Fiber testing - tips and tricks from our experts

What is fiber testing?

The purpose of any fiber optic network is to perform high speed, error-free data transmission. Fiber optic, with its almost unlimited bandwidth, is now the transport medium of choice in long-haul and metropolitan networks, and in evolving technologies such as 5G.

Fiber testing includes the methods of procedure, equipment and industry standards used to test fiber optic components, fiber links and fiber network deployments. It requires the use of tools and test instruments tailored specifically to the requirements of each phase of a network deployment. Performing fiber testing helps to guarantee that system components are working properly and within specifications.

For example, with a fiber to the home (FTTH) architecture, one of the initial tasks to consider is performing fiber tests in order to evaluate the acceptable loss budget according to industry standards and recommendations.

Fiber testing standards

There are two main groups working on international standards: the International Electrotechnical Commission (IEC) and the International Telecommunication Union (ITU).

The IEC is a global standards organization that prepares and publishes international standards for all electrical, electronic and related technologies. Formed in June 1906 in London, UK, the IEC is composed of (TCs) technical committees and SCs (subcommittees) who prepare technical documents on specific subjects within their respective scopes, this to define the related standards. For example, the TC86 is dedicated to fiber optics, and its SC86A focused on fibers and cables.

The ITU is the United Nations specialized agency for information and communications technologies (ICTs). It develops technical standards, methodologies and specifications related to telecommunications systems, networks and services. The ITU was founded in Paris in 1865 under the name International Telegraph Union and took its present name in 1932. It includes optical fiber and cable standardization and test and measurement applications; for example, Passive Optical Networks (PONs) such as those described in Recommendations ITU-T G.983.x and ITU-T G.984.x

The ITU has three main areas of activity organized in “sectors” which work through conferences and meetings: radiocommunications (ITU-R), telecommunication standardization (ITU-T) and telecommunication development (ITU-D).

In addition to the IEC and ITU, there are several other groups that provide guidelines and standards for the telecommunications industry: the Telecommunications Industries Association (TIA) the Electronic Industries Alliance (EIA) and the European Telecommunications Standards Institute (ETSI). The TIA is accredited by the American National Standards Institute (ANSI) to develop industry standards for a wide variety of Information and Communication Technologies (ICT) while the EIA provides additional recommendations for the United States. ETSI defines telecommunications standards and is responsible for the standardization of Information and Communication Technologies (ICT) within Europe.

Fiber optic test equipment (your toolbox essentials)

From installation to activation to troubleshooting, your testing toolbox should include equipment designed to minimize costs and increase fiber technician efficiency. Below is a list of toolbox essentials:

• Fiber inspection scope (with common inspection tips): uses automated analysis software to assess connector quality—an essential step during fiber commissioning and installation.
• Power meter and light source, optical loss test set (OLTS) and fiber optic adapters and test jumpers used to reference the instruments.
• Optical fiber multimeter (OFM): an essential go/no-go tool for link verification in just a few seconds.
• Optical time domain reflectometer (OTDR) and Intelligent Optical Link Mapper (iOLM) with launch and/or receive cables to characterize a fiber optic network.
• Other tools such as a visual fault locator or fiber tracing and cleaning kits (dry and/or wet method) to clean connectors that interconnect all network elements.

Fiber testing methods

To ensure reliable services, a network must meet specifications. Verification is performed using specific instruments and following the methods listed below.

Fiber inspection tool: Connectors are the most overlooked aspect of a network, but contamination from a wide range of sources can have a serious impact on network loss and reflectance. Using a fully automated connector solution is highly recommended to evaluate connector health.

Fiber continuity test: Fiber identifiers check that fibers are connected by identifying live fibers. This tool also identifies the frequency and direction of traffic.

A visual fault locator (VFL) helps identify bends, faulty connectors, splices and other causes of signal loss. For longer distances or where access is limited, an OTDR can be used to pinpoint any continuity problems.

Optical loss testing: An automated OLTS determines the total amount of loss or attenuation in a fiber span under test. Compared to a standard OLTS, the automated version has an integrated source and power meter in each unit (both in a single port), has bidirectional loss and ORL testing and length measurement capabilities.

Optical time domain reflectometer: Testing methods and tools based on reflectometry, such as OTDRs and iOLMs provide the IL/ORL during the construction phase, but it also detects and locates issues like: fiber-connector misalignment, fiber mismatch, splice loss, high-loss or reflective connectors, high-loss splitter branches, fiber breaks, fiber section attenuation (dB/km) and macrobends.

Fiber testing in 5G networks

To achieve the expected 5G level of performance, we need to drastically densify the network. The complexity- and cost-related challenges associated with deploying 5G—a network that’s denser and faster than ever—are numerous.

New higher rates have tighter budgets and are more difficult to get working right the first time. Add in new rates, new transceivers, new equipment, and it’s harder to know what and how to test.

Automated testing—with its efficient, smart and simple tools—will be critical to saving time, money and delivering 5G done right. EXFO’s innovative 5G testing solutions, including the industry’s first and only optical fiber multimeter, empowers frontline technicians with a new testing approach that enables them to keep up with the accelerated pace of fiber deployments while meeting 5G deployment challenges.

EXFO provides network operators with innovative solutions and expert testing knowledge that bridges the OPEX gap created by the increase in bandwidth demand. With field-proven methods and procedures, smart and integrated test solutions and cloud-based data management and cloud-automation, today’s networks can now be deployed reliably and cost effectively.

To learn more and ensure that your network can deliver high reliability and availability to your customers, visit our solution page.