Use and application of multi-fiber push-on (MPO) connectors

Multi-fiber push connector, MPO for short, is an optical fiber connector composed of multiple optical fibers. Although MPO is defined as an array connector with more than 2 fibers, it is usually 8, 12, or 24 fibers, and is oriented to common database and LAN applications. There are other fiber counts, such as 32, 48, 60, or even 72 fibers, but these are usually professional ultra-high-density multi-fiber arrays used in large optical switches.

You will also see the terms MTP connector and MPO connector used interchangeably. The term MTP is a registered trademark of the MPO connector provided by US Conec. The MTP connector is fully compatible with the MPO standard and is described by US Conec as an MPO designed to improve performance with stricter tolerances. In this article, we only discuss the MPO connector, because MTP is also considered an MPO connector.

For many years, MPO connectors have been used in duplex 10 Gig fiber optic applications in data centers to deploy pre-connected plug-and-play backbone cables between switches, which saves channel space and simplifies cable management while increasing deployment speed. In these 10 Gig applications, both ends use MPO's 12 fiber or 24 fiber backbone to form a permanent backbone link, which is then converted to a duplex fiber connector through an MPO-LC box or MPO-LC hybrid patch cord on the patch panel .

Because the demand for bandwidth speed far exceeds 10 Gig, the MPO connector becomes the actual interface for applications using parallel fiber optics for higher-speed switch-to-switch backbone data center applications. For example, 40 Gig and 100 Gig applications on multimode fiber (40GBASE-SR4 and 100GBASE-SR4) use 8 fibers to transmit at 10 Gbps or 25 Gbps by 4 and receive at 10 Gbps or 25 Gbps by 4. These common data center applications require 8 or 12 fiber MPO connectors (only 8/12 fiber is used when using 12 fiber MPO). Looking ahead, standards bodies are expecting higher speeds of 200, and MPO connectors and parallel fibers also support 400 Gig. The MPO connector interface is therefore retained.

Like all other fiber optic links used in data centers, links using MPO connectors still need to be tested to ensure that they are within the insertion loss budget. This is especially true for higher speed 40 and 100 Gig applications that require MPO. Because the loss budget for these applications is much lower, it is essential to ensure the highest test accuracy.

Before Fluke Networks introduced the MultiFiber Pro tester and the on-board MPO connector, MPO-style fiber optic links were usually tested using traditional duplex fiber testers. This is very time-consuming. It is necessary to use an MPO to LC fanout line that separates multiple fibers into one fiber channel, and the test reference line needs to be verified before connecting each pair of lines to be tested to both ends. This kind of complex testing also leads to more inconsistencies, and it is more difficult to ensure the cleanliness of all optical fibers in this process.