Fiber Optic Cables: An Overview of the Basics

Posted by Mike Chen on September 8, 2021

| Categories: Network Cabling

Many organizations planning a network upgrade are looking to replace their copper cables with fiber optic cables. Fiber optic cables offer faster data transmission speeds, greater bandwidth, and longer signal range. They are also thinner and lighter, making them easier to install in high-density environments and providing for better airflow in data center racks.

Selecting the right fiber optic cables can be complex due to the variety of fiber types, fiber counts, transceivers, and connectors. It’s also essential to understand how fiber optic cables are constructed to evaluate the quality of the product.

What does a fiber optic cable do?

Fiber optic cables transmit data as pulses of light through a glass or plastic fiber known as the core. Another layer of glass, called cladding, surrounds and protects the core. The cladding has a lower refractive index than the core, creating a reflection that causes light waves to travel the length of the fiber.

What is fiber optic cable made of?

The core of fiber optic cables is made from glass or plastic fibers, while the cladding surrounding the core is made of glass. The primary coating or buffer is a thicker layer of plastic that reinforces the core, absorbs shocks, and prevents excessive bending. Surrounding the primary coating are strengthening fibers that further protect the core from crushing and pulling forces. The cable jacket provides one last layer of protection and is color-coded to indicate the type of optical fiber.

How many strands of fiber are in fiber optic cable?

A cable may have two to more than 100 fibers, depending on the use case and level of redundancy required. Generally, fiber optic cables connecting devices have two to four strands, while those connecting network switches or A/V racks have four to 12 strands. 

Which connectors are used with fiber optic cabling?

Two types of connectors are primarily used in today’s data centers. The Little Connector (LC) is a cost-efficient 1.25mm diameter connector for high-density use cases. Multi-Fiber Push-On (MPO) is 2.5mm by 6.4mm and can support up to 24 fibers. Multi-fiber Termination Push-on (MTP) is a proprietary version of MPO with an improved connector that provides better performance.

How do fiber optic cables work?

Power is not required for fiber optic cables to transmit a signal. Reflection causes light pulses to travel down the core. The larger the core, the more light that can be transmitted. The smaller the core, the farther light will travel before it needs to be regenerated.

Single Mode Fiber vs. Multimode Fiber

Single-mode fiber (SMF) is prefixed with “OS” and has a small core, allowing light to travel up to 100km. It is typically used for telecom and campus data networks. Multimode fiber (MMF) is prefixed with “OM” and has a larger core that can transmit more data over relatively short distances. It is best used for short-haul networks or cabling within the data center.

What are the types of fiber optic cables?

There are seven types of fiber optic cables: OS1, OS2, OM1, OM2, OM3, OM4, and OM5. OS1 and OS2 fiber optic cables are single-mode cables with a relatively small core carrying just one light signal and enabling data to travel long distances. OM1, OM2, OM3, and OM4 fiber optic cables are multimode cables with a larger core carrying multiple light signals, but they can’t effectively transmit data over long distances. OM5 is an emerging technology that is capable of transferring multiple wavelengths on a single fiber.  

OS1 and OS2 allow speeds of 1-10GbE. OS1 can transmit data up to about 10km and OS2 about 200km. OM1 is used for 100MbE and OM2 for 1GbE. OM3 and OM4 have the same core size as OM2 but are optimized to support faster speeds. OM3 is most commonly used for 10GbE for distances up to 300m, although it can be used for 40GbE or 100GbE over shorter lengths. OM4 is used for 10GbE for distances up to 500m or 100GbE for up to 150m. 

Fiber Optic Cables from Enconnex

Enconnex offers a wide range of fiber optic cables, including single-mode OS2, multimode OM3, and multimode OM4, in various fiber counts and lengths. Our cables are available with multiple combinations of connectors, including LC to LC, MTP to MTP, and LC to MTP. All of our cables meet applicable standards and are designed for use in high-density environments. They include a test report and are assigned a unique serial number for traceability. 

Replacing copper cables with fiber optic cables can bring many benefits, but network administrators need to understand the basics. The cabling experts at Enconnex are here to help you sort through the options and make the right selections. Contact us today. 

Posted by Mike Chen on September 8, 2021

Mike has 20+ years of senior program management, product management, and consulting experience in IT, consumer electronics, and communication products, both at finished goods and components levels. Mike is the Product Manager for Network Cabling at Enconnex.

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