Optical transmission device, optical transmission system, and test method for alarm function

• US 9,647,789 B2
• Filed: 04/29/2014
• Issued: 05/09/2017
• Est. Priority Date: 06/03/2013
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Miyazaki, Satoshi
• Primary Examiner(s): Woldekidan, Hibret
• Application Number:
  US14/264,582
• Publication Number:
  US 20140355981A1
• Time in Patent Office: 1,106 Days
• Field of Search: 398 38, 398 32, 398 33, 398 45, 398 82, 398 83, 398 93, 398 94, 398197, 398195, 398192, 398162, 398158
• 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 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 including a processor that reduces an optical level of output light from the first port of the splitter to be monitored so that an alarm for testing of an alarm function is detected at a fourth port coupled to the first port of the splitter via a transmission path 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 of the splitter so as to maintain the optical level of output light from the third 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 photo detector 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,

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 photo detector issues the alarm.