Optical transmission system
First Claim
1. An optical transmitter system comprising;
- an input terminal receiving a binary data signal,an encoding circuit coupled with said input terminal for converting a binary data signal to a duobinary signal,an optical modulation means coupled with an output of said encoding circuit for providing optical intensity modulation to an optical carrier with said duobinary signal so that optical intensity of a modulated light for a center value of said duobinary signal is the minimum and optical intensity of the modulated light for other two values of said duobinary signal is the maximum, and phase of the modulated light for those two values is opposite with each other, andan output terminal coupled with output of said optical modulation means to provide a modulated optical signal to an optical transmission line.
2 Assignments
0 Petitions
Accused Products
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.
178 Citations
7 Claims
-
1. An optical transmitter system comprising;
-
an input terminal receiving a binary data signal, an encoding circuit coupled with said input terminal for converting a binary data signal to a duobinary signal, an optical modulation means coupled with an output of said encoding circuit for providing optical intensity modulation to an optical carrier with said duobinary signal so that optical intensity of a modulated light for a center value of said duobinary signal is the minimum and optical intensity of the modulated light for other two values of said duobinary signal is the maximum, and phase of the modulated light for those two values is opposite with each other, and an output terminal coupled with output of said optical modulation means to provide a modulated optical signal to an optical transmission line. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
Specification