Download Raman Amplification - E

Fiber Amplifiers- Raman
Sérgio Stevan, Paulo André, António Teixeira, J. Prat, J. A.
Lazaro, C. Bock, João Andrade
© 2005, it - instituto de telecomunicações. Todos os direitos reservados.
This tutorial is licensed under the Creative Commons
http://creativecommons.org/licenses/by-nc-sa/3.0/
Outline
Introduction
Physical principle
Propagation
Power and Field
Configurations and SETUPs
Co, Counter and Bi - directional
Distributed and lumped
Noise and Multi Path Interference
Raman fiber Lasers
.
E1- 2b Optical technologies
2 Jan 2006
Introduction - History
1970 –Stimulated Raman emission in optical fibers was observed
by Ippen, and by Stolen et al. in 1971 [3]
70 and 80 decades – Development of new types of fiber
Middle 90 decade –
1991 (first commercial EDFA amplified link) = attentions shifted
until 1997 (FBG and Development of suitable high power
pumps)
1999 - The first Demonstration of Raman amplification.
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3 Jan 2006
Raman Optical Amplifiers
 Based on fiber Non-Linear effects (larger pump power required)
http://www.research.att.com/viewProject.cfm?prjID=111
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4 Jan 2006
Introduction
Raman: Advantages and Disadvantages
Occurs in all fiber transparency
Maximum gain is shifted 13 THz from pump frequency
Uses the same medium of the signal transmission
Small Noise (compared with EDFA and SOA)
Gain spectrum adjustable with multiple pumps (width and
flatness)
Gain is distributed along the fiber span
Raman Gain occurs only at high pump powers
Low efficiency in typical fibers
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5 Jan 2006
Stokes and Anti-Stokes Effects
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6 Jan 2006
Stimulated Raman Scattering (SRS)
Islam M.N., "Raman Amplifiers for Telecommunication 1", 2004
(R.H. Stolen ,“Fundamentals of Raman Amplification in Fibers”)
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7 Jan 2006
Normalized Raman Gain (SMF)
Islam M.N., "Raman Amplifiers for Telecommunication 1", 2004
(R.H. Stolen ,“Fundamentals of Raman Amplification in Fibers”)
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8 Jan 2006
Raman Gain X type of optic fiber
Clifford Headley, Govind P. Agrawal, “Raman Amplification in fiber
optical communication systems,” Elsevier academic press , 2005
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9 Jan 2006
Signal and Pump : Polarization
M.N. Islam “Raman amplifiers for telecommunications” ,IEEE Journal
of Selected Topics in Quantum Electronics, 8, 548-559 (2002)
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10 Jan 2006
Lumped or Distributed Raman Amplifier
Lumped:
Distributed:
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11 Jan 2006
Distributed Raman Amplifier (DRA)
M.N. Islam “Raman amplifiers for telecommunications” , IEEE Journal
of Selected Topics in Quantum Electronics, 8, 548-559 (2002).
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12 Jan 2006
A Simple Raman Amplifier
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13 Jan 2006
Equations – Raman Amplification
- Simplified Differential
Equations
Ps
gR

Pp Ps   s Ps
z
Aeff
Pp
z

p gR
Pp Ps   p Pp
 s Aeff
- Pump Propagation (undepleted approach)
Pp c ( z )  Ppo exp(  p ( L  z ))
Pp ( z )  Ppo exp(  p z )
- Signal Propagation

 1  e  p z
gR
Ps ( z )  Ps (0) exp   s z 
Pp (0)
 
Aeff

p








 e p L e p z  1 
gR

Ps  c ( z )  Ps (0) exp   s z 
Pp (0)


