Heatsink requirements for coherent operation of high-power semiconductor laser arrays

The heatsink requirements for coherent operation of laser diode arrays are examined by thermal analysis of specific heatsinks and the phase locking of laser diodes. It is shown that mounting laser diode arrays at the edge of semi-infinite copper heatsinks results in temperature variations between individual laser diode elements that are too large to permit coherent operation except at relatively low-power levels. It is also shown that by the use of diamond and/or shaped heatsinks it is possible to operate large arrays coherently to high optical output levels.