Showing papers by "Yohei Sakamaki published in 2005"

Mode splitter and optical circuit

Abstract: PROBLEM TO BE SOLVED: To provide a low loss mode splitter and a low loss optical circuit using the mode splitter SOLUTION: The mode splitter is constituted of an optical waveguide formed by embedding a core whose cross section is rectangle in a clad, and it has a main waveguide (core) capable of guiding two or more kinds of propagation modes with different propagation orders and a sub-waveguide having a tapered part and a curved waveguide in which waveguide width (core) gradually increases from nearly zero to predetermined width, and the tapered part is arranged with a fixed gap with the main waveguide Width of optical waveguides of an output waveguide and that of the output part of the sub-waveguide are different from each other COPYRIGHT: (C)2006,JPO&NCIPI

Planar Lightwave Circuit, Design Method for Wave Propagation Circuit, and Computer Program

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Low loss and low crosstalk waveguide crossings with small angles designed by wavefront matching method

Abstract: We report experimental results for small-angle waveguide crossings designed with our recently proposed wavefront matching method. We successfully obtained lower loss and crosstalk values than conventional straight waveguide crossings. (2 pages)

Multi-port optical switch

Abstract: PROBLEM TO BE SOLVED: To provide a multi-port optical switch suitable for two-way optical communication. SOLUTION: The multi-port optical switch has N ports (N: an integer of ≥3) and is so constituted that the ports can be connected to all other ports. Consequently, two-way communication between respective ports becomes possible. In an embodiment, a multi-port optical switch has N one-input, M-output optical switches (M: an integer of ≥N-1), which are interconnected through N-1 output ports. In another embodiment, a one-input, M-output optical switch comprises a plurality of two-input, two-output optical switches, and respective one-input, M-output optical switches are interconnected through cross-side output ports of the two-input, two-output optical switches. Consequently, an optical signal between ports passes through a cross port twice without fail to provide the one-input, M-output optical switch having a superior extinction ratio. COPYRIGHT: (C)2006,JPO&NCIPI

Optical functional circuit

Abstract: The present invention provides an optical functional circuit where a holographic wave propagation medium is applied and a circuit property is excellent such as small transmission loss and crosstalk. The optical functional circuit where a plurality of circuit elements are formed on a substrate includes the wave propagation medium for converting an optical path of a leakage light so that the leakage light that is not emitted from a predetermined output port of the circuit element is not coupled to a different circuit element. This wave propagation medium is constituted by an optical waveguide that is provided with a clad layer formed on the substrate and a core embedded in the clad layer, and a part of the optical waveguide is formed in accordance with a refractive index distribution which is multiple scattered.

Flat optical circuit, design method for wave motion propagating circuit and computer program

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Planar lightwave circuit, including an optical branch circuit

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Planar lightwave circuit, including an improved arrayed waveguide grating filter

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Wavefront matching method: a new approach for need-oriented waveguide design

Abstract: We propose a new way for designing optical waveguides with the optimum shape This approach is called the wavefront matching method and we describe its fundamental aspects and report some experimental results

A planar lightwave circuit including a cross waveguide

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Planar lightwave circuit, including a slab type coupler

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.