If the transmit power of the optical module is still low, install another optical module on the interface or move the problematic optical module to another interface to determine whether the optical module itself is faulty. An optical module's actual transmit power measured by an optical power meter is lower than the nominal transmit power of the power module. Even minor deviations—whether too high, too low, or unstable—can impact signal integrity, trigger service alarms, or interrupt traffic on DWDM, OTN, or long-haul optical line systems. It mainly consists of TOSA, ROSA, and a PCBA board. Fault identification can be achieved by: These methods help isolate faulty components efficiently.