The mode-selection mechanism operative in a new class of large-index-step index-guided arrays is elucidated, and it is shown that such arrays may be designed to operate stably in the fundamental mode at high power levels. In contrast to evanescently coupled arrays, these devices operate in a new set of so-called leaky modes. The calculations demonstrate a significant discrimination between the fundamental and high-order leaky modes that is sensitive to the widths of the high-index coupling regions but insensitive to the drive current. This resulting mode discrimination combined with the inherently large index step present in these devices should allow them to operate stably under cw conditions and/or at high drive currents.
© 1989 Optical Society of America
G. Ronald Hadley, "Index-guided arrays with a large index step," Opt. Lett. 14, 308-310 (1989)