High-Quality CO2 Laser Machining of LTCC Structures for Thermal Management of a Group of Single-Emitter Laser Diodes

There has been recent interest in the use of LTCC (low temperature co-fired ceramics) technology as a platform for optical integration of both active and passive components because of its electrical, thermal and mechanical characteristics. Active components require methods for removing the heat generated without compromising the passive alignment of surrounding components. A thermal management structure for impingement water-cooling of a group of single-emitter laser diodes is reported, fabricated with CO2 laser cut layers of LTCC to within tens of micron accuracy. We present a technique that uses precisely fitted, laser-cut nanocarbon layers to remove the problem of the collapse of internal water channels during isostatic pressure lamination. The structure provides 5 water jets to localize cooling under the diode laser chip, reducing thermal impedance.