The Development Of Optical Signal Examination Module In Laser Ultrasound System

The non-contact ultrasound examination superiority of the laser ultrasound technology attracts enormous attention in many application fields. The thesis designs a laser ultrasound data-acquisition system based on USB2.0 and develops its optical signal examination module.Based on the principle of the Michelson interferometer and the characteristic of high frequency response and high distinguish rate of fiber sensor, this system detects minor variety in an object ultrasonic droved according to the relations among the interference intensity, the length different and wavelength.In the system, optical signal examination module plays an important role. This module transforms the optical signal to electronic signal and transforms electric current signal to voltage signal, and carries on the pre-amplification and preliminary processing of the signal. Firstly, the thesis analyzes experimentally the characteristic of the PIN, including its sensitivity and the linearity characteristic that was seldom involved in research, which helps a lot to thoroughly understanding and application of PIN. Based on USB2.0, the data acquisition system is designed, and a principium experiment is carried on. This work would improve the rate and the convenience for the data acquisition with certain innovation. In addition, an independent optical signal examination and demonstration module is developed which display the DC and AC power of the laser with LED.