MTP stands for Multifiber Termination Push-on/Pull-off. You can use the term MTP connector or MPO connector, they both indicate the same multi fiber connector style – MTP is just the trademark registered name that USConec uses for their MPO connectors. You typically see these types of connectors in the data center world, as they are commonly utilized for high density, high speed, and space saving applications. Take into consideration that you are housing multiple fibers within one single connector instead of using twelve connectors for twelve fibers. These connectors enable the fastest connection speeds and provide reliability to the user. Most MTP/MPO patch cords are manufactured in a cable assembly house and polished for optimal performance, making this an easy plug and play solution for consumers.
These connectors come standard in 8, 12, 16, 24, or 32 fiber offerings, with both Singlemode and Multimode fiber options available. Multimode MTP/MPO ferrules are typically ultra-polished and singlemode ferrules are angle polished. MTP/MPO connectors must comply with quality standards laid out in the IEC (International Electrotechnical Commission) and TIA (Telecommunications Industry Association), this means that all the connector brands must have standard features so different manufacturers’ connectors and adapters can be utilized interchangeably. These standard features include the size and dimensions of the connector, the pinholes, and other physical features, as well as color coding of the connector housings to simplify fiber type identification.
These connectors allow for the ability to utilize fast connection speeds, and superior reliability in applications that need multiple fiber connections and have limited installation space.
MTP/MPO connectors are composed of a ferrule and a connector housing. Housing kits come in a variety of colors which aid in the identification of the mode of the fiber and the quality of the ferrule, in the case of multimode connectors you will see beige, black, aqua, magenta or lime green housings and single mode housings are typically green or yellow.
MTP/MPO’s come in both single mode and multimode styles; there are differences in multimode and single mode MTP/MPO’s. For a single mode MTP/MPO, it is always an APC (angled physical contact) polish while in multimode applications it is generally an ultra physical polish (UPC).
MTP/MPO connectors are gaining popularity in the fiber world because they allow for the ability to utilize fast connection speeds, and superior reliability in applications that need multiple fiber connections and have limited installation space. Cable Options for the MTP/MPO Connectors
Most commonly MTP/MPO connectors are terminated on 12 or 24 fiber ribbon fiber optic cable because ribbon cable already comes in a multi-fiber array. Ribbonized fiber is most commonly constructed of 12 color coded bare fibers held together in a flat form by glue or adhesive called a matrix. MTP/MPO connectors are the ideal choice for this cable construction. Ribbon cable also assures the fiber lengths are equal, delivering high speed data requirements with minimum error rates. The MTP/MPO connector can be terminated easily on this cable style, and ribbon is usually compact in size compared to other fiber cable constructions, making this a space saving solution.
Micro Distribution Cable is also an option for building MTP/MPO cables as they are a small, compact cable solution that can house high fiber counts. This cable, like ribbon cable, allows for runs in small ducts, panels, and other tight spaces.
There are three main polarity types when referring to MTP/MPO’s there is Polarity A, Polarity B, and Polarity C, and also an 8 fiber option. If you are building a custom MTP patch cable you may have the option for custom configured polarities but in reality, the most common types of polarity are the 3 options listed above. Polarity refers to the configuration of the fibers within the connectors, each of these fibers corresponds to a transmit and receive fiber connecting your equipment, and if these fiber links do not match, your connection will not work properly.
Polarity is one of the most important factors when deploying an MTP patch cord; you must know what configuration is being utilized in the system in order to properly mate to the equipment. The adapters for the MTP’s will also need to correspond to the polarity of the MTP that will be mating with the adapter, all the polarities must be the same within a system.
Polarity A is also referred to as key up – key down polarity or Straight Through Polarity, this means that the fibers are configured with Fiber 1-Fiber 1, Fiber 2-Fiber 2, Fiber 3-Fiber 3, and Fiber 4-Fiber 4 and so on. Each 1 fiber must match the other 1 fiber in the configuration.
Polarity B is key up to key up configuration. In this polarity Fiber 1 is matched to Fiber 12, and Fiber 2 is matched to Fiber 11 and so on. This is also referred to as Reversed Polarity.
Polarity Type C is also key up to key down, but instead of the fibers going Fiber 1-Fiber 1 such as in Type A polarity, instead Fiber 1 will be matched with Fiber 2, and Fiber 3 will be matched with Fiber 4, and Fiber 5 will be matched with Fiber 6 and so on down the configuration. This polarity is also called Flipped Pairs Polarity.
12 Fiber MTP/MPO 40 Gig SR4 Pinout
An 8 fiber pinout is used for 40 Gig applications, in this configuration, only 8 of the fibers are lit up, 10G per lane (fiber) bi-directional multiplied by 8 fibers equals 40G bi-directionally, with 4 remaining unused within the connector. Commonly this configuration is Fiber 1-Fiber 12, Fiber 2-Fiber 11, Fiber 3-Fiber 10, and Fiber 4-Fiber 9 with Fibers 5, 6, 7 and 8 being dark.
MTP/MPO Adapters/Mating Sleeves
MTP/MPO adapters or mating sleeves must also be selected according to the polarity method of the system they are being installed in. So for Polarity A and C, you will need a key up to key down adapter or mating sleeve and for Polarity B you will need a key up to key up mating sleeve. It should also be known that you cannot mate two connectors of the same gender, so you cannot mate two male MPO connectors or two female connectors. Connectors are aligned within the mating sleeve by the guide pins of the male connector. You will choose the correct mating sleeve according to the system’s polarity.
MTP’s come in two different genders – Male and Female. The female MTP connector does not have any pins and the male connectors have two stainless steel guide pins within the connector housing. Each connector will align with a specific adapter depending on if the connector has pins or no pins and whether or not the polarity is a key up to key up type or key up to key down type.
Recently we have seen gender and polarity changeable MTP connectors. With a small tool, you can open the housing and remove the pins if necessary based on the needs of the installation. These types of connectors are especially valuable in the field because you do not need to send the connectors or the patch cord back to the manufacturer to have the gender changed.
MTP connectors are becoming more popular as bandwidth and space are at a premium in data center solutions and other applications, and the notion of why we would use twelve connectors when you can use one single connector. MTP/MPO cords are an easy plug and play solution for any fiber technician to use.