In optical module procurement decisions, thermal control is often overlooked as a "technical detail." But the latest research report from CITIC Securities offers a very different judgment: as 800G optical modules enter large-scale volume production and 1.6T enters its first year of ramp-up, per-module power consumption and requirements for temperature control precision are rising significantly. Optical module thermal control is upgrading from a "supporting link" to a "performance-determining link."
The logic behind this judgment is not complicated. The transmission performance of optical modules depends heavily on the stability of the laser's operating temperature. For every 1°C increase in temperature, the laser wavelength drifts by about 0.1 nm. In DWDM dense wavelength division multiplexing systems, this drift directly leads to channel crosstalk and higher bit error rates. When per-module power consumption climbs from around 15W in the 800G era to 30W or even higher in the 1.6T era, the impact of temperature control precision on transmission performance is sharply amplified.
CITIC Securities divides the optical module thermal control system into a three-layer architecture. Chip-level precise temperature control uses Micro-TEC and ceramic substrate heat sinks, acting directly on high-heat-generating components such as lasers and modulators; interfacial heat conduction relies on TIM gel or graphene gaskets to establish an efficient heat conduction path between the chip and the heat dissipation structure; module-level heat spreading is achieved through VC vapor chambers or cold plates, conducting heat from inside the module to the external cooling system.
In terms of the competitive landscape, core links such as TEC and ceramic substrates have long been dominated by Japanese manufacturers, but domestic Chinese manufacturers are accelerating breakthroughs, leaving broad room for domestic substitution. A CICC research report recommends focusing on opportunities in optical module VC vapor chambers, liquid-cooled cages, and liquid cooling for co-packaged switches. It points out that as optical module speeds upgrade, traditional air cooling is gradually approaching its heat dissipation limits, and the penetration rate of high-efficiency cooling solutions such as VC vapor chambers and liquid-cooled cages is expected to accelerate.
A GF Securities research report is also bullish on this trend, believing that data centers are the most important application scenario for liquid cooling. With the rapid development of intelligent computing centers, liquid-cooled switches and liquid-cooled optical modules in the network transmission segment are seeing substantial new demand.
