Fiber Sensing by Prisma Photonics

Prisma’s Distributed Fiber-Optic Sensing (DFOS) is the ideal solution for monitoring long-range infrastructure including pipelines, power & utility networks, railways, smart roads, perimeter & border control, and subsea pipelines. The system requires zero installation or capital expenditure, and it is easy to maintain.

The Magic of Fiber Sensing

In our world of technological advances, the benefits of real-time monitoring are clear. Yet, most long-range infrastructure is not monitored. The cost of installing the sensors, supplying them with power and communication capabilities, and maintaining the sensors over time outweighs any benefits they provide. 

With our revolutionary technology, Prisma Photonics transforms infrastructure into a smart monitoring solution without the need to install any sensors. To set up Prisma’s platform, an optical interrogator is connected to a standard single-mode optical fiber in a cable along the infrastructure. The cable is usually a pre-existing, buried cable, or a cable in a conduit. It can also be a cable hanging in the air. The interrogator transmits optical pulses that propagate down the fiber. A minute fraction of the light is reflected from each point along the fiber. 

interference A light pulse is transmitted into the fiber The light is scattered as it propagates through the fiber Environmental changes modify the properties of the scattered light Scattered light is detected, and environmental information is extracted

Real-Time Alerts of Events Along the Infrastructure

By performing ultra-sensitive interferometric measurements of this back-scattered light, changes in the fiber environment can be detected such as pressure, temperature, or vibrations. Changes can be measured that are as small as a millionth of a millimeter at any location along the fiber, for up to 100 km per Optical Interrogator (OI) unit.

These measurements are then used to reconstruct a map of all environmental changes along the infrastructure. The data is processed, and the system provides alerts regarding any changes along the infrastructure that are of interest to the customer.

100x Greater Sensitivity

In a DFOS system, the back-scattered signal is very low – typically, as low as 1 billionth of the transmitted pulse. This poses a challenge for most fiber-sensing systems on the market. The low signal makes it hard to differentiate between different signals, and the poor Signal-to-Noise Ratio (SNR) severely limits the performance of other, currently available fiber-sensing solutions. 

Prisma’s smart monitoring overcomes these limitations using our patented Hyper-Scan Fiber-Sensing™ for ultra-sensitive and intelligent-learning detection. Prisma’s solution identifies the acoustic signature of each event at a resolution that allows classification of events and their locations with unprecedented accuracy – while drastically reducing false positive & negative alarm rates (FAR) and nuisance alarm rates (NAR).

Key Features

  • It’s a distributed system: Instead of using an array of discrete sensors, each requiring installation, power, and communication, one can use a single optical fiber to collect information from all locations along the fiber’s entire length. The fiber itself is a complete “sensor.”

  • It uses pre-deployed fiber-optic cables: With Prisma’s solution, pre-deployed fiber-optic cables can be used replacing the need to install a dedicated optical fiber cable for sensing or many thousands of discrete sensors. (The cables can be used even when they have been placed in a conduit or concrete ditch - i.e., cables that were originally intended for communication purposes.)

  • It has 100x greater sensitivity sensing capabilities: When a pulse of light travels down the fiber-optic cable, the properties of the light are modified by the environment in which the fiber is located. Due to a physical phenomenon called Rayleigh backscattering, a small fraction of the traveling pulse’s energy is scattered back, holding the information about the fiber’s environment. After detection and smart processing, the environmental information is extracted.