Study A Wide Range Of Laser Power Measurement System

Carbon dioxide laser is widely used in laser engraving machine, laser cutting machines and other laser processing equipment and medical, military weapons, environmental measurements and so on. The power of laser is the key parameter to assess the quality and life of laser. In the areas of industry and science, the laser power measurement has widespread demand. Around laser power measurement, the main research contents of this thesis are as follows:First of all, the currently laser power measurements in common and their respective scope of application are analyzed. Considering request of detector in this topic, this thesis design a new scheme of laser power measurement. Under this approach, its feasibility is verified by related theoretical analysis and the preliminary experiments.Secondly, the laser power sensor which composed by energy absorber and AD590 chip is designed. On absorber, it is described in detail, including materials, process and sensor chip and absorber installation. Processed by a specific morphology, absorber is able to achieve self-cooling, with no additional cooling equipment, at the same time through the absorber surface treatment, which greatly improved the absorber on the absorption rate laser.Thirdly, signal processing circuit of the measurement system is detailed analysis, including signal conditioning circuit design, device selection, MCU and its peripheral circuit design and system software development. Such as designing AD590 drive circuit to I/V conversion and amplify in preliminary for output signal, optimizing differential circuits and low-pass filter circuit, inhibiting high-frequency gain and reduce output noise, all of this to improve a high signal processing speed and measurement accuracy.Finally, this measurement system is further optimized base on analyzing system error. Sensor non-linearity is compensated, system is calibrated, and circuit noise approach is studied. According to analysis, the system error is less than 2%, it consistent with relevant standards and design requirements.