Network Characterization

Physical-Layer Qualification

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), chromatic dispersion (CD) and multipath interference (MPI) 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.	FTB-400 Universal Test System with FTB-5800 CD Analyzer module OR FTB-200 Compact Platform with FTB-5700-CD Single-Ended Dispersion Analyzer module
PMD	Due to local changes in the fibers 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.	FTB-400 Universal Test System with FTB-5500B PMD Analyzer module OR FTB-200 Compact Platform with FTB-5700-CD Single-Ended Dispersion Analyzer module
P-OTDR	A polarization-ODTR allows users to locate fiber link sections where PMD is higher than a given standard for a specific data transmission rate. The P-OTDR is based on a DOP-based polarization optical time-domain reflectometer.	FTB-400 Universal Test System with POTDR-100 Polarization OTDR module
MPI	Multipath interference (MPI) is the ratio of the direct path to the double-reflected path. With high MPI—as is often the case with Raman amplification—comes substantial interference, which causes increased bit error rate. The MPI-800 is the only portable MPI meter currently available on the market. It integrates an MPI meter, a power meter and a light source for complete system characterization.	MPI-800 Multipath Interference Meter
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.	FOT-930 MaxTester Multifunction with Optical Loss Test set FTB-200 Compact Platform with FTB-3930 OLTS module
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.	FTB-400 Universal Test System or 200 Compact Platform with FTB-7000 OTDR module

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.	FTB-400 Universal Test System or FTB-200 Compact Platform with the FTB-8120NG/FTB-8130NG Transport Blazer module
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.	FTB-400 Universal Test System or FTB-200 Compact Platform with the FTB-8115 Transport Blazer module
Ethernet	Ethernet testers perform end-to-end Ethernet performance validation (RFC 2544), reliability (BER Testing), and TCP throughput testing.	FTB-400 Universal Test System or FTB-200 Compact Platform with the FTB-8510B Packet Blazer or FTB-8510G 10 Gbit/s Packet Blazer module

EXFO test modules are hosted in one or both of the following portable platforms:

FTB-200 Compact Platform A modular portable test set for the network technician	FTB-400 Universal Test System The ultimate multiple-module platform for network experts involved in optical and protocol testing