Fiber Optic Cabinets, Cables, Pedestals and Terminals

The broadband market’s general expectation of 900µm fiber is that they are all the same. They are NOT. FieldShield® StrongFiber is stronger than other 900µm fibers in the industry because it is manufactured with 3 aramid yard strands. And unique to this 900µm fiber is its ability to perform like a 250µm fiber in terms of temperature and attenuation.

Consider a tight buffer fiber. It is a standard 250µm fiber (core, cladding and coating) surrounded by a “tight buffer” material that adheres to the coating of the 250µm fiber. Manufacturers buffer the 250µm fiber to 900µm so it is easily handled and connectorized in the field. Historically, this was done only for Inside Plant (ISP) applications. Between the 900µm buffer and the 250µm coated fiber lies a slip layer. The purpose of this layer is to allow the 250µm and the 900µm layers to be bonded, yet allow the 900µm outer layer to be easily removed with a simple fiber stripper. This provides for fiber stripping operations that have less chance of damaging the fiber. The 900µm buffer did cause higher attenuation on the order of 1.0/0.75 dB vs. 0.35/0.25 dB (1310/1550 nm) for standard single-mode. During low temperature, the thermoplastic buffer material shrinks more than the glass and places additional stress (microbends) on the fiber so attenuation goes up as it gets cold. Since the fiber’s purpose was ISP, temperature and distance was of little consequence. This caused people to believe that 250µm was an OSP fiber and 900µm was an ISP fiber, not suitable for OSP.

Enter Clearfield®’s FieldShield StrongFiber. It too has an outside diameter of 900µm. Why then is it suitable for OSP use? As a manufacturer of fiber management elements that are placed in the harshest of environments, Clearfield’s experience with these passives and the impact of thermal expansion and contraction is extensive. Dissimilar materials shrink and expand at different rates and it is paramount that the product design accounts for this when it occurs and eliminates the unintended consequences – especially with the fiber itself. Clearfield’s history and success of properly packaging a fiber product to perform in temperature extremes was implemented in the design of FieldShield StrongFiber. The cable design allows for movement when it happens without impacting the bandwidth carrying capacity of the fiber itself. This allows for all the benefits of traditional OSP drop fiber packaged in the industries smallest footprint for this product class.

Why is this important? If you’re an employee or contractor who thinks 900µm is only an ISP fiber, you will be pleasantly surprised to discover the advantages of using it in OSP applications. It not only offers exceptional pull strength in a small form factor, but also speeds fiber-fed deployments. You can even deploy it in cold weather and with ice forces in a microduct! It’s manufactured to perform this way…and with our headquarters in Minnesota, we field-test in harsh environmental conditions.

If you want to know more, please reach out to Clearfield. We’re happy to help.

By Bill Sawyer

Bill Sawyer has a rich and varied career in the field of telecommunications. A degreed aerospace engineer, Bill has served the CATV, IXC, CLEC and wireless markets for 25 years with positions including Field, Systems and Application Engineering.

As a Clearfield Application Engineer, Bill assists the CATV MSO market in all aspects of FTTx deployments with specific emphasis on face-to-face technical issues such as installation, design guidance, product selection and problem resolution.