Abstract: The present disclosure aims to provide a short optical fiber-type mode converter having small wavelength dependency. The present disclosure is about a mode converter including a cladding having a constant refractive index, a core having a refractive index higher than the refractive index of the cladding in the cladding, and a refractive index modulation part provided to obliquely cross the core and having a different refractive index from a refractive index of surroundings.

Abstract: Provided are an LPFG and an optical transmission system in which a mode conversion amount does not depend on a polarization state and an electric field distribution. The LPFG according to the present invention includes cavity rows (25-1 and 25-2) of cavities 15 periodically arranged in a core region 11 of the few-mode fiber 10 at a position away from a central axis z of the core region 11 in parallel with the central axis z. Each of the cavity rows (25-1 and 25-2) is located at a different position in a longitudinal direction of the few-mode fiber 10 (where the position in a z direction is different), and the cavity rows (25-1 and 25-2) are located at positions shifted by 90° on a cross section of the core region 11 with the center of the cross section of the core region 11 (the intersection of an x-axis and a y-axis) as an origin.

Abstract: A mode loss difference compensator of the present disclosure includes a main waveguide configured to allow propagation of N or more modes (where N is an integer of 3 or more), a first auxiliary waveguide having, at one end thereof, a first coupling portion configured to mode-convert an LP0n mode (where n is an integer of 2 or more) propagating in the main waveguide into a fundamental mode in the first auxiliary waveguide and transfer the fundamental mode from the main waveguide to the first auxiliary waveguide and having, at the other end thereof, a second coupling portion configured to mode-convert the fundamental mode propagating in the first auxiliary waveguide into the LP0n mode (where n is an integer of 2 or more) in the main waveguide and transfer the LP0n mode from the first auxiliary waveguide to the main waveguide, and a second auxiliary waveguide having, at one end thereof, a third coupling portion configured to convert a higher-order mode, other than any LP0n mode (where n is an integer of 2 or mor

Abstract: An object of the present disclosure is to provide an optical side input/output circuit for allowing light for being input into or output from a side surface of an optical fiber with high efficiency. The present disclosure is an optical side input/output circuit including: a tap unit in which a tap waveguide is formed for allowing light for propagation through a core of an optical fiber for being input into or output from a side surface of the optical fiber; and a refractive index matching unit, having a refractive index higher than a refractive index of the tap waveguide, on the side surface of the optical fiber where the light is allowed for being input or output by the tap waveguide.

Abstract: An object of the present disclosure is to connect an optical fiber and an optical waveguide with a low loss. The present disclosure is an optical connector plug, including: an optical waveguide having two guide pin V-grooves engraved on one surface thereof and having a cross section of one or more cores appearing between cross sections of the guide pin V-grooves on one end face thereof; two guide pins separately arranged in the two guide pin V-grooves; a flat substrate so fixed as to tuck the two guide pins in the two guide pin V-grooves on the one surface of the optical waveguide; and a fixing member equipped with the optical waveguide, the two guide pins, and the flat substrate.

Abstract: An objective of the present invention is to provide a mode conversion device capable of designing any coupling efficiency and full width at half maximum, and a design method therefor. According to the present invention, a mode conversion device includes a long period grating at a core of an optical fiber through which light is able to propagate in at least two propagation modes. The long period grating satisfies a relationship of Expression C1, where a full width at half maximum FWHM is a wavelength band in which the coupling efficiency is a half of coupling efficiency of mode conversion at a center wavelength, C is coupling efficiency, Lc is a complete coupling length, Lg is a grating length, ? is a grating pitch, and ?? is a propagation constant difference between the two propagation modes at the center wavelength of a mode conversion target. [ Math .

Abstract: An object of the present invention is to provide a core position recognition method, a connection method, and a connection apparatus that can simplify connection operations, and reduce rotational displacement and positional displacement. The connection apparatus according to the present invention includes a function capable of acquiring the rotation amount of an MCF during the bonding/fixing step. Specifically, the connection apparatus of the present invention uses an MCF with lines drawn on a side surface thereof, thereby recognizing the rotation amount of the MCF from the side surface, and calculating the absolute positions of the cores. The connection apparatus according to the present invention can recognize the absolute position s of the cores from a side image of an MCF in a state in which the MCF has been rotated.

Abstract: An object is to provide an optical side input/output circuit that has wavelength selectivity and is easily disposed at multiple points in a transmission path, and an optical connector. An optical side input/output circuit 301 according to the present invention includes: a grating portion 20 in which a fiber Bragg grating 21 that reflects light of a desired wavelength is formed in the core 51 of an optical fiber 50, the light of the desired wavelength being of light propagating in the core 51; and a tap portion 10 that is disposed at a stage before the grating portion 20 in the propagation direction of the light, and is provided with a tap waveguide 53 that outputs the light reflected by the grating portion 20 from a side surface of the optical fiber 50.

Abstract: The present invention aims to provide an optical side input/output circuit that has wavelength selectivity and is easily disposed at multiple points in a transmission path, and an optical connector. The optical side input/output circuit 301 includes: a tap portion 10 in which a tap waveguide 53 that outputs light of a higher-order mode from a side surface of an optical fiber 50 is formed, the light of the higher-order mode being of light propagating in the core 51 of the optical fiber 50; and a grating portion 20 that is located in a stage before the tap portion 10 in the propagation direction of the light, and has a grating 21 that converts light of a desired wavelength from a basic mode to the higher-order mode, the grating 21 being formed in the core 51 of the optical fiber 50.

