TWIN OPTICAL AMPLIFIER WITH DUAL PUMP POWER CONTROL

• US 20070019284A1
• Filed: 07/24/2006
• Published: 01/25/2007
• Est. Priority Date: 07/25/2005
• Status: Active Grant

• Current Assignee: Neptune Subsea IP Ltd. (Xtera Topco Ltd.)
• Original Assignee: Azea Networks Limited
• Inventors: Olway, Alan
• Granted Patent: US 7,515,331 B2
• Time in Patent Office: Days
• US Class Current: 359/341.300
• CPC Class Codes: H01S 3/094003 the pumped medium being a fibre
• CPC Class Codes: H01S 3/094011 with bidirectional pumping, i.e. with injection of the pump light from both two ends of the fibre
• CPC Class Codes: H01S 3/1305 Feedback control systems
• CPC Class Codes: H01S 3/1312 by controlling the optical pumping

Abstract

An apparatus for amplifying optical communications systems is provided in which one or more amplifier modules, each containing an optical amplifier and at least two pump lasers, are optically isolated from a plurality of control modules. Each control module controls a single pump laser in one or more of the amplifier modules. A control module can thus be removed without disabling any amplifier module, while the plurality of pump lasers in each amplifier module allow for effective operation even if one of the pump lasers should fail. The pump lasers in each module are controlled by a master-slave relationship, whereby the master pump laser is adjusted to optimise overall output, while the slave laser(s) are adjusted to equalize the power output of the lasers.

Claims

1. An apparatus for amplifying optical communication signals, comprising:

one or more amplifier modules, each amplifier module comprising an optical amplifier and at least two pump lasers; and

,

at least two separate control modules, each control module adapted to control the output of one pump laser in one or more amplifier modules.

2. The apparatus according to claim 1, wherein the output of each pump laser is shared between co- and counter-pumping modes in the optical amplifier of the amplifier module containing that pump laser.

3. The apparatus according to claim 1, comprising two amplifier modules, each amplifier module comprising two pump lasers.

4. The apparatus according to claim 3, comprising exactly two control modules.

5. The apparatus according to claim 1, wherein the control modules are optically isolated from the amplifier modules.

6. The apparatus according to claim 1, wherein one or more of the control modules is adapted to measure the effective gain of one or more of the amplifier modules.

7. The apparatus according to claim 1, wherein the control modules are linked, thereby allowing status indicators to be passed between them.

8. The apparatus according to claim 1, wherein each control module is adapted to control a plurality of pump lasers.

9. The apparatus according to claim 1, wherein the optical amplifiers are erbium-doped fibre amplifiers (EDFAs).

10. The apparatus according to claim 1, wherein each control module is individually removable from the apparatus.

11. A method of adjusting the gain of an optical amplifier using a plurality of pump lasers controlled by a plurality of respective control modules, comprising the steps of:

electing which of the control modules is a master control module;

adjusting an operational parameter of the pump laser associated with the master control module towards the point at which the gain of the optical amplifier is equal to a predetermined ideal value; and

,

adjusting the operational parameter of each of the remaining pump lasers towards the point at which the operational parameters of all the pump lasers are equal.

12. The method according to claim 11, wherein the operational parameter is an input current applied to the pump lasers.

13. The method according to claim 12, wherein the operational parameter is an output of the pump lasers.

14. The method according to claim 11, wherein the step of adjusting the output of each of the remaining pump lasers comprises adjusting the operational parameter of each of the remaining pump lasers towards the operational parameter of the pump laser associated with the master control module.

15. A computer program product comprising computer executable code for performing the method of claim 11.