This paper analyzes the theoretical basis for the linear relationship between the Bit Error Rate（BER） in optical module sensitivity tests by extrapolation and sensitivity

which is verified in experiments.The test results indicate that the correlation coefficients of the sensitivities of 155 Mbit/s and 1.25 Gbit/s optical transceiver modules and lg [-lg（BER）] are 0.999 79 and 0.999 06 respectively

presenting a good linearity.Furthermore

it presents an optimized sensitivity measurement scheme by extrapolation method.