| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical transmission system transmitting a carrier-suppressed-carrier RZ (return to zero) signal, by modulating light intensity and a phase by a low-cost Mach-Zender light intensity modulator, without using a phase modulator. <P>SOLUTION: The optical transmission system includes a light source 30 for outputting optical carrier waves, an optical duobinary signal generator 100 for modulating the optical carrier wave corresponding to a NRZ (non-return-to zero) signal, and a carrier-suppressed RZ signal generator 200 for converting the NRZ signal into the RZ signal, in synchronization with a clock signal. The optical duobinary signal generator includes a coder 101 for converting the NRZ signal into a duobinary signal, a modulator driver 102 for generating a modulator drive signal by receiving the duobinary signal, a Mach-Zender light intensity modulator 103 for modulating the light intensity by shifting the phase of the optical carrier wave, after receiving the modulator drive signal, and a wide bandpass filter 104 for outputting the optical duobinary signal by receiving the modulated optical signal. <P>COPYRIGHT: (C)2004,JPO |
