800G Technology Overview

800G transceivers are advanced optical modules used for ultra-high speed 800Gbps data transmission. They are essential in modern data centres, cloud computing, high performance computing (HPC) and AI environments. 800G technology comes in two form factors: Octal Small Form-factor Pluggable (OSFP) and Quad Small Form-factor Pluggable – Double Density (QSFP-DD). While they are both capable of 800Gbps transmission, there are some key differences:

OSFP

• Larger footprint – refer to our knowledge base for further details
• Built in heat dissipation technology
• Maximum power consumption typically <15W
• QSFP compatible with an adaptor
• Eight lanes running at 100Gbps each
• Developed alongside 400G technology
• Finned top, Flat top and Closed top options
• Connectors – Duplex LC, MPO-12, MPO-16
• OSFP MSA Specification

QSFP-DD

• Smaller footprint – refer to our knowledge base for further details
• Heat dissipation technology is dependent on external hardware
• Maximum power consumption typically <12W
• Backwards compatible with previous QSFP form factors
• Eight lanes running at 100Gbps each
• Connectors – Duplex LC, MPO-12, MPO-16
• QSFP-DD MSA Specification

QSFP-DD backward compatibility allows for seamless integration with existing QSFP based systems, allowing data centres to incrementally scale to higher speeds without requiring a complete overhaul of hardware. OSFP modules have a larger physical footprint and so are not compatible with QSFP technology without an adaptor. The OSFP form factor was designed alongside 400G, meaning they offer a more future-proof solution for new infrastructure, supporting 1.6T developments and beyond.

OSFP Types

• Finned top – A heat sink made up of thin extended fins is attached to the top of the module, increasing the surface area and pulling heat away from the module.
• Flat top/Riding Heat Sink (RHS) – Developed by NVIDIA® for use in Network Interface Cards (NICs). There is no heat sink on the transceiver itself; instead, a riding heat sink is integrated in the OSFP module cage.
• Closed top – Similar to finned top, but with an additional metal cover over the fins. This enhances heat dissipation by increasing airflow along the entire transceiver and enabling better heat conduction from the fins.

See the OSFP MSA Rev 5.1 for more information.

Modulation Types

800G transceivers use advanced modulation techniques for efficient high speed data transmission. PAM4 (Pulse Amplitude Modulation 4-Level) is used in these modules as it allows for double the transmission speed compared to NRZ (Non-Return to Zero) common in technology up to 200G. Alternatively, coherent modulation methods like QPSK, 8-QAM or 16-QAM may be used for applications requiring ranges of hundreds or even thousands of kilometres. Unlike PAM4, which only uses amplitude variations, coherent optics uses the phase, polarisation and amplitude of light signals allowing for higher spectral efficiency and extended transmission distances. These modulation formats are common in ZR and ZR+ transceivers and long range DWDM modules. Find out more about coherent technology here.

 Optical Standards

Other OSFP Standards defined in MSA:

• DR8.2
• SR4.2
• DR4.2
• FR4-500
• 2VR/SR SWDM4

Below are some technical images taken from the relevant MSA documents demonstrating how these form factors work in 800G applications:

800G DR8 Block Diagram from OSFP MSA

800G SR8 Block Diagram from OSFP MSA

800G FR4 Block Diagram from OSFP MSA

800G FR8/LR8 Block Diagram from OSFP MSA

QSFP-DD Application Reference Model from QSFP-DD MSA

 

See our knowledge base article to find out more about optical standards for lower data rates.

Benefits of 800G

The high bandwidth capacity of 800G transceivers supports the growing demand for AI driven workloads, hyperscale data centres, and HPC applications across many industries. They offer reduced cost per bit transferred compared to previous technologies, making them a key solution for data intensive environments. Although they generally consume more power than 400G modules, advancements in Digital Signal Processing (DSP) and thermal management systems work to improve efficiency. Their scalability and support for both QSFP-DD and OSFP form-factors means 800G technology is well positioned for future advancements including the transition to 1.6Tbps and beyond.

800G Applications

• Hyperscale data centres
• AI and machine learning workloads
• 5G and future 6G networks
• High performance computing (HPC)
• Financial & trading networks
• Fibre backbone & subsea networks

ATGBICS offers a comprehensive range of 800G transceivers, DACs and AOCs in both OSFP and QSFP-DD form-factors, ensuring the right fit for any application.

View our range of 800G products