Multi-channel waveguide optical sensor

An optical sensor for sensing data on a surface, comprising:

• (a) n transmit optical fibers operative to convey light from a source toward an optical waveguide, n being an integer number at least equal to one;
• (b) m receive optical fibers operative to convey light from the optical waveguide to an optical detector associated with each receive optical fiber, m being an integer number at least equal to one;
• (c) said optical waveguide including n transmit channels for conveying lightthrough the optical waveguide, each transmit channel being connected to one of the transmit optical fibers, and a plurality of receive channels connected to the m receive optical fibers, each receive channel being joined with one of the transmit channels, light from the source exiting the waveguide and propagating toward data on the surface through a plurality of spaced-apart points, light reflected back from said surface re-entering the waveguide at said spaced-apart points and being conveyed along said receive channels, and through said m receive optical fibers to said optical detector.

An optical sensor disposed adjacent a surface on which data is optically encoded by varying the reflectance of light from the surface, comprising:

• an optical waveguide, said optical waveguide including a plurality of first path means, defined by regions of relatively higher refractive index within a substrate having a lower refractive index, for conveying light originating from an external source through the waveguide toward the surface, and second path means defined by regions of relatively higher refractive index compared to the refractive index of the substrate, for conveying light reflected from said surface through the waveguide toward a light detector, at least a portion of the first path means being coincident with the second path means, so that light passes bidirectionally through said portion.