交换机显示光功率与实际测得的光功率差距大

[H3C]display transceiver diagnosis interface

GigabitEthernet1/0/25 transceiver diagnostic information:

  Current diagnostic parameters:

    Temp.(°C) Voltage(V)  Bias(mA)  RX power(dBm)  TX power(dBm)  

    35         3.31        4.53      -40.00         -5.08          

  Alarm thresholds:

          Temp.(°C) Voltage(V)  Bias(mA)  RX power(dBm)  TX power(dBm)  

    High  81         3.80        44.00     0.00           3.00           

    Low   0          2.81        1.00      -16.99         -12.50         

GigabitEthernet1/0/26 transceiver diagnostic information:

The transceiver does not support this function.

GigabitEthernet1/0/27 transceiver diagnostic information:

  Current diagnostic parameters:

    Temp.(°C) Voltage(V)  Bias(mA)  RX power(dBm)  TX power(dBm)  

    43         3.35        4.76      -40.00         -5.51          

  Alarm thresholds:

          Temp.(°C) Voltage(V)  Bias(mA)  RX power(dBm)  TX power(dBm)      交换机型号华三（H3C） S3100V3-28TP-SI    光模块SFP-GE-SX-MM850-A

是不是还要设置什么  请教大佬们