MTP® vs MPO: Are There Really Any Differences?

Written by Ben Hamlitsch, trueCABLE Technical and Product Innovation Manager RCDD, FOI

There is often confusion when we say MTP® or MPO. Is an MPO an MTP®, and is an MTP® the same as an MPO? In this article we will clarify what the differences are and talk about why one may be preferred over the other. First, both MTP® and MPO fiber connectors, or array connectors, are designed as multi-fiber connectors. They are essentially the same connector however, with some differences under the hood. Both connectors have multiple fibers in a single connector, most commonly in configurations of 8, 12 and 24 fibers.

MTP® and MPO connector footprints are similar to ordinary duplex LC connectors. However, the density of MTP®/MPO connectors increases several times compared with ordinary duplex LC connectors. This can save a lot of space and resources for optical fiber cabling. You can see the similarity in size in the image below. However, these MTP/MPO connectors can house far more fibers which increases bandwidth to easily accommodate 40 and 100 Gb speeds. This provides for much greater cable density, which becomes extremely important when talking about data centers and enterprise applications that have large cable counts and need room for expansion in the future.

As we mentioned above MPO (Multi-Fiber Push On) connectors are multi-fiber array connectors with more than 2 fibers. These are designed to provide multi-fiber connectivity in one connector supporting high bandwidth and high-density cabling system applications.

MTP® connectors, short for (Multi-Fiber Pull Off), are equipped with MTP® connectors at either end. MTP® connector is a trademark of US Conec for a version of the MPO connector with improved specifications. So MTP® connectors are fully compliant with all generic MPO connectors and can interconnect directly with other MPO based infrastructures, providing the polarity is the same. However, the MTP® connector is a multiple engineered product enhancement to improve mechanical and optical performance when compared to generic MPO connectors.

The key difference between MTP® and MPO fiber optic cables lies in their connectors. The improved version MTP® cables equipped with MTP® connectors have better mechanical designs and optical performances.

Mechanical designs differences

Pin Clamp

Standard MPO connectors are equipped with plastic pin clamps, which may lead to easy breaking of pins with constant connector mating, while the MTP® connector has a metal pin clamp to ensure a strong clasp on the pins and minimize any inadvertent breaking when mating connectors. In the MTP® connector, the oval spring is used to maximize the gap between fiber ribbon and spring, which can protect the fiber ribbon from damages during inserting. The MTP® design includes a recessed pin clamp and an oval spring that will ensure a secure spring seat, and greater clearance between the spring and the ribbon cable to reduce the risk of damage to the MTP® connector.

Floating Ferrule

The ferrule is the component which surrounds the fiber strands and maintains their position throughout the physical connection. A major improvement to the MPO connector was the introduction of the innovative floating ferrule design of the MTP® connector. This allows all polished fiber tips in the ferrules to stay in contact while the connector housing rotates. This major step in the MTP® connector’s evolution allowed multi-fiber connectors to provide an even more consistent and reliable performance. The floating ferrule feature was particularly important for applications in which the cable plugs directly into an active transceiver device.
Another improvement of the MPO connector involved the original thermo-set compound design, which is more prone to moisture absorption and a main cause of performance degradation. This thermoplastic material maintains a constant diameter for the guide holes, resulting in more reliable physical connection.

Guide Pins

The function of the connector guide pins is to provide a controlled means of mating connectors to establish a secure and stable physical connection. The original MPO connector design uses a plastic pin clamp which can lead to damaged pins when mating connectors multiple times. MTP® connectors have guide pins attached to a recessed metal pin clamp, ensuring a strong clasp on the pins. This design minimizes the risk of accidental breaking when mating connectors. In addition to the clamp design, the MTP® connector features an improved pin design. Whereas the pins on a standard MPO connector have sharp edges, the MTP fiber optic connector pins were redesigned with elliptical edges. This significantly reduced damage and debris generation when mating the connector.
Guide pins are critical for accurate alignment when mating two MT ferrules. The guide pins adopted by MTP® and MPO connectors are different. The MTP® connector uses tightly held tolerance stainless steel elliptical guide pin tips. This reduces the amount of debris that may fall into the guide pin holes or on the ferrule end face.

MTP® vs MPO: Optical Performance

Insertion-loss

The MPO connector has been recognized as an international standard in network architecture for many years. MTP® connectors, as the advanced version, are improved to minimize issues like optical loss, dropped packets, and so on. MTP® connectors in MTP® cables are designed to ensure precision alignment of the male and female sides, which will help to reduce the insertion loss and return loss of the MTP cable when transmitting the data in high-density cabling systems. Furthermore, MTP® insertion loss rates have continued to improve, now rivaling loss rates that single-fiber connectors saw just a few years ago.

Reliability

Compared with the previous MPO connectors, the latest MTP® connectors can plug in without problems and are less likely to have accidental bumps that may result in signal instability. The internal connector components were redesigned in the MTP® connector to ensure perfectly centered normal forces between the mating ferrules, ensuring physical contact of all polished fiber tips in the ferrule. Besides the lead-in on the precision alignment guide pins, the elliptical shape has also been optimized reducing the wear and tear and debris generation from plugging and re-plugging the connector multiple times. These additional improvements to the MTP® connector components resulted in increased stability and boosted durability performance while continuing to enhance the connectors' overall reliability.

Major improvements to the original MPO connector design have led to the MTP® and MTP® Elite connectors that not only speed deployment of data center installations, but also enhance performance and reliability. While the latest generation of MTP® connectors is a big jump from the initial MT ferrule technology the improvements are still ongoing. MTP® connectors deliver exceptional value for a vast range of network technologies and, regardless of the technology you’re working with, MTP® connectors should be part of your data center design.

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