AN EXAMPLE OF A HYBRID SYSTEM - COHERENT OPTICAL-SYSTEM WITH COSTAS LOOP IN RECEIVER-SYSTEM FOR TRANSMISSION IN BASEBAND

The possibility of hybrid system construction is considered in this pa per, The coherent optical system is the constituent part of this syste m, The first part of the system is constructed in passband (optical ca ble is transmission medium), and the second part of the system is cons tructed in baseband, The heterodyne optical receiver is used as optica l receiver. Estimation is not done just after demodulation, but it is done at the end of the section in baseband, Taking into account shot n oise of photodetectors, laser phase noise (transmitter laser and local laser) and noise which is generated during transmission by means of t he section in baseband, we determine the performances of the proposed system.