A


eff
p


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Power Signal x pump direction
CO-PROPAGATING
COUNTER-PROPAGATING
F. Cisternino, B. Sordo, ''State of the art and prospects for Raman amplification in
long distance optical transmissions'', Exp, Vol. 2 n. 1, pp. 18-25, March 2002.
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Co-, Counter- and Bi-pumping
100% = Signal and Pump CO-PROPAGATING
0%
= Signal and Pump COUNTER-PROPAGATING
Intermediate values = Bidirectional pumps
J. Bromage, P.J. Winzer, and R.-J. Essiambre, in Raman Amplifiers for Telecommunications,
M.N. Islam, Ed., Springer, New York, 2003, Chap.15
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Pumping Methods
FORWARD
BACKWARD
BI DIRECTIONAL
Clifford Headley, Govind P. Agrawal, “Raman Amplification in fiber
optical communication systems,” Elsevier academic press , 2005
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17 Jan 2006
Power variation Equations
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18 Jan 2006
Field Equation : Nonlinearities
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19 Jan 2006
Nonlinearities Penalties
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20 Jan 2006
Multi pump – gain Spectrum tayloring
J.Bromage, J.Lightwave Technol.22,79 (2004)
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21 Jan 2006
Multi pump - Flat gain
S. Namiki and Y.Emori, IEEE J.Sel.Topics Quantum Electron,7,3 (2001)
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22 Jan 2006
Gain (Flat) and Noise – 45km SMF (example)
1502nm
1416nm
Used by permission from VPIphotonics, a division of VPIsystems
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23 Jan 2006
Gain (Flat) and Noise figure – 45km SMF
Bandwidth = 90nm
Used by permission from VPIphotonics, a division of VPIsystems
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24 Jan 2006
ASE and Noise Figure
F. Cisternino, B. Sordo, ''State of the art and prospects for Raman amplification in
long distance optical transmissions'', Exp, Vol. 2 n. 1, pp. 18-25, March 2002.
E1- 2b Optical technologies
25 Jan 2006
Gain and Noise Figure for many pump powers
Islam M.N., "Raman Amplifiers for Telecommunication 1", 2004
(C.R.S Fludger ,”Linear Noise Characteristics”)
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26 Jan 2006
MPI – Multi Path Interference
Clifford Headley, Govind P. Agrawal, Raman Amplification in fiber
optical communication systems, Elsevier academic press , 2005
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27 Jan 2006
MPI – Multi Path Interference
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28 Jan 2006
Raman Fiber Laser
Resonant Cavity
FBG reflectors
Multi-lasers
There is no coupler insertion loss
Setup simpler than traditional approach which consists of multiplexing laser diodes
Consequently: Smaller costs
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29 Jan 2006
Spectral positions of pump, gratings and gain distribution
S band
C band
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30 Jan 2006
L band
Setup of comb Raman fiber lasers with two pumps
Pump1
FBG for Pump1
Pump 2
FBG for Pump2
1430 nm
1520 nm
1460 nm
1548 nm
1529 nm
1554 nm
1535 nm
1569 nm
1570 nm
Ppump1 = 1.5 W
Ppump2 = 1.5 W
30km SMF
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31 Jan 2006
Raman Gain composition
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32 Jan 2006
Sixth-Order Cascaded Raman Amplification
E1- 2b Optical technologies S.B. Papernyi and V.B. Ivanov
33 Jan 2006
Rayleigh Backscatering (Virtual mirror): Raman Fiber Laser
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34 Jan 2006
Rayleigh Scattering and fiber lasing
a) Multiple chaotic oscillations
b) FBG inserted to
Pump power = 0.8W
c) FBG inserted to
Pump power = 1.2W
Teixeira A., Stevan Jr., S. Silveira T.; Nogueira R.; Tosi Beleffi G. M., Forin D.,
Curti F., “Optical Gain Characteristics of Rayleigh Backscattered Lasing in
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35 Jan 2006
Several Fibre Types”, NOC 2005-07-07
Hybrid Amplification with Raman
EDFA: population
inversion
Raman: bandwidth control
Islam M.N., Raman Amplifiers for Telecommunications 2:, Sub- Systems and Systems,
Springer , 2004 (Cap.13 Hybrid EDFA/ Raman Amplifiers, Hiroji Masuda)
E1- 2b Optical technologies
36 Jan 2006
Hybrid Amplification with Raman
22 dBm
11dBm
22 dBm
Islam M.N., Raman Amplifiers for Telecommunications 2:, Sub- Systems and Systems,
Springer , 2004 (Cap.13 Hybrid EDFA/ Raman Amplifiers, Hiroji Masuda)
E1- 2b Optical technologies
37 Jan 2006
Hybrid Amplification with Raman
Hybrid EDFA/Raman
Bandwidth can be tailored ~80nm
Lower NF than EDFA separate
Islam M.N., Raman Amplifiers for Telecommunications 2:, Sub- Systems and Systems,
Springer , 2004 (Cap.13 Hybrid EDFA/ Raman Amplifiers, Hiroji Masuda)
E1- 2b Optical technologies
38 Jan 2006
Tellurite-based Raman Amplifier
Islam M.N., Raman Amplifiers for Telecommunications 2:, Sub- Systems and Systems,
Springer , 2004 (Cap.13 Hybrid EDFA/ Raman Amplifiers, Hiroji Masuda)
E1- 2b Optical technologies
39 Jan 2006