Phase-locked arrays of antiguides: modal content and discrimination

Three classes of array modes of closely spaced antiguides are analyzed: modes consisting of coupled fundamental (element) modes, modes consisting of coupled first-order (element) modes, and modes adjacent to coupled fundamental modes. The behavior of coupled fundamental modes as a function of lateral index step is analyzed, and explained from a ray-optics point of view. Excellent agreement is found between experimental data (i.e., diffraction-limited in-phase-mode operation to 10 x threshold and 450 mW) and theoretical predictions based on the effective-index method.