| 摘要 |
An optical routing element (ORE) that can be incorporated into a variety of configurations, to provide the basis for such devices as crossbar switches, wavelength division multiplexers, and add/drop multiplexers. The ORE includes first, second, and third waveguide segments. The first and second waveguide segments extend along a common axis, and are separated by a routing region. The third waveguide segment extends from the routing region at a non-zero angle with respect to the common axis. The routing region is occupied by a selectively reflecting element that selectively reflects light based on a state of the element or a property of the light. The selectively reflecting element may be a thermal expansion element (TEE) or a wavelength-selective filter. A TEE has a body of material having contracted and expanded states at respective first and second temperatures. The contracted state defines an air gap disposed in the path of light traveling along the first waveguide segment so as to cause the light to be deflected into the third waveguide segment through total internal reflection. The expanded state removes the air gap so as to allow the light traveling along the first waveguide segment to pass into the second waveguide segment. The first, second, and third waveguide segments are formed in a monolithic planar waveguide device, and a trench is formed across the region where the waveguide segments intersect. The selectively reflecting element is disposed in the trench. Communication with the ORE is typically effected through optical fibers that are in optical contact with the waveguide segments at respective positions at the edges of the planar waveguide device. The optical fibers may have flared cores. OPTICAL ROUTING ELEMENT FOR USE IN FIBER OPTIC SYSTEMS
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