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Network Characterization
Physical-Layer Qualification
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Test Equipment
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Test Type
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CD Analyzer
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PMD Analyzer
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P-OTDR
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OTDR
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Optical Loss Test Set
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Chromatic dispersion
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PMD
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Loss and ORL budget
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End-to-end fiber characterization
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When it comes to high-speed transmission, especially when transmitting at 10 Gbit/s or more, assessing fiber quality is a must. Once the basic parameters (loss, ORL, etc.) are under control, the next step is to qualify the fiber as a high-speed transmission medium and make sure it is fit for transporting actual customer traffic. This is when polarization-mode dispersion (PMD) and chromatic dispersion (CD) optical testing come in.
Test Type
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Description
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Recommended Equipment
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Chromatic dispersion
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CD causes light pulses to broaden when traveling within the fiber, up to a point where bit error rate increases. CD can be compensated over a wide wavelength range but this can be costly, so precise measurement is key.
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PMD
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Due to local changes in the fiber's index of refraction and physical stresses on the cable, the two polarization states of light travel at slightly different speeds. This spreads the pulse over time and distance, eventually increasing BER. |
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Distributed PMD
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Loss and ORL budget
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Automated bidirectional optical loss test sets (OLTSs) are used in pairs and contain both a power meter and light source. They provide fully automated bidirectional loss and ORL test results in 10 seconds for up to three wavelengths, as well as a fiber-length measurement. They greatly reduce testing time and risk of human error. |
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End-to-end fiber characterization (OTDR)
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OTDRs are used to perform full link characterization. They can locate and assess connections, splices and splitter points within a network. OTDRs are also the preferred tool to accurately locate and characterize faults within the link. |
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Transmission-Layer Qualification
A primary goal of any communication network is to maintain the quality and integrity of the optical signal transmission. New or upgraded networks must be characterized to ensure their different parts and components do not induce bit-error-rate levels that exceed communication system requirements.
Test Type
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Description
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Recommended Equipment
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Next-generation SONET/SDH
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Next-generation SONET/SDH testers validate the functionality and performance of next-generation SONET/SDH networks through GFP performance characterization, VCAT conformance testing, differential delay measurement and dynamic bandwidth adjustment (LCAS) verification. |
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SONET/SDH
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SONET/SDH testers verify basic SONET/SDH functionality including power-level verification, frequency-offset testing, automatic protection switching (APS), stress testing and long-term bit-error-rate (BER) testing. |
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Ethernet
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Ethernet testers perform end-to-end Ethernet performance validation (RFC 2544), reliability (BER Testing), and TCP throughput testing. |
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EXFO test modules are hosted in one or both of the following portable platforms:
FTB-200 Compact PlatformA modular portable unit for the network technician
FTB-500 PlatformThe ultimate multiple-module platform for network experts involved in optical and protocol testing
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