Optical Isolator for Distributed Temperature Sensing Range Extension
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Solution Overview
Problem
Current distributed temperature sensing (DTS) systems face limitations in sensing distance due to the received power level of stimulated Raman signals exceeding that of spontaneous Raman signals, making it difficult to distinguish between the two and reducing the effective range of temperature measurements.
Innovation Solution
Incorporating a WDM/isolator combination that removes the forward traveling Stokes signal, allowing only backscattered signals to pass, thereby preventing interference and increasing the range of temperature detection by maintaining the power level of spontaneous Raman signals above that of stimulated Raman signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the sensing distance is increased in a distributed temperature sensing system, then the measurement range is improved, but the received power level of stimulated Raman signals exceeds that of spontaneous Raman signals, making it difficult to distinguish between the two and reducing measurement accuracy
Solution Approach 1:
The patent extracts and removes the forward-traveling stimulated Raman signal from the optical fiber using an optical isolator. This allows only the backscattered spontaneous Raman signal to reach the detector, eliminating the interference that limits sensing distance and maintains measurement accuracy over extended ranges.
Solution Approach 2:
The optical isolator acts as an intermediary component between the optical fiber and the detector. It selectively transmits the desired backscattered signal while blocking the harmful forward-traveling stimulated signal, enabling extended sensing distance without compromising measurement precision.
2Length of stationary object
If the power level of stimulated Raman signals is increased to extend sensing distance, then the measurement range is improved, but the stimulated Raman signal interferes with spontaneous Raman signal detection, reducing temperature measurement accuracy
Solution Approach 1:
The patent converts the harmful stimulated Raman signal into a beneficial configuration by using an optical isolator to block it. This allows the system to operate at higher power levels that would normally create interference, thereby extending sensing distance while maintaining signal clarity through the isolator's selective transmission properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly increases the sensing distance by at least 50%, preferably 75%, and up to 100% compared to systems without the WDM/isolator combination, ensuring accurate temperature measurements over longer distances.
Implementation Method 1
an optical isolator coupled between the first coupler and the second coupler. The optical isolator is configured to remove a Stokes signal traveling from the first fiber optic cable to the second fiber optic cable
Implementation Method 2
detecting backscattered light. The backscattered light comprises an anti-Stokes band and a Stokes band in the first fiber optic cable
Data Source
AI summary
Embodiments are directed to a distributed temperature sensing system. The system includes a first fiber optic cable and a second fiber optic cable. A first coupler is coupled to the first fiber optic cable. A second coupler is coupled to the second fiber optic cable. An optical isolator coupled between the first coupler and the second coupler to remove a Stokes signal in order to increase the range of the distributed temperature sensing system.