Optical systems including add drop devices and methods

• US 20040161237A1
• Filed: 03/10/2003
• Published: 08/19/2004
• Est. Priority Date: 09/18/1998
• Status: Active Grant

• Current Assignee: Optic153 LLC (Equitable IP Corporation)
• Original Assignee: Corvita Corporation (Boston Scientific Corporation)
• Inventors: Stephens, Thomas D.
• Granted Patent: US 6,934,473 B2
• Time in Patent Office: Days
• US Class Current: 398/82
• CPC Class Codes: H04J 14/0204 Broadcast and select arrangements, e.g. with an optical splitter at the input before adding or dropping
• CPC Class Codes: H04J 14/0205 Select and combine arrangements, e.g. with an optical combiner at the output after adding or dropping
• CPC Class Codes: H04J 14/0206 Express channels arrangements
• CPC Class Codes: H04J 14/021 Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements

Abstract

Optical systems of the present invention include an add/drop device and/or cross-connect device, which is reconfigurable to add and drop signal wavelengths between one or more transmission paths. The add/drop device includes a first selective element configurable to pass a first group of signal wavelengths including at least a first signal wavelength from an input path to a first add/drop path and pass continuing signal wavelengths differing from the first group of signal wavelength to a second add/drop path. A second selective element is provided that is configurable to pass a second group of signal wavelengths including at least a second signal wavelength from said first add/drop path and continuing signal wavelengths differing from the second group of wavelengths from said second add/drop path to an output path. The second selective element is further configured to pass the second group of signal wavelengths from said second add/drop path and wavelengths differing from the second wavelength from said first add/drop path to a drop path. The add/drop device may also include an add path to introduce add signal wavelengths directly to the output path or via at least one of the first and second selective elements.

Claims

1. An optical system comprising:

at least a first optical transmitter configured to transmit information via optical signals including at least one signal wavelength;

an add/drop device configured to receive the optical signal from said first optical transmitter via an input path, said add/drop device including

a first selective element configurable to pass a first signal wavelength from said input path to a first add/drop path and pass continuing signal wavelengths differing from the first signal wavelength to a second add/drop path,

a second selective element configurable to pass a second signal wavelength from said first add/drop path and continuing signal wavelengths differing from the second signal wavelength from said second add/drop path to an output path and pass the second signal wavelength from said second add/drop path and signal wavelengths differing from the second signal wavelength from said first add/drop path to a drop path;

at least a first optical receiver configured to receive the output signal from said add/drop device; and

,

at least a second optical receiver configured to receive the drop signal from said add/drop device.

2. The system of claim 1, wherein:

said add/drop device includes an add path configured to provide for add signal wavelengths to pass to said output path; and

,

at least a second optical transmitter configured to transmit information via optical signals including at least one add signal wavelength to said add path.

3. The device of claim 1, further comprising:

a first optical circulator having at least four ports including an input port optically connected to a first add/drop port, a second add/drop port optically connected by a first add/drop path to said first add/drop port, and to an output port;

a second optical circulator having at least three ports including a first add/drop port optically connected by a second add/drop path to a second add/drop port that is optically connected to a drop port;

wherein

said first selective element is optically connected between said first add/drop ports on said first and second circulators;

said second selective element is optically connected between said second add/drop ports on said first and second circulators; and

,

said input path, output path, and drop path are optically connected to said input port, output port, and drop port, respectively.

4. An optical add/drop device comprising:

a first selective element configurable to pass at least a first signal wavelength from an input path to a first add/drop path and pass continuing signal wavelengths differing from the first signal wavelength to a second add/drop path; and

,

a second selective element configurable to pass at least a second signal wavelength from said first add/drop path and continuing signal wavelengths differing from the second signal wavelength from said second add/drop path to an output path and pass the second signal wavelength from said second add/drop path and signal wavelengths differing from the second signal wavelength from said first add/drop path to a drop path.

5. The device of claim 4, wherein at least one of the first and second selective elements is configurable such that the first signal wavelength becomes equal to the second signal wavelength.

6. The device of claim 4, further comprising an add path optically connected to add signal wavelengths to said output path.

7. The device of claim 4, wherein said add path is optically connected to said first add/drop path via said first selective element.

8. The device of claim 4, wherein said first selective element includes a Bragg grating having a central reflective signal wavelength corresponding to the first signal wavelength.

9. The device of claim 4, wherein said second selective element includes a Bragg grating having a central reflective signal wavelength corresponding to the second signal wavelength.

10. The device of claim 4, wherein said first selective element is one of a plurality of first selective elements configurable to correspond to different signal wavelengths.

11. The device of claim 4, wherein said second selective element is one of a plurality of second selective elements configurable to correspond to different signal wavelengths.

12. The device of claim 4, wherein:

said first selective element includes at least one first multiple signal wavelength selective element configured to selectively a first set of at least two consecutive signal wavelengths; and

,

said second selective element includes at least one second multiple signal wavelength selective element configured to selectively pass a second set of at least two consecutive signal wavelengths, and said first and second selective elements being configurable to selectively pass the same signal wavelengths.

13. The device of claim 4, wherein at least one of said first and second selective elements is configured to selectively pass a plurality of signal wavelengths.

14. The device of claim 4, wherein said first and second selective elements include Bragg gratings configured to selectively reflect at least the first and second signal wavelengths.

15. The device of claim 4, wherein said first and second selective elements include Fabry-Perot filters configured to selectively transmit at least the first and second signal wavelengths.

16. The device of claim 4, further comprising an input coupler having an input port optically connecting said input path and said first selective element and a first add/drop port optically connecting said first add/drop path and said first selective element.

17. The device of claim 4, further comprising an output coupler having an output port optically connecting said output path and said second selective element and a first add/drop port optically connecting said first add/drop path, and said second selective element.

18. The device of claim 4, further comprising:

a first optical circulator having at least four ports including an input port optically connected to a first add/drop port, a second add/drop port optically connected by a first add/drop path to said first add/drop port, and to an output port;

a second optical circulator having at least three ports including a first add/drop port optically connected by a second add/drop path to a second add/drop port that is optically connected to a drop port;

wherein

said first selective element is optically connected between said first add/drop ports on said first and second circulators;

said second selective element is optically connected between said second add/drop ports on said first and second circulators; and

,

said input path, output path, and drop path are optically connected to said input port, output port, and drop port, respectively.

19. A method of dropping a first signal wavelength to a drop path comprising:

inputting an optical signal including at least one signal wavelength into an input path;

providing a first selective element configured to pass a first signal wavelength from the input path to a first add/drop path and pass continuing signal wavelengths differing from the first signal wavelength to a second add/drop path; and

,

providing a second selective element configured to pass a second signal wavelength from the first add/drop path and continuing signal wavelengths differing from the second signal wavelength from said second add/drop path to an output path and pass the second signal wavelength from the second add/drop path and signal wavelengths differing from the second signal wavelength including the first signal wavelength from the first add/drop path to a drop path.

20. A method of preventing a first signal wavelength from being dropped to drop path according to the method of claim 19 comprising:

adjusting the second selective element to pass the first signal wavelength from the first add/drop path and continuing signal wavelengths differing from the first signal wavelength from said second add/drop path to the output path and pass the first signal wavelength from the second add/drop path and signal wavelengths differing from the first signal wavelength from the first add/drop path to a drop path.