1/f Noise and G-r noise related to reliability in optoelectronic coupled devices

The reliability of Optocoupler devices is important since they provide an isolation from over-stress environmental conditions. In this paper, the electric ageing and Co-60 irradiation tests are performed on commercial optocouplers, and I-V characteristics and low-frequency noise are measured before and after the tests. It is found that the 1/f noise and g-r noise are more sensitive than conventional electric parameters, so the noise measurement can be used as an effective and non-destructive tool to evaluate the degradation of optocouplers. Based on the experimental results, in order to improve the validity of the approach, it is proposed to identify if the 1/f noise increases, observe if g-r noise exists, monitor output noise instead of input noise, and use the spectral magnitude instead of point-frequency or wide-band noise.