Cost Effective FBG Based Optical Sensor

Fiber Bragg Grating (FBG) based sensors constitute majority of optical sensors for measuring physical values such as strain, temperature, or both. While properties of FBG alone are well known, interrogation techniques have not been standardized. Most sensors use expensive equipment, such as optical spectrum analyzers, for measuring Bragg wavelength changes as a result of strain, or temperature change. Such method is reliable and gives good results, but cannot be used if we are to construct a cost effective sensor whose use could be widespread. In this paper we demonstrate an alternative way of measuring Bragg wavelength shift that could allow us to build cheap, reliable sensor. Furthermore, the proposed sensor can be thermally stabilized without additional resources. Sensor can, finally, be multiplexed offering quasi-distributed monitoring of smart structures while further reducing the cost.