Common-mode noise self-suppressed 3-component fiber optic accelerometer based on low-reflectivity Bragg gratings

Area of Science:

• Fiber Optic Sensing
• Instrumentation
• Seismology

Background:

• Common-mode noises (CMNs) are a significant challenge in fiber optic accelerometers.
• Effective suppression of CMNs is crucial for ultra-weak signal detection, such as in micro-seismic monitoring.

Purpose of the Study:

• To propose a novel 3-component (3C) low-reflectivity fiber Bragg gratings accelerometer for inherent CMN self-suppression.
• To evaluate the performance improvement compared to traditional CMN suppression methods.

Main Methods:

• Development of a 3C accelerometer utilizing low-reflectivity fiber Bragg gratings.
• Implementation of a push-pull structure to enhance signal amplitude.
• Experimental validation of CMN suppression and signal enhancement capabilities.

Main Results:

• Achieved an average CMN suppression improvement exceeding 4.5 dB across three axes.
• Doubled the effective signal amplitude due to the push-pull design, enhancing the signal-to-noise ratio.
• Eliminated the need for an additional reference interferometer, reducing system volume and cost.

Conclusions:

• The proposed 3C accelerometer offers superior CMN suppression and signal enhancement.
• The compact and cost-effective design is advantageous for large-scale quasi-distributed arrays.
• This accelerometer is a promising solution for weak vector vibration detection.