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Network Characterization


Physical-Layer Qualification

 

Test Equipment

Test Type
CD Analyzer
PMD Analyzer
P-OTDR
OTDR
Optical Loss Test Set
Chromatic dispersion

 
PMD
   •  •  
Loss and ORL budget
   
 
End-to-end fiber characterization
       •  

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 to transport actual customer traffic. This is when polarization-mode dispersion (PMD) and chromatic dispersion (CD) optical testing come in.

Test Type

Description

Recommended Equipment

Chromatic dispersion
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.
PMD
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.
Distributed PMD

Loss and ORL budget
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.
End-to-end fiber characterization (OTDR)
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.

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

Description

Recommended Equipment

Next-generation SONET/SDH
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.
SONET/SDH
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.
Ethernet
Ethernet testers perform end-to-end Ethernet performance validation (RFC 2544), reliability (BER Testing), and TCP throughput testing.

 

EXFO test modules are hosted in the following portable platform:

FTB-500 Platform
FTB-500 Platform
The ultimate multimodule platform for network experts involved in optical and protocol testing

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