Botdr (Brillouin Optical Time Domain Reflectometry) Distributed Temperature and Stress Sensor-30km

Basic Principle
The Brillouin scattering principle is similar to BOTDA: it is also based on Brillouin scattering to sense temperature and stress changes. However, BOTDR only uses one light pulse, which will produce spontaneous Brillouin scattering when transmitted in the optical fiber. The temperature and stress distribution along the optical fiber is determined by detecting the Brillouin frequency shift of the scattered light and the time when the light pulse returns.

Performance Characteristics
Advantages of distributed measurement: It also has the characteristics of distributed measurement and can monitor longer optical fibers. Its measurement range can reach more than ten kilometers or even farther depending on the type of optical fiber and system parameters, which is suitable for long-distance monitoring scenarios.

Relatively simple installation: Since only one-end injection of light pulses is required, it is more advantageous in some application scenarios that require installation space and complexity. For example, in some existing structures where optical fibers have been laid, BOTDR sensors are easier to modify and install.

High-precision measurement of temperature and stress: The temperature measurement accuracy can reach ±0.25ºC (2σ), and the strain measurement accuracy can reach ±5 με (2σ), which can provide accurate data for the safety assessment of engineering structures.

Application areas
Geological disaster monitoring: In the monitoring of geological disasters such as landslides and ground subsidence, the optical fiber is buried underground or on the slope of the mountain. The BOTDR sensor can monitor the strain changes of the optical fiber caused by the movement of the strata and warn the occurrence of geological disasters in advance.

Marine engineering: In the monitoring of submarine cables, offshore platforms and other structures, it is used to detect the impact of seawater temperature changes on the structure and the stress changes of the structure itself, to ensure the safe operation of marine engineering facilities.

Building structure health monitoring: Temperature and stress monitoring of the foundation, walls and other parts of large buildings to promptly detect problems that occur in the use of the building structure, such as uneven settlement and cracks.