WDM optical communication system having a dispersion slope compensating element

• US 6,522,455 B1
• Filed: 02/17/2000
• Issued: 02/18/2003
• Est. Priority Date: 02/17/2000
• Status: Expired due to Fees

• Current Assignee: Ciena Corporation
• Original Assignee: Ciena Corporation
• Inventors: Sardesai, Harshad
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/506,007
• Time in Patent Office: 1,097 Days
• Field of Search: 359/153, 359/161, 359/124, 359/130, 359/134, 359/237, 359/305, 359/180, 359/187, 359/173, 385/10, 385/12, 385/14, 385/16, 385/24, 385/31, 385/32, 385/37, 250/227.11, 250/227.12, 250/227.14
• US Class Current: 359/305
• CPC Class Codes: G02B 6/29317 Light guides of the optical fibre type
• CPC Class Codes: G02B 6/29376 coupling light guides for controlling wavelength dispersion, e.g. by concatenation of two light guides having different dispersion properties dispersion managed optical transmission systems H04B10/25253
• CPC Class Codes: H04B 10/2519 using Bragg gratings

Abstract

Consistent with the present invention, in-fiber Bragg gratings are used to demultiplex optical signals in a WDM optical communication system. The in-fiber Bragg gratings also perform dispersion compensation of the selected optical signals. As a result, additional segments of DCF for further dispersion compensation are rendered unnecessary. Improved performance is thus achieved with an inexpensive and simplified system design.

Claims

1. An optical device, comprising:

an optical splitter having an input port and a plurality of output ports, said input port being configured to receive a plurality of optical signals, each at a respective one of a plurality of wavelengths, each of said plurality of output ports supplying said optical signals in attenuated form; and

a plurality of in-fiber Bragg gratings, each of which being coupled to a respective one of said plurality of output ports, each of said plurality of in-fiber Bragg gratings being configured to reflect a respective one of said plurality of optical signals and substantially compensate for a dispersion associated with said respective one of said plurality of optical signals.

2. An optical device in accordance with claim 1, further comprising:

a segment of dispersion compensating fiber coupled to said input port of said splitter, said segment of dispersion compensating fiber being configured to provide dispersion compensation for said plurality of optical signals.

3. An optical device in accordance with claim 1, wherein a dispersion imparted by each of said plurality of in-fiber Bragg gratings varies as a function of wavelength.

4. An optical device in accordance with claim 3, wherein said dispersion imparted by each of said plurality of in-fiber Bragg gratings is equal in magnitude and opposite in sign to a residual dispersion associated with each said respective ones of said plurality of optical signals such that a net dispersion of said respective ones of said plurality of optical signals is substantially zero.

5. An optical device in accordance with claim 3, wherein said dispersion imparted by each of said plurality of in-fiber Bragg gratings varies in such a manner so that each of said plurality of optical signals reflected by a respective one of said plurality of in-fiber Bragg gratings has substantially the same net dispersion.

6. An optical device in accordance with claim 1, wherein a net dispersion associated with each of said plurality of optical signals after passing through said plurality of in-fiber Bragg gratings is within a range of ±

200 ps/nm.

7. An optical communication system, comprising:

a plurality of optical transmitters, each supplying a corresponding one of a plurality of optical signals, each of said optical signals being at a respective wavelength;

an optical combiner having a plurality of inputs and an output, said optical combiner receiving each of said plurality of optical signals at a respective one of said plurality of inputs, and supplying said plurality of optical signals through said output;

an optical communication path carrying said plurality of optical signals;

an optical splitter coupled to said optical communication path, said optical splitter having an input and a plurality of outputs, said optical splitter input receiving said plurality of optical signals, and each of said plurality of optical splitter outputs supplying said plurality of optical signals in attenuated form; and

a plurality of in-fiber Bragg gratings, each coupled to a respective one of said plurality of optical splitter outputs, each of said plurality of in-fiber Bragg gratings being configured to reflect a respective one of said plurality of optical signals and compensate for a dispersion associated with said respective one of said plurality of optical signals.

8. An optical communication system in accordance with claim 7, further comprising:

a segment of dispersion compensating fiber coupled along said optical communication path, said segment of dispersion compensating fiber being configured to provide dispersion compensation for said plurality of optical signals.

9. An optical communication system in accordance with claim 7, wherein a dispersion imparted by each of said plurality of in-fiber Bragg gratings varies as a function of wavelength.

10. An optical communication system in accordance with claim 9, wherein said dispersion imparted by each of said plurality of in-fiber Bragg gratings is equal in magnitude and opposite in sign to a residual dispersion associated with each of said respective ones of said plurality of optical signals such that a net dispersion of said respective ones of said plurality of optical signals is substantially zero.

11. An optical communication system in accordance with claim 9, wherein said dispersion associated with each of said plurality of in-fiber Bragg gratings varies in such a manner so that each of said plurality of optical signals reflected by a respective one of said plurality of in-fiber Bragg gratings has substantially the same net dispersion.

12. An optical communication system in accordance with claim 7, wherein a net dispersion associated with each of said plurality of optical signals after passing through said plurality of in-fiber Bragg gratings is within a range of ±

200 ps/nm.

13. An optical communication system in accordance with claim 7, further comprising a plurality of optical amplifiers coupled to said optical communication path, said optical amplifiers being configured to amplify said plurality of optical signals.

14. A method, comprising the steps of:

combining a plurality of optical signals onto an optical communication path;

transmitting said plurality of optical signals along said optical communication path;

substantially simultaneously separating and dispersion compensating said plurality of optical signals; and

detecting said separated plurality of optical signals,

wherein said separating and dispersion compensating steps are performed with an in-fiber Bragg grating.