Wavelength division multiplexing system, wavelength division multiplexing transmission system and optical path cross connection system

• US 6,297,895 B1
• Filed: 01/16/1998
• Issued: 10/02/2001
• Est. Priority Date: 01/17/1997
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Okuno, Hideki
• Primary Examiner(s): Pascal, Leslie
• Assistant Examiner(s): Phan, Hanh
• Application Number:
  US09/007,981
• Time in Patent Office: 1,355 Days
• Field of Search: 359/124, 359/133, 359/127
• US Class Current: 398/9
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0201 Add-and-drop multiplexing
• CPC Class Codes: H04J 14/0209 Multi-stage arrangements, e.g. by cascading multiplexers or demultiplexers
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements

Abstract

Disclosed is a method for wavelength-multiplexing signal lights with three or more wavelengths, wherein: a wavelength arrangement is made by providing at least a wavelength block of signal light with one wavelength and a wavelength block where signal lights with two or more wavelengths are wavelength-multiplexed or providing a plurality of wavelength blocks where signal lights with two or more wavelengths are wavelength-multiplexed, and by setting a wavelength interval between adjacent wavelength blocks to be wider than a wavelength interval between signal lights in a wavelength block.

Claims

1. A method for wavelength-multiplexing signal lights with three or more wavelengths comprising the steps of:

providing at least a wavelength block of signal light with one wavelength and a wavelength block where signal lights of two or more wavelengths are wavelength-multiplexed or providing a plurality of wavelength blocks where signal lights of two or more wavelengths are wavelength-multiplexed;

setting a wavelength interval between adjacent wavelength blocks to be wider than a wavelength interval between signal lights in a wavelength block;

using a wavelength multiplexing coupler for wavelength multiplexing said wavelength blocks; and

using a wavelength demultiplexing coupler of mirco-optics type having a dielectric multilayer film for wavelength demultiplexing said wavelength blocks.

2. A wavelength multiplexing transmission system for transmitting signal lights with three or more wavelengths through an optical fiber transmission line, comprising:

at least a wavelength block of signal light with one wavelength and a wavelength block where signal lights with two or more wavelengths are wavelength-multiplexed or a plurality of wavelength blocks where signal lights with two or more wavelengths are wavelength-multiplexed;

wherein a wavelength interval between adjacent wavelength blocks is wider than a wavelength interval between signal lights in a wavelength block; and

wherein wavelength multiplexing or demultiplexing is performed using a coupler of the micro-optics type having a dielectric multilayer film.

3. A wavelength multiplexing transmission system, according to claim 2, wherein:

said wavelength block is coupled or divided by using a wavelength multiplexing function.

4. A wavelength multiplexing transmission system, according to claim 3, wherein:

said wavelength block is coupled or divided by using an optical add-drop function comprising;

a single demultiplexer in said optical fiber transmission line for dropping a particular one of said wavelength blocks; and

a single multiplexer in said in said optical fiber transmission line for adding a new wavelength block to said multiplexed signal.

5. A wavelength multiplexing transmission system as recited in claim 3, wherein:

a signal light in said wavelength block is coupled or divided by using an optical add-drop function.

6. A wavelength multiplexing transmission system, according to claim 2, wherein:

said signal light in said wavelength block is coupled or divided by using an optical coupler.

7. A wavelength multiplexing transmission system, according to claim 6, wherein:

said wavelength block is coupled or divided by using an optical add-drop function comprising;

a single demultiplexer in said optical fiber transmission line for dropping a particular one of said wavelength blocks; and

a single multiplexer in said in said optical fiber transmission line for adding a new wavelength block to said multiplexed signal.

8. A wavelength multiplexing transmission system as recited in claim 6, wherein:

a signal light in said wavelength block is coupled or divided by using an optical add-drop function.

9. A wavelength multiplexing transmission system, according to claim 3, wherein:

said signal light in said wavelength block is coupled or divided by using an optical coupler.

10. A wavelength multiplexing transmission system, according to claim 2, wherein:

said wavelength block is coupled or divided by using an optical add-drop function comprising;

a single demultiplexer in said optical fiber transmission line for dropping a particular one of said wavelength blocks; and

a single multiplexer in said in said optical fiber transmission line for adding a new wavelength block to said multiplexed signal.

11. A wavelength multiplexing transmission system as recited in claim 2, wherein:

a signal light in said wavelength block is coupled or divided by using an optical add-drop function.

12. An optical path cross connection system for exchanging wavelength multiplexed signal light where signal lights with three or more wavelengths are wavelength multiplexed, wherein:

a wavelength arrangement is made by proving at least a wavelength block of signal light with one wavelength and a wavelength block where signal lights with two or more wavelengths are wavelength multiplexed or a plurality of wavelength blocks where signal lights with two or more wavelengths are wavelength multiplexed, and by setting a wavelength interval between adjacent blocks to be wider than a wavelength interval between signal lights in a wavelength block; and

wherein wavelength multiplexing or demultiplexing is performed using a coupler of the micro-optics type having a dielectric multilayer film.

13. A method for wavelength multiplexing light signals having an add/drop function, comprising:

providing a plurality of light channels;

dividing said light channels into a plurality of blocks each comprising one or more spaced frequencies;

separating adjacent said blocks by a frequency separation larger than a frequency separation of said light channels in said blocks;

multiplexing light channels in each of said blocks to produce a plurality of intermediate multiplexed signals;

multiplexing said plurality of intermediate multiplexed signals to produce a multiplexed signal containing said plurality of light channels for transmission over a fiber;

providing a signal demultiplexer for in said fiber path for dropping a particular one of said blocks from said multiplexed signal;

providing a signal multiplexer in said fiber path for adding a new block to said multiplexed signal.

14. A method for wavelength multiplexing light signals having an add/drop function as recited in claim 13 wherein said step of multiplexing light channels in each of said blocks is accomplished by providing a star coupler.

15. A method for wavelength multiplexing light signals having an add/drop function as recited in claim 13 wherein said step of multiplexing light channels in each of said blocks is accomplished by providing a waveguide coupler.

16. A method for wavelength multiplexing light signals having an add/drop function as recited in claim 13 wherein said step of multiplexing said plurality of intermediate multiplexed signals is accomplished by providing a waveguide coupler.