optical amplifiers and line spans
Download
Skip this Video
Download Presentation
Optical Amplifiers and Line Spans

Loading in 2 Seconds...

play fullscreen
1 / 17

Optical Amplifiers and Line Spans - PowerPoint PPT Presentation


  • 132 Views
  • Uploaded on

Optical Amplifiers and Line Spans. Josef Vojtěch CESNET Czech Republic josef.vojtech(at)cesnet.cz www.ces.net. Overview . Optical Amplifiers Optical Amplifiers in General Optical Fibre Amplifiers, EDFAs Ramans SOAs Amplifiers for (D)WDM Line Spans Single Span (NIL) Multi Span.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Optical Amplifiers and Line Spans' - connie


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
optical amplifiers and line spans

Optical Amplifiers and Line Spans

Josef Vojtěch

CESNET

Czech Republic

josef.vojtech(at)cesnet.cz

www.ces.net

The SEEFIRE project is co-funded by the European Commission under the FP6 IST contract no. 15817

overview
Overview
  • Optical Amplifiers
    • Optical Amplifiers in General
    • Optical Fibre Amplifiers, EDFAs
    • Ramans
    • SOAs
    • Amplifiers for (D)WDM
  • Line Spans
    • Single Span (NIL)
    • Multi Span

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 2

optical amplifiers in general
Optical Amplifiers in General
  • Ideal Optical Amplifier (OA)
    • High gain, polarization independent
    • Large bandwidth
    • High output power
    • Adds no noise
  • Basic types of OA (according principle)
    • Optical fibre amplifiers
    • Raman OA
    • Semiconductor OA (SOA)

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 3

optical fibre amplifiers
OpticalFibre Amplifiers
  • Active environment – special fibre doped with one or more rare earth element (Er, Nd, Pr, Tm,…or combination Er/Yb, Tm/Yb,..)
  • PDFA
    • Pr doped, suitable for (1280-1340nm)
    • G>30dB, Pout >16 dBm, NF <7dB
  • TDFA
    • Tm doped, suitable for (1440-1520nm)
    • G>30dB, Pout >20 dBm, NF <7dB

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 4

erbium doped fiber amplifiers
Erbium-Doped Fiber Amplifiers
  • Most widespread in telecommunications
    • Suitable for C band (lowest fiber attenuation)
    • common silica glass
  • Advantages
    • Operating range in 1520-1610nm
    • G>45dB, Pout >37 dBm, NF in <3.5,7>dB
    • Multi-channel crosstalk very low
    • Polarization independent
  • Disadvantages
    • Not small devices, cannot be integrated with other semiconductors
    • Gain spectrum not inherently flat

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 5

raman amplifiers
Raman Amplifiers
  • Based on simulated Raman scattering, active environment – common (non- doped) fiber
  • Gin <10,15>dB, Pout >30 dBm, NF < 1 dB
  • Advantages
    • Usable in 1250-1650 nm regions
    • Bandwith can be tailored (1 pump 35nm, more pump up to 90nm)
    • Lower NF than EDFA
    • High process efficiency in DCF (loss -> gain) component
  • Disadvantages
    • Higher interchannel crosstalk than EDFA
    • High pump powers (safety issues)

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 6

semiconductor optical amplifiers
Semiconductor Optical Amplifiers
  • Based on conventional laser principle, active environment – waveguide region sandwiched between n and p regions
  • G>25dB, Pout >15 dBm, NF in <7,10>dB
  • Advantages
    • Usable in 1310 1550 nm regions
    • Wide band (40-80nm)
    • Small compact semiconductors, easy to integrate
  • Disadvantages
    • Higher NF than EDFA
    • Higher interchannel crosstalk than EDFA
    • Polarization sensitive

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 7

spectral usability of amplifiers
Spectral usability of Amplifiers

O

C

L

S

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 8

amplifiers for d wdm i
Amplifiers for (D)WDM I
  • EDFA – needs gain flattening
    • Glass composition (F, Te glass host)
      • Single stage EDFA, silica host: bandwidth 15nm
      • Single stage EDFA, fluoride host: bandwidth 25nm
    • Equalizers
      • Two stage, silica or fluoride host, no gain flattening: 30nm
      • Two stage, silica host, gain flattening: 50nm
      • Two stage, tellurite host, gain flattening: 80nm
    • Hybrid OA
      • Multi-arm - two band operation, silica host: 85nm

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 9

amplifiers for d wdm ii
Amplifiers for (D)WDM II
  • Hybrid EDFA/Raman
    • Bandwidth can be tailored ~80nm
    • Lower NF than EDFA separate

Signal power in periodically amplified system. Comparison between original (EDFA system) and hybrid system

OSNR improvement

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 10

line spans
Line Spans
  • Main path length limitations
    • Losses
      • Optical power budget of a path

(System margin) = (Tx output power) – (Rx sensitivity) – (ƩLoses)

    • Chromatic dispersion
    • Polarization-mode dispersion(>=10Gb/s)

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 11

line spans1
Line Spans
  • Other limitations
    • OSNR (esp. in amplifier cascades)
    • Crosstalk
    • Fiber nonlinearities
      • Stimulated Raman and Brillouin scattering
      • Four-wave mixing, Self-phase mudulation, cross-phase modulation

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 12

single span
Single span
  • Loss limitations especially
  • CD - needn´t be fully compensated
  • No accumulation of noise and nonlinear effect
  • Results - vendor 1 Results - vendor 2
  • CESNET results

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 13

multiple span
Multiple span
  • Noise and nonlinear effect accumulation
  • Typical span 20 or 25 dB
    • Given by non amplified OSC channel (1510nm,1625nm)
    • Example of system performance
  • However exist 35 dBspan systems
    • OSC is amplified (1550nm)

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 14

bibliography
Bibliography
  • 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

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 15

amplifier examples
Amplifier Examples

EDFA

Raman

SOA

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 16

slide17

Thank you for your attention!

Questions?

SEEFIRE Technical Workshop – Sofia, Bulgaria, 14-15July 2005 17

ad