Optical head apparatus including a waveguide layer with concentric or spiral periodic structure
First Claim
1. An optical head apparatus including a converging means, said converging means comprising:
- a first waveguide layer having a central region;
a first concentric or spiral periodical structure formed on said first waveguide layer around said central region;
a laser beam source for generating a laser beam;
coupling means, having a center axis, for guiding said laser beam emitted from said laser beam source to a cross point between said center axis and said first wave-guide layer within said central region of said first waveguide layer,said first waveguide layer converting said laser beam into waveguide light and leading said waveguide light from said central region to said periodical structure which causes said waveguide light to be radiated outside of said first waveguide layer so as to be converged to at least one converging point outside of said first waveguide layer.
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Accused Products
Abstract
An optical head arranged in such a manner that light emitted from a semiconductor laser (8) is inputted and coupled in a waveguide layer (3C) by a grating coupler (4C) having a concentric or spiral structure formed by concavities and convexities so as to convert light into waveguide light (12C) passing toward to outer periphery in the layer, the waveguide light (12C) is shifted at the outermost peripheral portion of the waveguide layer (3C) to a waveguide layer (3B) so as to convert the waveguide light (12C) into waveguide light (12B), the waveguide light (12B) is radiated by a grating coupler (4B) having a concentric or spiral periodical structure, the concentrically polarized (or radially polarized) light (13) is converted into linearly polarized light (14) by a polarizing element (10B) so as to be converged on the reflection surface (16) of the optical disc, light reflected from the reflection surface (16) is again converted into concentrically polarized (or radially polarized) light (17A) and (17B) by the polarizing element (10B) so as to be inputted and coupled in waveguide layers (3A) and (3B) by a grating coupler (4A) and the grating coupler (4B), and then to be turned into waveguide light (18A) and (18B) each of which passes through the layer, and the waveguide light (18A) and (18B) is radiated at the end portions of the waveguide layers (3A) and (3B) so as to be respectively received by photo detectors (6A) and (6B) so that a control signal and a reproduction signal are obtained.
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Citations
18 Claims
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1. An optical head apparatus including a converging means, said converging means comprising:
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a first waveguide layer having a central region; a first concentric or spiral periodical structure formed on said first waveguide layer around said central region; a laser beam source for generating a laser beam; coupling means, having a center axis, for guiding said laser beam emitted from said laser beam source to a cross point between said center axis and said first wave-guide layer within said central region of said first waveguide layer, said first waveguide layer converting said laser beam into waveguide light and leading said waveguide light from said central region to said periodical structure which causes said waveguide light to be radiated outside of said first waveguide layer so as to be converged to at least one converging point outside of said first waveguide layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification