Fiber Ribbon Solution for the 10G to 40/100G Migration

With end-user connectivity now possible through various user devices, fiber optic cables have become the ubiquitous transport medium in the data center network. A well designed cable, namely the ribbon fiber cable which can improve the operation of the electronics potentially, as well as minimize the amount of power required for air conditioning is favored by many users. It is important to examine and consider both how and why an optical fiber ribbon cabling solution should be deployed for new 40Gbs /100Gbs installations. This article will explain the reasons from the follow three aspects.

Fiber Requirements

For every optical network, standards for fiber performance must be followed to ensure proper operation under planned conditions of the network. Typically, this means that both distance and link loss budgets must be established for the data center infrastructure. Two standards define the fiber performance that must be adhered to in the data center. They are the IEEE802.3ba standard for 40/100Gbs Ethernet and the TIA-942 Telecommunications Infrastructure Standard for Data Centers. Currently, both 1 and 10Gbs systems use a single fiber to transmit data at the requisite speed. This means one fiber and one connection each per transmit and receive signal channel. The process is accomplished using LC duplex connectors on fiber jumpers for one channel connection that can be applied to 1 and 10Gbs systems.

Form Factors

The transceiver form factor differs as speeds increase. In the following chart, we see that different data transmission schemes in the leftmost column are supported by various form factors. Since both 40G and 100G solutions can be installed using “4 by” parallel optics (i.e. four separate channels transmitting and receiving) it may be prudent for the data center manager to select a form factor for “future proofing” that uses this protocol, so that little or no changes are needed. The green box in the chart contains the “standard” transceiver in use today for 40Gbs. For instance, Finisar FTL4C1QE1C compatible 40GBASE-LR4 QSFP+ transceiver uses 4 parallel fibers for transmission and 4 lanes to achieve 10km over single-mode fiber with duplex LC connectors. The red box outlines a four lane solution for 100Gbs systems.

Connectivity and Cable Design

Today, MTP connector is the most prevalent connector type in 40G system and can easily terminate the fiber ribbon cable. It is commonly available in preterminated form—as a pigtail to be spliced onto a 12-fiber ribbon, or as a MTP patch cord which is terminated on each end. Many end-users are now using preterminated cables where the cable is factory terminated with MTP connectors and/or simplex or duplex connectors to ensure the highest quality connector insertion loss and return loss performance and to expedite the cable installation.

Fiber ribbon cables were initially built according to outside plant fiber cable standards. The designs later migrated to armored versions, dry outside plant cables, and riser and plenum rated indoor cables. The fiber density, particularly as fiber counts increase in the data center, is a very attractive feature of these types of cables. In addition, ribbon cable can be considered as an excellent choice in the data center environment because of the good crush resistance design.

Conclusion

With so many advantages, ribbon fiber cables have been widely deployed in data center communications. The ribbon fiber cable promotes a seamless migration from 10G to 40/100G. The ribbons in fiber optic cables are best suited for future expansion, since the transmission protocols progress to higher and higher data rates. It can save much time and money when upgrades are performed on existing data center end equipment while ensuring optimum data center installation speed, performance, connectivity, and cost efficiency.