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Automatic optical frequency acquisition and tracking apparatus for optical coherent communication system
Automatic optical frequency acquisition and tracking apparatus for optical coherent communication system
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机译:用于光学相干通信系统的自动光学频率获取和跟踪设备
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摘要
An automatic frequency control system, for an optical coherent communication system, in which an output frequency of a local oscillator is swept by a frequency sweep signal FM-modulated with a frequency shift signal. The FM-modulated local frequency is combined with an input optical signal and heterodyne-detected. A frequency shift signal component derived from a heterodyne detection output is compared with the frequency shift signal to verify whether or not the local oscillation frequency is in a predetermined range with respect to the input signal frequency. When it is in the predetermined range, the system operates to terminate the frequency sweep signal and remove the frequency shift signal and is switched to oscillation frequency control of the local oscillator by using a d.c. component of the hterodyne detection output.
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