Local Area Network (LAN) campus and building backbones as well as Data Center backbones are migrating to higher cabled fiber counts to meet increasing system bandwidth needs. In many cases, Ribbon Fiber Cables are now being deployed to meet this need, as they provide the highest fiber density relative to cable size, maximize use of pathway and spaces, and facilitate ease of termination.
Stranded loose-tube cable has been the dominant fiber optic cable design deployed in campus backbones for more than 25 years. In recent years, this design has also emerged as a major choice for building backbones where riser and plenum flame ratings are required. The loose-tube cable has demonstrated exceptional and reliable mechanical, environmental, and optical performance that has been unmatched by any other optical cable designs and other media types. Loose-tube design typically consists of multiple buffer tubes that contain up to 12 fibers and are stranded around a central member. High tensile strength yarns are helically applied around the stranded buffer tubes. Contingent upon the deployment location, a non-flame or flame-retardant jacket is applied. Recent technology innovations have resulted in a completely gel-free design that contains no filling or flooding compounds, eliminating the time and labor associated with cleaning and terminating fibers. (Related products sample in FOCC: Outdoor Loose Tube Cables)
Historically, tight-buffered cables have been limited to indoor premises applications. The cable normally has been deployed in low-fiber-count (24 or fewer fibers) building and data center backbone and interconnect (two fibers or fewer) applications. The cable design typically consists of multiple 900μm tight-buffered fibers stranded around a central element, with tensile strength yarns and a flame-retardant jacket applied. (Related products sample in FOCC: 900μm Tight-Buffered Fibers)
The Ribbon Unraveled Ribbon fiber optic cable has recently emerged as a primary cable choice for deployment in campus, building, and data-center backbone applications where fiber counts of more than 24 are required. This design offers robust performance equivalent to the stranded loose-tube cable, and provides the maximum fiber density relative to cable diameter when compared to stranded loose-tube and tight-buffered cable designs. (The following picture shows that a simulated fiber optic cable with up to 144 fibers is superimposed over a cluster of copper cables, depicting the space savings that optical transmission can achieve in high-density areas, such as data centers.)
The ribbon cable design characteristically consists of 12 to 216 fibers organized inside a central tube. For indoor designs, helically stranded strength elements provide tensile strengths of up to 600 pounds. The 12-fiber ribbons are readily accessible and identifiable with ribbon identification numbers and TIA-598-compliant fiber color-coding.
A non-flame-retardant jacket material is typically used in outside plant applications. Specially formulated flame-retardant outer jackets are used for indoor applications so that the cable design meets the requirements of the NFPA-262 flame test for ribbon plenum cables, as well as the requirements of the UL-1666 flame test for ribbon riser cables. Like the stranded loose-tube cable, completely gel-free designs are available.
For many years, designers and installers have been reluctant to specify ribbon fiber optic cable in the LAN and Data Center because 12-fiber ribbon field terminations were limited. But with the introduction of innovations such as ribbon-splitting tools, ribbon-furcation kits, and field-installable 12-fiber array connectors, 12-fiber ribbons can be easily terminated with simplex and duplex connectors (such as LC or SC type) or with the MTP® array connector.
The MTP® connector is a 12-fiber push/pull fiber optic connector with a footprint similar to the SC simplex connector. These high-density connectors are used to significantly accelerate the network cabling process, minimize errors, and reduce congestion in patch panels.
The MTP® connector is commonly available in preterminated form—as a pigtail to be spliced onto a 12-fiber ribbon, or as an MTP® connector backbone assembly that is terminated on each end. Field-installable MTP® connectors are also available with a no-epoxy, no-polish design that lets you terminate 12 fibers in less than five minutes. The MTP® connector is specified to conform to the TIA/EIA-604-5 intermateability standard.
Many end-users are now using factory-terminated cables with MTP® and/or simplex or duplex connectors to ensure the highest quality connector insertion-loss and return-loss performance, as well as to expedite cable installation. This is especially true in the data-center environment where short-cycle installations and limited time availability for moves, adds, and changes make simplified and fast installations critical.
