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Instead of amplifying optical power, an SS62COA board attenuates the optical power by 2 dB

Publication Date:  2012-07-25 Views:  46 Downloads:  0
Issue Description
An SS62COA board reports the OUT_PWR_ABN alarm. On the SS62COA, the input optical power is �21 dBm and the output optical power is �23 dBm. That is, instead of amplifying the optical power, the SS62COA attenuates the optical power by 2 dB.
Alarm Information
OUT_PWR_ABN 
Handling Process
1. Increase the optical attenuation at the upstream site to decrease the input optical power of the COA to a value between �39 dBm and �26 dBm, for example, �30 dBm. The COA can then work properly.
2. Alternatively, retain the original input optical power of the COA, �21 dBm. Increase the locked output optical power of the COA from the default �26 dBm to a value between �21 dBm and �8 dBm with the above command; 
Root Cause

 By default, the locked output optical power of the COA is �26 dBm. The maximum on-off gain of the COA is 13 dB.
The COA works properly only when the upstream site increases the optical attenuation and thus decreases the input optical power of the COA to less than �26 dBm.
Alternatively, increase the locked output optical power of the COA to more than �21 dBm with the PTP command.
For 62COA the query and set the locked output optical power command is as follows:
Query command:
:ptp:bid,12,ee,1; //query command
>Para[0]bid: slot ID (in hex)
>Para[1]12,means query,always 12
>Para[2]ee, Command ID of locked gain
>Para[3] Channel ID: always 1;

Set command:

:ptp: bid, ee, 1, 1, higher bits (in hex), lower bit0s (in hex),a5;
>Para[0]bid: slot ID (in hex)
>Para[1]ee, Command ID of locked gain
>Para[2] Channel ID: always 1;
>Para[3] Sign bit: 0, plus; 1, minus, has to be 1,otherwise the command can not be executed;
>Para[4] Higher bits (in hex) of the power to be locked
>Para[5] Lower bits (in hex) of the power to be locked
>Para[6] a5 --fixed check bit,its value has to be a5;
Usually 10 times of optical power is the value which board software shows;so for -16db, higher bits should be '0',lower bits should be 'A0';

But after the board hard reset, it will return to defaulted value -26dbm,command ' :ptp:bid,79,e7,e7,e7,e7,e7,e7'is needed to save this setting;

Suggestions
1. 62COA is an amplifier with a locked output optical power.the input optical power must be between -20~-38dbm,this is input optical power of COA board;
Otherwise, the COA cannot work properly.
2. The maximum on-off gain of the COA is 13 dB.so while the input optical power meet the requirement,output optical power can be set according to the gain,
output optical power should more than input optical power,otherwise, an alarm will be reported;

END