The Zhitong Finance App learned that Dongwu Securities released a research report saying that the optical module continues to iterate to 800G, 1.6T, and 3.2T, and power consumption continues to rise, but the cross-sectional size of the module itself has not changed much, causing the internal unit space heat load to continue to increase. The external heat dissipation of the optical module uses a switch cage as an interface to transfer the heat from the module case to the external radiator, and is finally discharged through an air cooling or liquid cooling system. Although the industrialization of new technologies such as silicon light and NPO is accelerating, traditional pluggable solutions still have a certain advantage and significant share in the scale-out scenario. Future optical module rate upgrades will drive an increase in overall thermal load, which will drive the demand for the entire cooling chain to upgrade.
The main views of Dongwu Securities are as follows:
High-speed optical module iteration, heat dissipation bottleneck revealed
The optical module continues to iterate towards 800G, 1.6T, and 3.2T, and power consumption continues to rise, but the cross-sectional size of the module body has not changed much, leading to a continuous increase in internal unit space heat load. However, optical chips are highly sensitive to temperature changes, and the light output characteristics of EML are significantly different at different temperatures. Thermal management not only affects device performance, but is also directly related to the transmission stability and service life of optical modules. Specifically, optoelectronic devices such as DSP, lasers, and modulators are the main heat sources inside optical modules. As optical modules continue to evolve to higher speeds, core device performance upgrades and overall heat load growth will drive the demand for high-performance heat dissipation materials and devices to continue to rise. In addition, there is also domestic replacement demand for high-end heat dissipation materials: domestic demand for optical modules is expanding, demand for autonomous control is increasing, and high-end cooling materials and modules are expected to usher in domestic replacement opportunities. At the level of industrial catalysis, on August 13, 2026, Zhongji Xuchuang plans to transfer 31.3725 million shares of Zhongshi Technology. The bank believes that this strategic investment reflects the increased emphasis placed by optical module leaders on cooling, and that thermal management is expected to become an important incremental direction in the optical module industry chain.
Sorting out the three-level heat dissipation system and core materials for optical modules
Optical module cooling runs through the three levels of chip packaging, module interior, and switch interface, forming a complete thermal management system that is transferred step by step from a local heat source to the external environment. Specifically, within the optical chip package, active optical chips such as EML are the main heat source. Through ceramic carrier board heat transfer and TEC precise temperature control, the microscopic gaps at the contact interface are filled with TIM1 thermal conductive material with high barriers to conduct the heat generated by the optical chip outward. DSP and optical devices in the optical module case are the main heat sources. TIM materials such as thermal conductive gels and thermal pads fill the gap between the device and the heat dissipation structure, reduce contact thermal resistance, and transfer heat to the metal case; some high-power solutions can further introduce VC heat evaporation plates to quickly spread the heat of local hot spots to a larger area. The external heat dissipation of the optical module uses a switch cage as an interface to transfer the heat from the module case to the external radiator, and is finally discharged through an air cooling or liquid cooling system.
Optical interconnection technology continues to evolve, and silicon light and NPO have spawned new variables in heat dissipation
Optical interconnection technologies such as silicon light and NPO/CPO continue to evolve, and as the speed of optical modules is upgraded, it will have an impact on cooling solutions. Specifically, the silicon light solution gradually increased penetration from the 800G/1.6T optical module. Compared with traditional EML solutions, where multiple integrated lasers and EML devices with modulators are responsible for each optical signal emission, silicon light uses CW continuous wave lasers to provide light sources. Through silicon light PIC integrated multi-channel modulation, the heat source is more concentrated, which in turn promotes the upgrading of TEC and ceramic substrates in the direction of high performance and high value. The NPO program promotes the migration of light engines to the vicinity of ASICs, and no unified technology route has yet been formed. Among them, the built-in light source solution integrates the laser with the silicon light PIC, which is closer to the high-power ASIC, and the thermal crosstalk problem is prominent, and places higher demands on local heat dissipation and accurate temperature control; the external light source solution keeps the laser away from the ASIC heat zone, which is conducive to reducing thermal crosstalk, but additional optical path coupling loss may increase the laser output power requirements, thereby increasing the demand for supporting heat dissipation materials; the VCSEL solution uses a high-density laser array, which needs to focus on array temperature uniformity and local hot spot control. In the future, we need to pay attention to the industrialization progress of different technology routes and the evolution of supporting solutions for cooling devices. Although the industrialization of new technologies such as silicon light and NPO is accelerating, traditional pluggable solutions still have a certain advantage and significant share in the scale-out scenario. Future optical module rate upgrades will drive an increase in overall thermal load, which will drive the demand for the entire cooling chain to upgrade.
Related companies in the industry chain: TEC and ceramic substrates: Fulade, Fuxin Technology, Sinocera Materials, Sanhuan Group, etc.; TIM materials and VC heating plates: Zhongshi Technology, Suzhou Tianmai, Feirongda, Debon Technology, Hongfucheng, etc.; Cage: Yidong Electronics, Dingtong Technology, etc.
Risk warning: risk of demand falling short of expectations, risk of technology iteration, risk of customer introduction falling short of expectations.