MTP® connectorized ribbon cable typically is terminated in patch panels using one of two methods:
Method 1 is normally used in an interconnect application where a harness assembly is used on the front of the patch panel. Harness assemblies are used to break out the 12-fiber MTP® connectors terminated on ribbon cables into simplex- or duplex-style connectors. Harness assemblies have MTP® connectors on one end of the cable while the other end is equipped with simplex or duplex style connectors. The harness assembly interconnects with the backbone ribbon cable at the patch panel MTP® connector adapter. (Related products sample in FOCC: MTP® Harness Cables)
Method 2 is used in both interconnect and cross-connect applications where an MTP® connector module is used. MTP® connector modules are used to break out the 12-fiber MTP® connectors terminated on a ribbon cable into simplex or duplex style connectors. Simplex and duplex style fiber optic patch cords then can be used to patch into system equipment ports, patch panels, or client outlets. The module features simplex or duplex port adapters across the front and one or two MTP® connector adapters across the back. Fiber polarity is maintained with an integrated wiring scheme built into the module that ensures proper transmitter-to-receiver continuity throughout the system; so, when end equipment patch cords are installed, transmit goes to receive. (Related products sample in FOCC: MTP® Cassette Modules)
Pathway and Spaces It is critical to maximize use of pathway and spaces, especially in campus and data-center backbones where space is a premium. Ribbon fiber cables offer up to 45 percent space savings, and three times the fiber-tray capacity over traditional bulkier cable solutions while minimizing cable tray weight. Optimal cabled fiber density in data-center pathway and spaces is important to facilitate efficient cooling systems as well as for removal of abandoned cable in accordance with the National Electrical Code.
In summary, ribbon fiber optic cable is now being deployed in areas where stranded loose-tube and tight-buffered cable have historically been used. Ribbon cable offers the highest fiber packing density to maximize pathway and space utilization in ducts, raceways, and patch panels. Preterminated or field-terminated ribbon cable is now easily obtained using traditional simplex or duplex connectors, as well as the MTP® array connectors.
What Is Ribbon Fiber Optic Cable? An In-Depth Guide
A ribbon fiber optic cable is a specialized type of cable where multiple optical fibers (typically ranging from 4 to 24, with 12 being the most common) are laid out in a parallel, flat array. These fibers are bonded together with a matrix material, forming a thin, ribbon-like structure. Multiple ribbons can then be stacked to create cables with extremely high fiber counts (up to 3,456 fibers or more) in a remarkably compact design. The primary purpose and overwhelming advantage of this design is to enable mass fusion splicing.
Structure of a Ribbon Fiber Cable
While designs vary, a typical ribbon cable consists of several key components:
Optical Fiber Ribbons: The core of the cable. Each ribbon contains multiple 250μm fibers arranged side-by-side, perfectly color-coded for identification.
Central Strength Member: Often a Glass Reinforced Plastic (GRP) rod that provides anti-buckling support and tensile strength.
Cable Core: Stacked ribbons are housed within a central tube or multiple buffer tubes.
Water-Blocking Elements: Water-swellable yarns or tapes are used to protect the fibers from moisture ingress in outdoor cables.
Outer Jacket: The final protective layer, which can be made from materials like LSZH (Low Smoke Zero Halogen) for indoor safety or durable HDPE for outdoor applications.
Key Advantages of Ribbon Fiber Cable
Drastic Reduction in Splicing Time: This is the number one benefit. A mass fusion splicer can fuse an entire 12-fiber ribbon in a single operation. This can reduce installation and restoration labor time by up to 80% compared to splicing individual fibers one by one.
Superior Space Efficiency: By arranging fibers in a flat, stackable format, ribbon cables achieve a much higher fiber density than traditional loose tube cables. This allows more fiber to be run through limited-space conduits and ducts, a critical factor in modern data centers and urban networks.
Simplified Cable Management: The organized nature of ribbons helps in maintaining a cleaner and more manageable infrastructure within splice closures and patch panels.
Disadvantages and Considerations
Higher Initial Tooling Cost: Working with ribbon cable requires specialized, more expensive equipment, including a mass fusion splicer and ribbon-specific fiber stripping and cleaving tools.
