The Principle and Architectures of Optical Stress Sensors and the Progress on the Development of Microbend Optical Sensors

Abstract

For example, a graphene sensor has been used to detect various gas molecules such as NO 2 . [7] For important healthcare applications, medical devices built with sensors have been used to measure various vital signals such as blood pressure, body temperature, blood glucose, etc. [8] For example, pressure sensors can be used to test the pulse [9] while chemical sensors allowed the measurement of lactate concentration in blood and analysis of sweat composition for the real time physiologic monitoring. [10] Among the various types of sensors mentioned above, stress sensors play an important role in the sensor family. With the rapid development in the Internet of Thing (IoT) and the big data technology [11] in recent years, the use of artificial intelligence (AI) becomes increasingly significant, [12] accelerating the progress in robotics and automation. Because of this, stress sensors are more and more significant for the development of robotic science and AI technology, including artificial skin. [13] In addition, stress sensors can also be applied in photonics, for example microbend optical stress sensor is a typical application. With the advantages presented by microbend optical stress sensors, such as their flexibility, sensitivity, low-cost, and reliability, [14] they can be used in extreme environments, [15] which greatly extends the applied range of the stress sensors. Despite recent advancement of the microbend optical sensors, almost no review to account for the achievements and promote the future development in this area of research is found in the literature. In this review, the theoretical principles and the assembly of typical optical stress sensors are presented. Three physical mechanisms of the bend-loss-based optical stress sensors are introduced. As one type of the bend-loss-based optical stress sensor, the progress of microbend optical sensors for applications in various areas is discussed. The optical stress sensors have already shown potential in a broader spectrum of applications, from healthcare to robotic science. We anticipate that optical stress sensors, in particular microbend optical sensors, will continue to attract attention of researchers globally. This review provides a comprehensive information pack for the community to advance the future development in optical stress sensor. Optical Stress SensorsStress sensors are designed to sense changes in pressure. Traditional stress sensors detect the stress via the Optical stress sensors have been considered to be amongst the most important categories in the development of stress sensors. Recently, the advancement of microbend optical sensors has been playing a pivotal role in the stress sensor development. In this review, the principles and the architectures of the optical stress sensors are reviewed, and the physical mechanisms of the bend-loss-based optical stress sensors are presented. The latest development and applications of microbend optical sensors in key areas are discussed. The authors aim to provide some guidance in the optical sen...

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