Spatial frequency multiplexing of optical fiber sensor arrays

Optical Fiber Sensors and Sensing Networks: Overview of the Main Principles and Applications

Optical fiber sensors present several advantages in relation to other types of sensors. These advantages are essentially related to the optical fiber properties, i.e., small, lightweight, resistant to high temperatures and pressure, electromagnetically passive, among others. Sensing is achieved by exploring the properties of light to obtain measurements of parameters, such as temperature, strain, or angular velocity. In addition, optical fiber sensors can be used to form an Optical Fiber Sensing Network (OFSN) allowing manufacturers to create versatile monitoring solutions with several applications, e.g., periodic monitoring along extensive distances (kilometers), in extreme or hazardous environments, inside structures and engines, in clothes, and for health monitoring and assistance. Most of the literature available on this subject focuses on a specific field of optical sensing applications and details their principles of operation. This paper presents a more broad overview, providing the reader with a literature review that describes the main principles of optical sensing and highlights the versatility, advantages, and different real-world applications of optical sensing. Moreover, it includes an overview and discussion of a less common architecture, where optical sensing and Wireless Sensor Networks (WSNs) are integrated to harness the benefits of both worlds.

Spatial-frequency-multiplexed optical fiber sensor array for structure monitoring

A novel optical fiber sensor system suitable for monitoring the strain/stress distribution of mechanical structures is reported, in which an array of interferometric-type sensors is integrated based on a new spatial-frequency-multiplexing technique. It not only maintains the inherent advantage of the high dynamic range of interferometric sensors but also offers the additional benefits of simple robust system configuration, direct digital readout, and low building, installation, and maintenance cost. Preliminary experimental results on a suspension beam are reported.