Fibre Characterization Testing

What are Fibre characteristics?

Fibre characterization testing is crucial for determining a network’s capacity to handle specific applications. This process provides a comprehensive snapshot of the connection, including all connection points, splices, and Fibre sections.

Fibre characterization testing verifies key parameters such as insertion loss, optical return loss, and chromatic and polarization mode dispersion to ensure the Fibre can handle traffic effectively. It also serves as a reference for future commissioning and troubleshooting.

In lab and network equipment production environments, R&D and carrier engineers rely on scalable Fibre characterization testing solutions with port density, multi-user access, and automation capabilities to test SONET, SDH, OTN, and Fibre Channel technologies.

The importance of Fibre characteristics

Many things are at risk whenever you buy or lease a new Fibre route. If the Fibre does not meet the requirements for its intended purpose, it will cost significantly more than the purchase price. It can also lead to lost revenue, troubleshooting and maintenance costs, and poor customer satisfaction. 

So how can a hyper-scale, an MTDC, a company’s IT department, and a service provider ensure the Fibre works as advertised? Fibre Characterization.

Fibre characterization validates that a Fibre path supports a specific application before it even shines. It is an essential step during initial deployment and when expanding or upgrading your network. Fibre characterization is one of the crucial steps in ensuring a solid foundation for your network.

CommScope has been deploying new Fibre for years, helping some of the world’s largest network operators ensure performance. Below is a step-by-step process to help characterize the Fibres. It is a collection of best practices developed through experience.

There are four steps to a smoother upswing.

• The first thing to do is to ensure the Fibre you are buying or leasing is the one you are trying to get. Unfortunately, Fibre optic providers do not always keep their contractual promises. 

The customer is responsible for ensuring that the product delivered (Fibre and connector type) matches the invoice and is in good condition.

Dirt bends, poor connections, or obvious physical defects do not meet contracted optical specifications and can adversely affect optical networks later, if not immediately, after a severe network failure occurs. Increase.

• Then make sure the Fibre is appropriately prepared and installed. Today’s high-bandwidth networks are highly susceptible to all kinds of signal degradation. To minimize Fibre problems, ensure the end faces are clean, adequately cut, and spliced ​​before wrapping. For example, CommScope uses industry-standard analysis to inspect all Fibre termination pads.
• Third, we test the Fibre to ensure it meets vital performance characteristics. These tests include optical time domain reflectance (OTDR), chromatic dispersion (CD), polarization mode dispersion (PMD), insertion loss, and optical return loss. Most importantly, if you have contracted with a third-party testing provider, ensure that you receive a complete copy of all results. 

Be prepared to ask your dark Fibre vendor to fix it. Testing alone is not enough, as the key to Fibre characterization is to ensure smooth and seamless transshipment. You should be able to fix any problems you find to avoid serious problems later.

• Finally, document everything, including creating route and span drawings so you can see what you have and find connection points if necessary. Other valid documents are:
• POP location
• Cable size, channel size, and critical splice points
• use by the circuit identification service or customer
• Total losses, including construction routes, junctions, and GPS mapping
• Create dynamic tracks and light paths end-to-end

Larger implementations may require third-party project management in coordination with line acquisition teams and Fibre provider technical staff.

In many cases, other third parties may be necessary to perform fusion splicing or further repair work. These activities are typically managed within tight time frames within maintenance windows determined as part of project planning.

Fibre optic networks are the foundation for building telecommunication networks. During the early stages of planning a network transformation or expansion, operators must perform a complete and thorough assessment of the underlying Fibre infrastructure to determine its capabilities and limitations. 

Industry experts predict that up to one-third of Fibre optic networks will require modifications to existing systems. Front-end Fibre analytics ensure key metrics are met and Fibre is at optimal performance levels to handle the increased bandwidth needed to transport data-intensive applications over long distances.

It also saves service providers time and money and prevents delays in the final testing and commissioning phases of expansion or upgrade projects.

Potential Problems & Testing Options

Fibre optic networks consist of multiple Fibre types, ages, and qualities, all of which significantly impact Fibre infrastructure and transmission capabilities. Also, the Fibre may come from several different Fibre suppliers. The bottom line is that Fibre optic transmission has several potential problem areas:

1. Aging Fibre: 

Some Fibre optic networks are over 25 years old. These traditional Fibre systems were not designed to handle the massive amounts of data transmitted over next-generation networks.

