ATM switch

• US 5,892,604 A
• Filed: 05/07/1997
• Issued: 04/06/1999
• Est. Priority Date: 05/09/1996
• Status: Expired due to Fees

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Yamanaka, Naoaki, Oki, Eiji, Shiomoto, Kohei, Yasukawa, Seisho
• Primary Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US08/852,396
• Time in Patent Office: 699 Days
• Field of Search: 359/117, 359/123, 359/128, 359/137, 370/395
• US Class Current: 398/48
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/5605 Fibre
• CPC Class Codes: H04L 2012/5672 Multiplexing, e.g. coding, scrambling
• CPC Class Codes: H04L 49/256 Routing or path finding in ATM switching fabrics
• CPC Class Codes: H04Q 11/0001 using optical switching

Abstract

An ATM switch includes a plurality of input line corresponding units, a plurality of output line corresponding units, and a wavelength shifting unit. The wavelength shifting unit is arranged between the input line corresponding units and the output line corresponding units to shift optical signals having different wavelengths in a plurality of wavelength-multiplexed optical signals arriving from the input line corresponding units and output the wavelength-multiplexed optical signals. Each input line corresponding unit includes an input-side basic switch for distributing N (N is a positive integer) cells respectively input to input ports to N lines, an electro-optic converter for converting the cells into optical signals having different wavelengths in units of N lines, and a multiplexer for multiplexing the optical signals into one wavelength-multiplexed optical signal. Each output line corresponding unit includes a demultiplexer for demultiplexing the wavelength-multiplexed optical signal in units of wavelengths, an opto-electric converter for converting outputs from the demultiplexer into electrical signals, respectively, and an output-side basic switch for distributing the cells converted into the electrical signals to a plurality of output ports.

Claims

1. An ATM switch for distributing cells arriving from a plurality of input lines to a plurality of output lines, comprising:

a plurality of input line corresponding units each connected to said plurality of input lines;

a plurality of output line corresponding units each connected to said plurality of output lines; and

wavelength shifting means, arranged between said input line corresponding units and said output line corresponding units, for shifting optical signals having different wavelengths included in a plurality of wavelength-multiplexed optical signals arriving from said input line corresponding units and outputting the wavelength-multiplexed optical signals,

wherein each of said input line corresponding units includes an input-side basic switch for distributing N (N is a positive integer) cells which are respectively input to a plurality of input ports to N lines, electro-optic conversion means for converting the cells distributed to the N lines into optical signals having different wavelengths in units of lines, and a multiplexer for multiplexing the optical signals converted in units of lines into one wavelength-multiplexed optical signal, and

each of said output line corresponding units includes a demultiplexer for demultiplexing in units of wavelengths the wavelength-multiplexed optical signal obtained by wavelength-multiplexing the optical signals having N wavelengths, opto-electric conversion means for converting outputs from said demultiplexer into electrical signals, respectively, and an output-side basic switch for distributing the cells converted into the electrical signals to a plurality of output ports.

2. A switch according to claim 1, wherein said wavelength shifting means is constituted by a barrel shifter which distributes an optical signal having a pth (p=0, 1, 2, . . . , (N-1)) wavelength in an nth (n=0, 1, 2, . . . , (the number of input line corresponding units -1)) wavelength-multiplexed optical signal to an (n+p)th output line and distributes the optical signal to an output of an ordinal number obtained by subtracting the number of output line corresponding units from (n+p) when n+p is not less than the number of output line corresponding units.

3. A switch according to claim 1, wherein at least some input terminals of said input line corresponding unit are connected to a circuit to which some signals processed by another input line corresponding unit are supplied.

4. A switch according to claim 1, wherein at least some input terminals of said input line corresponding unit are connected to a feedback circuit to which some signals processed by said output line corresponding unit are supplied.

5. A switch according to claim 1, wherein at least some of output ports constituting one output-side basic switch of said output line corresponding unit are connected to a feedback circuit connected to input ports of said input line corresponding unit corresponding to said one output-side basic switch.

6. A switch according to claim 1, wherein at least some of output ports constituting each input-side basic switch of each input line corresponding unit are connected to a feedback circuit connected to input ports constituting an input-side basic switch of another input line corresponding unit.

7. A switch according to claim 1, wherein all output terminals of at least one of said output line corresponding units are connected to all input terminals of a corresponding one of said input line corresponding units.

8. A switch according to claim 1, further comprising additional electro-optic conversion means converting input cells into optical signals having different wavelengths in units of inputs, and an additional multiplexer for multiplexing the optical signals converted in units of inputs,

said additional multiplexer being connected to an input-side of said wavelength shifting means, and

all output terminals of one of said output line corresponding units being connected to an input-side of said additional electro-optic conversion means.

9. A large-scale ATM switch comprising multiple-connected ATM switches,

wherein an ATM switch at a first stage comprises a plurality of input line corresponding units each connected to a plurality of input lines, a plurality of output line corresponding units each connected to a plurality of output lines, and wavelength shifting means, arranged between said input line corresponding units and said output line corresponding units, for shifting optical signals having different wavelengths included in a plurality of wavelength-multiplexed optical signals arriving from said input line corresponding units and outputting the wavelength-multiplexed optical signals,

each of said input line corresponding units including an input-side basic switch for distributing N (N is a positive integer) cells which are respectively input to a plurality of input ports to N lines, electro-optic conversion means for converting the cells distributed to the N lines into optical signals having different wavelengths in units of lines, and a multiplexer for multiplexing the optical signals converted in units of lines into one wavelength-multiplexed optical signal, and

each of said output line corresponding units including a demultiplexer for demultiplexing in units of wavelengths the wavelength-multiplexed optical signal obtained by wavelength-multiplexing the optical signals having N wavelengths, opto-electric conversion means for converting outputs from said demultiplexer into electrical signals, respectively, and an output-side basic switch for distributing the cells converted into the electrical signals to a plurality of output ports, and

each of ATM switches at subsequent stages comprises a plurality of input line corresponding units each connected to a plurality of input lines, a plurality of output line corresponding units each connected to a plurality of output lines, and wavelength shifting means, arranged between said input line corresponding units and said output line corresponding units, for shifting optical signals having different wavelengths included in a plurality of wavelength-multiplexed optical signals arriving from said input line corresponding units and outputting the wavelength-multiplexed optical signals,

each of said input line corresponding units of each ATM switch at the subsequent stages including electro-optic conversion means for converting outputs from said output line corresponding units of said ATM switch at the previous stage into optical signals having different wavelengths in units of lines, and a multiplexer for multiplexing the optical signals converted in units of lines into one wavelength-multiplexed optical signal, and

each of said output line corresponding units of each ATM switch at the subsequent stages including a demultiplexer for demultiplexing in units of wavelengths the wavelength-multiplexed optical signal obtained by wavelength-multiplexing the optical signals having N wavelengths, opto-electric conversion means for converting outputs from said demultiplexer into electrical signals, respectively, and an output-side basic switch for distributing cells converted into the electrical signals to a plurality of output ports.