Design and fabrication of rib ARROW couplers

In the conventional waveguiding concept the coupling distance between two waveguides is limited in order to ensure a sufficient overlap of the evanescent tails of the model field profiles. The Anti-Resonant Reflecting Optical Waveguide (ARROW) scheme provides modal fields exhibiting an oscillating nature in the coupling region too, thus allowing for remote coupling. The design of low-loss and loss-free rib ARROW couplers is demonstrated. In order to give precise predictions of the coupling length, the computation of the propagation constants demands full vectorial numerical methods for solving the wave equation. In a SiO sub x N sub 1-x configuration the coupling over a spacing distance up to 93 mym between two rib ARROW's has been demonstrated experimentally. Experimental and theoretical results are compared and discussed.