2. Connector Contamination and Damage: 

End-face contamination is one of the most common problems with connectors. Environmental conditions such as oil, dirt, dust, or statically charged particles can lead to contamination.

3. Splice Loss: 

Fibres are commonly spliced ​​together by fusion splicing. Any difference between the type of Fibre (manufacturer) and the type of splice used (fusion or mechanical) can lead to losses.

4. Bending: 

Excessive bending of Fibre optic cables can deform or damage the Fibres. Light loss increases as the bend gets sharper. Industry standards define acceptable bend radii.

Fibre characterization tests evaluate your Fibre infrastructure to ensure that all Fibres, connectors, splices, laser sources, detectors, and receivers operate optimally.

It consists of a suite of industry-standard tests to measure optical transmission characteristics, allowing operators to know precisely how their Fibre optic network will cope with current modernization and future expansion. 

For network expansions that require new dark Fibre, evaluate how the existing Fibre network will interact with the newly added Fibre to ensure Fibre meets service provider expectations and industry standards such as TIA/ANSI and Telcordia. It is essential to ensure that the criteria are met or exceeded.

Fibre characterization Testing

There are five basic Fibre characterization tests:

Two-way Optical Time Domain Reflectometer (OTDR)

Sends a pulse of light down the Fibre and measures the strength and duration of the return signal. This test shows the Fibre strand’s overall condition, including connectors, splices, and Fibre loss. Cleaning, re-terminating, or re-splicing can usually fix the problem.

Do this test you must need the best equipment kit that will help you to give an Approximately 100% result. So, most of the experts considered that the Expo FTB is the best choice. The question is why?

EXFO FTB-2:

The FTBx-735C has been designed to test FTTH/PON networks and longer links in the metro range. This OTDR has 42 dB of dynamic range to test up to 150 km of optical Fibre. The PON-optimized performances of the FTBx-735C enable it to fully characterize links up to a 1:128 FTTH/PON splitter ratio. 

The FTB-2 is by far the smallest, most compact, high-speed multi-technology test platform out there. The FTB-2 offers the most versatility: This is your go-anywhere, test-anything platform.With its high dynamic range, the FTBx-735C empowers technicians to test optical Fibres with greater speed and accuracy.

Optical Insertion Loss (OIL)

Measures the visual power loss that occurs when two cables are connected or spliced. Insertion loss is the amount of light lost. At longer distances, the loss of light can weaken the signal strength.

Optical Return Loss (ORL)

Send a pulse of light down a Fibre and measure the amount of light returned. Some light is lost at all connectors and splices. If the plug is dirty or not connected properly, it will cause scattering and reflections, resulting in poor light reflection.

Chromatic Dispersion (CD)

Measures the Fibre’s dispersion. In a single-mode Fibre, different wavelengths of light travel at slightly different velocities through the Fibre, propagating light pulses. Furthermore, information is lost when light pulses are emitted too close together and spread out too much. Chromatic dispersion can be compensated using dispersion-shifted Fibre (DSF) or a dispersion compensation module (DCM).

Polarization Mode Dispersion (PMD)

Occurs in single-mode Fibres and is caused by inherent Fibre imperfections that create a polarization-dependent delay of an optical pulse. The light travels at different speeds, resulting in random light pulse propagation.

Once the Fibre characterization is complete, the service provider receives a detailed analysis of the condition of the Fibre plant, including splice point and feedthrough locations, panels, racks, and port assignments.

It will also tell you if you have legacy Fibre that cannot support higher data rates due to current or future upgrades. 

More importantly, characterizing Fibre before redesigning or expanding a communications network allows service providers to reduce the potential for Fibre infrastructure that can cause significant delays during the final testing and commissioning stages. Through this, you can quickly eliminate the risk.

For the Fibre characterization test VIAVI MTS 8000E V2 Fibre Characterization Kit is more suitable equipment kit because the Viavi (JDSU) E81DISPAP is an Optical Dispersion Measurement (ODM) module for MTS/T-BERD-6000 and MTS/T-BERD-8000 optical test platforms.

The E81DISPAP offers a combined long range CD, PMD and attenuation profile module (1260-1640nm).