Wavelength division-multiplexing optical transmission system
AssigneeNEC Corporation
InventorsShigekazu Harada, Akio Tajima
Life of this patent
Estimating the term…
Abstract
A wavelength division-multiplexing system is provided that uses wavelength grids in conformity with the ITU-T Recommendation G.692 and that is realizable at lower costs. In the system, the wavelengths of signal light beams transmitted from plural optical transmitters are respectively spaced apart in such a manner that multiplexed wavelengths are set at regular intervals within the band range of the optical amplifier 5. The wavelength range of each laser beam covers at least two grids including neighboring grids. The wavelength demultiplexer 3 on the receiving side has the passband passing the wavelengths in a laser wavelength range corresponding to each channel.
Claims9
1 A wavelength division-multiplexing optical transmission system comprises:
- a plurality of optical transmitters for producing optical signals respectively, a wavelength on each of wavelength grids being defined as a center wavelength of each optical signal, said wavelength grids on which laser wavelengths are allocated at intervals of 100 GHz, the wavelength interval between respective channels being spaced apart at least two grids, the band of each channel covering at least two grids including neighboring grids;
- a wavelength multiplexer for receiving optical signals output from said plurality of optical transmitters, multiplexing wavelengths of said optical signals, and then outputting multiplexed optical signals;
- a wavelength demultiplexer for receiving optical signals transmitted output from said wavelength multiplexer, demultiplexing wavelengths of said optical signals, and then outputting optical signals having different wavelengths;
- and
- a plurality of optical receivers for converting optical signals, each with a predetermined wavelength range, output from said wavelength demultiplexer, into electrical signals.
2 The system defined in claim 1, wherein said wavelength multiplexer has a passband in which optical signals pass within a laser wavelength range of a corresponding channel of an optical transmitter;
- and wherein said wavelength demultiplexer has a passband in which optical signals pass within a laser wavelength range of a corresponding channel of an optical transmitter.
3 The system defined in claim 1, wherein said wavelength multiplexer multiplexes wavelengths using a thin film interference filter;
- and wherein said wavelength demultiplexer demultiplexes wavelengths using a thin film interference filter.
4 A wavelength division-multiplexing optical transmission system comprises:
- a plurality of optical transmitters for producing optical signals respectively, a wavelength on each of wavelength grids being defined as a center wavelength of each optical signal, said wavelength grids on which laser wavelengths are allocated at intervals of 100 GHz, the wavelength interval between respective channels being spaced apart at least two grids, the wavelengths multiplexed within an optical amplifier being set so as to arrange at regular intervals, the band of each channel covering at least two grids including neighboring grids;
- a wavelength multiplexer for multiplexing wavelengths of optical signals input from said plurality of optical transmitters and then outputting multiplexed optical signals;
- an optical amplifier connected to said wavelength multiplexer and to an optical fiber, for amplifying said optical signals input;
- a wavelength demultiplexer for demultiplexing wavelengths of optical signals output from said optical amplifier, and then outputting optical signals having different wavelengths;
- and
- a plurality of optical receivers for converting optical signals, each with a predetermined wavelength range, output from said wavelength demultiplexer, into electrical signals.
5 The system defined in claim 4, wherein said optical amplifier comprises an Erbium-doped fiber amplifier (EDFA).
6 The system defined in claim 4, wherein said wavelength multiplexer has a passband in which optical signals pass within a laser wavelength range of a corresponding channel of an optical transmitter;
- and wherein said wavelength demultiplexer has a passband in which optical signals pass within a laser wavelength range of a corresponding channel of an optical transmitter.
7 The system defined in claim 4, wherein said wavelength multiplexer multiplexes wavelengths using a thin film interference filter;
- and wherein said wavelength demultiplexer demultiplexes wavelengths using a thin film interference filter.
8 A wavelength division-multiplexing optical transmission system comprises:
- a plurality of optical transmitters, wavelengths being positioned on said wavelength grids on which laser wavelengths are allocated at intervals of 100 GHz, the wavelength interval between respective channels being spaced apart at least two grids, the band of each channel covering at least two grids including neighboring grids, laser wavelengths of said plurality of optical transmitters being selected so as to be set at irregular intervals within a passband;
- a wavelength multiplexer for receiving optical signals output from said plurality of optical transmitters, multiplexing wavelengths of said optical signals, and then outputting multiplexed optical signals;
- a wavelength demultiplexer connected to said wavelength multiplexer via a dispersion shifted fiber, for demultiplexing wavelengths of optical signals transmitted from said wavelength multiplexer, and then outputting optical signals of respective wavelengths;
- and
- a plurality of optical receivers for receiving optical signals each in a predetermined wavelength range from said wavelength demultiplexer and then converting said received said optical signals into electrical signals.
9 The system defined in claim 8, wherein said wavelength multiplexer multiplexes wavelengths using a thin film interference filter;
- and wherein said wavelength demultiplexer demultiplexes wavelengths using a thin film interference filter.