(technology sharing) optical fiber solutions (2)

Bocda stimulated Brillouin scattering solution
    Bocda technology uses frequency modulated continuous pump light and probe light to calculate their correlation functions. It is a technical scheme that can significantly improve the distributed optical fiber sensor system's spatial resolution. The spatial resolution of the experimental procedure can reach millimeter level in theory

   Both ends of the sensing optical fiber are respectively incident with continuous probe light and steady pump light. These two synchronously modulated lights produce a related periodic peak on a sine wave and receive the lock-in amplifier's synchronous signal on the photodetector. After stimulated Brillouin scattering of probe light and pump light, they pass through a circulator, optical filter, and photoelectric detector in turn. Brillouin distribution on the optical fiber is determined by the correlation degree of detection period peak of a lock-in amplifier to realize distributed measurement.

Bocdr stimulated Brillouin scattering solution
   As a single terminal system, BOTDR is more advantageous than a double terminal design. Still, it can not meet the requirements of high precision and high spatial resolution measurement at the same time.

The coupler divides the light source into two ways; one is the reference light used as the local vibration light. After the delay, the autocorrelation is added on the balanced photoelectric detector; the other is the pump light, sent to the sensing optical fiber through the circulator, and the Stokes light scattered by the sensing optical fiber is sent to the balanced photoelectric detector. The two signals are sent to the spectrum analyzer after the flat photoelectric sensor.

Φ - OTDR - Rayleigh scattering solution
   In the OTDR system, if the light source's linewidth is narrow enough and the coherence is high enough, the scattered light returned from different parts of the fiber will interfere. The phase-sensitive OTDR system designed using the scattered light's coherence can detect the interference of the weak signal, which the traditional OTDR system can not see.