OPTOCOUPLER BASED ON THE AVALANCHE LIGHT-EMISSION IN SILICON

The photon emission in silicon light-emitting diodes is very inefficient, due to the indirect bandgap. Moreover the photon energy of 1.1 eV, which equals the bandgap, is outside the visible part of the spectrum and is not sufficient to generate electron-hole pairs in a silicon photodetector. When used in avalanche mode, the emission spectrum covers the visible range and the range where silicon photodetectors show high sensitivity. Therefore, silicon integrated displays and silicon integrated optical devices, such as optocouplers can be realized. When used in an accurate analog optocoupler circuit, the low efficiency of the current transfer ratio of the optocouplers makes the design of the electronic circuit more difficult. However, a circuit of an input stage of an isolated amplifier is given using an optocoupler based on the avalanche light emission in silicon.