Main signal controlling apparatus and method in a WDM optical communications system

• US 7,133,611 B2
• Filed: 10/15/2002
• Issued: 11/07/2006
• Est. Priority Date: 04/24/2002
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kaneko, Shinichi
• Primary Examiner(s): Phan, Hanh
• Application Number:
  US10/269,982
• Publication Number:
  US 20040208521A1
• Time in Patent Office: 1,484 Days
• Field of Search: 359/124, 398/30, 398/79, 398/33, 398/38, 398/10, 398/11, 398/17, 398/18, 398/26, 398/27, 398/25, 398/37, 398/81, 398/97, 398/104, 398/105, 398/140, 398/141, 398/158, 398/159, 398/160, 398/173, 398/177, 398/181
• US Class Current: 398/30
• CPC Class Codes: H04B 10/25133 including a lumped electrical or optical dispersion compensator H04B10/2519, H04B10/2525 takes precedence
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant

Abstract

If a repeater supervisory control (SV), a pre-emphasis automatic adjustment (PE), a receiving side threshold value automatic adjustment (Vth), a transmitting side dispersion compensation value setting (VDC(T)), and a receiving side dispersion compensation value setting (VDC(R)) are executed for an optical main signal, these controls are executed in the above described priority order. Accordingly, if the controls are independently executed, or if two or more controls simultaneously occur, a control with a higher priority is executed. In this way, a transmission quality of an optical signal is prevented from being badly influenced as a result that the controls are simultaneously executed.

Claims

1. A main signal controlling apparatus in a termination station of a WDM optical communications system, comprising:

a repeater supervisory control unit executing a supervisory control for a repeater arranged on a transmission line of the WDM optical communications system;

a pre-emphasis control unit making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

a threshold value setting control unit setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

a wavelength dispersion compensation control unit adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

a priority control unit preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when at least two of the controls occur simultaneously, including if a repeater supervisory control from an opposed terminal station and a repeater supervisory control from a local terminal station occur simultaneously, information is exchanged via a dedicated line which connects priority control units of both of the terminal stations, and an earlier started control is executed with a higher priority.

2. A main signal controlling apparatus in a termination station of a WDM optical communications system, comprising:

a repeater supervisory control unit executing a supervisory control for a repeater arranged on a transmission line of the WDM optical communications system;

a pre-emphasis control unit making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

a threshold value setting control unit setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

a wavelength dispersion compensation control unit adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

a priority control unit preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when controls associated with different transmission lines, which connect an opposed terminal station and a local terminal station, in the WDM optical communications system, among respective controls are executed simultaneously.

3. A main signal controlling apparatus in a termination station of a WDM optical communications system, comprising:

a repeater supervisory control unit executing a supervisory control for a repeater arranged on a transmission line of the WDM optical communications system;

a pre-emphasis control unit making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

a threshold value setting control unit setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

a wavelength dispersion compensation control unit adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

a priority control unit preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when at least two of the controls occur simultaneously, with the threshold value control, a threshold value in an amplitude direction and a threshold value in a phase direction of a received signal are controlled.

4. A main signal controlling apparatus in a termination station of a WDM optical communications system, comprising:

a repeater supervisory control unit executing a supervisory control for a repeater arranged on a transmission line of the WDM optical communications system;

a pre-emphasis control unit making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

a threshold value setting control unit setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

a wavelength dispersion compensation control unit adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

a priority control unit preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when at least two of the controls occur simultaneously and if a control with a lower priority is interrupted by a control with a higher priority, the control with the lower priority is stopped, and at the same time, a recovery process for recovering status of the WDM optical communications system to status before the control with the lower priority starts is performed.

5. The main signal controlling apparatus according to claim 4, wherein if the control with the lower priority is a wavelength dispersion compensation control of a local terminal station, the recovery process is not performed.

6. A main signal controlling apparatus in a termination station of a WDM optical communications system, comprising:

a repeater supervisory control unit executing a supervisory control for a repeater arranaed on a transmission line of the WDM optical communications system;

a pre-emphasis control unit making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

a threshold value setting control unit setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

a wavelength dispersion compensation control unit adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

a priority control unit preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when at least two of the controls occur simultaneously and if a fault occurs while any of the controls is being executed, the control is stopped, and a recovery process for recovering status of the WDM optical communications system to status before the control is executed is performed.

7. A main signal controlling method for use in a terminal station of a WDM optical communications system, comprising:

executing a supervisory control for a repeater arranged on a transmission line of the WDM optical communications system;

making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when at least two of the controls occur simultaneously and if a repeater supervisory control from an opposed terminal station, and a repeater supervisory control from a local terminal station occur simultaneously, information is exchanged via a dedicated line of both of the terminal stations, which is used in said preferentially control executing, and an earlier started control is executed with a higher priority.

8. A main signal controlling method for use in a terminal station of a WDM optical communications system, comprising:

executing a supervisory control for a repeater arranged on a transmission line of the WDM optical communications system;

making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when controls associated with different transmission lines, which connect an opposed terminal station and a local terminal station, in the WDM optical communications system, among respective controls are executed simultaneously.

9. A main signal controlling method for use in a terminal station of a WDM optical communications system, comprising:

executing a supervisory control for a repeater arranged on a transmission line of the WDM optical communications system;

making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when at least two of the controls occur simultaneously, with the threshold value control, a threshold value in an amplitude direction and a threshold value in a phase direction of a received signal are controlled.

10. A main signal controlling method for use in a terminal station of a WDM optical communications system, comprising:

executing a supervisory control for a repeater arranged on a transmission line of the WDM optical communications system;

making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when at least two of the controls occur simultaneously and if a control with a lower priority is interrupted by a control with a higher priority, the control with the lower priority is stopped, and at the same time, a recovery process for recovering status of the WDM optical communications system to status before the control with the lower priority starts is performed.

11. The main signal controlling method according to claim 10, wherein if the control with the lower priority is a wavelength dispersion compensation control of a local terminal station, the recovery process is not performed.

12. A main signal controlling method for use in a terminal station of a WDM optical communications system, comprising:

executing a supervisory control for a repeater arranged on a transmission line of the WDM optical communications system;

making a pre-emphasis that adjusts a level difference among wavelengths of a WDM optical signal transmitted from the terminal station;

setting and controlling a threshold value that an optical signal receiving device uses to detect a signal;

adjusting a wavelength dispersion compensation amount at a transmitting end or a receiving end; and

preferentially executing a repeater supervisory control, a pre-emphasis control, a threshold value setting control, and a wavelength dispersion compensation control in this order, so that the controls are executed without exerting a bad influence on a quality of a main signal transmitted/received by the WDM optical communications system, when at least two of the controls occur simultaneously and if a fault occurs while any of the controls is being executed, the control is stopped, and a recovery process for recovering status of the WDM optical communications system to status before the control is executed is performed.