Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Patent
1995-09-11
1996-08-06
Boudreau, Leo
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
359188, 375291, H04B 1004
Patent
active
055439527
ABSTRACT:
In a transmitter side in an optical transmission system, an input binary signal is converted into a duobinary signal, and the duobinary signal is applied to an optical modulation device which provides an optical intensity modulation signal, wherein the optical intensity for a center value of the duobinary signal is a minimum, the optical intensity for the other two values of the duobinary signal is a maximum, and an optical phase for those two values is opposite to each other. In a receiver side, simple direct detection is carried out for receiving optical signal through an optical transmission line to provide a demodulated binary signal. Thus, an original binary signal is recovered without a duobinary decoder and receiver sensitivity degradation. In the optical transmission system, an optical carrier frequency component in a signal spectrum is suppressed, a signal bandwidth of the modulated light is reduced in half to that of a prior art, so an optical transmission system for long distance, high bit rate and large traffic capacity is obtained.
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Kuwano Shigeru
Norimatsu Seiji
Shibata Nori
Yonenaga Kazushige
Bacares Rafael
Boudreau Leo
Nippon Telegraph and Telephone Corporation
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