Switching using three-dimensional rewriteable waveguide in photosensitive media

An optical switch comprising:

• a photosensitive substrate having at least one surface;
• at least one inlet port in a surface and at least one outlet port in a surface of said substrate;
• a source of one light beam;
• a means for splitting said light beam into at least two light beams;
• a means for focusing said light beams at a selected location line of intersection within said substrate, said line of intersection being drawn between one inlet port and one outlet port, thereby creating at least one waveguide in the photosensitive substrate corresponding to said line of intersection.

A method of forming a waveguide in a substrate comprising:

• selecting a three-dimensional photosensitive substrate having a plurality of planar surfaces, said photosensitive substrate comprising a plurality of inlet ports in one of said plurality of surfaces and a plurality of outlet ports in another one of said plurality of surfaces;
• providing a source of at least two light beams;
• and
• focusing said light beams at a selected line of intersection within the substrate drawn between one inlet port and one outlet port to change the refractive index of the photosensitive substrate at said line of intersection, thereby creating a waveguide in the substrate corresponding to the line of intersection.