In the value chain of AI computing power, computing power chips, interconnection technology and cooling systems constitute a closely coordinated “golden triangle”. As a carrier of intelligence, chips lay the foundation for computing power; Interconnection becomes the thread of collaboration for efficient transmission – especially as the speed of optical modules continues to evolve and power consumption rises dramatically, making heat dissipation increasingly a key bottleneck in performance and reliability. High temperature will not only cause wavelength drift and bit error rate increase in the laser (TOSA) in the optical module, but also accelerate the aging of optical devices, directly threatening the stable operation of the entire communication system. Therefore, heat dissipation is not only the “cornerstone of stability”, but also the core guarantee to ensure the continuous release of interconnection efficiency.
The heat dissipation dilemma of high-speed optical modules
High power density and heat flux density
As the transceiver rate increases, the power consumption of a single module increases significantly, resulting in a surge in heat flux density. For example, 800G optical modules consume up to 18W/unit, and 1.6T modules consume higher power consumption, which accumulates heat quickly, which directly affects the stability and lifespan of the module.
Miniaturized package limitations
High-speed optical modules are mostly in compact packages (such as QSFP-DD), and the internal space is small, making it difficult for traditional heat dissipation solutions to effectively fill the gaps. The integration of multiple heat sources is easy to form local hot spots, and the thermal conductive materials in the heat dissipation shell are not well bonded, further exacerbating the heat dissipation problem.
Reliability issues of thermal conductive materials
Performance degradation: After long-term operation, the performance of thermal conductive materials degrades, such as silicone oil volatilization and spillage, which may lead to the attenuation of optical signal scattering and accelerate the performance degradation of the module.
Interfacial thermal resistance: The longitudinal thermal conductivity of traditional thermal conductive materials (such as gels and gaskets) is insufficient, and the roughness of the multi-stage heat dissipation interface leads to air gaps, and the interfacial thermal resistance accounts for more than 50%.
Mechanical and aging problems: overly soft gel is easily extruded by thermal circulation, and high-hardness gaskets are difficult to fit the curved surface; Long-term aging may also cause problems such as optical path pollution, filler settling, and matrix embrittlement.
Cooling solution cost and compatibility
High-performance cooling solutions, such as liquid cooling, are costly and need to be compatible with existing equipment. For example, liquid cooling technology involves complex issues such as structural design and material selection, which is difficult to implement. In addition, the heat dissipation requirements of different technical paths (such as CPO and LPO) vary significantly, increasing the complexity of heat dissipation design.
In summary, the heat dissipation of 800G/1.6T optical modules needs to take into account many challenges such as high power density, miniaturized packaging, material reliability and cost control, and promote the innovation of heat dissipation technology to become the key to the development of the industry.
High-speed optical module thermal management HFC product matrix
With years of deep cultivation and technology accumulation in the field of thermal management materials, HFC has launched a series of innovative and reliable system cooling solutions to meet the growing demand for optical modules, escorting the rapid development of the optical communication industry.
TOSA & ROSA
The heat dissipation design of the optical module needs to be accurately optimized according to the characteristics of its core components: the laser at the transmitter (TOSA) is highly sensitive to temperature, and temperature fluctuations can easily lead to wavelength drift and power instability.
Although the transimpedance amplifier (TIA) at the receiving end (ROSA) has low power consumption, the temperature stability directly affects the reception sensitivity and bit error rate, requiring TIM materials to work stably for a long time under low heat load, and without silicone oil precipitation, eliminating the risk of polluting the optical path, so as to ensure the heat dissipation reliability of the whole life cycle.
TIM type 1丨HFC thermal conductive gel HTG-S1200C
Precise temperature control ensures stable laser performance
HTG-S1200C thermal conductivity gel has a thermal conductivity of up to 12 W/m·K, which can efficiently export concentrated heat in the TOSA region, effectively control the junction temperature of the laser chip, ensure that the luminous wavelength and power are in a stable working range, and significantly improve the quality and reliability of optical communication.
