OPTICAL TRANSMISSION DEVICE, OPTICAL TRANSMISSION SYSTEM, AND TEST METHOD FOR ALARM FUNCTION

• US 20140355981A1
• Filed: 04/29/2014
• Published: 12/04/2014
• Est. Priority Date: 06/03/2013
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Miyazaki, Satoshi
• Granted Patent: US 9,647,789 B2
• Time in Patent Office: Days
• US Class Current: 398/38
• 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 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04J 14/02219 Distributed control
• CPC Class Codes: H04J 14/0267 Optical signaling or routing

Abstract

An optical transmission device includes a splitter configured to have at least a first port, a second port, and a third port that output branched input light, branching ratios of the first port and the second port being variable, and a controller configured to reduce an optical level of output light from the first port to be monitored and increase an optical level of output light from the second port according to the reduced optical level of output light from the first port by controlling the branching ratios.

Claims

1. An optical transmission device comprising:

a splitter configured to have at least a first port, a second port, and a third port that output branched input light, branching ratios of the first port and the second port being variable; and

a controller configured to reduce an optical level of output light from the first port to be monitored and increase an optical level of output light from the second port according to the reduced optical level of output light from the first port by controlling the branching ratios.

2. The optical transmission device according to claim 1, wherein the controller controls the branching ratios so as to maintain the optical level of output light from the third port.

3. The optical transmission device according to claim 1, further comprising:

a first alarm output unit configured to monitor the optical level of output light from the first port and generate an alarm according to the optical level of output light from the first port.

4. The optical transmission device according to claim 2, further comprising:

a first alarm output unit configured to monitor the optical level of output light from the first port and generate an alarm according to the optical level of output light from the first port.

5. The optical transmission device according to claim 1, wherein the splitter is an optical splitter.

6. An optical transmission system comprising:

a first optical transmission device configured to include

a splitter that has at least a first port, a second port, and a third port that outputs branched input light, branching ratios of the first port and the second port being variable, and

a controller that reduces an optical level of output light from the first port to be monitored and increases an optical level of output light from the second port according to the reduced optical level of output light from the first port by controlling the branching ratios; and

a second optical transmission device coupled to the first optical transmission device via a transmission path, the second optical transmission device including

a second alarm output unit that monitors the optical level of output light from the first port and generates an alarm according to the optical level of output light from the first port.

7. The optical transmission system according to claim 6, wherein the controller controls the branching ratios so as to maintain the optical level of output light from the third port.

8. The optical transmission system according to claim 6, wherein the second optical transmission device further includes a switch that selects one of output light from the first port of the first optical transmission device and output light from another optical transmission device, the switch selecting the output light from the other optical transmission device when the second alarm output unit issues the alarm.

9. The optical transmission system according to claim 7, wherein the second optical transmission device further includes a switch that selects one of output light from the first port of the first optical transmission device and output light from another optical transmission device, the switch selecting the output light from the other optical transmission device when the second alarm output unit issues the alarm.

10. A test method for an alarm function comprising:

controlling branching ratios of a first port and a second port so as to reduce an optical level of output light from the first port to be monitored and to increase an optical level of output light from the second port according to the reduced optical level, at least the first port, the second port, and a third port being included in a splitter that outputs branched input light.

11. The test method according to claim 10, wherein the branching ratios are controlled so that an optical level of output light from the third port is maintained.

12. The test method according to claim 10, wherein the optical level of output light from the first port is monitored and an alarm is generated according to the optical level of output light from the first port.

13. The test method according to claim 11, wherein the optical level of output light from the first port is monitored and an alarm is generated according to the optical level of output light from the first port.