There is no technology better than fiber optics for high-speed communications, which offers plenty of bandwidth, exceedingly fast and reliable data transmission, and significantly high returns for improved network and telecommunications solutions. However, with the latest technological evolution, selecting the right cables for a network requires the consideration of several different parameters, features, and specifications.
This brief buyer's guide will help you identify some of the primary things to consider when selecting a suitable fiber optic cable based on your specific requirements.
Key Considerations when Selecting Fiber Optic Cable
When selecting a fiber optic cable, one must evaluate the intended application, which will then drive most of the decisions. First, selecting the appropriate optical fiber type is critical since numerous fibers have been developed to address to address a wide array of applications and therefore differ in performance specifications, optical characteristics, and installation requirements. Distance is also a critical variable when selecting the fiber type, along with the cabling jacket type, connector type, and number of fibers (ie, fiber count) for each cable. As with any investment, price and budget are other important factor in the final decision phase, but only after the correct fiber cable has been identified.
Let’s dig into a few of these a bit further:
1. Selecting the Appropriate Optical Fiber Type and Length
There are two primary types of optical fiber used in most of today’s high-speed communications systems: Singlemode fiber (SMF) and Multimode Fiber. The most notable difference between these two is the design approach of the glass fiber itself, specifically the diameter size of the core in which light signals are transmitted, resulting in differences in the types and number of light modes and distances that can be achieved.
Single Mode Fiber has a typical core size diameter of 9um, which allows for only a single mode of light but enables significantly greater transmission distances. In contrast, Multimode Fiber has larger core size diameters of either 62.5um or 50um, which can accommodate multiple modes of light but the larger core sizes result in greater signal attenuation/loss as the distances grow, so it is useful for very short distance applications.
Therefore, the intended distance plays a key role in the decision of whether to select a single-mode fiber or a multimode fiber. If the network application is just a few hundred meters (ex: inside of a data center), a multimode fiber may be utilized, whereas if the signal transmission is required for a kilometer or more, in almost all instances, single-mode fiber is required.
Single Mode Optical Fibers
There are several types of SMF that are generally identified by their International Telecommunications Union (ITU) standard. While differences between each type are numerous, for the purposes of this article, it’s important to note each type of SMF is designed to address specific network applications. Below we have highlighted a few of these:
G.652: Standard, single-mode fiber. The most frequently deployed type of SMF with brands including Corning® SMF-28® Ultra and OFS® AllWave®.
G.654: Cut-off shifted single mode optical fiber. These fibers provide superior low-loss characteristics and are utilized for submarine and other long-haul applications. Leading brands include Corning® VASCADE® and OFS® TeraWave® Scuba.
G.655: Non-Zero Dispersion-Shifted single mode optical fiber. NZDSF fibers are also designed for longer distances but offer significantly lower chromatic dispersion characteristics. Examples of this fiber type include Corning® LEAF® and OFS® TrueWave-RS®.
G.657: Bend loss-insensitive single mode optical fiber. These fibers have been designed to support significantly greater bending capabilities before incurring transmission losses, making them ideal for cable and connectivity applications where frequent bending will occur (ex: in a building). While some standard G.652 fibers are now also G.657 as well like Corning® SMF-28® Ultra and OFS® AllWave®, manufacturers have designed G.657 fiber types offering even greater bending performance like Corning® ClearCurve® and OFS® AllWave® Flex MAX®.
Multimode Optical Fibers
Similar to SMF, multiple types of MMF are in the market and identified by ISO standards per the OM(x) nomenclature summarized below. Differentiating these types are the core size along with the intended bandwidth and distance parameters:
OM1 & OM2: Both OM1 and OM2 multimode optical fibers comprise the earliest type of multimode fibers, with OM1 and OM2 both having an orange cable jacket color. They support a data rate of 1GB at 850nm. The main difference between the two types is that OM1 fibers have a core size of 62.5um and offer a transmission range of up to 300 meters, while OM2 fibers have a smaller core size of 50um and offer a transmission range of up to 600 meters.
An example of OM1 fiber is Corning® Infinicor® 300, and an OM2 fiber is Corning® ClearCurve OM2®.
