FIBER OPTICS FIBER OPTICS O ne night in 1996, an unusually hard rain sent a wall of water onto the campus of Colorado State Univer- sity (CSU) in Fort Collins, Colo. The flood gutted the ground floor and basement levels of 14 buildings, sub- merging main distribution frames in each building. Panels were ripped from walls, rooms filled with mud, patch cords floated away, and fiber optic cable filled with water. No one on campus was hurt but, needless to say, the network was down. At the time of the flood, CSU used a variety of fiber pan- els and connectors from different manufacturers for sup- porting the data, video and environmental control applications that served over 30,000 students, faculty and guests at the university. With much of the network infra- structure badly damaged, CSU turned the disaster into an opportunity to improve the network and standardize with one vendor for fiber optic network components. There was a hitch in the new network design, however. With the disaster of the flood still fresh in their minds, CSU network managers decided to consolidate the main fiber dis- tribution frame in a new and more secure, yet smaller, space in the already crowded computer room. With less space for the main fiber frame and a forecast for doubling active net- work connections to more than 25,000 within five years, CSU managers faced a decision: how to aggregate the fiber plant in less space and allow room to at least double capac- ity without adding floor space. After evaluating many solutions, CSU chose ADC fiber products, including the new LX.5™ small form factor (SFF) connector and adapter. With the SFF, two single circuit fiber terminations are housed in a single adapter that fits in BY MICHAEL S. MCCAHEY High-Density Solution High-Density Solution Cable Management Required for Small Form Factor Fiber Connectors and Adapters Colorado State University in Fort Collins where a 1996 flood was a catalyst for change in the university’s network design. the same footprint as the single fiber SC connector and adapter, allowing CSU to double the density of fiber ter- mination equipment. And because the SFF and SC adapters feature identical footprints, CSU was even able to reuse fiber termination equipment, saving time and money by avoiding some unnecessary equipment upgrades. “A small form factor connector was the perfect choice for us,” said Randy Simon, the CSU telecommunications specialist charged with installing and maintaining the fiber plant. “In our new network design, we were given very limited space. We now have a high-density solution that won’t require more floor space as we grow.” In evaluating small form factor solu- tions on the market, Simon preferred an SFF designed for single circuit access instead of those designed only as pairs of fibers, products aimed pri- marily to handle future desktop appli- cations. The reason was simple. He determined that a single circuit design would cut down on maintenance time and reduce network downtime. Also, he wanted to standardize on an SFF that could be deployed throughout the network, not just at the desktop. “Single circuits are just easier to troubleshoot and to rearrange, and having just one connector type for the network is a time saver,” said Simon. “It just makes sense to have one cable to move, especially in a high-density situation.” The inherent density of SFF solu- tions requires more attention to cable management to ensure that routine maintenance and rearrangements are quick and easy to perform. To create more room for cables, Simon found that an SFF that features a smaller 1.7 mm, instead of a 2.0 mm or 3.0 mm cable diameter, provides needed space in panels and racks. With an SFF solution that handles up to 1,152 fibers on a single rack, cable diameter is critical. To support the high-density SFF configurations, CSU required other cable management features in termi- nation equipment to ensure that the fiber plant is easy to manage and pro- vides reliable performance. With angled retainers, integral slack man- agers for excess cable lengths and ample troughs for vertical and hori- zontal cable management, CSU has a cable management system that is capable of handling the high density of fiber connections. “A small form factor solution is much more than just the connector and adapter. Storage, termination and strain relief become more important with high-density panels,” Simon said. “These (ADC) panels are the most workable and most user-friendly pan- els I have used. The more organiza- tion there is within the panel, the eas- ier it is for troubleshooting and main- tenance. I am a real stickler on how the panel looks in a room because this is the part everyone sees.” Another requisite in choosing an SFF solution was high quality and durability. For this, tried-and-true ceramic ferrules were required to ensure that the connectors provide both long-term service and reliability as compared to less expensive plastic ferrules. As an added benefit, having a hinged mechanism that automati- cally covers the ceramic ferrule and fiber end when connectors are removed not only provides safety for technicians but also helps keep con- nectors free from dust and dirt. “You can spend a lot of time blowing out couplers and running lens paper and alcohol across the face of connec- tors to eliminate debris. With