Phase-locking phenomena in coupled waveguide semiconductor lasers

Under some simplifying assumptions, an inequality is derived which must be satisfied for a pair of index guided coupled waveguide semiconductor lasers to be phase-locked. The physically realistic situation of small technological differences between the devices is included. If this criterion is not met then, in the most severe case, the system operates in a scanning mode whereby the far-field pattern scans with a period of a few hundred picoseconds. If phase locking is only weakly broken a stable far-field pattern results, punctuated by periodic phase jumps of 2π