INNOVACERA | technical ceramic solutions

From laser junction temperature and package thermal resistance to submount material selection   As CW DFB lasers move toward higher output power for external laser sources, silicon photonics and next-generation optical interconnects, the packaging challenge is changing. The question is no longer only whether a laser can reach the required optical power, but whether that power can be maintained at elevated operating temperatures without excessive junction-temperature rise.   This puts the thermal path beneath the laser die under much greater scrutiny. As heat flux increases, the submount becomes an increasingly important part of package thermal resistance – and this is where aluminum nitride (AlN) ceramic can provide a useful combination of thermal, electrical and mechanical properties.   1. High Optical Power Is Not Enough – Power at Temperature Matters   High-power CW DFB lasers are expected to provide stable continuous optical output while meeting demanding require...

In high‑voltage electrical systems, vacuum equipment, semiconductor devices and scientific instruments, large‑size insulating structures typically use ceramics to deliver reliable electrical insulation, while metal parts undertake mechanical connection, flange mounting and sealing duties under given operating conditions. Joining alumina ceramics with metals including Kovar and stainless steel is a core technical solution to realize these composite assemblies.   Unlike standard small ceramic insulators and vacuum feedthroughs, large cylindrical ceramic – to – metal brazed assemblies come with bigger overall dimensions, longer body lengths and substantially larger bonding interfaces between ceramic and metal. Certain large parts can have a total length of several hundred millimeters, which places stricter requirements on material compatibility, machining tolerance, assembly concentricity and brazing processes.   For this reason, large – scale ceramic – to – metal brazing cannot ...