A Quick Guide to 50G Optical Transceiver

NADDOD Jason Dec 23, 2022

The 50GE standard refers to the 50 Gbit /s Ethernet standard. The 50G optical transceiver refers to the optical transceiver with a transmission rate of 50 Gbit /s. As an important connector of the 10/100G Ethernet connection standard, 50Gbps per channel technology will be the foundation of the future 400Gbps (8*50Gbps) Ethernet standard. And it is widely expected to replace the existing 10Gbps rate.

In an effort to counter the IEEE standard, the 25G Ethernet Alliance announced that its initial work on single-channel 25Gbps Ethernet and dual-channel 50Gbps Ethernet standards will be free of royalty charges. The 50GE standard will address connectivity between the server network interface controller in the data center and the ToR switch at the top of the rack, including physical layer and MAC layer requirements such as virtual channel adjustment, auto-negotiation, FEC, and more.

In the 5G era, 50G wireless optical transceivers will be commercially available on a large scale. It is estimated that 50 million 25G/50G optical modules will be needed in the 5G Fronthaul field alone. Meanwhile, the Middle-haul field is also a new growth point. In the future, 25G/50G interfaces need to be introduced into the access layer and aggregation layer of 5G, and interfaces with speeds of more than 100G need to be introduced into the core layer.

A Quick Guide to 50G Optical Transceiver

As shown in above figure, the demand for 50G optical transceivers may be underestimated. 50G transceivers using PAM4 modulation in the 5G Middle-haul scenario will be the main solution, and if widely adopted by 5G bearer networks, the demand will reach tens of millions in the next few years. The demand for 50G optical transceivers mainly comes from the construction of 5G bearer network. In the Data Center scenario, 50 Gbit/s optical transceivers are connected between the NIC and ToR in the super-large Data Center.

The 50G optical transceivers via single-mode fiber transmission are mainly concentrated in the telecommunications field: to save the cost of 5G deployment, combined with the base rate of 25Gbps, a small number of 50G optical transceivers based on PAM4 modulation will be used in the aggregation layer of the middle-haul & back-haul application in 5G transmission.

50G Optical Transceiver

NADDOD QSFP-50G-LR is a transceiver module designed for 10km optical communication applications. The transceiver incorporates one channel optical signal on 1310nm center wavelength, operating at 26Gbaud data rate. The transmitter path incorporates an EML Driver and a cooled EML together.

On the receiver path, the input optical signal is coupled to a PIN photo-diode detector. A DSP based gearbox is used to convert 2x 26Gbps NRZ signals to 1x 26Gbaud PAM4 signal. Also a 2-channels re-timer and FEC block are integrated in this DSP.

The electrical interface is compliant with IEEE 802.3bm and QSFP28 MSA in the transmitting and receiving directions, and the optical interface is compliant to IEEE 802.3cd 50GBASE-LR standard. Regarding to the power consumption, this transceiver has a maximum power consumption of only 4.0W.