400G Optics – Form Factors QSFP-DD vs OSFP vs CFP8
With the rapid advancement of 5G and 400G Ethernet making waves in Data Centers, an important question needs to be answered. This question is – Which 400G Optics Form Factor is the best for linking the past to the future?
When talking about transceivers, form-factor and its capabilities play a vital role. Adding to this, widespread adoption of 400G Optics is the next big step. That is why there is a debate on the best-suited factor for 400G Optics. The main competing form factors are QSFP-DD, OSFP, and CFP8. 400G Optics Form Factors shows a comparison between the said three form factors.
Each form factor has advantages and drawbacks. There will be applications and solutions that will utilize one of these QSFP-DD, OSFP, or CFP8 form factors to ensure maximum efficiency.
400G Optics – QSFP-DD vs OSFP vs CFP8 :
| Dimensions | 18.35mm× 8.5mm x 89.4mm | 22.58 mm × 13mm x100.4 | 40 mm × 9.5 mm × 102 mm |
|---|---|---|---|
| Port Density 1U | 36 | 32 | 16 |
| Power Consumption | ≤12W | ≤15W | ≤28W |
| Future to 800G | No | Yes | Yes |
| Backwards to QSFP | Yes | With Adapter | No |
| Alliance | QSFP-DD MSA | OSFP MSA | CFP MSA |
However, QSFP-DD in its current state looks like a favorite due to how much of the industry is in love with the QSFP form-factor and 100G QSFP28 modules. Additionally, QSFP-DD provides the highest Port Density compared to the competition. This gives QSFP-DD manufacturers much greater appeal than the new OSFP form-factor modules and bulkier CFP8 modules. Furthermore, QSFP-DD is developed to ensure backward compatibility with QSFP from-factor ports. Allowing for a more gradual upgrade from 100G QSFP28 systems to 400G capable solutions.
Nevertheless, Power Consumption – Maximum amount of Power that can be Dissipated by the module without damaging internal components – is of great importance. Main Power Consumption comes from the Micro-Controller and PAM4 DSP that have to perform at mind-boggling speed. Solutions are developed to improve the efficiency of QSFP-DD to ensure internal component heating will be reduced below critical. An upside is the emergence of practical and applied EUV (Extreme Ultraviolet Lithography) that will reduce the power draw of logic components.
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400G QSFP-DD Optical Transceivers
Unlock next-level performance with 400G QSFP-DD modules, engineered for high-density, high-speed data transmission in modern data centers. With double-density architecture, QSFP-DD supports 400G in a compact form, providing efficient scalability and optimal power usage for next-gen network demands. Our 400G QSFP-DD portfolio offers connectivity from short to long range. Here you will also find the 400G QSFP-DD Coherent section for high-speed data transfer, and ultra-reliable connectivity. Explore how 400G QSFP-DD technology is powering innovation and enabling the next era of connectivity across industries.
400G OSFP & OSFP112 Optical Transceivers
400G OSFP and OSFP112 transceivers deliver 400 Gigabit Ethernet connectivity in the OSFP form factor, built for data center spine-leaf fabrics, campus backbones, and metro links. Both variants share the same cage and the same optics. The difference sits entirely on the host side, in how many electrical lanes the module expects from the connected switch or NIC. OSFP modules use a 400GAUI-8 electrical interface: eight lanes at 53.125 Gbps PAM4, converted by an internal gearbox to four 100G-class optical lanes. These suit host platforms built on 50G-class SerDes. OSFP112 modules use 400GAUI-4: four lanes at 106.25 Gbps PAM4 mapped one-to-one onto four optical lanes with no gearbox, for platforms built on 100G-class SerDes. Because the optical side is identical, an OSFP DR4 and an OSFP112 DR4 can interoperate across the fiber when the PMD and link parameters match at both ends. The form factor choice is dictated by what the host equipment presents electrically, not by what sits at the far end of the link. Our portfolio spans the full range of reach requirements. Short-reach VR4 and SR4 modules handle intra-rack connections over multi-mode fiber at 50m and 100m, while DR4 and DR4+ variants extend parallel single-mode connectivity to 500 meters and 2km. For cross-building and metro links, FR4 and LR4 modules provide CWDM4-based transmission reaching 2km and 10km respectively. The OSFP112 modules in this range use a flat-top (RHS) design, relying on a riding heat sink integrated into the host cage, while the OSFP modules are finned-top and cool through their own fin stack. Some cages accept only one style, so confirm the exact port specification before ordering. All modules support DDM/DOM diagnostics and comply with OSFP MSA standards. Confirm the electrical interface and heatsink variant the platform expects before ordering. The module reports the same identifier for the finned-top and flat-top heatsink variants, so it will not flag a heatsink mismatch on its own.