Uncertainty in a Calibration of a Photodiode Type Power Meter Due to Spectral Width of a Light Source

An error due to a spectral width of a light source in a calibration of a photodiode type power meter has been studied. Three types of Si, Ge and InGaAs photodiode have been examined in the wavelength of 750~1700nm. A theoretical calculation has shown that more than 5% error arises on a Si or a Ge photodiode in a specific wavelength region. A measured difference between two photodiode type power meter agreed the theoretically estimated difference within 0.5%.