In order to acquire high optical power for practical applications, technologies of beam combination which have been applied to semiconductors in near-infrared band successfully can also be employed to quantum cascade lasers (QCLs). The coplanar arrangement of QCLs is discussed which is helpful to maintain stable and reliable continuous-wave room-temperature operation of QCLs. In the experiment of collimation for a single QCL, collimated beams with beam quality factor M2 less than 2.3 are achieved. In the experiment of high-efficiency beam combination, the efficiency of 85% is achieved.