Abstract: It is an object of the present disclosure to reduce the risk of information exploitation by a malicious third party while allowing communication data to be demodulated in real time.

Abstract: Provided are an LPFG and an optical transmission system in which a mode conversion amount does not depend on a polarization state and an electric field distribution. The LPFG according to the present invention includes cavity rows (25-1 and 25-2) of cavities 15 periodically arranged in a core region 11 of the few-mode fiber 10 at a position away from a central axis z of the core region 11 in parallel with the central axis z. Each of the cavity rows (25-1 and 25-2) is located at a different position in a longitudinal direction of the few-mode fiber 10 (where the position in a z direction is different), and the cavity rows (25-1 and 25-2) are located at positions shifted by 90° on a cross section of the core region 11 with the center of the cross section of the core region 11 (the intersection of an x-axis and a y-axis) as an origin.

Abstract: An object of the present invention is to provide a simple method capable of reducing MDL after construction of a transmission path. An optical connector 301 is an optical connector including a multimode optical fiber 11, in which a core 20 of the multimode optical fiber 11 includes a plurality of cavities 25 along a central axis. The optical connector 301 further includes a ferrule 12 surrounding the multimode optical fiber 11 and a connector plug 13 serving as a connection with another optical connector. The shape of the optical connector 13 is a shape of a generally used SC connector, FC connector, MT connector, or the like.

Abstract: A mode loss difference compensator of the present disclosure includes a main waveguide configured to allow propagation of N or more modes (where N is an integer of 3 or more), a first auxiliary waveguide having, at one end thereof, a first coupling portion configured to mode-convert an LP0n mode (where n is an integer of 2 or more) propagating in the main waveguide into a fundamental mode in the first auxiliary waveguide and transfer the fundamental mode from the main waveguide to the first auxiliary waveguide and having, at the other end thereof, a second coupling portion configured to mode-convert the fundamental mode propagating in the first auxiliary waveguide into the LP0n mode (where n is an integer of 2 or more) in the main waveguide and transfer the LP0n mode from the first auxiliary waveguide to the main waveguide, and a second auxiliary waveguide having, at one end thereof, a third coupling portion configured to convert a higher-order mode, other than any LP0n mode (where n is an integer of 2 or mor

Abstract: An object of the present disclosure is to allow gain compensation with a simple configuration without adding a new device to the outside. The present disclosure discloses a rare earth doped fiber including a core doped with a rare earth and a cladding region around the core, wherein one or more cavities are provided inside the core, and at least one of the cavities are provided along a longitudinal direction of the rare earth doped fiber.

Abstract: The present disclosure addresses the problem of providing at least a composition for suppressing obesity and the problem is solved by a composition for suppressing obesity comprising a prenylflavonoid represented by general formula (1), as an active ingredient, below.

Abstract: An object of the present invention is to provide a core position recognition method, a connection method, and a connection apparatus that can simplify connection operations, and reduce rotational displacement and positional displacement. The connection apparatus according to the present invention includes a function capable of acquiring the rotation amount of an MCF during the bonding/fixing step. Specifically, the connection apparatus of the present invention uses an MCF with lines drawn on a side surface thereof, thereby recognizing the rotation amount of the MCF from the side surface, and calculating the absolute positions of the cores. The connection apparatus according to the present invention can recognize the absolute position s of the cores from a side image of an MCF in a state in which the MCF has been rotated.

Abstract: Provided is a differential modal attenuation compensation fiber that has a simple structure and can reduce MDL while eliminating the need for precise alignment work, an optical amplifier, and a transmission line design method. The differential modal attenuation compensation fiber according to the present invention, imparts excess loss to a desired propagation mode by forming a cavity portion or a ring-shaped high refractive index portion in a core of an optical fiber. By forming the cavity portion or the ring-shaped high refractive index portion in a part of the profile of the core, electric field distribution of a particular mode propagating through the fiber can be controlled, and different losses can be imparted to different propagation modes at an interface between the cavity portion or the ring-shaped high refractive index portion and a region not including the cavity portion or the ring-shaped high refractive index portion.

Abstract: According to the connection device, the connection method, the optical connector manufacturing device, and the method for manufacturing an optical connector, rotation alignment of an MCF becomes unnecessary because an image of an end surface of the MCF to be connected is captured, the position of the core is located, and an optical waveguide is formed on a substrate so as to match the position. Thus, it is possible to solve the problem of increasing loss or complex connection work caused by rotational misalignment in association with rotation alignment.

Abstract: According to the connection device, the connection method, the optical connector manufacturing device, and the method for manufacturing an optical connector, rotation alignment of an MCF becomes unnecessary because an image of an end surface of the MCF to be connected is captured, the position of the core is located, and an optical waveguide is formed on a substrate so as to match the position. Thus, it is possible to solve the problem of increasing loss or complex connection work caused by rotational misalignment in association with rotation alignment.

Abstract: A game machine is provided comprising a game board which is constructed so that a game ball is movable on the side of a board face, and a game mechanism which includes a shooting portion for shooting a game ball onto the side of the board face of the game board, and game components arranged on the game board so that game balls moving on the board face of the game board may be capable of winning the prize; wherein the game mechanism is constructed so as to be capable of changing-over, at least between a first playable state where a first game is playable under a condition in which the inclination angle of the board face of the game board relative to a virtual horizontal plane exceeds a predetermined angle, and a second playable state where a second game is playable under a condition in which the inclination angle is equal to or less than the predetermined angle.