How to Select Patch Cable for Optical Transceiver

People are always amazed by the development of optical communication. Things move really fast in this industry. Fiber optic transceiver, a small-size but important optical component, can best represent the advancing of the optical communication industry. The form factor of optical transceivers has changed from GBIC for Gigabit Ethernet to SFP+ for 10GbE, QSFP+ for 40GbE and 100G CFP and QSFP28. Even a double density QSFP—QSFP-DD for 200/400GbE is under research. It’s not difficult to recognize all these different types of fiber optic transceivers. However, customer could be confused about how to connect these transceiver to the telecommunication network. This post will introduce how to select patch cables for optical transceivers in details.

Patch Cable Selection Guide

To select the right patch cable for your modules, you should firstly have a comprehensive understanding of the modules mainly from the following aspects: transmission media, interface, transmission distances and data rate.

Transmission Media

There are mainly two types of transmission media that are widely used in today’s telecommunication network. One is fiber optic and the other is copper. Transceivers can also be divided into two types, copper based transceivers and fiber optic based transceivers. MSA has defined several copper based transceiver like: 100BASE-T, 1000BASE-T and 10GBASE-T. These copper based transceiver are available in GBIC, SFP and SFP+ form factors, which usually has a RJ45 interface to connect with the patch cords. These transceivers is generally used with Cat5/6/7 cables attached with RJ45 connectors as shown in the following picture. However, with technology advanced, Cat 8, which is still under research, is expected to support higher data rate up to 40G.

 

While for fiber optic transceivers, things become more complex. This is because most of the transceivers are based on fiber optic which can support higher and longer data rates. Generally for fiber optic transceivers, there are mainly two type of fiber patch cable are used: single-mode and multimode. Single-mode patch cable can further be classified into OS1 and OS2. While multimode can be further divided into OM1, OM2, OM3 and OM4. The larger the number following after OM/OS, the better performance the fiber optic patch cable has. Usually for short distance transmission up to 500 meters multimode patch cable is suggested. For long distance transmission, single-mode transmission is suggested. However, the transmission data rate which can also affect the transmission distance should also be considered.

Transmission Distance and Data Rate

MSA has defined a variety of transceivers that can support different transmission distances and data rates. The following chart provided some of the most commonly used transceiver descriptions which imply the transmission distance and data rate that a transceiver can support.

Description Wavelengh Cable Type Data Rate Distance
SX 850nm MM 1G 500 m
LX 1310nm SM 1G 8 km
EX 1310nm SM 1G 40 km
ZX 1550nm SM 1G 70 km
SR 850nm MM 10G 300 m
LR 1310nm SM 10G 10 km
ER 1550nm SM 10G 40 km
ZR 1550nm SM 10G 80 km
SR4 850nm MM 40G 100 m
SR10 850nm MM 100G 100 m
LR4 1310nm SM 40G 10 km

It is commonly known that transmission data rate decrease as the transmission distance increases in a fiber optic cable. Apparently single-mode patch cords offer the best performance for different data rates in both long and short distances. However, single-mode fiber optic cable is more expensive. To achieve reliable performance in short distances with cost effective solutions, you should know the performance of multimode fiber optic cables. The following chart provides the detailed transmission distances and data rates information for different multimode fiber optic cables over wavelength of 850 nm for your reference.

850 nm Ethernet Distance
Fiber Type 1G 10G 40/100G
OM1 300 m 36 m N/A
OM2 500 m 86 m N/A
OM3 1 km 300 m 100 m
OM4 1 km 550 m 150 m

Transceiver Interfaces

The selection of patch cable for transceiver should also consider the interfaces through which patch cords is connected to the transceiver. In addition, transceiver usually used one port for transmitting and one port for receiving. Generally, fiber optic transceivers usually employs duplex SC or LC interfaces. However, for BiDi transceivers only one port is used for both transmitting and receiving. Thus, simplex patch cord is used with BiDi transceiver.

Some 40G/100GBASE QSFP+ transceivers used MTP/MPO interfaces, which should be connected to the network with multi-fiber patch cords attached with MTP/MPO connectors. If these ports are used for 40G to 10G or 100G to 10G connection, then fanout patch cable should be used. For example, a MTP to 8 LC fanout cable can splitter 40G data rate to four 10G data rate.

Conclusion

Combine the factors of transmission media, transmission data rate and distance, transceiver interfaces, you can roughly know how to select the patch cable for transceivers. FS.COM also provide customized solutions for patch cable. Kindly contact sales@fs.com for more details.

Source: http://www.fs.com/how-to-select-patch-cable-for-optical-transceiver-aid-484.html

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