| 摘要 |
FIELD: devices for fiber-optical communications. SUBSTANCE: instead of single optical amplifier a diplexing circuit that has at least two optical amplifiers is used. Said circuit outputs signal to input of optical directed splitter through controlled phase shifter. Another input of said splitter receives signal to be received. Outputs of optical directed splitter are connected to input optical ports of compensating photodetector, which output signal is used by control unit for generation of signal for automatic keeping quarter phase shift between information and heterodyne signals, which are sent to inputs of compensating photodetector. In addition excitation source of optical amplifier is controlled. Circuit for control of excitation source is connected to circuit for automatic level control of compensating photodetector. Excitation source of optical amplifier and control circuit of excitation source provide feedback circuit for automatic control of level of output signal of optical amplifier. Device may be used for fiber-optical trunk lines with large distance between relays. Device does not use special optical-electronic components such as high- stable lasers, heterodyne lasers with automatic control of wavelength. EFFECT: increased sensitivity, increased stability of operations in wide range of power of input optical signal, decreased cost, increased reliability. |
