The BA2 single board at station A reported an abnormal alarm, and the fault was lifted after adjusting the input optical wavelength to 1530nm to 1560nm.

Products

OptiX OSN1500

Fault category

PUM_BCM_ALM

OUT_PWR_ABN

Other

Phenomenon Description

The OptiX OSN 1500s at two sites A and B form a 1+1 Linear Multiplexing Segment for protection. the single boards at site A include: SLD4 single board, CXL4 (master and standby), and twoBA2 single boards. the single boards at site B include: SLD4 single board, CXL4 (master and standby), and oneBA2 single board. the SLD4 single boards have an optical interface of the Ve-4.2 type, and the CXL4 single boards have the L-4 . 1 type, and the BA2 boards output optical power of +14 dBm. The interface type of SLD4 single board is Ve-4. 2, the optical interface type of CXL4 single board is L-4.1, and the output optical power of BA2 single board is +14dBm. The distance between A and B stations is 120km.

When the fiber is connected for tuning and testing, it is found that there are abnormal alarms PUM_BCM_ALM and OUT_PWR_ABN on the two BA2-S boards at station A, and there is no alarm on the BA2-D board at station B.

Cause analysis

PUM_BCM_ALM is the pump laser drive current overrun alarm. This alarm is generated when the drive current exceeds the built-in maximum operating current.

OUT_PWR_ABN is the output optical power abnormal alarm. This alarm is generated when the output optical power exceeds the output optical range ( BA: +13dBm to +15dBm, PA: gain <19dB ) when the input light is within the normal range ( BA: -6 to +3dBm, PA: -36dBm to -10dBm ), the operating current is not alarmed, and there is no adjustment. The general possible causes are: aging or failure of the EDFA module, damage to the drive circuit or damage to the drive current detection circuit.

Operation Procedure

Check the performance value of one BA2-S single board in station A with the network manager.

In the main topology, select the network element of station A, right-click it, and select "Network Element Manager".

Select a BA2 board in the board list of the Element Manager.

Select "Performance > Current Performance" in the function tree.

In the right part, select "Physical Quantity", select "Luminous Power" and "Received Power", and select "Show Current Value" in "Options". In the "Options", select "Show Current Values".

Click "Query".

Analyzing the data, the input optical power of BA2 board is -2.6dBm, which is within the normal range ( -6dBm to +3dBm ), but the output optical power is +12.9dBbm, which is not within the normal range ( +13dBm to 15dBm ), so the OUT_PWR_ABN alarm is reported. is 188mA, so the PUM_BCM_ALM is reported.

Replace a BA2 board.

Check the alarm on the network management. Find that OUT_PWR_ABN and PUM_BCM_ALM alarms are not canceled. Troubleshoot the single board.

Check the fiber connection. It is found that the BA2 veneer at station A is connected to the CXL4 veneer. the output optical wavelength of the CXL4 veneer is 1280 nm to 1335 nm, which is not within the normal amplification range of 1530 nm to 1560 nm of the EDFA, and it cannot correctly amplify the input optical.

Unplug the pigtail connecting the CXL4 veneer and the BA2 veneer.

Connect the SLD4 veneer board and BA2 veneer board with the pigtail fiber.

Query the current network element alarm. Abnormal alarms are automatically released.

Reference Information

Be sure to pay attention to the input optical signal wavelength and power, output optical signal power and other related indexes of the BA2/BPA veneer in engineering or maintenance.

The working wavelength of PA module is 1550.12nm, when its working wavelength deviates far from 1550.12nm, the input optical power value and output optical power value will produce a large error. Its normal input optical power range is -36dBm ~ -10dBm, the input optical power is too large to reduce the service life of the laser, the input optical power is too small will lead to the EDFA module can not be amplified normally.

The input optical wavelength of BA module is 1530nm～1560nm, i.e. 1550nm window wavelength. If it is not within this range, the input optical signal cannot be amplified correctly, and the PUM_BCM_ALM alarm and OUT_PWR_ABN alarm may occur. In addition, the normal input optical power range of the BA module is from -6dBm to +3dBm; if the input optical power is not within this range, an abnormal input optical power alarm will be generated, and the service life of the laser may be reduced if the input optical power is too large.