Abstract: An optical amplifier of the present disclosure includes an optical resonator that includes an amplification fiber capable of amplifying signal light having one or more propagation modes and resonates at least one propagation mode of the signal light amplified by the amplification fiber; an excitation light source that outputs excitation light for exciting the amplification fiber; and a multiplexer that multiplexes the signal light and the excitation light, in which the optical resonator includes a gain clamp setting unit which sets gain clamp for at least one propagation mode out of a plurality of propagation modes resonating in the optical resonator.

Abstract: The optical fiber of the present invention includes a core, and a cladding that is provided on an outer periphery of the core and has a refractive index lower than a refractive index of the core region. In the optical fiber of the present invention, a V value representing a normalized frequency of an LP02 mode is greater than or equal to 4.8 and less than or equal to 6.4.

Abstract: An example of an information processing apparatus acquires action data based on an output of a sensor according to a fitness action performed by a player, and executes a game event. In the game event, the information processing apparatus designates at least one type of fitness event from among a plurality of types of fitness events. Each fitness event causes the player to perform a fitness action. During the game event, the information processing apparatus executes a fitness event that causes the player to perform a fitness action corresponding to the designated fitness event until an ending condition is satisfied. The information processing apparatus determines whether or not the achievement condition has been satisfied, based on the action data acquired during the fitness event. The information processing apparatus repeats designation and execution of the fitness event until it is determined that the achievement condition has been satisfied.

Abstract: A clamp-on type ultrasonic flowmeter which is detachably attached to an outer wall of cylindrical piping is provided. An ultrasonic signal is transmitted to the piping from one of the first and the second ultrasonic devices, a plate wave corresponding to the ultrasonic signal is generated, and an ultrasonic signal corresponding to the plate wave is received by the other ultrasonic device. A pipe wall thickness of the piping and a frequency of the ultrasonic signal are in a state in which a plate wave of a low order asymmetric mode is significantly excited in the piping. A flow rate is calculated corresponding to phase velocity characteristics of the low order asymmetric mode.

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: In the exemplary embodiment, a computer is caused to: perform question presentation processing of designating a correct direction for each question by display; specify an input direction on the basis of the operation data transmitted from an operation device; perform correct answer determination for whether the input direction is the designated correct direction or a direction other than the designated correct direction on the basis of a predetermined determination condition; in performing the correct answer determination, change the determination condition in accordance with the correct direction so that the specified input direction becomes likely to be determined to be the correct answer; and progress a game on the basis of a result of the correct answer determination.

Abstract: An example of an information processing apparatus acquires action data based on an output of a sensor according to a fitness action performed by a player, and executes a game event. In the game event, the information processing apparatus designates at least one type of fitness event from among a plurality of types of fitness events. Each fitness event causes the player to perform a fitness action. During the game event, the information processing apparatus executes a fitness event that causes the player to perform a fitness action corresponding to the designated fitness event until an ending condition is satisfied. The information processing apparatus determines whether or not the achievement condition has been satisfied, based on the action data acquired during the fitness event. The information processing apparatus repeats designation and execution of the fitness event until it is determined that the achievement condition has been satisfied.

Abstract: An example of a training tool includes a first sensor. The training tool deforms from a stationary state when a force is externally applied thereto. The first sensor output according to deformation of the training tool. A processor receives first sensor information based on an output of the first sensor. While a menu is presented, the processor executes a process according to a first instruction performed on the menu, in a case where the received first sensor information indicates an output obtained when the training tool deforms in a first direction, and executes a process according to a second instruction that is performed on the menu and is different from the first instruction, in a case where the received first sensor information indicates an output obtained when the training tool deforms in a second direction opposite to the first direction.

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: The optical fiber according to the present disclosure is an optical fiber having a pure silica core which is a step index core through which an LPm1 mode with an effective area of 250 ?m2 or more is propagated by setting a relative refractive index difference to 0.60% or less, considering an effective cutoff condition, and only 2 or more modes or the LPm1 mode are propagated, with the optical fiber as the transmission line.

