Integrated optical read/write head and apparatus incorporating same

Claim 1

Apparatus for writing and/or reading information on a recording element having a plurality of data tracks along which such information is, or is to be, recorded, said apparatus comprising: (a) a laser for producing a beam of radiation; (b) an integrated optical write/read head, said head comprising (i) a planar optical waveguide disposed on one surface of a planar substrate, said waveguide being positioned to receive and guide said beam along a predetermined path, (ii) means for deflecting a beam of radiation guided by said waveguide out of a data track on the recording element and for bringing such deflected beam to focus at a spot, such deflected beam emerging from said waveguide at an egress zone; (c) means for detecting any displacement of said spot from a desired data track and for producing a tracking error signal proportional to said displacement; (d) means responsive to said error signal for selectively varying the effective refractive index of said waveguide in the vicinity of said egress zone, said refractive index-varying means comprising a pair of spaced, parallel electrodes positioned in close proximity to said waveguide, and means for producing a variable electric field between said electrodes, said field varying as a function of said error signal.