Abstract

Bistable, polarization- and wavelength-independent optical switching has been accomplished by using the electrochemical generation and destruction of bubbles in an aqueous solution. Formation or destruction of bubbles in slots cut or etched into the 90° intersection of waveguides routes light into one or the other of the two guides. If the fluid is index-matched to the guide and no bubble is present, light passes straight through the intersection. When a bubble displaces the fluid, total internal reflection routes the light into the intersecting guide. Bubbles are formed by the electrolytic dissociation of water into oxygen and hydrogen and are destroyed by catalyst-assisted recombination. They can be formed or destroyed in less than a second and remain indefinitely; such time scales are suitable for protection switching. We have previously reported a demonstration of this concept that uses macroscopic slots cut in planar waveguides. Here we describe the behavior of bubbles in slots of the size needed for a waveguide matrix switch; typical slots are 6 µm deep and 3-15µm wide. Bubble formation, the achievement of longterm stability, and conditions for complete destruction of bubbles will be discussed, and a means of integrating large numbers of these switches into a matrix will be presented.

© 1990 Optical Society of America