the hinged cover, we virtually eliminate that step. Keeping connectors clean is a priority for me because it saves us a lot of time in the long run,” Simon said. In the end, selecting an SFF was more than just selecting a connector style. It was a selection of a total solu- tion for the fiber plant that includes connectors, adapters, cables and fiber termination equipment that are designed to work together. “The con- nector and adapter were just one ele- ment in our decision. We needed a complete solution that includes not just the connector, but also how the solution installs, how it maintains and how it shows in panels.” “In planning fiber for the future, CSU decided it needed a high-quality solution that provides a high-density, scalable, and most importantly, an incredibly high-quality product,” said Pat Burns, director of Academic Com- puting and Networking Services at CSU. “To support our long-range plan, we need to install fiber systems and forget about them. We can’t keep coming back to existing plant to upgrade and change,” Burns said. Angled retainers make installation, rearrangements and maintenance easier to perform with high-density SFF configurations. High-density created with SFF connectors and adapters requires exceptional cable management and smaller diameter cable. With an SFF solution, CSU is now set to meet future network challenges. As is so often the case, an adverse sit- uation proved to be the catalyst for positive change. Michael S. McCahey, a freelance writer for ADC, has over 20 years expe- rience delivering marketing communi- cations solutions for high technology companies in telecommunications and software. McCahey is based in Min- neapolis and can be reached at mcca- hey@mindspring.com To find out more about ADC Telecommunications, call 800-366- 3891 or visit the company online at www.adc.com. Where optical fiber is concerned, multimode fiber is ideal for the majori- ty of premises applications. Multimode fiber offers high bandwidth for cur- rent and envisioned applications in the local area network (LAN) environment, and it enables the use of inexpensive light sources such as light emitting diodes (LEDs) or vertical cavity surface emitting lasers (VCSELs). Currently, low-cost lasers and new laser-optimized multimode fibers are providing the means to cost-effectively transmit data at gigabit speeds over distances required by LANs. Today’s network managers are looking toward the future and seeing the need to aggregate and transmit data at multi-gigabit speeds. These developments have brought renewed interest in 50 micron multimode fiber, which is ideally suited for high-speed transmission. Multimode fibers are available in two core sizes: 50 micron and 62.5 micron. The latter is the FDDI standard fiber and has been widely adopt- ed in North America since its introduction in the mid-1980s. Compatible with the installed base of 62.5, 50 micron fiber is becoming increasingly important in premises cabling, because it offers three times the bandwidth of standard 62.5 micron fiber at 850 nm: 500 MHz•km vs. 160 MHz•km. The short wavelength is crucial, because low-cost 850 nm lasers, such as VCSELs, recently have been developed for network applications. These inexpensive light sources are ideal for use with multimode fiber when opti- mized for the shorter wavelength. Using 50 micron fiber and inexpensive laser transmitters, network designers can achieve longer link lengths and higher data rates than with 62.5 micron fiber. The IEEE standard for Gigabit Ethernet acknowledges the enhanced performance of 50 micron fiber through its specification of link lengths. Fifty micron fiber is written into the standards to transmit up to 550 meters while 62.5 micron fiber is written to transmit to only 220 meters. The combination of laser-optimized 50 micron multimode fibers and VCSELs represents the lowest-complexity, lowest-cost option for high-speed premises networks as they move steadily into multi-gigabit data rates. Recent real-world experiments have demonstrated that new versions of 50 micron multimode fiber can transmit 10 gigabits per second for link lengths up to and beyond 300 meters. These fibers also will support Gigabit Ether- net over much longer distances. Laser-optimized multimode fibers will provide a migration path to at least 10 Gbps using emerging transceiver technology. These attributes will continue to make multimode fiber the medium of choice for premises net- work applications long into the future. Preston Buck is market manager, premises, for Corning Inc. He can be reached at 607-974-4732 or via email at buckpd@corning.com. Core Issues: Core Issues: Reconsidering 50 Micron Multimode Fiber BY PRESTON BUCK A hinged cover automatically closes over the fiber end when the connector is pulled from the adapter, reducing exposure to dirt and providing added safety for technicians. ADC’s LX.5™ connector is half the size of the traditional SC connector. SFF such as the ADC LX.5 provide two terminations in the space of one. . housed in a single adapter that fits in BY MICHAEL S. MCCAHEY High-Density Solution High-Density Solution Cable Management Required for Small Form Factor. our new network design, we were given very limited space. We now have a high-density solution that won’t require more floor space as we grow.” In evaluating