Fiber optic sensing: The Millennium of Photonics- Part 1

About 200 years ago, Who would have thought that light, when conducted through a narrow fiber, could transmit data at a lightning speed? An industry that relied solely on electric cables to transmit data discovered a new profitable and promising alternative in optic cables. Fiber optic sensing is the most useful and widespread application of photonics which revolutionized many industries including remote sensing, railways, subsea monitoring, oil and gas, nuclear power plants, and smart roads.

Fiber optic sensing understands and utilizes the speed and other major physical properties of light. They found that the light transmitted through a thin fiber was capable of traveling at a lightning speed and delivering data efficiently to the endpoint. The first waves of photonics reached the shore with the arrival of optical fibers to the scene.

Before reaching the high-end industries, fiber optics commenced its journey in the medical field where it was employed in endoscopy. The use of fiber optic cables for endoscopy started in the 1950s. Understanding the immense possibilities of fiber optics, It was used in telecommunications during the 1960s. This in turn helped optical fiber companies to prove the capabilities of optical cables and move into the mainstream market, which was ruled by copper cables until then.

Even though fiber optic sensing set its foot during the telecommunication revolution of the 1980s, the researchers had already realized the scope and extensive range of fiber optic sensing long ago. In 1967, the patent for the first photonic sensor was acquired.

It was an externally attached fiber sensor, unlike the modern integrated sensors. It was mainly used for monitoring non-contact vibration measurements. The next milestone was the fiber optic gyroscope principles which has been established by the mid of 1980s. The rotational data is obtained by analyzing the phase shift in the fiber’s laser light source.

The fiber optic sensing widened its range into other industries without limiting itself to fiber optic communication. But there wasn’t a need to develop new components and infrastructure. The same single-mode fiber, splitters which was used in communication was used for fiber optic sensing also. The fiber optic cables are immune to external electric stimuli.

It has a range of long distances and the cables are highly resistant to corrosion. These added advantages heavily benefitted the industries and increased the popularity of fiber optic sensing. Even though fiber optic sensing was developed in the 1970s, it had to wait until the 1990s for its usage in industries and other purposes. During the 1990s, the oil and gas industry realized the irreplaceable benefits of fiber optic distributed temperature sensing systems. This increased the use of distributed fiber optic sensing (DFOS) for measuring temperature, strain, pressure, acoustics, and other parameters.

The researchers found that fibers are better than metal wires in many aspects. The data transfer through fiber optic cables is at higher bandwidths and can be used for long-distance communications. The copper wires have less bandwidth as it was originally designed solely for voice transmission. Single-mode fibers can carry more bandwidth than multi-mode fibers.

When we use fibers instead of metal wires, there will be only very less signal loss compared to the traditional systems. Also, the fibers are highly immune to electromagnetic interference than metal wires. As there is no electromagnetic interference, the signals will not get intercepted or mixed up with other signals. Fibers have various uses and capabilities such as illumination and extracting images out of confined and remote places.

When compared to their copper opponents, fiber optic cables are more flexible. They are less prone to breakage and damage in a long term. They are also light in weight and thinner than the copper cables. Copper cables are easily worn out when exposed to moisture and air thus increasing the cost and time for repair and maintenance.

Whereas fiber optic cables can last longer than them with little maintenance. Copper can get brittle and sometimes even cause a fire hazard if we do not safeguard it well. This can create high damage in critical sectors like the oil and gas industries. As optical fibers don’t create this risk, they are more reliable in long-term data transmission.