Ultra-High Fatigue Life Elastocaloric Micro­cool­ing for Photonic Systems

Modern photonic systems require precise thermal manage­ment to ensure stabil­ity and perfor­mance. This inter­dis­ci­pli­nary project devel­ops a new type of elastocaloric micro­cool­ing device capable of operat­ing for more than one million cycles. By combin­ing advanced materi­als research on shape memory alloy films with innov­a­tive device engineer­ing and photonic system integra­tion, the project aims to create a highly efficient solid-state cooling technol­ogy. The collab­o­ra­tion between KIT, ETH Zurich, and Fraun­hofer IWM addresses key challenges in durabil­ity and relia­bil­ity of microscale cooling technolo­gies for next-gener­a­tion photonic and neuro­mor­phic systems.

Efficient thermal manage­ment is becom­ing increas­ingly impor­tant as electronic and photonic systems continue to shrink in size while growing in perfor­mance. Photonic compo­nents such as optical modula­tors, multi­plex­ers, and integrated circuits are partic­u­larly sensi­tive to temper­a­ture fluctu­a­tions. Even small local temper­a­ture changes can lead to signal degra­da­tion, wavelength drift, and reduced efficiency. At the same time, conven­tional cooling technolo­gies based on vapor-compres­sion systems consume signif­i­cant energy and rely on refrig­er­ants with high global warming potential.

Elastocaloric cooling offers a promis­ing alter­na­tive. This solid-state cooling technol­ogy uses stress-induced temper­a­ture changes in super­elas­tic shape memory alloys (SMAs) to gener­ate cooling without environ­men­tally harmful refrig­er­ants. Recent advances have demon­strated large temper­a­ture changes and high cooling efficiency. Thin-film SMA materi­als are especially promis­ing for microscale appli­ca­tions because their large surface-to-volume ratio enables rapid heat trans­fer and compact device integration.

However, current elastocaloric thin-film devices face a major challenge: their limited fatigue life. Many exist­ing systems fail after only a few thousand operat­ing cycles, which is insuf­fi­cient for practi­cal use in photonic systems that require long-term stabil­ity. The goal of this project is there­fore to develop an elastocaloric micro­cool­ing device capable of operat­ing reliably for more than one million cycles.

To achieve this goal, the project combines exper­tise from materi­als science, device engineer­ing, and photon­ics. The collab­o­ra­tion between Prof. Peter Gumbsch (KIT and Fraun­hofer IWM), Prof. Juerg Leuthold (ETH Zurich), and Dr. Jingyuan Xu (KIT) combines this comple­men­tary exper­tise in fatigue mechan­ics, photonic systems, and elastocaloric microde­vices. Together, the partners aim to estab­lish a new class of durable and energy-efficient cooling technolo­gies for next-gener­a­tion micro­elec­tron­ics and photonic systems.