High-accuracy measurement of linearity of optical detectors based on flux addition of LEDs in an integrating sphere
Abstract
We present an instrumental realization of linearity measurement of optical detectors based on flux addition of two light-emitting diodes (LEDs) in an integrating sphere. The instrument measures the linearity ratios at pre-defined photocurrent levels according to the algorithm which eliminates the drift effect of LED flux (Shin D J et al 2005 Metrologia 42 154). As a result, the non-linearity correction factors for detector responsivity are determined with their relative standard uncertainties ranging from 2 × 10-5 to 6 × 10-5 (k = 1) for photocurrent ranges from 10-8 A to 10-3 A. By changing the type of LEDs, the wavelength dependence of non-linearity can also be measured, which is demonstrated at 390 nm, 670 nm and 750 nm for a Si photodiode used as a transfer standard for spectral responsivity scale comparisons.
- Publication:
-
Metrologia
- Pub Date:
- February 2014
- DOI:
- 10.1088/0026-1394/51/1/25
- Bibcode:
- 2014Metro..51...25S