Abstract: An inexpensive multi-layered holographic read-only memory having a large capacity is provided. In the memory in which single-mode slab waveguides are multi-layered, a periodic scattering center whose period approximately agrees with the period of the guided mode is provided in at least one of a core layer and a clad layer in each waveguide so that a guided wave in the waveguide is diffracted by the periodic scattering center to the outside of the waveguide and a holographic image is generated.

Abstract: An inexpensive multi-layered holographic read-only memory having a large capacity is provided. In the memory in which single-mode slab waveguides are multi-layered, a periodic scattering center whose period approximately agrees with the period of the guided mode is provided in at least one of a core layer and a clad layer in each waveguide so that a guided wave in the waveguide is diffracted by the periodic scattering center to the outside of the waveguide and a holographic image is generated.

Abstract: An inexpensive multi-layered holographic read-only memory having a large capacity is provided. In the memory in which single-mode slab waveguides are multi-layered, a periodic scattering center whose period approximately agrees with the period of the guided mode is provided in at least one of a core layer and a clad layer in each waveguide so that a guided wave in the waveguide is diffracted by the periodic scattering center to the outside of the waveguide and a holographic image is generated.

Abstract: A laminated optical medium for read-only information recording has ultra-high memory capacity and reliably extracts desired information from laminated memories. Methods for low-cost mass production of laminated read-only medium are demonstrated. The optical medium is a lamination of planar type waveguides made of polymeric materials, in which each waveguide has information recorded as periodic scattering factor to generate scattered light by injection of input light into a waveguide layer. Therefore, read-only information recording medium of ultra-high memory capacity, equivalent to the memory capacity achievable by volume holography, can be produced by using a low-cost planar holographic technique. The laminated medium is simple and energy conserving, because it does not require rotation mechanisms for reproduction of music and video holographic recordings.

Abstract: An inexpensive multi-layered holographic read-only memory having a large capacity is provided. In the memory in which single-mode slab waveguides are multi-layered, a periodic scattering center whose period approximately agrees with the period of the guided mode is provided in at least one of a core layer and a clad layer in each waveguide so that a guided wave in the waveguide is diffracted by the periodic scattering center to the outside of the waveguide and a holographic image is generated.

Abstract: An inexpensive multi-layered holographic read-only memory having a large capacity is provided. In the memory in which single-mode slab waveguides are multi-layered, a periodic scattering center whose period approximately agrees with the period of the guided mode is provided in at least one of a core layer and a clad layer in each waveguide so that a guided wave in the waveguide is diffracted by the periodic scattering center to the outside of the waveguide and a holographic image is generated.

Abstract: A packaging platform for optically coupling one or more optical waveguides of one or more optical components having the optical waveguide to one or more optical fibers is provided with a reference structure portion for the horizontal and vertical positioning of the optical component. The platform is further provided with one or more fiber positioning portions for inserting and holding the optical fiber and positioning the optical fiber at a position where the optical fiber is optically connected to the optical waveguide. The provided packaging platform and an optical module using the platform can simplify all alignment steps for optical coupling, electrical connection and sealing in the coupling of the optical component and the optical fiber.

Abstract: A plastic ferrule for an optical connector comprises a cylindrical portion having one insertion hole for fixing an optical fiber and directly related to connection, a holding portion for allowing the cylindrical portion to be stably held in an optical connector, and an guiding portion for allowing an optical fiber to be guided into the ferrule. The ferrule has a hollow, cylindrical hole centering around the insertion hole inside the cylindrical portion. Thus, the ferrule has excellent dimensional accuracy of the outer diameter, and achieves connection of single mode fibers excellent in connection reliability and economy.

Abstract: An inexpensive polarization independent optical nonreciprocal circuit which does not require a use of expensive birefringent crystals, optical branching circuits, and a phase adjustment. The optical nonreciprocal circuit is formed by at least one lens through which a light propagating between two waveguides passes; and a polarization rotation circuit for sequentially applying a nonreciprocal rotation and a reciprocal rotation to a first half of the light propagating between two waveguides, and sequentially applying a reciprocal rotation and a nonreciprocal rotation to a second half of the light propagating between two waveguides, so that the first half and the second half of a light propagating forward are set to have an identical polarization to form an even guided mode and coupled, while the first half and the second half for a light propagating backward are set to have opposite polarizations to form an odd non-guided mode and dissipated.