Fiber-optic sensors have been developed to measure co-located temperature and strain simultaneously with very high accuracy using fiber Bragg gratings. This is particularly useful when acquiring information from small or complex structures. What is an optical strain sensor? What. Fiber-optic sensors (also called optical fiber sensors) are fiber -based optical sensors for some quantity, typically temperature or mechanical strain, but sometimes also displacements, vibrations, pressure, acceleration, rotations (measured with optical gyroscopes based on the Sagnac effect), or. Luna's fiber optic sensing solutions deliver strain measurements that go beyond what's possible with traditional strain gages. An overview of the different types of FOS used for strain/temperature sensing in.