MPO technology with multifiber connectors offers ideal conditions for setting up high-performance data networks in data centers to achieve greater bandwidth and handle future requirements. This technology makes scaling and migration to network operation with 40/100 Gigabit Ethernet all the easier and more efficient. This paper introduces the practical application of MPO technology, which shows the solutions for 40 Gigabit Ethernet.
In order to provide an introduction and basic information to the reader, this section begins with a presentation of the components needed for a parallel optical MPO connection. As is known to all, MPO connectors (known as multi-fiber push-on and also as multi-path push-on) can contact up to 72 fibers in a single connection. A connection must be stable and its ends correctly aligned, which is essential for achieving the required transmission parameters. A defective connection may even damage components and cause the link to fail altogether.
MPO connectors are available in a female version (without pins), or a male version (with pins) as shown in the following picture. The pins ensure the exact alignment of the fronts of the connectors, and also they ensure the end faces of the fibers are not offset.
Noses and guide grooves (key) on the top side are the two other clearly visible features, which ensures the adapter hold the connector with the correct ends aligned with each other. Based on the placement of the key, two types of MPO adapters are available. One is “key-up to key-down”. It means the key is up on one side and down on the other. The two connectors are connected turned 180° in relation to each other. The other one is “key-up to key-up”. It means both keys are up. The two connectors are connected while in the same position in relation to each other.
- Always use one male connector and one female connector plus one MPO adapter when creating a MPO connection (see the following picture).
- Never connect a female to a female or a male to a male. It should be connected with a male and a female as stated above. With a female-to-female connection, the fiber cores of the two connectors will not be at the exact same height because the guide pins are missing. That will lead to losses in performance. A male-to-male connection has even more disastrous results. There the guide pins hit against guide pins so no contact is established. This can also damage the connectors.
- Never dismantle a MPO connector. The pins are difficult to detach from a MPO connector and the fibers might break in the process. In addition, the warranty becomes null and void if you open the connector housing.
MPO cable has the advantages of shorter installation times, tested and guaranteed quality and greater reliability. It has several different kinds of types.
Trunk Cables: trunk cables serve as a permanent link connecting the MPO modules to each other. They are available with 12, 24, 48 and 72 fibers. Their ends are terminated with 12-fiber or 24-fiber MPO connectors according to customer’s choice. These trunk cables like 12 fibers MPO trunk cable could help to create a simple, cost-effective 40G networking by installing a structured cabling system. MPO trunk cable requires greater care in planning but has a number of advantages, such as higher quality, minimal skew, shorter installation time, better protection, smaller volume of cable and lower total costs.
Harness Cables: harness cables provide a transition from multifiber cables to individual fibers or duplex connectors. For instance, 8 fibers 12 strands MPO harness cable has eight LC high fiber density connectors and a MPO connector, which is convenient for wiring and management system in 40G network with stable performance.
Y Cables: Y cables are generally used in the 2-to-1 version. A typical application is to join two 12-fiber trunk cables to a 24-fiber patch cord as part of a migration to 100 GbE. The rather rare version of 1 to 3 allows three eight-fiber MTP connectors to be joined to a 24-fiber permanent link, e.g. for migration to 40 GbE.
OM3 and OM4 fiber optic cables put in a parallel optical connection, terminated with MPO/MTP connectors. These are the ingredients for 40 GbE technology in a structured cabling environment. Parallel optical channels with multifiber multimode optical fibers of the categories OM3 and OM4 are used for implementing 40 GbE. The small diameter of the optical fibers poses no problems in laying the lines, but the ports suddenly have to accommodate four or even ten times the number of connectors. This large number of connectors can no longer be covered with conventional individual connectors. So the 802.3ba standard incorporated the MPO connector for 40GBASE-SR4.
MPO connectors and cables are the central components of a 40G parallel optical link. This connection decides whether the insertion loss exceeds the attenuation budget and whether the return loss is high enough. In the end, the desired bandwidth can only be reached if all components in a parallel optical link satisfy the highest requirements.
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