Server optical module model

Server optical modules are pluggable transceivers installed in network adapters (NICs) to enable fiber-optic communication between servers and switches.

Overview of Optical Modules

An optical module is a photoelectric converter that transforms electrical signals into optical signals and vice versa, operating at the physical layer of the OSI model. It typically consists of a transmitter optical subassembly (TOSA) with a laser diode or LED, a receiver optical subassembly (ROSA) with a photodetector, functional circuits, a control PCB, housing, and optical/electrical interfaces. These modules support various transmission distances and speeds, such as 10Gbps, 25Gbps, 100Gbps, and beyond, depending on the design and form factor (SFP, SFP+, QSFP, CFP, XFP, or XPO) .

Integration with Servers

Servers generally do not have direct ports for optical modules. Instead, optical modules are inserted into network adapters (NICs), which are then installed in the server's PCIe slots. Popular NIC manufacturers include Intel, Broadcom, Mellanox, and QLogic, each with specific compatibility requirements for optical modules. Selecting a module requires confirming that it matches the NIC's supported types and speeds .

Common Optical Module Models

• SFP/SFP+: Small form-factor pluggable modules for 1–10Gbps connections, widely used in enterprise servers.
• QSFP/QSFP28: Quad small form-factor pluggable modules for 40–100Gbps, suitable for high-density server interconnects.
• CFP/XFP/X2/XENPAK: Larger modules for 100Gbps and above, often used in data center aggregation switches.
• XPO (eXtra-dense Pluggable Optics): Next-generation modules designed for AI data centers, delivering up to 12.8Tbps per module with liquid cooling and high front-panel density .

Selection Considerations

When choosing a server optical module, consider:

1. NIC compatibility: Ensure the module is supported by the installed network adapter.
2. Transmission distance: Modules are available for short-range (SR), long-range (LR), and extended-range (ZR) applications.
3. Data rate: Match the module's speed with server and switch capabilities.
4. Form factor: Ensure the module fits the NIC slot and meets density requirements.
5. Power and cooling: High-speed modules like XPO may require liquid cooling and higher power budgets .

Conclusion

Server optical modules are essential for high-speed fiber connectivity, installed via NICs rather than directly on the server motherboard. Choosing the right model involves matching the form factor, speed, distance, and NIC compatibility. Advanced modules like XPO are emerging for AI and hyperscale data centers, offering unprecedented bandwidth and density while maintaining pluggability for easy upgrades and maintenance.