fig1 shows the surface of an article 3 which is sensitive to signal waves , with a regular covering of similar modulation electrodes ma and mb , between each of which are disposed the respective readout electrodes a . a signal wave p ( t ) which is distributed as equally as possible generates charge carriers in the modulation and readout region , identified in that way , between the electrodes . the modulation electrodes are modulated by the modulation source mq at the terminals mka and mkb with the associated modulation voltages uma and umb and thus influence distribution and the direction of the read - out charge carrier current ia at the readout terminal ak . the readout potential uak is preferably selected to be zero or earth potential by means of a low - ohmic readout unit vaeh . clearly defined modulation conditions which can be predetermined by way of the input terminal mqk of the modulation source mq are firstly the condition , identified by mzp , with maximum positive current condition iamax , secondly mzn with maximum negative current condition iamin and thirdly the compensation or zero condition mz 0 with ia = 0 . with this illustrated single oep , a zero circuit in the modulation condition mz 0 with ia = 0 is achieved in that asymmetries in the modulation voltages involves current equalisation between the readout electrodes which are short - circuitedly connected . here , for reasons relating to the drawing , maximum interleaving of the two groups of modulation electrodes has been selected , but in practice that is not required with for example 50 to 100 strip electrodes . in addition fig1 , by virtue of the broken - line expansion of the interlinking and the readout unit vaeh , makes it clear that , in the case of the single oep , by means of current sum interlinking , an oep - inherent interlinking of the various readout currents which can be influenced already takes place prior to further signal processing , on the oep element . as shown in fig2 the properties which in principle are the same can also be achieved with division of the oep structure into two partial oeps with the so - called twin oep . in that respect , the basic starting point adopted is initially a single signal wave p ( t ) involving equally distributed power . the sum of the currents can be combined by a wired - or circuit wor at the corresponding readout terminal aks . by virtue of modulation of the currents of the two partial oeps 1 and 2 in the same or opposite directions , they can be controlled in the sum from imax through zero to imin . the two currents ia 1 and ia 2 can also be read out separately from an interlinking and readout unit vaeh — as illustrated in fig2 alternatively to the wired - or readout wor — by a difference miller integrator with the two operational amplifiers v . that corresponds to the effect of subtraction of the currents and the result obtained is the zero condition mz 0 with the combination mzp 1 / mzp 2 or mzn 1 / mzn 2 . the common - mode components which inevitably occur in that situation charge the readout capacitors c a1 and c a2 and after the delay time of the operational amplifiers v , the miller capacitors cf 1 and cf 2 , in the same direction , without thereby involving the falsification of a push - pull output voltage δu a which is of interest for evaluating for example the correlation function or logical interlinking of optical and electrical signals . steady conditions of that kind however can also result in common - mode overdriving of the circuit . they are avoided depending on the respective mode of operation of the oep circuit cyclically by the reset switches rs of the miller capacitors cf 1 and cf 2 . common - mode overdriving is securely and adequately avoided by the specified circuit according to the invention by way of the r ev — r ev bridge circuit which only takes off the output - side common - mode component u bv and feeds it in in amplified form by way of r 1 and r 2 in feedback relationship and as a compensating current to the two amplifier inputs ak 1 and ak 2 . in that feedback circuit amplification of the control parameter u ev and compensating symmetrical current feed - in at the terminals ak 1 and ak 2 can advantageously be effected 1 ) by way of a circuit gkv 2 , a controlled voltage source vuev , at the output terminals g 1 and g 2 or 2 ) by way of the circuit gkv 3 , a controlled current source su ev ; 3 ) highly symmetrical feedback and current division can be effected by way of an fet differential amplifier as a gate - base amplifier gbv which is desirably microelectronically integrated in a very small space , saving on r 1 and r 2 — advantageously with a current amplification effect which can be set by way of equal gate voltages uga and ugb , by way of the internal resistance rev / 2 of the common - mode voltage source u ev and by way of the fet - gradients . capacitive crosstalk of the modulation signals to the readout electrodes can be compensated at the two terminals k 1 and k 2 by suitable push - pull signals at c k1 and c k2 . fig3 diagrammatically