Coherent Laser Beam Addition with Holographic Binary Phase Gratings

Single lasers are usually limited in total output power by some physical mechanism. For example, GaAs lasers suffer catastrophic facet damage at output power levels exceeding a few tens of milliwatts. Other semiconductor lasers are constrained to low power output by heat dissipation limitations. We have developed a holographic method of laser beam addition which is capable of producing large optical powers from the coherent sum of many modular laser sources. The coherent addition of six GaAlAs lasers has been demonstrated.