Photodetector device for fiber-optical telecommunication systems

The properties of a photodetector device with a balanced photodetector, which includes an avalanche silicon photodiode with a Schottky barrier, have been analyzed in this work. Considered here are the advantages of the analyzed semiconductor photodetectors as compared with other detectors of the optical signal, in particular, their ability to register long-wave radiation, since the formation of mobile carriers in them is not related to overcoming a significant surface potential barrier. To provide a high multiplication factor of an avalanche silicon photodiode with the Schottky barrier, an approach consisted of using the latter together with a receiving optical module for fiber-optic telecommunications systems has been proposed. A spectral characteristic for the Si-Au system has been obtained; it is not inferior to a germanium photodiode, with the possibility of further optimization. The frequency and noise characteristics of the device have been presented. The dynamic range and the threshold of its sensitivity have been determined. The physical equivalent circuit for the photodiode of the specified type has been presented. The frequency characteristics of the output power and the noise characteristics of the receiving optical module have also been presented. It has been determined that the sensitivity threshold is 36 dB for the information transfer rate close to 5 Gbit/s. Reduction of intersymbol interference has been experimentally detected, which will be especially effective in the case of the propagation of a signal with the corresponding shape. The obtained characteristics totally satisfy the requirements imposed on photodetectors of this type.