What is the difference between Class B and Class C GPON SFP module

GPON stands for ‘Gigabit Passive Optical Network’. GPON is one of the key technologies that are being used in fiber-based (FTTx) access networks, including fiber to the home (FTTH), fiber to the business (FTTB), fiber to the curb (FTTC), etc.
Optical Line Termination (OLT) is the most important equipement in GPON systems. Modern OLTs use compact GPON SFP modules to achieve Triple-play GPON services.



What Is a GPON SFP Module?

SFP stands for ‘Small Form-factor Pluggable’. A GPON SFP is one type of Gigabit Optical Transceivers that are used in GPON system, which is compliant with ITU-T G.984.2 standard. It is a bidirectional module that has SC receptacle and works over simplex single-mode fiber optic cable.

A GPON SFP module transmits and receives signals of different wavelengths between the OLT at the ‘Central Office’ side and the ONT at the end users side. GPON SFPs utilize both the upstream data and downstream data by means of Optical Wavelength Division Multiplexing (WDM).

GPON SFP OLT module,1490nm 2.5Gbps continuous-mode transmitter with DFB laser,1310nm 1.25Gbps burst-mode receiver with APD-TIA.Gigabit Passive Optical Networks (G-PON) – OLT side


What is difference GPON SFP: Class B+ vs. Class C+ vs. Class C++

There are three types GPON SFP modules Class B+ GPON SFP and Class C+ GPON SFP and Class C+++ GPON SFP module used for GPON OLT.

The main difference is the output optical power. Class C++ GPON SFP module output optical power is about 7dBm, the Class C+ GPON SFP module output optical power is about 5dBm. Of course, their optical receiver sensitivity is also different. The Class C++ optical receiver sensitivity is best.

The detail specification parameter table comparision as below:

Type Class B+ GPON SFP module Class C+ GPON SFP module Class C++ GPON SFP module
wavelength Tx:1490nm Tx:1490nm Tx:1490nm
Rx:1310nm Rx:1310nm Rx:1310nm
rate Tx:2.488Gbit/s Tx:2.488Gbit/s Tx:2.488Gbit/s
Rx:1.244Gbit/s Rx:1.244Gbit/s Rx:1.244Gbit/s
Mini Output Power 1.5dBm 3dBm 6dBm
Mini Output Power 5dBm 7dBm 10dBm
Optical Receiver Sensitivity -28dBm -32dBm -35dBm
Optical Connector SC SC SC
Fiber type Single mode Single mode Single mode
Receiver Overload -8dBm -8 dBm -15dBm
Extinction Ratio 10dB 10dB 8.2dB


Post time: 2020-06-22


Lomoveishiy – Finland

I needed those to connect my PC on the third floor to have internet access in that room, and ISP installed their modem on the first floor only. After dropping fiber patch cables, plugged in all cables into these media converters at both sides, and link came up instantly. Was much easier than I thought!

Raymond – USA

Great experience – units worked straight out of the box – just needed plug in cables and we were done. I also like the possibility to enable jumbo frames, while we do not have a need for this feature at the current moment it’s great to have this option.

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