PAM4

  • 200G QSFP56 AOC and 200G QSFP-DD AOC

    Why does the 200G QSFP56 AOCuse PAM4 modulation butthe200G QSFP-DD AOCuse NRZ modulation to provide solutions up to 200G aggregate? PAM4 (Pulse Amplitude Modulation 4) enables a PAM4 waveform to transmit twice as many bits as an NRZ waveform at the same symbol rate. The 200G QSFP-DD AOC employs eight lanes that operate up to 25Gbps NRZ modulation each to provide bandwidth up to 200Gbps. However, the 200G QSFP56 AOC have only four-lane electrical interfaces, so it is required to use PAM4 modulation up to 50Gbps per lane so as to provide bandwidth up to 200 Gbps. The different of 200G QSFP56 AOC and 200G QSFP-DD AOC will be introduced as follow. The 200G AOCs are suitable for short distances and offer a cost-effective solution to connect within racks and across adjacent racks. Gigalight offers a full range of 200G AOCs in both QSFP-DD and QSFP56 form-factors. The Gigalight 200G AOC product line includes 200G QSFP-DD AOC,200G QSFP-DD to 2x 100G QSFP28 AOC,200G QSFP-DD to 4x 50G QSFP28 AOC,200G QSFP56 AOC,200G QSFP56 to 2x 100G QSFP56 AOC,200G QSFP56 to 4x 50G SFP56 AOC. All of…

    July 4, 2019 0 0 3
  • Trends in 400G Optics for the Data Center

    Data Center Connections are Driving Optics Volume Due to the ongoing large increase in bandwidth demand, data center connections are expected to move from 25G/100G to 100G/400G. Within the Data Center Racks: 10GE is still being deployed, 25GE is starting to be deployed in volume, and 100GE or 50GE will follow. Between Data Center Racks: 40GE is still being deployed, 100GE is starting to be deployed in volume, and 400GE will follow at large cloud service providers. Long Spans, DCI and WAN: 10G DWDM/tunable is still being deployed, 100G/200G coherent starting to be deployed, and 400G coherent will follow—then 600G or 800G. Forecasted Data Center Ethernet Port Shipments Forecasted 400GE Shipments by Market Segment Mainstream 1RU Ethernet Switch Roadmap 3.2Tb/s switches based on 100G QSFP28 modules are being deployed in cloud data centers today. Given the multiple switching ICs expected to be available, the market is likely to be fragmented in the future. Large growth in bandwidth demand is pushing the industry to work on technologies and standards to support future 12.8T switches. 400G and Next-Gen 100G Ethernet Optical Standardization…

    May 13, 2019 0 0 1
  • The Research of WDM-PON Technology for 5G Fronthaul Applications

    At present, the research on 5G network has formed the first wave, entering into the key stage of technical standard research and R&D(research and development)test. Compared with 4G technology, the performance of 5G network has been significantly improved in terms of handling capability, latency, the number of connection, etc. At the same time, 5G has new challenges for the fronthaul network, such as a lot of new demands on dense optical fiber deployment, higher transmission broadband and low latency. WDM-PON combines the characteristics of WDM technology and PON topology. It has the advantages such as high bandwidth, low latency, saving fiber, simple operation and management, low cost, etc. It has its unique advantages in the application of 5G fronthaul, paid great attention in recent years. Limited by standard and technical maturity, the rate of WDM-PON commercial network or experimental prototype is relatively low, the wavelength of single wave usually not exceeding 10Gbps. In 2015, ITU-T defined the architecture and index of WDM-PON (PtP WDM option) in the NG-PON2 standard. Simultaneously, the line rate was defined to 10Gbps; wavelength assignment information…

    April 12, 2019 0 0 3
  • 50G PAM4-based Optical Transceiver Technologies

    With the PAM4 encoding technology, the amount of information transmitted on 50G PAM4-based optical transceivers within each sampling cycle doubles. A 25G optical component can be used to achieve a 50Gbps transmission rate, reducing the costs of optical transceivers. 50G PAM4 applies to multiple scenarios, such as single-lane 50GE PAM4 optical transceivers, 4-lane 200GE optical transceivers, and 8-lane 400GE optical transceivers. Functions This section introduces the functions of a single-lane 50GE PAM4 optical transceiver. The working principle of a 50GE PAM4 optical transceiver is described as follows: In the transmit direction, the PAM4 encoding chip aggregates two 25Gbit/s NRZ signals into one 25GBaud PAM4 signal. The laser drive chip amplifies the PAM4 signal, and the 25Gbps laser converts the electrical signal into a 25GBaud(50Gbps) single-wavelength optical signal. In the receive direction, the detector converts the 25GBaud single-wavelength optical signal into an electric signal. The electric signal is shaped and amplified, and then output to the PAM4 decoding chip. The PAM4 decoding chip converts the signal into two 25Gbps NRZ signals. The 50GE PAM4 optical transceiver uses the QSFP28 encapsulation mode, LC optical interfaces,…

    April 11, 2019 0 0 10

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