Phase locked laser arrays have important and unique characteristics and serve as a platform to investigate the behavior of coupled oscillators and complex network dynamics, as well as combining of many lasers to obtain high power and high brightness sources.

Two methods for phase locking several thousands of lasers are presented. Both incorporate all the lasers into one common degenerate cavity where coupling occurs as a result of diffraction. The diffraction in one method is introduced by a spatial filter and in the other by free space propagation. With the spatial filter method, the coupling range and coupling sign can be readily controlled by varying its size and shape, allowing detailed investigations of phase locking mechanism. With the free space propagation method, short range negative coupling of nearest neighbor lasers can be easily achieved, allowing investigation of highly frustrated network geometries.

The details of these methods the experimental configurations and experimental and theoretical results will be presented.