About Fiber Optics | Fiber Optic Support

The Building Blocks of High-Speed Communication

The Basics of Fiber Optics

Fiber optics is a method of transmitting data using pulses of light through strands of ultra-pure glass. This technology enables faster speeds, higher bandwidth, and longer-distance performance with minimal signal loss—making it the backbone of modern communication systems.

There are different types of fiber, each with specific functions. In this section, we’ll cover the differences between singlemode and multimode fiber, explore the internal structure of a fiber cable—including the core, cladding, and protective jacket—and explain the role of wavelengths in optical data transmission.

Understanding Fiber Types
and Light Transmission

Fiber optic cables come in two main types, each suited for varying distances and network requirements.

Singlemode fiber sends light in a straight path, offering the longest reach and best signal quality. It’s the most common installation type today, especially in telecom, enterprise networks, and long-distance connections.

Multimode fiber sends light in multiple paths at once, which can cause signals to arrive slightly out of sync. It’s ideal for short runs in buildings or equipment rooms, but it’s important to ensure connector and cable compatibility throughout the entire fiber route.

Wavelengths refer to the light frequencies used to transmit data through fiber. They impact how far signals can travel and how clearly they arrive. Below are the most commonly used wavelengths for each fiber type:

Singlemode: 1310 nm, 1490 nm, 1550 nm, 1625 nm
Multimode: 850 nm, 1300 nm

Core, Cladding, Buffer & Jacket:
Inside a Fiber Optic Cable

Every fiber optic cable is made up of three key layers that work together to carry, contain, and protect the light signal—ensuring speed, clarity, and durability in real-world conditions.

Core: The central glass strand where light signals are transmitted. Its size determines how light travels—either in a single path or multiple paths—and plays a key role in the cable’s speed, distance, and performance.

Singlemode core: ~9 µm (microns)
Multimode core: 50 or 62.5 µm (microns)

Cladding: A layer of glass that surrounds the core and reflects light inward, keeping the signal contained and stable.

Outer Jacket: A protective layer that shields the cable from damage. Jacket colors help identify the cable type:

Singlemode: Yellow
Multimode: Orange, Aqua

Where Light Meets Hardware

Connectors & Terminations

At the end of every fiber optic cable is the connection point—where light meets hardware. After understanding the structure of fiber cables in the previous section, it’s important to know how those cables physically connect to devices, panels, or test equipment in the field.

This section covers the most common connector types, the difference between APC and UPC polish styles, and how simplex vs. duplex configurations affect signal direction and data flow. These elements are essential for clean terminations and reliable performance.

Common Fiber
Connector Types

Connectors are installed at the ends of fiber cables to create low-loss connections between devices or panels. They're often secured through bulkheads—adapter ports that hold connectors in place and ensure proper fiber alignment.

LC Connector – 1.25mm ferrule. Compact snap-in connector, common in telecom rooms and patch panels.
SC Connector – 2.5mm ferrule. Push-pull connector used in many standard installations.
ST Connector – 2.5mm ferrule. Twist-lock design, often found in older or industrial networks.
MTP®/MPO Connector – Multi-fiber connector for 12, 24, or more fibers. Used in ribbon fiber and backbone links.

APC
vs. UPC

The way a connector is polished affects how light reflects at the connection point. Two main polish styles are used in fiber networks: UPC and APC. Choosing the right type depends on the application's sensitivity to signal loss and reflection.

APC (Angled Physical Contact): 8° angled end-face reduces signal reflection. Ideal for high-precision uses like FTTx and RF video.
Color: Green

UPC (Ultra Physical Contact): Flat end-face with a slight curve. Low insertion loss. Common in Ethernet, telecom, and general-purpose fiber.
Color: Blue

Simplex
vs. Duplex

Fiber optic cables are classified as simplex or duplex, based on the number of fiber strands and the direction of data flow. Choosing the right configuration is essential for compatibility with your equipment and network setup.

Simplex: Uses a single fiber strand for one-way communication. Common in monitoring systems, sensors, or applications where data only flows in one direction.
Duplex: Uses two fiber strands—one to send and one to receive data. This is the standard setup for most fiber optic networks, allowing bidirectional communication.

Both simplex and duplex cables can use the same connector types, but the number of fibers determines how the cable is built and how it functions in the system.

Fiber Fiber

Joining the Light: Introduction to Fiber Splicing

After understanding how fiber optic cables are built and how connectors are used to terminate them, the next step is learning how two fibers are permanently joined. Fiber splicing is essential when extending cable runs, repairing breaks, or building out large fiber networks.

In this section, we’ll break down what fiber splicing is, why it’s used, and how it compares to using connectors—so you’ll know when and why splicing is required in the field.

TAGLINE

Fiber Splicing in the Field

Fiber splicing permanently joins two fiber optic cables to create a continuous path for light. It’s commonly used in long-distance runs, backbone networks, and field repairs where connectors aren’t practical.

There are two main methods: fusion splicing, which fuses the glass ends together using heat, and mechanical splicing, which aligns fibers inside a sleeve without melting them. Both are used in different field scenarios based on speed, cost, and performance needs.

Precision Splicing, Minimal Loss

Fusion
Splicing

Fusion splicing melts two fiber ends together using an electric arc, forming a durable, low-loss connection. It’s the preferred method for permanent joins in high-performance or long-distance installations and field repairs.

Fast Fixes in the Field

Mechanical
Splicing

Mechanical splicing aligns fiber ends inside a sleeve without fusing the glass. It’s a faster option often used for temporary fixes or when specialized equipment isn’t available.

The Right Tools for Every Fiber Job

How Fiber Connects Us All

You've seen how fiber optic networks are built—from the cable itself to the connectors and splicing methods that bring everything together. But making those connections possible requires the right tools at every step.

In this section, we’ll introduce the core categories of fiber optic equipment. Whether you're planning to rent gear or need expert support in the field, understanding what each tool does will help you match your project with the equipment it requires.