Design and Application of a Photoacoustic Sensor for Monitoring the Laser Generated Stress Waves in Optical Fiber

Abstract

Measurement of stress transients generated by a 400ns pulsed HF laser in an infrared fluoride glass fiber has been made using fast time – response piezoelectric film transducer. Acoustic signals up to 12 mV with frequencies ranging in megahertz generated by 21 mJ laser pulse when passed through the fiber axis in the linear region. It is shown that useful information such as onset of non - linear behavior of the fiber can be gained from such measurements, which in turn can be used as a means of monitoring the quality of fiber surface during an operation.