physical principle of slow light and multiwavelength fiber laser of achieving slow light via stimulated Brillouin scattering in optical fibers are studied.2.A widely tunable multiwavelength Brillouin/erbium fiber laser based on FBG is presented. The certain wavelength is reflected using FBG, thus the self-laseing effect is reduced and subsequently the number of output channels is inceased. The Brillouin gain threshold is effectively reduced by the double-pass Brillouin pump signal amplification. The fiber laser provides a tuning range of 30 nm from 1530 nm to 1560 nm. At the Brillouin pump power of 2 mW and the 980 nm pump power of 60 mW, 16 output channels with 0.088 nm channel spacing from 1540 nm to1554 nm are achieved.3.A new technique is presented for improving the pulse-delay performance of a SBS based multi-line delay structure by using fiber Bragg gratings (FBG).Two FBGs and a 15km-long standard single-mode fiber (SSMF) are used in the structure. We design the Bragg wavelength and dispersion of the FBGs so that the probe can be amplified by the pump through SBS several times in the same fiber. The effect of two-line delay structure are achieved. In addition FBG can provide additional delay to the signal. Experimental results show that, by optimizing the parameters in this SBS based broadband slow light system using FBGs, a 1.72ns delay for a 1.25ns Guassian pulse is achieved, and the maximum fractional delay increases to 1.01 finally. In contrast to conventional optical fibers by two double delay structure, the delay performance of the proposed system is improved 36.4%.
Keywords/Search Tags:Stimulated Brillouin scattering, fiber optics, Multiwavelength Brillouin erbium fiber laser, Tuning range, slow light, two-line of delay, FBG, delay efficiency
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