Termination Complexity: To terminate a ribbon with single-fiber connectors (like LC or SC), a fan-out kit is required. This kit separates the ribbon’s fibers into individual, color-coded 900μm buffer tubes for protection and connectorization.
Slightly Less Flexible: The flat ribbon structure can be less flexible than individual fibers, which may pose a minor challenge when routing in very tight or complex pathways.
Primary Applications
Ribbon fiber is the preferred choice in any application demanding high fiber counts and rapid deployment:
Data Center Interconnects: Used for high-density MPO/MTP® trunk cables that connect switches and servers.
Telecommunication Backbones: Ideal for long-haul and metro networks where thousands of fibers are needed.
FTTx (Fiber to the x) Networks: Used in distribution portions of the network to efficiently connect large numbers of subscribers.
Disaster Recovery: The speed of mass fusion splicing makes ribbon cables invaluable for quickly restoring critical high-capacity network links after an outage.
Frequently Asked Questions (FAQ)
1. What is a ribbon fiber optic cable?
It is a type of fiber optic cable where multiple fibers are arranged side-by-side in a flat, parallel array, encapsulated in a matrix material to form a ribbon. This design is optimized for high-density applications and rapid splicing.
2. What is the main benefit of using ribbon fiber?
The single greatest benefit is the ability to perform ‘mass fusion splicing,’ where an entire ribbon of fibers (e.g., all 12) is spliced in a single operation, drastically reducing installation time and labor costs compared to single-fiber splicing.
3. How many fibers are typically in one ribbon?
While ribbons can come in various counts like 4, 8, 16, or 24, the most common and standard number of fibers in a single ribbon is 12.
4. What is mass fusion splicing?
It is a process that uses a specialized machine to align and fuse an entire ribbon of fibers simultaneously. This is significantly faster than the traditional method of splicing one fiber at a time.
5. Is ribbon cable more expensive than traditional cable?
The per-fiber cost of the cable itself is often comparable to loose tube cable. However, the initial investment in specialized tools like a mass fusion splicer can be higher.
6. Where are ribbon cables most commonly used?
They are most common in high-density environments like data centers (for MPO trunking), telecommunication backbones, and in the distribution sections of FTTx networks.
7. Can you put connectors directly onto a fiber ribbon?
Not single-fiber connectors. To attach connectors like LC or SC, you must use a fan-out kit to separate the ribbon into individual protected fibers. However, multi-fiber MPO/MTP® connectors can be terminated directly onto the ribbon.
8. What is a fan-out kit for ribbon cable?
A fan-out kit is a device that separates the individual 250µm fibers of a ribbon and encloses each one in a color-coded 900µm buffer tube, making them robust enough for standard connector termination.
9. Is ribbon fiber harder to work with?
It requires different skills and tools. For technicians trained in ribbon handling and mass fusion splicing, it can be much faster and easier to work with for high-count splices. For single-fiber breakouts, it adds the extra step of using a fan-out kit.
10. How does ribbon cable save space?
Its flat, compact design allows for a much higher fiber density in a smaller overall cable diameter compared to loose tube cables, meaning more fibers can fit into a crowded duct or cable tray.
11. What special tools are needed for ribbon fiber?
The primary specialized tools are a mass fusion splicer, a ribbon fiber cleaver (which can cleave all 12 fibers at once), and a thermal ribbon stripper.
12. What is the difference between ribbon and loose tube cable?
In a ribbon cable, fibers are bonded together in a flat matrix. In a loose tube cable, individual fibers are loose inside gel-filled buffer tubes that are stranded around a central member.
13. Can ribbon cables be used outdoors?
Yes, absolutely. Ribbon cables are manufactured in rugged, outdoor-rated constructions with features like water-blocking elements and durable jackets to withstand environmental conditions.
14. How do MPO connectors relate to ribbon cable?
MPO/MTP® connectors are perfectly suited for ribbon cable as they are designed to terminate all 12 fibers of a ribbon into a single, compact connector interface, making them ideal for high-speed data center links.
15. Does ribbon cable really reduce installation time?
Yes, significantly. For a high-count cable splice (e.g., 144 fibers), mass fusion splicing 12 ribbons is dramatically faster than performing 144 individual single-fiber splices.
