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Fiber Characterization and Troubleshooting


Submarine network cableHigh-speed connectivity that protects the current network infrastructure requires broad expertise and a wide-range of tests to qualify the state of the fiber, perform fiber characterization and assess the integrity of data transmission over long-haul and ultra-long-haul networks—as is the case with cable testing in submarine networks. And, when it comes to high-speed, transoceanic transmission, assessing fiber quality is a must.

Expertise for Every Transmission Stage

EXFO's 40G/100G submarine network expertise encompasses network components and fiber testing throughout all the transmission network stages. Once the basic parameters (i.e., insertion loss (IL), optical return loss (ORL), etc.) are confirmed, the next step is to qualify the fiber to ensure that it is fit to transport actual traffic. This is when polarization-mode dispersion (PMD) and chromatic dispersion (CD) testing are required. CD causes light pulses to broaden when traveling within the fiber, up to a point where the bit error rate increases. While CD can be compensated over a wide wavelength range, it is costly to do so. Therefore, knowing where the issue lies is key. In addition, for submarine cable testing, PMD is also critical. Due to changes in the fibers’ refraction index 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 bit error rate, making CD and PMD testing critical.

Total link characterization is an important step that provides a snapshot of the entire link, including all interconnection points, fusion splices and fiber sections. Link characterization also serves as a future reference when performing commissioning and troubleshooting on the same link. Naturally, with submarine cables, distance is always an issue—for coastal networks of up to 250 km, the solution is an OTDR with a dynamic range of up to 50 dB that can test over distances of up to 250 km.

Finally, the critical weakness of undersea cables is their vulnerability to damages caused by fishing and vessel anchoring. How can you keep a constant and vigilant eye on these optical fiber cables? With a stand-alone OTDR test solution. Providing a measurement range of up to 200 km, these easy-to-manage units will cost-effectively monitor coastal route topologies (festoon style). They will also keep you up-to-date on the status of the fibers and cables, and alert you and your systems—through various messaging channels—when your most valuable asset is potentially impaired.

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Recommended Equipment


Single-Ended Dispersion Analyzer—FTB-5700

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 Analyzer—FTB-5500B
or
Single-Ended Dispersion Analyzer—FTB-5700

Polarization Mode Dispersion

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.

Distributed PMD Analyzer—FTB-5600

Distributed PMD Analysis

The first distributed PMD analyzer on the market breaks down PMD assessment to pinpoint faulty sections on the link, enabling cost-effective, targeted upgrades.

Ultra-Long-Haul OTDR—FTB-7600E

End-to-End Fiber Characterization (OTDR)

When distance is an issue, the FTB-7600E OTDR, with a dynamic range of up to 50 dB, is the solution. Taking full advantage of EXFO’s industry-leading expertise in OTDR development, this module can test over distances of up to 250 km.

Stand-Alone Remote OTDR Unit—Fiber Guardian

Remote OTDR with Fiber-Optic Cable Monitoring

Remote fiber characterization, testing, 24/7 monitoring and alerting functions. Delivers the measurement of fiber, splice and connector aging.