MPO cables are usually made of ribbon or micro-distribution cables and occupy a considerable share of today’s optical industry. This is understandable because they allow high-speed transmission of optical data in a compressed manner. This is ideal because it is conceivable that in a data center environment, space is sold at a high price. Furthermore, MPO cable assemblies are an obvious choice for high-end bandwidth systems because they offer a variety of advantages to network owners and installers.
In the final analysis, they are mainly used to consistently deliver large amounts of sensitive data to customers, making them the most reliable form of data transmission with high redundancy. With these advantages, 12 or even now 24 optical fiber MPO connectors are becoming the preferred connector for the optical fiber industry.
Therefore, a well-known challenge is not only to accurately test the dB loss of these cables but also to test their “polarity” configuration. The polarity of an MPO cable refers to the arrangement of optical fibers inside the cable. There are typical polarities in this industry; “A”, “B” or “C” polarities. For example, a-type polarity (straight-through) is simple-fiber 1 to fiber 1, 2 to 2, 3 to 3, and so on. The b-type polarity (inversion) is to arrange the fiber 1 to the fiber 12, the fiber 2 to the fiber 11, the fiber 3 to the fiber 10, and so on. The c-type polarity (twisted pair) is arranged from fiber 1 to fiber 2, 2 to fiber 1, 3 to fiber 4, 4 to fiber 3, and so on.
Traditionally, to perform attenuation (loss) testing on MPO cables, users must use the MPO to LC disconnect cable, use a traditional power meter, and test each optical fiber once through each LC connector. In addition, all polarity tests must be done manually, as well as a visual fault locator or continuity tester. This will result in longer test times, which means higher labor costs and an overall headache when trying to track which cable is which polarity and what number of fibers.
In the past few years, the popularity of MPO cables has increased dramatically. The market has developed a tester that can adapt to the growing demand to test and certify these cables faster and easier. The MPO loss tester can complete all the core functions required by the industry: polarity check, dBm power reference, dB loss test “pass/fail”, continuity check, and report software that can verify newly installed MPO cables. This product shortens the test time from a few minutes to a few seconds!
Once you have determined the polarity type, the method of referring to the power meter is basically the same as the traditional power meter/light source setup. Attach the reference line(s), press the zero/reference button, connect your test cable, select the polarity test cable, and within about 10 seconds you have the entire MPO cable certification loss and transfer results can be stored and prepared to be organized into a report of yours The computer is for you and the client.
With the ability to save up to thousands of tests and define your own pass/fail thresholds, you can flexibly test MPO cables in any situation you or your customers need. When reporting results, each file slot on the meter contains 12 channels (fiber) results, and the pass/fail mark is visible, so you can easily identify and organize the test results. If you want, you can export hundreds of files in a few seconds. Then, the PC software program allows you to customize the header information. You can include details such as test location, date/time, operator, company, etc.
The optical fiber industry provides MPO loss test kits for single-mode and multi-mode cables, which are of great value to all-optical fiber technicians. Multi-modules usually include a power meter and 850nm light source and appropriate reference cables. If you are testing a large number of multimode cables, it is important to ensure that your multimode source is “surround flux compatible.” Due to the nature of the multimode LED light source emitted to the cable, there are other modes of light in the first few meters of fiber cladding, which can invalidate the power reference (dBm).
This is the traditional reason why the mandrel is used for MM testing, but the design of the surrounding magnetic flux compliance source and/or reference line allows for a more consistent reference, which means less variation in insertion loss results after testing. As for single-mode kits, they can include 1310nm or 1550nm light sources. The power meter and light source can also be obtained separately.
When it comes to customers and their expectations for MPO test applications, it should be noted that more than insertion loss testing and polarity verification are needed; there are other tools for maintaining and properly verifying these types of cables. Since insertion loss is a major problem in testing, and most cable loss comes from the connector itself, MPO detection probes are becoming more and more popular to ensure that the MPO end face is clean. This works hand in hand with appropriate cleaning consumables to keep the 12-24 fiber end-faces clean and defect-free.
Today, most MPO test sets are used in conjunction with MPO visual inspection probes, and the pass/fail software follows the IEC industry standard. This can ensure that the cable is checked and passed by the user during installation and testing. These images can be uploaded to the report in the same way as typical single fiber images.
As far as cleaning is concerned, there are various cleaning agents available. The most effective is the “click” type cleaning pen; it can clean MPO male and female threaded joints, and can also clean the matching sleeve bulkhead. The user can also press the connector into the gel pad. When the connector is removed from the gel pad, any debris on the connector end face will remain in the gel, keeping the end face clean.
MPO test kits commonly include MPO meters, MPO light sources, reference cables, matching sleeves, AC power adapters, and reporting software. Separate additional accessories to aid maintenance: MPO connector push cleaner, MPO gender change tool, MPO/LC disconnect cable, additional reference wire, and mating sleeve.
As you can see, MPO-type connectors have not made any progress, and now the industry provides some options that allow technicians to properly verify, test, and certify all aspects of their MPO cable assemblies. Whether it is polarity or continuity verification, insertion loss testing, or end-face inspection, these tools exist to ensure that these components are manufactured for high-density and high-bandwidth applications.
