Summary of the technology
A Spanish research group from the Department of Electronics of Alcalá University has developed a system and method for optical fiber sensing based on Brillouin stimulated scattering. This method consists in separating the two signals which comprises the probe signal to obtain the difference between amplification band and attenuation stimulated band or vice versa. The group is looking for companies in the technology sector and telecommunications to reach licensing agreements, collaboration and commercial agreements with technical assistance.
New and innovative aspects
Sensing system and method that implements any of the techniques based on stimulated Brillouin scattering by a differential detection of amplified and attenuated bands.
Distributed sensing comprising separating the two signals corresponding to the amplified band and attenuated band. Obtaining a signal with higher amplitude and improving the signal to noise ratio.
Main advantages of its use
With this method the sensor signal relationship between signals to noise is improved. Dynamic range and scope length increase as well as reduces the measurement uncertainty.
The common noise presented in the two bands of the probe signal is eliminated.
In the case of using a balanced detector for detection, the detector saturation characteristics are improved, and can be obtained with much larger amplitudes than in the conventional case of signal detection.
As a first aspect of the invention, a distributed sensing system is presented which comprises:
- Light emitting means adapted to emit the probe and pump signals on the optical fiber.
- Discriminating means adapted to separate the two signals corresponding to the amplified band and attenuated band along the optical fiber subject to monitoring.
- Detection Means adapted to obtain the difference between band of amplification and stimulated attenuation band or vice versa.
- Analyzing means, adapted to implement the distributed sensing technique based on Brillouin scattering using the differential measurement of amplification band and the attenuation stimulated band, instead of the measurement of a single band as in conventional systems.
Two preferred options for the discriminating means are:
• A device which discriminates in frequency.
• A device which discriminates in polarization.
Once separated the two signals (amplified band and attenuated band) so that they can be analyzed independently, two preferred detection means methods are:
• A balanced detector
• Two simple sensors (photoreceptors)
As a second aspect of the invention, a distributed sensing method is shown consisting in separating the two signals corresponding to the amplified band and attenuated band along the optical fiber subject to be monitoring. Thus is obtained a signal with higher amplitude than in the case of performing a detection with a single band. With this increase in the amplitude the signal-to-noise ratio of the sensor signal is improved, improving the dynamic range and increasing the length scope and at the same time decreasing the uncertainty of the measurement.
The present invention solves the long-standing problems by means of the system and method of sensing which implements any of the techniques based on Brillouin stimulated scattering (systems BOTDA, BOCDA and BOFDA including their variants) by a differential detection of amplified and attenuated bands.
- Civil engineer, industry, energy and environment