Method for generating duobinary signal and optical transmitter using the same method
AssigneeNEC Corporation
InventorsTakashi Ono, Yutaka Yano
Life of this patent
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Abstract
Disclosed is a method for generating a duobinary signal which has the step of: modulating individually an intensity and a phase of a carrier wave. Also disclosed is a duobinary-manner optical transmitter which has: a laser device which outpus signal light; an optical intensity modulator which intensity-modulates the signal light according to a first data signal generated by dividing a data signal into two signals; a precoder which inputs a second data signal generated by dividing the data signal into two signals; and an optical phase modulator which phase-modulates the intensity-modulated signal light according to a signal which is obtained delaying 0.5 bit an output signal of the precoder.
Claims4
A method for generating a duobinary signal, comprising:
- providing two carrier waves with an equal frequency;
- intensity-modulating individually said two carrier waves by first and second intensity modulators;
- shifting by π an output of one of said first and second intensity modulators;
- and
- coupling said two intensity-modulated carrier waves, thereby narrowing an optical spectrum of a signal light.
A duobinary-manner optical transmitter, comprising:
- a laser device which outputs signal light;
- an optical divider which divides said signal light into two light signals;
- a first optical intensity modulator which inputs first signal light divided by said optical divider;
- a second optical intensity modulator which inputs first signal light divided by said optical divider;
- an optical coupler which couples output lights of said first and second optical intensity modulators after phase-shafting at least one of said output lights so as to give a phase difference of between said output lights of said first and second optical intensity modulators;
- and
- a precoder which inputs a data signal;
- wherein said first optical intensity modulator is driven by a first encoded signal generated by dividing an encoded signal to be output from said precoder into two signals, and said second optical intensity modulator is driven by a signal which is obtained by delaying by 1 bit a second encoded signal generated by dividing said encoded signal into said two signals, thereafter inverting 0 to 1 or vice versa.
Dependencies are inferred from the claim text.