Optical Communication – An Introduction

01 Jun Optical Communication – An Introduction

Optical communication—which includes both fiber optic and free-space optical (FSO) systems—is rapidly emerging as the preferred method for high-speed data transfer. This evolution is driven by the increasing demand for greater bandwidth, longer transmission distances, and enhanced reliability in modern communication infrastructures. Consequently, optical technologies are swiftly supplanting traditional radio frequency (RF)-based systems across industries such as telecommunications, data centers, defense, and aerospace. These systems deliver the speed, scalability, and efficiency essential to meet the needs of a world that is becoming ever more interconnected.

What is Optical Communication?

Optical communication is a technology that uses light to transmit information over long distances. A typical optical communication system includes a light source—usually a semiconductor laser—paired with a modulator that converts electrical signals into optical signals. These signals travel through a transmission medium, such as optical fiber or free space, and are then received by a detector and demodulator, which convert the optical signals back into their original electrical form.

Optical communication systems are oftentimes characterized by the medium in which they are transmitted, namely free space optical communication and fiber optic communication.

Free space optical communication

Free space optical communication is a wireless technology that uses light to transmit data through the air instead of using physical waveguides such as optical fibers. It relies on laser beams to send information between two points with a clear line of sight. While free space optical communication systems are capable of high-speed data transmission and are flexible, and cost effective their performance can be severely impacted by conditions like fog, rain or dust.

Although all electromagnetic waves—including radio waves—travel at the speed of light, optical systems outperform others due to their much higher frequencies in the terahertz (THz) range, which allow for significantly greater bandwidth. In addition, unlike radio frequencies, the optical spectrum is unregulated, eliminating the need for costly licenses and making it a more cost-effective solution for high-capacity data transmission.

Applications of free space optical communication

Free-space optical communication is mainly used in scenarios where deploying fiber optic cables is either impractical or too expensive. Typical applications include:

• Backhaul links between cellular towers
• Temporary or emergency point to point communications
• Satellite to satellite or satellite to ground communication links
• Unmanned aerial vehicle (UAV) and drone communication
• Temporary broadband services in natural disaster zones

Fiber optic communication

Since its inception in the 1980s, fiber optic communication has become a vital component of our modern communication ecosystem. Rather than transmitting signals through free space, this technology uses optical fiber—thin strands of glass about the width of a human hair—as the transmission medium. Thanks to the extremely low signal loss of optical fiber, especially when using infrared light, data can be transmitted over very long distances. With the help of optical amplifiers and other advanced technologies, these signals can span tens of thousands of kilometers with minimal degradation. The exceptionally broad bandwidth of optical fiber, combined with its capability to carry multiple wavelength channels through a single strand, enables the transmission of vast amounts of data over a single fiber. The optical C-band alone, with a spectral width exceeding 4 THz (4,000 GHz), can support up to 88 wavelength channels at 100 Gb/s each—equivalent to a total capacity of 8.8 Tb/s! Furthermore, ongoing technological advancements are pushing channel data rates to 1.6 Tb/s, with future developments aiming for 3.6 Tb/s per channel.

Applications of fiber optic communication

Fiber optic communication has found a wide range of use cases over the years. Some of the most telecommunication and non-telecommunication applications include:

• Core networks, often referred to as backbone networks, serve as the central framework of telecommunications systems. They are designed to handle high-capacity, long-distance data transmission, connecting key nodes, data centers, and various other networks. These networks are essential to supporting the infrastructure of today’s internet and communication systems.
• Terrestrial long-haul networks are land-based fiber optic systems designed to carry large volumes of data across extensive distances—often ranging from hundreds to thousands of kilometers. These high-capacity networks serve as the core of national and continental communication systems, enabling the transmission of internet, voice, video, and enterprise data between cities, regions, and even across countries.
• Submarine networks consist of high-capacity fiber optic cables laid beneath oceans and seas to facilitate data transmission between countries and continents. These undersea systems are the foundation of global connectivity, handling over 95% of international data traffic, including internet services, voice communication, video streaming, and private business data.
• 5G transport refers to the foundational network infrastructure that links various components within the 5G environment, allowing data to move efficiently and with extremely low latency between devices, radio units, and data centers. This infrastructure plays a vital role in delivering the high performance, scalability, and adaptability that define 5G technology.
• Fiber access network is the part of a telecommunications network that connects end users—such as homes, businesses, or cell towers—to the core network using fiber optic cables.

Fiber optic communication also has a broad range of uses outside conventional communication networks. They are commonly found in medical instruments, industrial sensing and monitoring, security and government surveillance systems, decorative and lighting applications, and in various energy and utility industry operations.

Explore our fiber certification page to learn out our fiber optic training programs.