Improvement of measurement uncertainties in laser power detector calibration by convolving with the detector’s impulse response function

Abstract

For the calibration of thermal type laser power detectors with slow response time, instability of the input laser significantly contributes to the measurement repeatability. A convolution method is adopted to reduce the impact of source instability. The equivalent incident power is calculated by convolving the real-time power input and the detector impulse-response function (IRF). The value is applied in place of the traditional input power value for the calibration. The IRF is measured using the (1-70) W laser power primary standard at National Institute of Metrology of China. The measurement repeatability of the transfer detector's responsivity is improved from 1.1% using the traditional method to 0.19% using this method. The systematic errors, primarily due to source drift are also reduced. The proposed method can be applied in the calibration of general thermal type laser power detectors.