GPON optical modules typically have output power ranges from 1.5 dBm to 10 dBm depending on the module class, with corresponding receiver sensitivities to ensure reliable signal transmission.

Typical Output Power by Module Class

GPON modules are classified according to ITU-T G.984 standards, with each class having specific optical power ranges:

• Class B+: Transmit power 1.5–5 dBm, receiver sensitivity -28 dBm
• Class C+: Transmit power 3–7 dBm, receiver sensitivity -32 dBm
• Class C++: Transmit power 6–10 dBm, receiver sensitivity -35 dBm These ranges ensure that the optical signal from the OLT is strong enough to reach the ONU without exceeding the ONU's saturation threshold, which could cause signal distortion or module damage .

Key Parameters Affecting Output Power

1. Transmitting Optical Power (Tx Power): Determines the strength of the signal sent from the OLT or ONU. It must be within the ONU's receiver sensitivity range to maintain proper communication .
2. Receiving Optical Power (Rx Power): Indicates the power level received by the ONU or OLT. If it falls below the minimum threshold, alarms may trigger, and packet loss or registration failures can occur .
3. Alarm Thresholds: GPON systems allow configuration of upper and lower optical power thresholds. Exceeding these thresholds triggers alarms to prevent module damage or service degradation .
4. Saturation Power: The maximum optical power the ONU can safely receive. Exceeding this can lead to signal distortion or module burnout .

Practical Considerations

• Ensure OLT transmit power is higher than the ONU's minimum sensitivity but below its saturation limit.
• Monitor real-time optical parameters such as Tx power, Rx power, temperature, and bias current to maintain network reliability .
• Different GPON modules may have wavelength compatibility requirements, so always verify module compatibility with the OLT/ONU devices . By adhering to these output power specifications and monitoring thresholds, GPON networks can maintain high reliability, prevent optical module damage, and ensure consistent service quality.