Nec Corporation

Toshiharu Yasugi

Makoto Shibutani

Akihiro Kanazawa

The subcarrier frequency multiplexed optical transmission system disclosed is one in which a plurality of analog subcarrier signals and at least one digital subcarrier signal is optically transmitted by frequency multiplexing. The system includes an amplitude limiter, a filter, a multiplexer and a semiconductor laser. Portions of the analog subcarrier signals which are lower in level than the threshold value of the semiconductor laser are eliminated by the amplitude limiter, and further impulse distortions generated due to clipping in the frequency band of the digital subcarrier signal are eliminated by the filter. Then, the analog and digital subcarrier signals are frequency multiplexed to be inputted to the semiconductor laser. The system enables to reduce the transmission quality deterioration of digital subcarrier signal caused by clipping.

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Tokyo, Japan

Toshiharu Yasugi