Comparing the new-generation fiber-optic connectors

The standardization debate within the Telecommunications Industry Association (Arlington, VA) about the new small-form-factor fiber-optic connectors has made end-users increasingly concerned about how to compare these types of products. While unfortunate, this level of concern is not unexpected. Any evolution in technology, such as this movement from larger SC-style fiber-optic connectors to the smaller offerings, naturally raises a number of questions until end-users become familiar with the ne

Richard L. Akins,

Panduit Corp.

The standardization debate within the Telecommunications Industry Association (Arlington, VA) about the new small-form-factor fiber-optic connectors has made end-users increasingly concerned about how to compare these types of products. While unfortunate, this level of concern is not unexpected. Any evolution in technology, such as this movement from larger SC-style fiber-optic connectors to the smaller offerings, naturally raises a number of questions until end-users become familiar with the new products.

Several issues about the new fiber-optic connectors have been raised repeatedly by users of our connector during its more than 18 months of deployment. Some of these issues follow.

Termination time--One concern repeatedly voiced about the new breed of small fiber-optic connectors is field-termination time. There are actually two issues involved: the termination of the plug and the termination of the jack. Comparing termination times can be an effective gauge for end-users, but how do they compare a fully field-terminable connector (plug and jack) with other connector styles that require that the plugs be factory-terminated? Factory termination limits the flexibility of the installer, may increase costs if damage occurs, and may restrict users to purchasing the preterminated patch cords directly from the vendor instead of through traditional distribution channels.

An additional factor is termination yield. The robustness of the connector and the familiarity of the installer with termination techniques and tooling are crucial in reducing the scrap rate for these new, small fiber-optic connectors.

Cable-style flexibility--As fiber moves to the desk (often terminated between modular patch panels and wall outlets), end-users usually employ fully jacketed duplex cables to better protect the fiber. This fully jacketed cable should be terminable within the jack side of each connector style. For those connector styles that can only use buffered fibers within the jacks, the end-user must be aware of the limitations of this approach.

Multiple termination techniques-- Over the years, tens of millions of dollars have been invested by the five leading fiber-optic connector vendors and others to develop a variety of termination techniques (i.e., epoxy, adhesive, cleave, and stub) for the 2.5-millimeter ferrules used within ST- and SC-style connectors. Each style has its adherents for reasons of cost, quality, reliability, and similar issues. Customers of the new generation of small fiber-optic connectors should be aware of the limitations some of the designs may place upon termination techniques.

Use of existing tools--Each of the termination techniques listed above requires a skill set learned by the installer as well as a set of tools. As the new, small connector styles come to the market, end-users should carefully consider the amount of retraining and retooling each of the connector solutions will require.

Port density--Despite vendors` claims that each of these new connectors provides the same port density as RJ-45 style copper connectors, port density is also a concern. At the outlet, where low-profile, surface-mount boxes may be used, and at the telecommunications closet, where modular patch panels or single-rack-space fiber-optic enclosures may be used, port density becomes critical. Fitting 24 duplex connections within a single rack space is a must, as is the ability of the jack to take up the same vertical space as the 8-pin modular connector.

Reliability--Fiber-optic cabling is becoming more critical to the ever- increasing bandwidth demands of today`s data networks. Fiber is being installed because end-users are looking for a medium with enough bandwidth to be effective for a full 10 to 20 years of service. This type of cabling system requires "futureproof" connectors that must be capable of handling ultrahigh-bandwidth singlemode fiber as well as multimode fiber. Also, this new breed of small fiber-optic connector needs to be reliable enough to stand up to the abuse that fiber-to-the-desk applications will certainly create.

The 2.5-mm ferrule technology used in ST- and SC-style fiber connectors has kept America`s long-distance communications systems working reliably for more than a decade. Which of the new connector designs provide solutions that are this reliable, as fiber moves closer to the desktop?

Richard L. Akins is fiber-optic product manager at Panduit Corp. (Orland Park, IL), which produces the opti-jack connector.

More in Home