The race for AI computing power and the ever-growing demands of data centers are presenting optical data transmission system developers with unprecedented new challenges. The transition to 800G, 1.6T, and 3.2T speeds is not merely an evolution but a revolution, demanding a fundamental rethinking of thermal management approaches. As performance increases, the heat flux in optical modules skyrockets, while the stringent requirements for laser source temperature stability remain unchanged.
This problem becomes particularly acute in co-packaged optics (CPO) architectures with external laser sources (ELSFP). Laser output power reaches levels of 200–400 mW and operating conditions involve elevated ambient temperatures of up to 75°C. Under such conditions, passive cooling methods become not just ineffective, but downright impractical. The solution lies in the use of thermoelectric coolers (TECs).
Thermoelectric modules possess a unique set of qualities that make them indispensable for laser source temperature stabilization tasks:
· Compactness – the ability to integrate into the smallest optical transceiver housings.
· High cooling power density – the ability to remove significant heat fluxes from a small area.
· Excellent controllability – precise maintenance of a set temperature with a high response speed.
· High reliability and environmental safety.
The heat flux density that modern TECs must handle in CPO systems reaches 30–40 W/cm². Moreover, on the laser source itself, this figure can be several times higher – up to 200 W/cm². Operating under such extreme conditions requires modules with minimal thermoelectric pellet heights and maximum mounting density. RMT has unique experience in developing modules with pellet heights as low as 0.25 mm and a fill factor of up to 0.7, allowing them to effectively solve the most complex challenges.
RMT specialists carried out optimization of the TEC for a standard ELSFP module with 8 CW lasers at 400 mW per channel. The optimization was performed in two directions:
1. selection of materials and design for maximum coefficient of performance (COP) in operating mode;
2. investigation of the impact of operating conditions and a recommendation to ensure a heat sink with minimal thermal resistance.
The results of this work are impressive and have been confirmed both by calculations and field tests. In the operating mode, with a thermal load of 4 W ± 0.5 W, we achieved an electrical power consumption 1.5 times lower than the amount of heat extracted. This means that for every watt of electricity consumed, the module removes more than one and a half watts of heat. This high Coefficient of Performance (COP ≈ 1.5) is critically important for scaling CPO systems, making it possible to minimize the power consumption of the laser source temperature stabilization unit and reduce the total cost of equipment ownership.
RMT Thermoelectric Modules are not just a cooling component. They are an efficient solution that allows you to overcome thermal limitations on the path to new data transmission speeds. The combination of cutting-edge microtechnology (pellets down to 0.25 mm, fill factor up to 0.7), high efficiency (COP > 1.5), and consistent reliability makes RMT products the optimal choice for developers of next-generation optical transceivers and CPO systems.
Invest in the future of your products with proven solutions from RMT.
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