Broadcom's 800G Optical Platform Solutions
Content and images in this article are sourced from: https://www.broadcom.com/blog/800g-optical-platform-solutions
Broadcom's IC solutions have long been a bellwether for optical communications product development. With its 100GbE and 400GbE portfolios well established, 800GbE has been the topic major optical vendors have been talking about for the past few years.
Today's mainstream Ethernet switch ICs, such as Broadcom's Tomahawk 3 (TH3) and Tomahawk 4 (TH4), run at 50Gbps lane rates driven by 50G PAM-4 technology. When these switch ICs are used in chassis-based systems, a 16:16 retimer PHY is typically needed to ensure 16x50G PAM-4 data is carried from the switch to the optical interface.
For optical transceivers, Broadcom offers a 400G 8:4 gearbox PHY that converts 50G PAM-4 electrical signals into 100G-per-lambda optical signals to drive the optoelectronic components. Paired with VCSELs or EMLs and multimode fiber (MMF) or single-mode fiber (SMF), it supports a range of transmission distances. The figure below illustrates transmission for the various 400G interfaces.
800GbE applications must support 100Gbps lane rates. Broadcom's Tomahawk 4-100G (TH4-100G) uses 100Gbps signaling per lane, allowing 1:1 conversion between electrical and optical I/O. So for 800GbE optical modules, all that's needed is an 800G 8:8 PHY such as Broadcom's BCM8780x to connect 100G PAM-4 electrical I/O to 100G optics — and by building on the existing 100G single-lambda optical components already proven in 400GbE systems, 800GbE can be realized.
Comments