US 5,786,918 AGranted

Optical communication system and optical transmitting device

AssigneeKokusai Denshin Denwa Kabushiki Kaisha

InventorsMasatoshi Suzuki, Hidenori Taga, Noboru Edagawa, Hideaki Tanaka, Shu Yamamoto, Shigeyuki Akiba

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Abstract

An optical communication system of a construction wherein the average wavelength dispersion value of the transmission optical fiber used, the optical output intensity of each optical amplifier repeater inserted in the transmission optical fiber and the widths of return-to-zero optical pulses transmitted over the transmission line are determined so as to compensate for the pulse compression effect by the nonlinear optical effect produced on the optical pulses by the pulse spreading effect by the wavelength dispersion effect. An optical multiplexer in the optical transmitting device time-division multiplexes the return-to-zero optical pulses, and the optical multiplexed signal is provided as an alternating-amplitude optical signal with the amplitudes of the return-to-zero optical pulses alternated.

Claims13

Dependent claims

An optical communication system, comprising:

an optical fiber transmission line having a required number of optical amplifier repeaters connected to a transmission optical fiber at required intervals,
an optical transmitting device for transmitting over said optical fiber transmission line optical multiplexed signals obtained by optical time-division multiplexing return-to-zero optical pulses having digital information, and
an optical receiving device having an optical demultiplexer for receiving and demultiplexing said optical multiplexed signals received from said optical fiber transmission line into original optical signals,
an average wavelength dispersion value of said transmission optical fiber, an optical output intensity of each of said optical amplifier repeaters and widths of said return-to-zero optical pulses being determined so as to compensate for a pulse compression effect by a nonlinear optical effect produced on said optical pulses and a pulse spreading effect by a wavelength dispersion effect produced on said optical pulses,
said optical transmitting device further comprising an optical multiplexer for time-division multiplexing said return-to-zero optical pulses into said optical multiplexed signals to have alternate amplitudes of said return-to-zero optical pulses;
said optical demultiplexer in said optical receiving device comprising an optical splitter for branching said optical multiplexed signals into a plurality of optical signals and an optical time-division demultiplexer for dividing each repetition rate of each branched optical signal to an original transmission rate by a rectangular synchronizing optical gate of a width about the same as the full time slot at a transmission rate after multiplexing.

3 more elements

An optical transmitting device, for transmitting return-to-zero optical pulses having digital information after time-division multiplexing, comprising:

pulsed light source means for generating said return-to-zero optical pulses, said pulsed light source means comprising a single wavelength laser for continuously emitting light of a fixed amplitude;
an optical splitter for branching the output from said single-wavelength laser into a plurality of outputs;
a plurality of optical modulators for each modulating one of said plurality of outputs by a modulating signal;
a plurality of optical soliton pulse train generating parts which receives the outputs from said optical modulators and generate return-to-zero optical pulses;
and
an optical multiplexer for time-division multiplexing the outputs from said optical soliton pulse train generating parts on a bit-interleave basis;
said optical multiplexer having an optical coupler whereby the modulated output from one of said plurality of optical modulators, which has passed through one of said plurality of optical soliton pulse train generating parts, is combined with a delayed at least one modulated output from at least one of said plurality of optical modulators.

4 more elements

Dependencies are inferred from the claim text.