What Are They and How to Use MTP/MPO Cables

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With
ever-greater bandwidths and network connections to deal with in data centers,
conventional dual-fiber patch cables like LC cable can no longer meet the
demands. To solve this problem, MTP/MPO cables accommodating more fibers in one
multi-fiber MTP/MPO connector came into the market, which proves to be
practical solutions for 40G/100G/400G high-density cabling in data centers.
This article is going to introduce different
MTP/MPO cable types and their applications.

 

MTP/MPO
Cable Overview

MPO
(Multi-Fiber Push-on) is the first generation of clip clamping multi-core
optical fiber connector. MTP® is a registered trademark of US Conec Ltd. ,
which is an advanced version of MPO, with better mechanical and optical
performance. They look alike and are completely compatible and intermateable.
MTP/MPO cables are composed of MTP/MPO connectors and optical fibers. MTP/MPO
connectors have a female type (without pins) or a male one (with pins) as shown
in Figure 1. The position of guide grooves also results in “Key Up” and “Key
Down” MTP/MPO connectors. And a white dot is for identifying fiber position in
connectors. MTP/MPO connectors largely increase the cable density and save
circuit card and rack space, which are well suited for current 40G/100G cabling
and future network speed upgrades.

 

MTP/MPO
Cable Solutions

A
variety of MTP/MPO cables are available for different application environments
and requirements based on functions, polarity, fiber count, fiber mode and
jacket rating.

 

By
Function

MTP/MPO
trunk cables, MTP/MPO breakout cables and MTP/MPO conversion cables are ideal
for high density cabling network, offering better network capacity and
flexibility.

 

MTP/MPO
Trunk Cables

 

MTP/MPO
trunk cables are terminated with an MTP/MPO connector (female/male) on both
ends, which are available in 8-144 fiber counts for users’ choices. Typically,
these multi-fiber MTP/MPO trunk cables are ideal for creating a structured
cabling system, including backbone and horizontal interconnections such as
40G-40G and 100G-100G direct connections, so as to achieve a simple and
efficient high-performance networking.

 

MTP/MPO
Breakout Cables

 

MTP/MPO
breakout cables (aka. harness cables or fanout cables) are terminated with a
female/male MTP/MPO connector on one end and 4/6/8/12 duplex LC/FC/SC/ST
connectors on the other end, such as 8-fiber MTP/MPO to 4 LC harness cables and
12-fiber MTP/MPO to 6 LC harness cables. Typically, these breakout cables are
ideal for short-range 10G-40G and 25G-100G direct connections or for connecting
backbone assemblies to a rack system in the high-density backbone cabling.

 

MTP/MPO
Conversion Cables

 

MTP/MPO
conversion cables have the same fanout design as MTP/MPO breakout cables but
are different in fiber counts and types. They are terminated with MTP/MPO
connectors on both ends. Specifically, commonly-used ones are 24-fiber to
2×12-fiber, 24-fiber to 3×8-fiber, 2×12-fiber to 3×8-fiber MTP/MPO conversion
cables. They are especially ideal for 10G-40G, 40G-40G, 40G-100G, 40G-120G
connections, which eliminate fiber wasting and largely increase the flexibility
of the existing 12-fiber and 24-fiber MTP/MPO cabling system.

 

By
Polarity

Polarity
refers to the matching of the optical transmitter and receiver at both ends of
a fiber link. In traditional cabling systems, connectors like LC/ SC can be
easily matched, so there is no polarity issue. However, due to the special
design of MTP/MPO connectors, polarity issues must be addressed in high-density
MTP/MPO cabling systems. To ensure proper polarity, the TIA 568 standard
defined three connectivity methods called Method A, Method B, Method C. So
there are Type A, Type B and Type C MTP/MPO cables with different structures
according to these methods. These MTP/MPO cables usually connect with different
MTP/MPO cassettes and fiber patch cables to ensure the right polarity of the
optical circuit. Read the white paper Understanding MTP/MPO Cable Polarity for
more information about common 8/12/24-fiber MTP/MPO cable polarity and
connectivity methods.

 

By
Fiber Count

8/12/24-fiber
MTP/MPO cables are usually used for 40G/100G and the latest 16-fiber cables are
especially designed for short-reach 400G cabling in Hyperscale data centers.
12-fiber MTP/MPO cable is the earliest developed and most commonly-used
solution in 10G-40G, 40G-100G connections. But when using it to transmit 40G
QSFP+ module or 100G QSFP28 module, 4 fibers will be left unused, leading to
much lower fiber utilization than 8-fiber cables. While 8-fiber MTP/MPO cable
system can transmit the same data rate as 12-fiber cabling with less cost and
insertion loss, making it a more cost-effective solution. 24-fiber MTP/MPO
cable is commonly used to establish 100GBASE-SR10 links between CFP to CFP
transceivers. It allows the use of the ratified 100GBASE-SR10 20-fiber
technology today, maximizing the infrastructure investment in the event of 4×25
Gb/s ratification.16-fiber MTP/MPO cables utilize the same external footprint
as traditional 12-fiber MT (Mechanically Transferable) ferrule. MTP/MPO-16
solution is ideal for aggregation of multiple 8-fiber parallel transceivers and
direct coupling to emerging 16-fiber parallel optic links such as 400G QSFP-DD
and OSFP.

 

By
Fiber Mode

MTP/MPO
cables fall into multimode OM3/OM4 and single-mode OS2 cables. Multimode
OM3/OM4 MTP/MPO cables are mostly used for short distances such as inside a
building or campus, allowing maximal transmission distance of 100m (OM3) or
150m (OM4) at 40 Git/s. Single-mode OS2 MTP/MPO cables are suitable for
long-reach transmission and widely deployed in carrier networks, MANs
(Metropolitan Area Network) and PONs (Passive Optical Network). With less modal
dispersion, the bandwidth of OS2 is higher than OM3/OM4.

 

By
Jacket Rating

According
to different fire rating requirements, MTP/MPO jackets are classified as LSZH
(Low Smoke Zero Halogen), OFNP (Optical Fiber Nonconductive, Plenum), CMP
(Communications Multipurpose Cable, Plenum) etc. LSZH MTP/MPO cables are free
of halogenated materials (toxic and corrosive during combustion), which are
ideal for confined places due to better protection for people and equipment
during a fire. OFNP MTP/MPO cables contain no electrically conductive elements
and are designed with the highest fire rating, which can be installed in ducts,
plenums and other spaces for building airflow. CMP MTP/MPO cables can restrict
flame propagation and smoke exhaust rate during a fire, which are suitable for
plenum spaces, where air circulation for heating and air conditioning systems
are facilitated.