OM3 & OM4: OM3 and OM4 cables offer superior transmission to their predecessors, utilizing the 50um core but with a laser-optimized design approach that supports data rates of 10G, 40G, and 100G. OM3 fiber cables are built using an aqua color jacket, while OM4 can have either the same aqua color or a violet color, depending on the manufacturer. While OM3 fibers support transmission distances up to 300 meters, OM4 fibers support up to 550 meters, although distances can vary based on data rates. These cables are very visible in today’s data centers, large enterprises, campuses, and other networks where high data rates are supported.
Brand examples include Corning® ClearCurve® OM3 and OM4.
OM5: Finally, there's OM5, a multimode optical fiber in the earlier phases of its use and deployment. Designated by a lime color cable jacket, OM5 supports 100G data transmission up to 150 meters in distance.
An example of this type of fiber is Corning® ClearCurve® OM5.
2. Cable Jacket Type
After determining the appropriate type of optical fiber, the type of cable jacket used must also be specified for the application. Since both indoor and outdoor cable applications exist, different jacket types and materials are available to ensure optimal performance across varied environments. Desired cable flexibility, strength, fire resistance, and temperature/enviromental factors are all items to keep in mind when selecting a fiber optic cable
Indoor fiber optic cables typically use low-cost, fire-resistant polyvinylchloride (PVC) jackets, although some installations require Low Smoke Zero Halogen (LSZH) jackets. These jackets are flame retardant and produce less smoke when burned. Polyethylene (PE) is used outdoors, which is resistant to moisture and UV rays. Lastly, cable buffering and other “hardening” materials within a cable construction may need to be considered for applications requiring maximum protection against tampering or environmental elements.
- Connector Type
There are numerous types of fiber optic connectors utilized in networks today, but in this article we will only highlight the most common types. Most importantly, a fiber optic cable must have the appropriate type of connector for supporting the intended application, meaning the connector type must match the equipment or connectivity panels that the cable will be mating to/with.
Common types of connectors include single-fiber types like LC, SC, FC, and ST, while the most popular multi-fiber connector type is the MPO.
4. Number of Fibers
The last major consideration when selecting a fiber optic cable is the number of fibers that are needed in the cable itself. This is dependent on the application, but we have quickly highlighted the most common types below.
Simplex Fiber Optic Cable: These are designed for single direction fiber transmission and thus consist of a single stand of optical fiber. Often referred to as a patch cable, they are frequently used to connect two devices with the signal transmission flowing in one direction.
Duplex Fiber Optic Cable: As the name implies, a duplex fiber optic cable provides two-way transmission, in a transmit/receive format - one fiber for transmission in one direction, the other fiber for the received signal in the return direction. They are primarily used in data transmission applications that require a transmit-receive function, for example with fiber optic transceivers that include both transmit (Tx) and receive (Rx) connections.
A suplex fiber optic cable can be offered as a single jacketed cable with two individual fibers terminated independently of each other at the ends of the cable, or more often as two individual simplex cables bound together using an adhesive material.
Multi-Fiber Cable: When requiring more than one or two fibers, a multi-fiber cable will be required to support greater fiber counts. Whether a 12-fiber cable is used with MPO or breakout individual connectors between network equipment in a data center, or a high-density 288-fiber cable is being being deployed underground between two network points in a metropolitan area, there are numerous types and approaches when requiring the use of multi-fiber cables. The most important thing to note is that these cables are specifically designed and constructed to offer greater densities of fibers for any network applications where higher fiber counts are required.
Summary - Fiber Optic Cable Buyer’s Guide
To wrap things up, key considerations when purchasing fiber optic cables for a communications network application include evaluating and selecting the appropriate:
- Optical fiber type and length
- Cable jacket type
- Connector style
- Number of fibers/fiber count
After determining these key items, other procurement considerations and processes like vendor selection along with achieving pricing and delivery lead time objectives can be addressed before the final decision is made.
Leverage M2’s Optical Fiber Expertise
Focused on supporting people first, M2 Optics offers engineering teams extensive optical fiber expertise when determining the appropriate fibers and cables for their networks. Whether requiring technical performance specifications for specific fiber types or customized Fiber Lab network simulators for efficiently replicating optical characteristics and latency performance in the test lab environment, the M2 team is available to help at your convenience.