Optical transmission method, optical transmitter, optical receiver, and optical transmission system
First Claim
1. An optical transmission method for modulating an optical signal having longitudinal modes based on a partial response encoded signal and outputting the modulated signal, comprising the steps of:
- receiving a clock signal from a system clock source;
modulating a single mode optical signal based on the clock signal and generating an optical pulse signal having two longitudinal modes, the frequency interval between the two modes being n×
B, where n is a natural number and B is a transmission speed;
generating a partial response encoded signal by converting a binary NRZ encoded signal output from a digital signal source in synchronism with the system clock source; and
modulating the optical pulse signal having two longitudinal modes based on the partial response encoded signal, and outputting a binary RZ modulated signal obtained by the modulation.
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Accused Products
Abstract
A system which improves wavelength tolerance, compensates dispersion in a simple way, reduces limitation of the fiber input power is disclosed. The operation includes receiving a clock signal from a system clock source; modulating a single mode optical signal based on the clock signal and generating an optical pulse signal having two longitudinal modes, the frequency interval thereof being n×B, n being a natural number and B being a transmission speed; generating a partial response signal by converting a binary NRZ signal from a digital signal source in synchronism with the system clock source; and modulating the optical pulse signal based on the partial response signal, and outputting a binary RZ modulated signal. The binary RZ modulated signal is input into a receiver, where two partial response components in the optical spectra of the input signal are divided, and one or both of the components are received.
77 Citations
27 Claims
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1. An optical transmission method for modulating an optical signal having longitudinal modes based on a partial response encoded signal and outputting the modulated signal, comprising the steps of:
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receiving a clock signal from a system clock source;
modulating a single mode optical signal based on the clock signal and generating an optical pulse signal having two longitudinal modes, the frequency interval between the two modes being n×
B, where n is a natural number and B is a transmission speed;
generating a partial response encoded signal by converting a binary NRZ encoded signal output from a digital signal source in synchronism with the system clock source; and
modulating the optical pulse signal having two longitudinal modes based on the partial response encoded signal, and outputting a binary RZ modulated signal obtained by the modulation. - View Dependent Claims (2, 3, 4)
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5. An optical transmitter comprising:
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a system clock source for generating a clock signal;
a binary NRZ digital signal source for generating a binary NRZ digital signal in synchronism with the clock signal;
an electric partial response encoding section for receiving the binary NRZ digital signal and generating an electric partial response encoded signal;
a dual-mode beat optical pulse generating section for generating an optical pulse signal having two longitudinal modes, the frequency interval between the two modes being n×
B, where n is a natural number, B is a transmission speed, and the generated optical pulse signal is in synchronism with the binary NRZ digital signal;
a pulse light source driving section for generating a signal for driving the dual-mode beat optical pulse generating section, by using a clock signal in synchronism with the clock signal generated by the system clock source; and
an optical modulating section for modulating the optical pulse signal having two longitudinal modes based on the electric partial response encoded signal, and outputting a binary RZ modulated signal obtained by the modulation. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification