Optical exchanger

• US 6,496,289 B1
• Filed: 07/08/1998
• Issued: 12/17/2002
• Est. Priority Date: 02/20/1998
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Maeda, Takuji, Kuroyanagi, Satoshi, Nishi, Tetsuya, Nakajima, Ichiro, Tsuyama, Isao
• Primary Examiner(s): Pascal, Leslie
• Assistant Examiner(s): SINGH, DALZID E
• Application Number:
  US09/111,770
• Time in Patent Office: 1,623 Days
• Field of Search: 359/117, 359/127, 359/128, 359/176
• US Class Current: 398/49
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems

Abstract

In addition to the configuration of a conventional optical XC node, a former-stage regenerator for converting optical signals to electrical signals and regenerating optical signals again is provided at an output stage of a demultiplexer and at the input stage of an optical switch unit. Since the regenerator has a 3R function, the regenerator compensates for the influence of the noise and crosstalk generated during propagation in the transmission line, and improves the S/N ratio of the optical signals. Since the optical signals with S/N ratios improved in this way are inputted to the optical switch unit, it is sufficient only if a latter-stage regenerator compensates for the S/N ratio degradation generated in the optical switch unit, and thereby the error rate characteristic of the optical signals can be improved.

Claims

1. An optical exchanger for accommodating a plurality of wavelength-multiplexed input/output optical links, routing wavelength-multiplexed optical signals inputted from each input link, and outputting the optical signals to output links, comprising:

first demultiplexing means for demultiplexing wavelength-multiplexed optical signals inputted from the input link to optical signals of each wavelength;

first regenerating means for regenerating optical signals of each wavelength outputted from the demultiplexing means;

first multiplexing means for wavelength-multiplexing optical signals of each wavelength outputted from the first regenerating means;

wavelength selecting means, consisting of one or more optical couplers and a multi-wavelength selection filter, for routing wavelength-multiplexed optical signals outputted from the multiplexing means;

second demultiplexing means for demultiplexing optical signals outputted from the wavelength selecting means to optical signals of each wavelength;

second regenerating means for regenerating optical signals outputted from the second demultiplexing means and compensating for an S/N ratio degradation; and

second multiplexing means for wavelength-multiplexing optical signals of each wavelength outputted from the second regenerating means.

2. An optical exchanger for accommodating a plurality of wavelength-multiplexed input/output optical links, routing wavelength-multiplexed optical signals inputted from each input link, and outputting the optical signals to output links, comprising:

demultiplexing means for demultiplexing wavelength-multiplexed optical signals inputted from the input link to optical signals of each wavelength;

first regenerating means for regenerating optical signals of each wavelength outputted from the demultiplexing means and compensating for an S/N ratio degradation generated in the transmission line;

first multiplexing means for wavelength-multiplexing optical signals outputted from the first regenerating means;

wavelength selecting means, consisting of two couplers and a wavelength selection filter, for routing wavelength-multiplexed optical signals inputted from the first multiplexing means and outputting the optical signals of each wavelength;

second regenerating means for regenerating optical signals of each wavelength outputted from the wavelength selecting means and compensating for an S/N ratio degradation; and

second multiplexing means for wavelength-multiplexing optical signals of each wavelength outputted from the second regenerating means.

3. The optical exchanger according to claim 2, further comprising:

noise elimination filter means for enabling changing of the transmission band thereof, provided at the former stage of said second regenerating means and on the output side of said wavelength selecting means.

4. An optical exchanger for accommodating a plurality of wavelength-multiplexed input/output optical links, routing wavelength-multiplexed optical signals inputted from each input link, and outputting the optical signals to output links, comprising:

a first demultiplexer demultiplexing wavelength-multiplexed optical signals inputted from the input link to optical signals of each wavelength;

a first regenerator regenerating optical signals of each wavelength outputted from the first demultiplexer;

a first multiplexer wavelength multiplexing optical signals of each wavelength outputted from the first regenerator;

a wavelength selector including one or more optical couplers and a multi-wavelength selection filter for routing wavelength-multiplexed optical signals outputted from the first multiplexer;

a second demultiplexer demultiplexing optical signals outputted from the wavelength selector to optical signals of each wavelength;

a second regenerator regenerating optical signals outputted from the second demultiplexer and compensating for an S/N ratio degradation; and

a second multiplexer wavelength multiplexing optical signals of each wavelength outputted from the second regenerator.

5. An apparatus comprising:

a plurality of optical links, each link transmitting a wavelength division multiplexed (WDM) light;

a plurality of first demultiplexers corresponding, respectively, to the plurality of optical links, each first demultiplexer demultiplexing the WDM light of the corresponding optical link into a plurality of optical signals;

a plurality of regenerators corresponding to each first demultiplexer, respectively, the plurality of regenerators regenerating the demultiplexed plurality of optical signals of the corresponding first demultiplexer;

a plurality of first multiplexers associated with the plurality of first demultiplexers, respectively, each first multiplexer multiplexing together the plurality of regenerated optical signals of the plurality of regenerators corresponding to the first demultiplexer associated with the respective first multiplexer, to thereby output a plurality of WDM lights from the plurality of first multiplexers, respectively;

a wavelength selector including at least one optical coupler and a multi-wavelength selection filter to route the plurality of WDM lights output from the plurality of first multiplexers to a plurality of output ports, respectively;

a plurality of second demultiplexers corresponding to the plurality of output ports, respectively, each second demultiplexer demultiplexing the WDM light output from the corresponding output port into a plurality of optical signals;

a plurality of regenerators corresponding to each second demultiplexer, respectively, the plurality of regenerators regenerating the demultiplexed plurality of optical signals of the corresponding second demultiplexer;

a plurality of second multiplexers associated with the plurality of second demultiplexers, respectively, each second multiplexer multiplexing together the plurality of regenerated optical signals of the plurality of regenerators corresponding to the second demultiplexer associated with the respective second multiplexer, to thereby output a plurality of multiplexed lights from the plurality of second multiplexers, respectively; and

a plurality of output links outputting the plurality of multiplexed lights, respectively.

6. An optical exchanger for accommodating a plurality of wavelength-multiplexed input/output optical links, routing wavelength-multiplexed optical signals inputted from each input link, and outputting the optical signals to output links, comprising:

a demultiplexer demultiplexing wavelength-multiplexed optical signals inputted from a respective input link of the plurality of wavelength-multiplexed input/output optical links to optical signals of each wavelength;

a first regenerator regenerating optical signals of each wavelength outputted from the demultiplexer and compensating for an S/N ratio degradation generated in the transmission line;

a first multiplexing means for wavelength multiplexing optical signals outputted from the first regenerating means;

a wavelength selector, consisting of two couplers and a wavelength selection filter, to route wavelength-multiplexed optical signals inputted from the first multiplexer and outputting the optical signals of each wavelength;

a second regenerator regenerating optical signals of each wavelength outputted from the wavelength selector and compensating for an S/N ratio degradation; and

a second multiplexer wavelength multiplexing optical signals of each wavelength outputted from the second regenerator.

7. The optical exchanger according to claim 6, further comprising:

a noise elimination filter enabling changing of the transmission band thereof, provided at the former stage of said second regenerator and on the output side of said wavelength selector.

8. An apparatus comprising:

a plurality of optical links, each link transmitting a wavelength division multiplexed (WDM) light;

a plurality of first demultiplexers corresponding, respectively, to the plurality of optical links, each first demultiplexer demultiplexing the WDM light of the corresponding optical link into a plurality of optical signals;

a plurality of regenerators corresponding to each first demultiplexer, respectively, the plurality of regenerators regenerating the demultiplexed plurality of optical signals of the corresponding first demultiplexer;

a plurality of first multiplexers associated with the plurality of first demultiplexers, respectively, each first multiplexer multiplexing together the plurality of regenerated optical signals of the plurality of regenerators corresponding to the first demultiplexer associated with the respective first multiplexer, to thereby output a plurality of WDM lights from the plurality of first multiplexers, respectively;

a wavelength selecting means including at least one optical coupler and a multiwavelength selection filter to route the plurality of WDM lights output from the plurality of first multiplexers to a plurality of output ports, respectively;

a plurality of second demultiplexers corresponding to the plurality of output ports, respectively, each second demultiplexer demultiplexing the WDM light output from the corresponding output port into a plurality of optical signals;

a plurality of regenerators corresponding to each second demultiplexer, respectively, the plurality of regenerators regenerating the demultiplexed plurality of optical signals of the corresponding second demultiplexer;

a plurality of second multiplexers associated with the plurality of second demultiplexers, respectively, each second multiplexer multiplexing together the plurality of regenerated optical signals of the plurality of regenerators corresponding to the second demultiplexer associated with the respective second multiplexer, to thereby output a plurality of multiplexed lights from the plurality of second multiplexers, respectively; and

a plurality of output links outputting the plurality of multiplexed lights, respectively.