1 / 27

New Raman Fibers

New Raman Fibers . Islam M.N., Raman Amplifiers for Telecommunication 1 , Springer ,2004. References (1 -2). Ramaswami R., Sivarijan K.N., “Optical Networks“, 2 nd edition, 2002. Agrawal G.P., “Fiber-Optic Comminications Systems”, 2002.

justis
Download Presentation

New Raman Fibers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. New Raman Fibers Islam M.N., Raman Amplifiers for Telecommunication 1, Springer ,2004 E1- 2b Optical technologies

  2. References (1 -2) Ramaswami R., Sivarijan K.N., “Optical Networks“, 2nd edition, 2002. Agrawal G.P., “Fiber-Optic Comminications Systems”, 2002. Islam M.N.,”Raman Amplifiers for Tellecomunication 1,2”, 2004. Becker P.C., Olsson N.A., Simpson J.R., “Erbium-Doped Fiber Amplifiers”, 1999 F. Cisternino, B. Sordo, “State of art and prospects for Raman amplification in long distance optical transmissions”, http://exp.telecomitalialab.com Third-order cascaded Raman amplification - 2002.pdf [1] M.N. Islam “Raman amplifiers for telecommunications,” IEEE Journal of Selected Topics in Quantum Electronics, 8, 548-559 (2002). P. Parolari, L. Marazzi, L. Bernardini, and M. Martinelli, “Double Rayleigh scattering noise in lumped and distributed Raman amplifiers,” J. Lightwave Technol. 21, 2224-2228 (2003). Raman amplification for fiber communications systems - J. Lightwave Technol. - Jake Bromage 22, 79 (2004) (equation) WDM Pumping and highly nonlinear fibers for Raman amplification - Furukawa - Namik - 2003 - 40p.pdf A. Teixeira, et al., “Optical Gain Characteristics of Rayleigh Backscattered Lasing in Several Fibre Types”, NOC 2005 S.B. Papernyi and V.B. Ivanov, “Sixth-Order Cascaded Raman Amplification”, OFC/NFOEC 2005 René-Jean Essiambre, “Design of Bidirectionally Pumped Fiber Amplifiers Generating Double Rayleigh Backscattering”, IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 14, NO. 7, JULY 2002 E1- 2b Optical technologies

  3. Raman Amplifiers • Raman amplifiers use the intrinsic fiber properties to obtain amplification of the information signal. This means that the fibers used to optical signal transmitting can also be used as an amplification media; • they are distributed amplifiers; • The amplification obtained through SRS, when an elevated energy signal(pump), with a wavelength inferior to the signal whose amplification is desired, is injected in the fiber at the same time; • The Raman gain depends on the wavelegth of the pumping signal and from the spectral separation in relation to the signal to be amplified; • A photon from the pump signal generates a phonon and a new photon with a lesser wavelength (equal to the wavelength of the signal to amplify. E1- 2b Optical technologies

  4. E1- 2b Optical technologies

  5. Pi - incident P, L – Length of the Fiber, Seff - nucleus area b - Polarization factor gr  1/pump E1- 2b Optical technologies

  6. 1480 nm Raman Gain Coefficient X 10-13 mW-1 1545 nm -1590nm Raman Deviation (THz) E1- 2b Optical technologies

  7. E1- 2b Optical technologies

  8. Raman Fiber Amplifiers These amplifiers are based on the previously mentioned Raman stimulated emission phenomenon. It can be developed in any fiber; however it need’s high pumping power switch has been up to now, it’s biggest problem to conquer the market. The highest gain happens at 13.2THz It’s gain is proportional to the pump intensity The relation between the gain factor and length is given by G() = exp(g()L) Where L is the length of the fiber Raman Gain (x10-13m/W) Frequency Translation (THz) g(w)=gR(w)Ip=gR(w)Pp/ap Ip Pump Intensity Pp Pump Power ap Transversal area of the pump beam in the fiber Govind P. Agrawal, Nonlinear Fiber Optics, Optics and Photonics, 2nd edition,Academic Press,1995 E1- 2b Optical technologies

  9. Raman gain example We want 30dB at 1550nm with Raman We look at the gain curve at 1000nm e obtain the maximum gain gr=0.93E-13m/w. To normalize by 1550nm, dividing: 1550/1000=> gr=0.6E-13m/w • The used  should be the one from the pump, and not from the signal, but to state this example it will be enough. considering 1km of fiber Knowing that Ip=Pp/Ap, being Ap=50m2, and G(w)=1000 (desired value) We get P=80W, which is very high for a semiconductor laser. E1- 2b Optical technologies

  10. Raman Amplifier Gain Effective Length, Leff and signal power Ps(L) If the losses are low (pL<<1) the small signal gain can be given by Output Signal Power with amplification Output signal Power without amplification where P0=Pp(0) is the INPUT PUMP POWER E1- 2b Optical technologies

  11. Raman Amplifier Up to some given pump power there’s an exponential growth of the gain When the signal has its magnitude comparable to the pump’s magnitude, there will be a saturation effect this will happen sooner as the bigger the signal power is. However, given the power magnitude of the pump, the saturation powers will always be high enough and superior to the EDFA’s powers. M.Ikeda, Opt.Commun.39, 148 (1981) E1- 2b Optical technologies

  12. Raman Amplifier Besides being used for amplification this phenomenon can be used for wavelength conversion, • An high bandwidth wave will appear centered on the Stokes frequency. Since this bandwidth is very big, some modifications will have to be made in order to reduce the spectrum By enchaining this given principle, almost all conversions can be obtained E1- 2b Optical technologies IBM WhiteBook, Pags.182,183