Abstract: A differential mode attenuation compensator includes a first multi-mode optical fiber and a third multi-mode optical fiber in which a plurality of propagation modes propagate in a wavelength of a propagating optical signal; and a second multi-mode optical fiber including a core and a clad and arranged with a central axis aligned between the first multi-mode optical fiber and the third multi-mode optical fiber, in which each loss in the plurality of propagation modes is different in the first multi-mode optical fiber and the third multi-mode optical fiber.

Abstract: The optical fiber of the present invention includes a core, and a cladding that is provided on an outer periphery of the core and has a refractive index lower than a refractive index of the core region. In the optical fiber of the present invention, a V value representing a normalized frequency of an LP02 mode is greater than or equal to 4.8 and less than or equal to 6.4.

Abstract: An optical transmission system according to the present disclosure is a mode multiplexed optical transmission system using a multi-mode optical fiber in which a plurality of propagation modes propagate as a transmission line, the optical transmission system including an optical fiber transmission line (83) that includes an optical fiber with two or more propagation modes; and a plurality of mode converters (91) that are configured to generate mode coupling between at least one pair of the propagation modes, in which a variation in an installation interval of the plurality of mode converters (91) is equal to or less than a threshold value determined by the transmission line length (Lt) of the optical fiber transmission line (83).

Abstract: A clamp-on type ultrasonic flowmeter which is detachably attached to an outer wall of cylindrical piping is provided. An ultrasonic signal is transmitted to the piping from one of the first and the second ultrasonic devices, a plate wave corresponding to the ultrasonic signal is generated, and an ultrasonic signal corresponding to the plate wave is received by the other ultrasonic device. A pipe wall thickness of the piping and a frequency of the ultrasonic signal are in a state in which a plate wave of a low order asymmetric mode is significantly excited in the piping. A flow rate is calculated corresponding to phase velocity characteristics of the low order asymmetric mode.

Abstract: An optical fiber having a graded index (GI)-type core refractive index profile in which a propagation mode can propagate Z (Z is an integer of 2 or more) or more is provided. In the optical fiber, an ?-parameter is a value in which a propagation constant mutual difference is 1000 rad/m or less in a propagation mode group of a mode group M (M is M=2p+l?1 and 3 or more when a propagation mode is denoted by LPlp).

Abstract: The optical fiber according to the present disclosure is an optical fiber having a pure silica core which is a step index core through which an LPm1 mode with an effective area of 250 ?m2 or more is propagated by setting a relative refractive index difference to 0.60% or less, considering an effective cutoff condition, and only 2 or more modes or the LPm1 mode are propagated, with the optical fiber as the transmission line.

Abstract: An optical amplifier of the present disclosure includes an optical resonator that includes an amplification fiber capable of amplifying signal light having one or more propagation modes and resonates at least one propagation mode of the signal light amplified by the amplification fiber; an excitation light source that outputs excitation light for exciting the amplification fiber; and a multiplexer that multiplexes the signal light and the excitation light, in which the optical resonator includes a gain clamp setting unit which sets gain clamp for at least one propagation mode out of a plurality of propagation modes resonating in the optical resonator.

Abstract: A differential mode attenuation compensator includes a first multi-mode optical fiber and a third multi-mode optical fiber in which a plurality of propagation modes propagate in a wavelength of a propagating optical signal; and a second multi-mode optical fiber including a core and a clad and arranged with a central axis aligned between the first multi-mode optical fiber and the third multi-mode optical fiber, in which each loss in the plurality of propagation modes is different in the first multi-mode optical fiber and the third multi-mode optical fiber.

Abstract: An optical transmission system according to the present disclosure is a mode multiplexed optical transmission system using a multi-mode optical fiber in which a plurality of propagation modes propagate as a transmission line, the optical transmission system including an optical fiber transmission line (83) that includes an optical fiber with two or more propagation modes; and a plurality of mode converters (91) that are configured to generate mode coupling between at least one pair of the propagation modes, in which a variation in an installation interval of the plurality of mode converters (91) is equal to or less than a threshold value determined by the transmission line length (Lt) of the optical fiber transmission line (83).