Pulling an 800G optical module out of an air-cooled rack and immersing it directly in coolant—this sounds like "torture" for precision optical devices, but in 2026 AI data centers are turning this into standard practice. The reason is simple: when the heat flux density of GPU clusters exceeds 100W/cm², traditional air cooling can no longer effectively remove heat, and immersion liquid cooling has changed from an "optional solution" to the "only choice." Optical modules, as the throat through which data flows, must prove in this new environment that they can not only "stay alive" but also "run fast."
The challenges that liquid-cooling environments pose to optical modules are multidimensional. The first is chemical compatibility of the coolant—different immersion coolant formulations have very different effects on optical module housing materials, fiber connectors, and sealing structures. The second is stability of optical performance: the refractive index of coolant differs from that of air, and optical path designs need to be re-verified for immersion conditions. The third is long-term reliability: under the dual pressure of thermal cycling and liquid immersion, MTBF data for modules needs to be re-evaluated based on actual liquid-cooling environments, rather than simply using test results from the air-cooling era.
From a selection perspective, 800G optical module products specifically designed for liquid-cooling environments have already appeared on the market. For example, an immersion 800G OSFP DR8 module based on a silicon photonics solution has power consumption controlled below 15 watts, supports 500-meter single-mode fiber transmission, and has completed SI parameter verification under liquid-cooling conditions. The value of such products lies in the fact that they are not simply air-cooled modules "stuffed into" coolant, but have considered the particularities of immersion environments from the design stage.
For procurement teams at North American data centers, the certification checklist for liquid-cooled optical modules needs to be longer than that for traditional optical modules. In addition to conventional IEEE 802.3 protocol compliance, MSA packaging specifications, and FCC and UL certifications, attention also needs to be paid to coolant compatibility test reports, optical eye diagram test data under immersion conditions, and at least six months of accelerated aging data in liquid-cooling environments. These materials are not "nice-to-haves," but hard thresholds to ensure that your liquid-cooled cluster will not experience localized thermal runaway due to the failure of a single optical module.
Another trend worth watching is the combination of liquid cooling and LPO (Linear Pluggable Optics) technology. LPO solutions greatly reduce module power consumption by removing DSP chips, and some implementations can reduce 800G module power consumption to below 8 watts. In liquid-cooling environments, low power consumption means not only less heat dissipation burden, but also longer coolant service life and lower overall operating costs.
If you are planning an AI data center expansion for the second half of 2026 or 2027, supplier evaluation for liquid-cooled optical modules should already be on your procurement timeline. In this field, the technical verification cycle is longer than for traditional optical modules. Locking in supply partners that have been verified in liquid-cooling environments in advance is far wiser than waiting until the data hall is built to look for modules.
