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Understanding DWDM. Traffic - The Future!. The Optical Layer as the new mux fabric. WDM multiplexing technology: The basis for Optical Networking. new layer is born: the Optical Layer. Broadband Applications. Broadband Applications. IP. IP. ATM. ATM. SDH / SONET. SDH / SONET.
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WDM multiplexing technology: The basis for Optical Networking new layer is born: the Optical Layer
Broadband Applications Broadband Applications IP IP ATM ATM SDH / SONET SDH / SONET Photonic layer: WDM Photonic layer: WDM New proposals The mainstream view Future Broadband Network Layers
1310 nm/1550 nm TDM point-to-point connections with opto-electrical regenerators
Classic WDM point-to-point connection with opto-electrical regenerators
TDM point-to-point connections with optical fiber amplifiers (OFAs) OFA basics
Transmission of multiple channels using WDM systems with 8, 16, 32, ... channels (multiplexing of 2.5 Gbit/s signals)
DWDM test parameters • Power levels of the individual carriers • to ensure even power distribution over the entire bandwidth • to notice immediately whether any channels have dropped out • Channel wavelength / Channel spacing • to indicate possible wavelength shifts for individual laser sources • Signal-to-noise ratio • to ensure that error-free transmission is possible in each data channel • Overall power • to check the optical fiber amplifiers of the system • to check against safety limit of currently +17 dBm • Crosstalk • to provide a quality indication for the system components (couplers, ...)
OFA monitor output: 8 data signals and ASE spurious spectrum
DWDM system with the recommended reference test points from ITU-T Rec. G.692
100 GHz channel grid in the range 1530 to 1565 nm from ITU-T Rec. G.692
Possible system wavelengths in the ITU-T 100 GHz channel grid
Optical add/drop multiplexing principleand monitoring of system parameters
Optical add/drop multiplexing principle and monitoring of system parameters
4-channel DWDM signal with characteristic noise floors and ASE spurious spectrum
Superimposition of the actual data signal and accumulated noise and incorrect interpretation of S/N measurements
Cyclical recording and stability measurement of • Channel-No. • Actual • Power / -stability • S/N / -stability
Spectrum analysis and power leveladjustment in DWDM systems Due to the irregular gain/wavelength response of todays EDFAs cascading of optical amplifiers result in power shifts ! To minimize crosstalk effects ( Rx side) of each DWDM channel powerequalization becomes necessary.
Quality monitoring through wavelength-selective bit error analysis (automatic evaluation of bit error histograms)
DWDM System AnalyzerOSA-155 New portable DWDM System Analyzer for 50 GHz/0.4 nm and higher spaced optical DWDM systemswith up to 256 channels
DWDM System Analyzer OSA-155 Complete Solution: OSA-155 +ANT-20 +CATS Optics OSA-155 WDM-channel-selector for in-depth system analysis