GPON optical module parameters

GPON optical modules are defined by key parameters including transmission power, reception sensitivity, bias current, operating temperature, and power supply voltage, with class B+ and C+ modules supporting 1.25 Gbps upstream and 2.5 Gbps downstream rates.

Key Technical Parameters

1. Transmission Power (Tx Power)

• Defines the optical power emitted by the module.
• Typical values for GPON OLT modules: +0.5 dBm to +5 dBm for class B+, +2 dBm to +7 dBm for class C+ .
• Critical for ensuring sufficient signal reaches ONUs over the fiber network. 2. Reception Sensitivity (Rx Sensitivity)
• Minimum optical power required for proper signal reception.
• Class B+ modules: around -28 dBm, Class C+ modules: around -31 dBm .
• Determines the maximum reach and splitting ratio of the PON network. 3. Overload Optical Power
• Maximum optical power the receiver can tolerate without errors.
• Typically -8 dBm to 0 dBm, depending on module class . 4. Bias Current
• Current applied to the laser diode to maintain proper operation.
• Monitored to detect laser degradation or failure . 5. Operating Temperature
• Modules are designed to operate reliably within 0°C to 70°C for commercial grade, and -40°C to 85°C for extended industrial grade . 6. Power Supply Voltage
• Standard GPON SFP modules operate at 3.3 V DC, with tight tolerances to ensure stable operation . 7. Bandwidth and Data Rates
• Upstream: 1.25 Gbps, Downstream: 2.5 Gbps for standard GPON modules .
• Maximum service bandwidth may reach 1.1 Gbps upstream and 2.3 Gbps downstream in practical deployments . 8. Power Consumption
• Typical SFP modules consume up to 1.9 W per port .

Module Classes

• Class B+: Standard GPON modules with moderate reach and splitting ratio.
• Class C+: Higher power modules for extended reach or higher split ratios.
• Future Evolution: XG-PON and XGS-PON modules support higher asymmetric or symmetric rates (up to 10 Gbps downstream) while maintaining similar optical parameters .

Monitoring and Alarms

GPON modules support Digital Optical Monitoring (DOM) to track:

• Transmitting and receiving optical power
• Bias current
• Module temperature
• Supply voltage Alarms can be configured for thresholds to prevent service degradation or ONU registration failures .

Summary

GPON optical modules are characterized by precise optical power ranges, sensitivity, bias current, temperature, and voltage specifications, which ensure reliable high-speed data transmission over fiber networks. Selection of module class (B+ or C+) depends on network reach, split ratio, and environmental conditions, while monitoring features help maintain network stability and performance.