Theory: MPO and MTP® Explained

As consumers push for faster delivery of larger digital content, streaming audio, video on demand, digital gaming downloads and more, data networks have to evolve to remain competitive. Businesses are reinforcing the need for bigger capacity and faster transfer rates too, with large amounts of data and services being stored and provided in the cloud.

This progression has lead to 40Gb and 100Gb interconnects becoming more common in datacentres, and as existing technologies develop and reach their ceiling of performance, new ideas are needed. Part of this is the QSFP+ and QSFP28 format for optical network connections, upping the abilities of commonplace SFP+ by 4-fold and 10-fold respectively.

On the face of it these new formats are not much more than an evolution of existing technologies, simplying combining the abilities of multiple SFP+ modules into a single package, and as a result there is an increased number of fibre optic cores required to support the data links. Simply throwing more cores at an application is totally possible, but utilising existing, commonplace LC connectors is not possible due to size constraints and also the logistical nightmare of ensuring multiple cores, potentially up to 72, are polarised correctly.

A new connector therefore has been devised, called MPO or “multi-fibre push on”. Typical applications today use up to 12 or 24 cores in a single assembly with a simple connector with repeatable insertion results. There are specialist applications that can currently utilise up to 72 cores, but these are rare. Currently 40Gb and 100Gb applications are standard, with 400Gb applications indicated as the next major development which is expected to use 36 cores.

The connector uses multi-core cables, with the fibre cores presented in straight arrays of 12 cores on the connector, with multiple arrays stacked one above the other in higher core count applications. Two alignment pins and a key ensure the connector is mated accurately and each core makes good contact with the correct core on the other side of the connection.

There is another connector on the market called MTP®. This is in fact a trademark rather than a standard, registered by US Conec, and is a fully compliant product with the industry standard MPO solution. The MTP® products are engineered to provide users with an alternative, premium product, with slightly improved insertion loss and mechanical performance due to a number of small upgrades to the accepted format whilst still maintaining full interoperability with non-branded MPO products. These include modifications to the alignment pins and connector springs and clamps. MTP® products also have a removable housing, meaning ferrules can be repolished, although field polishing of such highly optimised connectors is probably not to be recommended.

Advance offer a range of MPO products that are perfect companions for our QSFP+ and QSFP28 products. We manufacture bespoke products in a range of fibre types, core counts and lengths to your requirements. Contact our team to find out more about Advance fibre products.