| 摘要 |
An optical transmission system which provides bandwidth restricted optical signal comprises an input terminal ( 10 ) for accepting an electrical binary signal, an amplifier ( 12 ) for amplifying said electrical binary signal to the level requested for operating an electrical-optical converter ( 16 ) such as a Mach Zehnder light modulator, a bandwidth restriction means ( 14 ) which is for instance a low pass filter for restricting bandwidth of said electrical binary signal, and an electrical-optical conversion means ( 16 ) such as a Mach Zehnder light modulator for converting electrical signal to optical signal. Because of the location of the low pass filter ( 14 ) between an output of the amplifier ( 12 ) and the Mach Zehnder light modulator ( 16 ), the amplifier ( 12 ) may operate in saturation region to provide high level output signal enough for operating the Mach Zehnder light modulator, and a signal shaped by the low pass filter ( 14 ) is applied to the Mach Zehnder light modulator ( 16 ) with excellent waveform. The invention is useful for long distance, large capacity and low cost optical transmission system.
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