shows a plan view of a quadruple oep which can replace both the function of the single oep and also that of the twin oep and which flexibly serves for 4 - times , 2 - times and 1 - time measurement . in addition the operation of determining the phase of a correlation function is implemented in one procedure by possible parallel measurement — for example iq - measurement in the case of sine signals . the orthogonal orientation of the adjacent finger structures advantageously results in minimal crosstalk . fig4 is a block circuit diagram showing the structure of an oep sensor system by means of the example of a twin oep which is representative here of an oep line or oep matrix . an optical signal source sq is modulated by way of the modulation source mq with a selectable delay δt or δφ and emits the signal wave p s ( t ). for example in fluorescence spectroscopy it excites a sample or in the case of laser radar illuminates a 3d scene . the received signal wave p ( t )= p 1 ( t )+ p 2 ( t ) is demodulated by suitable modulation voltages which are related to the signal source modulation . the processing / interlinking and evaluation units vaeh , signal and data processing system sdv and actuator system asy follow . the control st provides for matching and optimising the measuring procedures . fig5 diagrammatically shows the block circuit diagram for information exchange of two systems or network subscribers by way of oep arrays and led / laser diode arrays , in particular for new applications in the free - space communication , for example in space travel , within rooms , vehicles , items of equipment and in optically transparent circuit boards , but also in bidirectionally used local polymer fibre networks . a transmitter / receiver system tr 1 , by way of the electrooptical interface of the leds or laser diodes , by way of the beam path 8 , sends data in encoded form , by way of predominantly diffuse scatter , to an oep interface having a plurality of oep receivers and a downstream - connected electronic system ( el system ). depending on the respective use the return channel goes directly by way of the transmitter t 2 or by way of a local or wide - area network . fig6 diagrammatically shows in the simplified form of a block circuit diagram a router controlled by way of the inputs st 1 – 4 or an optical switching unit ( optical cross connect ). the serial input data flow is passed by way of an input - side demultiplexer demux and by way of a parallel transmitter interface itf to an led or laser diode or vcsel array and further by way of a diffractive optical system for uniform power distribution to an oep matrix . association of the channels to be switched is implemented in code and time multiplex procedures . the parallel outputs of the oep matrix go by way of the parallel receiver interface rif to an output - side multiplexer mux for predominantly serial output of the routed or switched data flows . fig7 diagrammatically shows a novel oep logic component which is intended to demonstrate by way of example how an optical - electronic interface can both substantially increase speed and also substantially simplify structure . two signal sources sq 1 and sq 2 couple the signal waves p 1 and p 2 by way of optical wave guides lwl to the twin oep with oep 1 and oep 2 . the output currents ia 1 and ia 2 are controlled by um 1 a / b and um 2 a / b and brought together to form i ab . the current / voltage amplifier v r with positive gain and the output uout is followed by an amount member abs with iu out i and an led / laser diode with p out . 1 . p 1 and p 2 are logically interlinked by way of xor in respect of iu out i and p out for the modulation conditions mz 1 p / mz 1 n . 2 . p 1 and p 2 are interlined by way of or for mz 1 p / mz 2 p . 3 . with p 1 and p 2 “ high ” a logic condition um 2 a / b can be very quickly read out purely optically as p out . 4 . with p 1 “ high ” and the modulation condition um 1 p / um 2 n the p 2 condition can be passed purely optically directly to u out and can be written for example into a memory . fig8 shows a possible way of increasing sensitivity of the oep principle . in a first embodiment without the illustrated micro - channel plate mcp the oep image amplifier comprises the left - side photocathode on which the signal wave p ( t ) impinges . on the vacuum side of the photocathode there is an image of the photon incidence as an electron issue . by virtue of a sufficiently positive voltage in respect of the oep receiving surface which acts as a positive anode in relation to the cathode , the electrodes impinge with a correspondingly high level of energy eua on the photosensitive region 3 . that increase in energy results in a corresponding increase in the formation of pairs and thus an increase in the level of sensitivity . by virtue of the insertion of a micro - channel plate mcp as illustrated the level of sensitivity can be further increased , with suitable operating voltages . the right - hand part in fig8 diagrammatically shows a view onto the pixel structure .