| 摘要 |
The optically-based frequency synthesizer for generating an electric output signal at a preselected frequency having a given period that can be changed over a wide band of frequencies for communication purposes, comprises a modulator having an input for receiving a command signal, and an output for generating a current driving signal having a DC component, and a modulating component formed of an AC signal having a predetermined time period which is an integer multiple of the period of the preselected frequency, and an amplitude responsive to the command signal, a laser having an input for receiving the current driving signal, the coherent light signal having a given coherence time; optical isolators for receiving the light signal emitted by said laser; a splitter having an input optically connected to the isolators; a first optical path having an end optically connected to the splitter; and a second optical path having an end optically connected to the splitter, and a delay means along its length, the time delay being shorter than the coherence time. The synthesizer also comprises a recombiner having first and second inputs optically connected to the paths respectively; and a non-linear device having an input optically connected to an output of the recombiner, and an output for generating the electric output signal at the preselected frequency.
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