Study On The Miniature Fiber Laser Accelerometers

Fiber laser sensor has numerous advantages as the fiber bragg grating of small size, simple structure, electromagnetic disturbance resistance, and ease to be multiplexed by wave division multiplexing(WDM), moreover, its advantages include single frequency, narrow linewidth and ultra-low noise. Combining with coherent demodulation technique, signal detection with supreme sensitivity can be realized. It has huge advantages in the field of weak signal detection. Therefore, fiber laser sensing can be widely used in oil exploration, earthquake forecast and security monitoring.The sensitive component of the fiber laser accelerometer is the linear cavity fiber laser. In this fiber laser accelerometer, light oscillates back and forth in the cavity. So the weak phase signal can be accumulated by the oscillation. Compared to the interferometric fiber accelerometer with the same sensitivity, the fiber laser accelerometer has smaller size, simpler structure. Fiber laser accelerometer is the ideal choice to achieve miniature optical fiber accelerometer.Aimed to the design, package and the acceleration response of the miniature fiber laser accelerometer, a lot of research was carried out in the paper. Based on the ultra-short linear cavity fiber laser whose cavity length was less than 10 mm, the parameters such as packaged structure, acceleration sensitivity and resonant frequency were analyzed to design the best packaged structure. Two kinds of miniature fiber laser accelerometer with different size were packaged and experiments were carried out to study the characteristic of acceleration response.The main innovatory results are as follows:1. A metal-shell-packaged single-cylinder-mandrel structure of the fiber laser accelerometer was designed. Based on a 6 mm linear cavity fiber laser, the miniature structure with a size of ?24×38mm was achieved.2. The experimental results show that the acceleration sensitivity of the fiber laser accelerometer is 17.5 dB re rad/g, with a fluctuation of 0.95 dB between 20 Hz and 1000 Hz and the maximum crosstalk is-30 dB @ 80 Hz.