when cannot set gain of OAU boards on OSN8800 equipment

Hello friend!

Root Cause:

The DCM fibers connected to the RDC and TDC ports of the OAU, had too much attenuation.
 

You can try below steps:

1. Reset to the OAU board.
2. Check laser status of the OAU board.
3. Check optical power in the OAU board.
4. Check attenuation between RDC and TDC ports of the OAU board and the DCM.

Thanks!

Hello, friend!

The OAU board uses a preset nominal gain. The total gain of the board PA and BA is fixed. The nominal gain of the board is adjusted based on the intermediate insertion loss. The intermediate insertion loss consists of two parts: VOA attenuation and DCM loss introduced between the TDC and RDC. If the TDC insertion loss and the RDC are too large, a large nominal gain cannot be set. In this case, the gain spectrum of the board deteriorates.

Maximum gain of the board = Maximum gain of the board – VOA attenuation – Insertion loss between the TDC and RDC

The VOA attenuation is automatically adjusted by the software. You do not need to adjust the attenuation.

Set the gain of the TN11OAU101 board. The following uses the TN11OAU101 board as an example:

When loss is introduced by TDC and RDC, a DCM with an insertion loss of 7 dB is connected.

In this case, the maximum gain of the board is 31 dB-7 dB = 24 dB.

If the board is set to 24 dB, the VOA attenuation is 0 dB (automatically adjusted by the software).

If the board is set to 22 dB, the VOA attenuation is 2 dB.

When the TDC and RDC are short-circuited, the board gain can be set to the maximum gain of 31 dB.

A certain loss can be allowed between the TDC and the RDC, but the loss cannot be greater than 0.5 dB. Keep the TDC and RDC optical ports clean.

If the intermediate insertion loss is too large, it exceeds the maximum intermediate insertion loss of the board. The board gain may not reach the nominal gain. In this case, the board locks the gain based on the intermediate insertion loss. The intermediate insertion loss can be obtained by subtracting the actual gain upper threshold from the nominal gain upper threshold.

Thanks!

Hello, friend!

Maximum gain of the board = Maximum gain of the board – VOA attenuation – Insertion loss between the TDC and RDC

The VOA attenuation is automatically adjusted by the software. You do not need to adjust the attenuation.

Set the gain of the TN11OAU101 board. The following uses the TN11OAU101 board as an example:

When loss is introduced by TDC and RDC, for example, a DCM with insertion loss of 7 dB is connected.

In this case, the maximum gain of the board is 31 dB-7 dB = 24 dB.

If the board is set to 24 dB, the VOA attenuation is 0 dB (automatically adjusted by the software).

If the board is set to 22 dB, the VOA attenuation is 2 dB.

When the TDC and RDC are short-circuited, the board gain can be set to the maximum gain of 31 dB.

A certain loss can be allowed between the TDC and the RDC, but the loss cannot be greater than 0.5 dB. Keep the TDC and RDC optical ports clean.

If the intermediate insertion loss is too large, it exceeds the maximum intermediate insertion loss of the board. The board gain may not reach the nominal gain. In this case, the board locks the gain based on the intermediate insertion loss. The intermediate insertion loss can be obtained by subtracting the actual gain upper threshold from the nominal gain upper threshold.

Thanks!