Stack-shaped optocoupler module, comprising - a transmitter module with a transmitting region, wherein the transmitting region has a surface, - a receiving module with a receiving region, wherein the receiving region has a surface, - a plate-shaped electrical insulator, - wherein the insulator is formed between the transmitter module and the receiver module, - the transmitter module, the receiver module and the insulator are arranged in stack shape one on the other, - the transmitter module and the receiver module are electrically separated from one another, but optically connected together, wherein the insulator is transparent at least for a part of the emission wavelengths of the transmitting region, and - the median line of the surface of the transmitting region and the median line of the surface of the receiving region are arranged substantially or exactly parallel to one another, characterised in that - the offset between the two median lines is smaller than half or smaller than a tenth or smaller than a fifteenth of the spacing of the respective median lines from an outer edge of the surface of the transmitting region or from an outer edge of the surface of the receiving region so that the light of the transmitter module acts on the receiver module predominantly or exclusively through the insulator, - the insulator projects in balcony shape from the stack on all sides, - the receiver module comprises a number N of sub-voltage sources connected with one another in series, wherein N is a natural number and ≥ 2, - the difference of the sub-voltages of the individual sub-voltage sources from one another is less than 20%, - each of the sub-voltage sources comprises a semiconductor diode (D1,..., DN) with a p-n transition, - a tunnel diode (TD1,, TDN-1) is formed between each two successive sub-voltage sources, wherein - the sub-voltage sources and the tunnel diodes (TD1,, TDN-1) are monolithically integrated together, - the transmitter module and the receiver module comprise a III-V material, and - the difference between the size of the surface of the transmitting region and the size of the surface of the receiving region is less than 20%. - a transmitter module with a transmitting region, wherein the transmitting region has a surface, - a receiving module with a receiving region, wherein the receiving region has a surface, - a plate-shaped electrical insulator, - wherein the insulator is formed between the transmitter module and the receiver module, - the transmitter module, the receiver module and the insulator are arranged in stack shape one on the other, - the transmitter module and the receiver module are electrically separated from one another, but optically connected together, wherein the insulator is transparent at least for a part of the emission wavelengths of the transmitting region, and - the median line of the surface of the transmitting region and the median line of the surface of the receiving region are arranged substantially or exactly parallel to one another, - the offset between the two median lines is smaller than half or smaller than a tenth or smaller than a fifteenth of the spacing of the respective median lines from an outer edge of the surface of the transmitting region or from an outer edge of the surface of the receiving region so that the light of the transmitter module acts on the receiver module predominantly or exclusively through the insulator, - the insulator projects in balcony shape from the stack on all sides, - the receiver module comprises a number N of sub-voltage sources connected with one another in series, wherein N is a natural number and ≥ 2, - the difference of the sub-voltages of the individual sub-voltage sources from one another is less than 20%, - each of the sub-voltage sources comprises a semiconductor diode (D1,..., DN) with a p-n transition, - a tunnel diode (TD1,, TDN-1) is formed between each two successive sub-voltage sources, wherein - the sub-voltage sources and the tunnel diodes (TD1,, TDN-1) are monolithically integrated together, - the transmitter module and the receiver module comprise a III-V material, and - the difference between the size of the surface of the transmitting region and the size of the surface of the receiving region is less than 20%.