Ultra-soft and low-stress, protect chip safety
The gel is in the form of a semi-flowing paste that fully fills microgaps under contact pressure and automatically adapts to uneven interfaces. After curing, an elastomer is formed, with extremely low hardness (Shore 00), which effectively absorbs mechanical vibration and thermal expansion stress, avoiding internal and external stress damage to the laser chip, especially suitable for long-term use of sensitive components.
Efficient interface bonding, excellent anti-aging performance
For TOSA metal surfaces, HTG-S1200C exhibits high surface affinity and strong wettability, enabling near-zero porosity interfacial heat conduction. The product has passed the test of high temperature and high humidity (85°C/85%RH), cold and hot cycling (-40~125°C) and other harsh environments, without oil separation, no dry cracking, long-lasting and stable performance, and adapts to the needs of the whole life cycle of optical modules.
Recommended TIM Type 2丨HFC Thermal Conductive Gasket Low Oil Output TP-LY series
Moderate thermal conductivity, balancing performance and cost
The TP-LY series provides a wide range of thermal conductivity options of 1~15W/m·K, which accurately matches the low power heat dissipation requirements of TIA modules. While ensuring effective heat conduction, it avoids cost increases due to over-design, especially suitable for optical module products that need to be deployed on a large scale.
Clean protection to ensure reliable optical interface
The optical interface inside the optical module is extremely sensitive to contaminants. The gasket adopts a low silicone oil precipitation formula, which has been verified by 85°C/85%RH high temperature and high humidity test, and has almost no oil separation phenomenon, which can keep the optical interface clean for a long time and ensure the high reliability of the receiving signal.
High suppleness and weather resistance, suitable for harsh environments
The material has excellent compressibility and can achieve efficient interface filling under low stress conditions, adapting to tolerance fluctuations between the housing and the PCB. The product has passed the hot and cold cycle (-40°C to 125°C) and long-term high-temperature aging tests, showing excellent structural stability and long-lasting thermal conductivity, with a minimal change rate of thermal resistance, ensuring reliable heat dissipation throughout the life cycle of the product.
Driver Chip & DSP Chip
The driver and DSP chip in the optical module are high-power, high-heat concentrated bare die chips, usually using the PCB to conduct heat to the housing. These chips have a high heat flux density and need to rely on ultra-high thermal conductivity materials to quickly conduct away heat. There is uncertainty about the installation gap.
Recommended TIM type丨HFC graphene thermal conductive gasket
Extreme thermal conductivity breaks through thermal management bottlenecks
Relying on graphene orientation arrangement technology, HFC graphene thermal conductivity gasket achieves a longitudinal thermal conductivity of ≥ of 130W/m·K, and thermal resistance as low as 0.04°C·cm²/W, which has greater thermal benefits than 12W-18W thermal conductive gel. It can quickly conduct chip heat to the heat dissipation housing to ensure the stable operation of 1.6T and higher speed optical modules under high load.
Ultra-thin and flexible, in line with the trend of high-density design
The thickness can be controlled from ≤0.3mm, and multiple thickness and hardness options are available, making it easy to embed into narrow gaps between chips, PCBs, and housings. It not only establishes efficient heat dissipation channels for high-power chips, but also realizes collaborative heat dissipation from multiple heat sources, which strongly supports the continuous miniaturization and integration of optical modules.
Low-stress bonding ensures long-term reliability of the device
With a high compression ratio of 70%, it can fully fill interface unevenness at very low installation pressure, greatly reducing contact thermal resistance. The low-stress, porous buffer structure of the material itself effectively absorbs mechanical strain, protects the sensitive optical path and chip structure, and prevents warping and pumping. It has passed rigorous tests such as 1000 hours of high temperature, high humidity, cold and thermal shock, and the thermal resistance change rate is <5%, ensuring stable heat dissipation performance throughout the life cycle of the optical module.