Measurement range enlargement in Brillouin optical correlation-domain reflectometry based on double-modulation scheme

Area of Science:

• Optics and Photonics
• Materials Science
• Electrical Engineering

Background:

• Fiber-optic distributed sensing is crucial for structural health monitoring.
• Brillouin optical correlation-domain reflectometry (BOCDR) offers precise strain sensing capabilities.
• Existing BOCDR methods face limitations in measurement range and resolution.

Purpose of the Study:

• To enhance the measurement range of BOCDR for fiber-optic distributed strain sensing.
• To improve the simultaneous resolution and measurement range of BOCDR systems.
• To demonstrate a novel double-modulation scheme for advanced fiber sensing.

Main Methods:

• Implemented a double-modulation scheme by simultaneously modulating laser output frequency with two distinct frequencies.
• Employed Brillouin optical correlation-domain reflectometry (BOCDR) for distributed strain measurements.
• Utilized a noise-floor compensation technique to further enhance performance.

Main Results:

• Achieved a 1.5-km measurement range with 53-cm resolution using the double-modulation scheme.
• Attained a 1.5-km measurement range with an improved 27-cm resolution when incorporating noise-floor compensation.
• Demonstrated the effectiveness of the double-modulation technique in expanding BOCDR capabilities.

Conclusions:

• The double-modulation scheme significantly enlarges the measurement range of BOCDR for distributed strain sensing.
• Simultaneous high resolution and extended measurement range are achievable with this novel approach.
• Noise-floor compensation further refines the resolution, offering enhanced performance for fiber-optic sensing applications.