Modeling the performance characteristics of optocoupler under irradiated fields

Optoelectronic devices, including optocouplers, are used in optical communication, controlling and sensing applications. Many of these applications are used under the influence of radiation; in some applications, it is difficult to shield the devices from radiation. The interaction of radiation with devices materials produces the defects. Several studies have been conducted on the effects of radiation on the optocoupler; most of them were interested in practical experiments, recording and describing the results. The behavior of an irradiated optocoupler still needs a mathematical model that can describe the optical and electrical characteristics of the device under the effect of radiation. This paper presents a mathematical model that includes the governing equations of the radiation effect in digital optocouplers. The validity of the model is verified by comparing its numerical values with the previous experimental results of neutrons and gamma radiations’ effects in one of the most popular digital optocouplers (4N49); the maximum error of the current transfer ratio of the device is 14% at 100 krad gamma dose and error reduces at the low doses. By adapting input parameters, this model can be applied to describe the effect of other types and doses of radiation on different types of optocouplers.