Table 1.

Comparison between fiber optic sensors.

Sensor	Measurand	Field(s)	Sensing Application(s)	Network Config	Performance [27]
Fiber Bragg Gratings	Wavelength shift	Engineering, Physics, Cryogenics	Temperature, pressure, strain, liquid level, displacement, salinity.	Single/Multi-point sensing	Strain res. < 0.5 $\mathsf{\mu }\mathsf{ϵ}$ Long-term accuracy < 1% Temp. res. 1 °C
Interferometers	Phase-shift in light	Navigation, Engineering, Networks	Gyroscope (inertial navigation, surveying, defense), hydrophone (refractive index sensor, pressure monitoring of structural components), and optical switching.	Single/Multi-point sensing	N.A.
Rayleigh-OTDR	Rayleigh scattering	Engineering, Physics, Cryogenics	Distributed acoustic sensing.	Distributed sensing	Freq. range 1 mHz to 100 kHz Spatial res. 1 m Length up to 50 km
Raman-OTDR	Raman scattering	Engineering, Physics, Cryogenics	Long-distance and real-time monitoring, distributed temperature sensing.	Distributed sensing	Temp. res. 0.5 °C Meas. range up to 15 km w/ 1 m spatial resolution Meas. range up to 25 km w/ 1.5 m resolution
Brillouin-OTDR	Brillouin scattering	Engineering, Physics, Cryogenics	Long-distance and real-time monitoring, distributed temperature, and strain sensing.	Distributed sensing	Typical strain res. 20 $\mathsf{\mu }\mathsf{ϵ}$ but can achieve up to 0.1 $\mathsf{\mu }\mathsf{ϵ}$ Meas. range up to 10 km w/1 m spatial resolution, but supports larger ranges w/reduced accuracy Temp. res. 0.5 °C