Abstract: An opto-coupler and a process for fabricating an opto-coupler are disclosed. The opto-coupler includes at least one light-emitting diode and a photodiode for galvanically isolating electric circuits. The optical components are mounted in a yielding material, such as silicone rubber, in a housing. The interior walls are coated with a pigmented yielding coating which includes TiO2 to enhance light reflection inside the housing and increase the current transfer efficiency of the device. The opto-coupler has a high dielectric breakdown voltage and is immune to radiation. The device can be employed in space applications.