  13. Raman amplification To flatten the Raman gain over a larger bandwidth several pumps may be used. http://www.tlc.unipr.it/bononi/ricerca/edfa.html Distributed Raman gain improves the OSNR budget significantly. Raman pumping is most used in backward pumping configuration to minimize noise transfer. The Raman gain BW is limited by pump to pump energy transfer which takes over at BW < 100 nm. 1 to 8 LD 300mW rating. Raman gain is polarization dependent, that’s why polarization multiplexed pumps or an Optical Depolarizer are used. E1- 2b Optical technologies

  14. Fiber amplifiers – doped vs Raman E1- 2b Optical technologies

  15. António Teixeira, Sérgio Stevan Other Amplifiers

  16. Other amplifiers with dopants Plastic fiber amplifiers • Organic composits can be mixed in plastic fibers and still mantaining their own properties. • eg Rodamine B doped PolyMethilMethilAcrylate (PMMA) fibre a 24dB gain with 33% a efficiency at 610-640nm was achieved. Erbium doped planar amplifiers • Increasing growth in the search for integrated functionalities leads to the development of plannar structures • One can dope these guides with Erbium and achieve gain. E1- 2b Optical technologies IBM WhiteBook, pag.179

  17. Earth Rare x Band Emission - Er (C, L-Band), - T (S-Band), - Pr (O-Band) Makoto Yamada and Makoto Shimizu "Ultra-wideband AmplificationTechnologies for Optical Fiber Amplifiers", NTT Technical Review, Vol. 1 No. 3 pag. 80 June 2003 E1- 2b Optical technologies

  18. Telluride Fiber Raman Amplifiers Atsushi Moriand Hiroji Masuda Makoto Yamada and Makoto Shimizu "Ultra-wideband AmplificationTechnologies for Optical Fiber Amplifiers", NTT Technical Review, Vol. 1 No. 3 pag. 80 June 2003 E1- 2b Optical technologies

  19. Level 5 1G4 3F2 3F3 3H4 4 P3 3H5 3F4 3 P2 1.47m Signal band 3H6 2 P1 1 0.8m band ASE 1.8m band ASE Pump Signal & ASE 0 Other amplifiers – Thulium doped fiber Source:Seoul National University-Optical Communication Systems Labs Due to: installed non dispersion shifted fibre (SMF) operating at 1300 nm at low chromatic dispersion increased request of bandwidth increased interest in other technologies as optical wireless technology a full exploitation of the existing network requires the development and use of amplifier operating also in other bands E1- 2b Optical technologies

  20. Other Doped Fiber Amplifiers Praseodymium Doped Fiber Amplifiers • Emission spectrum in the 1300nm window. • Limited bandwidth • Gain on the order of 12dB, if well optimized 24dB can be achieved and 60% efficiency • Fiber of Fluoroziconate (ZBLAN) is used to avoid the rapid decay (100ns) • Can be pumped at 1017nm with semiconductor lasers or crystal Nd:YLF • Low diameter fibers(2m) which brings added problem on the fusion. Neodymium Doped Fiber Amplifiers • For the 1310-1360nm in ZBLAN and 1360-1400nm in silica • Pumped at 810nm or 795nm • Low efficiency and high noise figure • The life time is of the order of the 390s leading to some X-talk effects. E1- 2b Optical technologies

  21. Other Amplifiers – praseodymium doped fiber amplifiers In metro networks, where data in the 1.3 µm regime can coexist with regular telecommunication services at 1.5 µm, amplification is needed to overcome fiber and optical add/drop multiplexer losses. In this window Praseodymium-Doped Fiber Amplifiers (PDFA) are good candidates for compensation of these losses. Standard configuration for such kind of DFAs can be made by: a 1030 nm optical pump (obtained for exampled by using an ytterbium fiber laser) a WDM coupler 1030/1300 Everything is then injected into the praseodymium doped fiber module. E1- 2b Optical technologies

  22. Amplifiers – comparison Denis Barbier, “Er-doped Waveguide amplifiers provide optical-networking evolution” E1- 2b Optical technologies

  23. FOPA – Parametric Amplifiers Based in FWM effect: the gain bandwidth is determined by dispersive properties of the fiber medium. T. Torounidis, “Applications of Fiber Optical Parametric Amplifiers“ E1- 2b Optical technologies

  24. Doped amplifiers- Gain bands E1- 2b Optical technologies

  25. Amplification bandwidth of each type of amplifier and Loss Spectrum http://www.ntt.co.jp/tr/0306/files/ntr200306080.pdf E1- 2b Optical technologies

  26. Broadband Amplifiers Technologies Haruki Ogoshi *, Seiji Ichino * and Katsuya Kurotori E1- 2b Optical technologies

  27. References E. Desurvire, "Erbium-doped fiber amplifiers: Principles and Applications", John Wiley & Sons, New York, 1994 http://www.npl.co.uk/photonics/nonlinear/coem24_fwm.pdf Haruki Ogoshi *, Seiji Ichino * and Katsuya Kurotori , “Broadband Optical Amplifiers for DWDM Systems” , Furukawa Review, No. 19. 2000 Atsushi Mori† and Hiroji Masuda, “Tellurite Fiber Raman Amplifiers”, NTT Technical Review, Vol. 2 No. 12 Dec. 2004 E1- 2b Optical technologies

More Related