What are MTP / MPO Fiber Cables?
MTP/MPO — High-Density Fiber Optic Cabling
The quantity of data
transmitted worldwide is growing exponentially and the need for
ever-greater bandwidths is unrelenting. Though the current data volumes
demanded in backbone cabling can still be handled with 10 GbE, the
forecast trends will require the introduction of the next technologies,
40 GbE and 100 GbE. As a result, data centers must respond to provide
sufficient capacities and plan for upcoming requirements. To meet this
demand, 40G QSFP+ transceivers, MTP/MPO cables and other related
products are now in the market. MTP/MPO cables in the data centers play
an important role in ultra-high density cabling.
Why are MTP/MPO Cables Used?
The number of network
connections in data centers is rising rapidly. Traditional fiber cables
can make the data center crammed and difficult to manage. To solve this
problem, data centers have to achieve ultra-high density in cabling to
accommodate all of the cabling required. The MTP/MPO cables, which bring
together 8, 12 or 24 fibers in a single interface have been proven to
be a practical solution. Incorporating to meet the 40GBASE-SR4 and
100GBASE-SR10 standard, The MTP/MPO multi-fiber connector of MTP/MPO
cables is about the same size as a SC connector but can accommodate 8,
12 or 24 fibers, thus offering savings in circuit card and rack space.
Details of MTP/MPO Cables
MTP/MPO cables are
composed of MTP/MPO connectors and fiber optic cables, other connectors
such as LC may also be found in some kinds of MTP/MPO cables. The fiber
cables used are generally OM3 and OM4, which are laser optimized
multi-mode optical fibers. It is important to have an overall
understanding of MTP/MPO connectors (known as multi-fiber push-on and
also as multi-path push-on).
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.
Connection Rule
- 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.
MTP/MPO Cables
MTP/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 MTP/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 MTP/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. MTP/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 MTP/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/MPO connectors to be joined to a 24-fiber permanent link, e.g. for migration to 40 GbE.
MTP/MPO Solutions for 40 Gigabit Ethernet Cabling
OM3 and OM4 fiber
optic cables put in a parallel optical connection, terminated with
MTP/MPO 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.
By Polarity
MTP®/MPO cable types by polarity refer to the difference between the optical transmitters and receivers at both ends of the fiber link. Due to the special design of MTP®/MPO connectors, polarity issues must be addressed in high-density MTP®/MPO cabling systems.
The TIA 568 standard defines three connection methods to ensure the correct polarity of the optical path, called Type A, Type B, and Type C. The cables of the three MTP®/MPO connector types have different structures.
Summary
MTP/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.