What’s a fiber optic cable?

A fiber optic cable is a type of cable that contains one or more optical fibers, which are thin strands of glass or plastic capable of transmitting data using light signals. These cables are a key component of fiber optic communication systems, providing high-speed data transmission over long distances with minimal signal loss.

The features of the fiber optic cable

The fiber inside the cable, which is made of glass or sometimes plastic, is fragile by its own so to avoid the risk of breaking the fiber core the cables are reinforced with a protective layer. The typical fiber optic cable consists of following layers: the core, cladding, coating, strength member and an outer jacket. The core component of the cable is the optical fiber, which is designed to carry light signals.

Optical fibers are typically made of glass or plastic and have the ability to transmit data at extremely high speeds. The core is surrounded by a cladding (which reflects the light back into the core). This design enables the principle of total internal reflection, allowing the light to propagate through the fiber. The coating and outer jacket is to shield the optical fiber from environmental factors, physical stress, and damage.

Two types of fiber: Single-mode and multi-mode

There are two types of fiber optic cables, single- and multimode. The main differences between the two types are that multi-mode has a larger core and can therefore not transfer data as far as the single-mode fiber cable. The multi-mode optical fibers are used in internal networks and single-mode is used in outdoor applications

Differences between single-mode and multi-mode

Core diameter

Multi-mode: Has a larger core diameter, typically ranging from 50 to 62.5 micrometers. This allows multiple modes (light paths) to travel simultaneously.

Single-mode: Features a smaller core diameter, typically around 9 micrometers. It allows only one mode of light to propagate, resulting in a more focused and direct signal.

Light dispersion

Multi-mode: Experiences modal dispersion, where different modes of light travel at different speeds, causing signal distortion over long distances.

Single-mode: Exhibits minimal modal dispersion since only one mode of light travels through the core, making it suitable for long-distance transmissions.

Bandwidth and data rates

Multi-mode: Offers higher bandwidth, suitable for shorter-distance transmissions and applications with moderate data rates.

Single-mode: Provides higher bandwidth and supports much higher data rates, making it ideal for long-distance transmissions in high-speed networks.

Distance capability

Multi-mode: Typically used for shorter distances, typically within data centers or campus networks. Distances are limited due to modal dispersion.

Single-mode: Well-suited for long-distance transmissions, making it suitable for telecommunications, metropolitan area networks (MANs), and inter-city connections.

Light source

Multi-mode: Often used with LED (light-emitting diode) or VCSEL (vertical-cavity surface-emitting laser) light sources due to its larger core size.

Single-mode: Requires a laser light source for optimal performance due to its smaller core size.


The typical fiber optic cable is widely used in telecommunications networks, internet infrastructure, data centers, and various applications where high-speed, reliable, and secure data transmission is essential. These environments are relatively clean, and the fiber optic cable are not exposed to wear and tear in the same extend compared to the ruggedized and armored fiber optic cable which are used in harsh environments such as military applications, aerospace, tactical communication, mining industry etc.

What does it mean when the fiber optic cable is rugged or armored?

Both the ruggedized and armored fiber optic cables is developed for harsh environments and is often used by military or in industry applications where the surroundings can be dusty, wet, changing weather conditions or where the cable must lay on the ground and be driven over etc. Rugged or armored fiber optic cables are both reinforced to cope with demanding environments, but they have different constructions and therefore different features.

What is a rugged fiber optic cable?

Rugged fiber optic cables have a durable outer jacket made of materials like thermoplastic elastomers (TPE) or polyurethane, which is providing resistance to abrasion, chemicals, and UV radiation. Most of the rugged fiber optic cables have a reinforcing strength members made of aramid yarn or fiber glass to enhance their resistance to pulling and bending stresses. The cable has a high flexibility, which makes it easy to install even in cramped spaces and changing environments. Rugged fiber optic cables are ideal for applications where flexibility, durability and resistance to environmental changes are crucial, because it can withstand bending, pulling and abrasions.

What is armored fiber optic cable?

Armored cables have a layer of metallic armor, often made of steel or aluminum, providing robust protection against physical threats, including crushing, impact, and rodent damage. Some of the armored fiber optic cables have a layer of a polyethylene jacket or inner strength members. Compared to the rugged cable the armored cable must compromise the flexibility to instead be great for installations where risk of crushing, impact, or rodent damage is significant. Armored fiber optic cables are deployed in environments where enhanced protection against physical damage and rugged conditions is critical. Common applications include industrial settings, military installations, and outdoor deployments.

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