Caracterizacion de la fibra optica

A rough guide to parameters and test procedures for fibre characterisation.

This is not intended as a definitive testing manual, but as a guide for engineers contemplating fibre characterisation prior to system line up and activation

Typical network testing. The testing requirements of a typical network development can be summarised as below into a number of distinct deployment phases:Installation & Datacom Deployment Fibre Characterization System Lineup and Install & Testing Phase Test (SLAT) Characterize fibre Fibre cuts Damaged connector Clean fibres Dispersion Return loss Span loss OTDR ORL Span loss PMD, CD Video Scope Fibre routing Clean fibres Commission eqpt, Optical channel equalization OSNR BER testing Install data eqpt Test data eqpt Remote Validation Testing Remoteend-toend testing SOAK testing (24 to 72 BER testing) Remote monitoring Monitoring & Field Service

Field Operations

Remotely monitor traffic quality at traffic handoff sites Troubleshoot faults

Required Test Equipment

Optical Loss Test Sets OSAs Video Scope 2.5/10G BERT Variable Optical Attenuator Optical channel selector Polarization OTDR

Gigabit Ethernet Protocol Analyzer ATMDigital Wrapper Sonet/SDH

OSA Protocol Analyzer STS1, OC3/12/48/192, 10/100M & 1G Ethernet Remote monitoring capability

OTDR OSA Variable Optical Attenuator BERT Video Scope ORL

What is often found in practice is that the technicians performing these tests have to carry around a wide range of sophisticated equipment. Obviously this equipment has to be of the highest technical standards: Compliance to internationally accepted test methods  High accuracy and repeatability Additionally, the equipment has to confirm to some practical and commercial requirements too:  For field operation: portability, weight, ruggedness, battery operation  Ease of use for the technician  Speed of testing  Ease of data download and concatenated reporting  Capex and Opex considerations

Particulartest challenges of 10Gbps and DWDM systems. In addition to the requirements above, when the network is operating at transmission speeds of 10Gbps and/or with DWDM topology, some testing requirements become critical. The following schematic comes from a British Telecom Laboratories Technical Journal 2003 (authors Sikora, Zhou and Lord), and outlines the advanced network parameters which have to beproperly evaluated.

Hence for networks destined for 10Gbps and higher transmission, signal dispersion levels are critical and accurate measurement is crucial. Similarly, for specific DWDM topologies, an understanding of the 4-wave mixing effects is also crucial to be sure of error-free transmission. For a deeper understanding, the reader is suggested to consult EXFO‟s “Guide to WDM technology”(author Dr. André Girard). EXFOs product range EXFOs product offer revolves around the FTB-400 modular mainframe. This is a PC based instrument, which is capable of housing a range of physical, optical and protocol layer test cards. Asides the obvious CAPEX savings with a modular approach, there are many „hidden‟ OPEX savings inherent in the system: removing the need for an engineers PC, reducedcalibration costs, flexibility from module portability between mainframes, ability to rent specific modules for short term projects, multitasking for time efficiency, local report generation etc etc. Many of our peers now have „me-too‟ products, but due to the EXFO product maturity, none match up to the flexibility, number of test modules, reliability and feature rich environment of the FTB-400. Oneof the purposes of this document will also be to highlight the technical and practical advantages of the EXFO product range.

List of Test equipment The following test equipments are recommended for fibre characterisation: Test Equipment 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Modular test platform Light Source/Power meter OTDR PMD Analyzer Make/Model EXFO FTB-400 EXFO FOT-930 EXFO, FTB-7000D...