Optical strain gauges (also called fiber optical (strain) sensors or FOS, optical (strain) sensors or Fiber Bragg Grating sensors) are used to measure strain, but can easily be integrated into different types of transducers, for example for temperature, acceleration or displacement. Compared to traditional electrical strain gauges, optical strain gauges do not need electricity. Instead, the technology is based on light that propagates through a fiber.
Therefore, the sensors are completely passive and immune, for example, to electromagnetic interference. This is just one of the reasons why optical strain gauges are superior to electrical ones in certain applications.