For the conversion coefficient K of sapphire-fiber pyrometer’s temperature-voltage

the calculation principle and the experimental calibration method are analyzed detailedly

and several issues that impact the accuracy of coefficient K is revealed. Design method of K calibration system is elaborated from four aspects

which are work principle

choosing photodetectors

designing preamplifier circuit and signal’s coupling and transmission.The experiments show that the system has high accuracy

good signal to noise ratio and good stability characteristics.