A novel linearity tester for optical detectors using high-brightness light emitting diodes

We present a linearity tester for optical detectors, which is based on the flux-addition method using two high-brightness light emitting diodes (LEDs) as the light source. The tester is operated with a novel data-acquisition algorithm that determines the switching and data-reading sequence for eliminating the measurement error caused by a drift of the LED radiant flux. Linearity measurement with an uncertainty of as low as 10−4 in a dynamic range over six decades is experimentally demonstrated with simple setup, short measurement time and fully automated operation.