Abstract: An optical fiber that communicates in a predetermined communication band includes: a signal light propagation core that propagates light beams of up to (x+1)-th order LP mode, where x is an integer of two or more; and a coupler that propagates a light beam that is: coupled with a light beam of the (x+1)-th order LP mode propagating through the signal light propagation core, and suppressed from being coupled with light beams of up to the x-th order LP mode propagating through the signal light propagation core, wherein, mode coupling of the light beams of up to the x-th order LP mode propagating through the signal light propagation core is performed, and mode coupling between the light beam of the x-th order LP mode and the light beam of (x+1)-th order LP mode is suppressed.

Abstract: A multicore fiber includes a plurality of cores including a first core and a cladding surrounding the plurality of cores. The first core includes: an inner core; and an outer core surrounding the inner core with no gap and having a refractive index higher than a refractive index of the inner core and a refractive index of the cladding. The core is not doped with any rare earth element. At least two LP mode light beams at a predetermined wavelength propagate through the first core at an attenuation of 0.3 dB/km or less.

Abstract: A method of measuring crosstalk of a multicore fiber, the method including capturing an emitted light pattern at an end portion of a dummy fiber and obtaining a correlation data between a power of the light incident on the dummy fiber and the emitted light pattern, irradiating one core of the multicore fiber with a light through the dummy fiber, and measuring a power of a reference light emitted from the core, capturing a crosstalk light emitted from a different core different from the core on which the light is incident under a state where the reference light is masked, and estimating a power of the crosstalk light from a captured data of the crosstalk light and the correlation data, and calculating the crosstalk from the power of the reference light and the power of the crosstalk light.

Abstract: A multicore fiber that includes: three or more cores that transmit in single-mode transmission; a common clad that covers a periphery of the three or more cores; and a low-refractive index portion that has a refractive index lower than a refractive index of the clad. The multicore fiber further includes a region having the three or more cores arranged annularly on a cross-section perpendicular to a longitudinal direction. At least a portion of the low-refractive index portion is arranged inside a minimum inscribed circle of two adjacent cores within the region.

Abstract: A characteristic-measuring apparatus for a multi-core fiber includes: a coupling device that couples, at a first end of the multi-core fiber, light to a plurality of cores in the multi-core fiber; an imaging device that takes an image, at a second end of the multi-core fiber, of emission light emitted from the plurality of cores, where the plurality of cores are imaged at the same time; and a calculating device that determines a characteristic of the multi-core fiber based on images obtained by the imaging device.

Abstract: A multicore fiber including two or more cores each capable of single mode transmission, a cladding covering around the two or more cores in common, and a low refractive index portion having a refractive index lower than a refractive index of the cladding, wherein a cross-section perpendicular to a longitudinal direction includes a region where two or more cores of a part or all of the two or more cores are arranged in a circular shape and at least a part of the low refractive index portion is arranged inside an inscribed circle of the cores included in the region.

Abstract: A multicore fiber including two or more cores each capable of single mode transmission, a cladding covering around the two or more cores in common, and a low refractive index portion having a refractive index lower than a refractive index of the cladding, wherein a cross-section perpendicular to a longitudinal direction includes a region where two or more cores of a part or all of the two or more cores are arranged in a circular shape and at least a part of the low refractive index portion is arranged inside an inscribed circle of the cores included in the region.

Abstract: An electrostatic chuck includes an anisotropic heat conductor which is disposed between an attraction substrate and a first heater member, and has an upper surface and a lower surface, and a coefficient of thermal conductivity which varies depending on directions. The anisotropic heat conductor is disposed so that the coefficient of thermal conductivity in a plane direction is larger than the coefficient of thermal conductivity in a thickness direction. Further, the electrostatic chuck includes metal layers which are joined to the anisotropic heat conductor so as to cover the upper surface and the lower surface of the anisotropic heat conductor, and an adhesive layer which is provided on a surface of each metal layer, and joins the metal layer to the attraction substrate or the heater member. Moreover, at least one of the metal layers is a fused metal layer formed by solidifying a melted metal.

Abstract: A switching element (A) is connected in parallel to a load (L). A switching element (B) is connected between the switching element (A) and a grounding point. The drive circuit (1) drives the switching element (A). The drive circuit (2) drives the switching element (B). Upon detecting a load short circuit, a load short circuit detection circuit (3) outputs a first signal. A timer (6) outputs a second signal after a lapse of a predetermined time after inputting the first signal. Upon receiving the first signal, the drive circuit (1) turns ON the switching element (A). Upon receiving the second signal, the drive circuit (2) turns OFF the switching element (B).

Abstract: A switching element (A) is connected in parallel to a load (L). A switching element (B) is connected between the switching element (A) and a grounding point. The drive circuit (1) drives the switching element (A). The drive circuit (2) drives the switching element (B). Upon detecting a load short circuit, a load short circuit detection circuit (3) outputs a first signal. A timer (6) outputs a second signal after a lapse of a predetermined time after inputting the first signal. Upon receiving the first signal, the drive circuit (1) turns ON the switching element (A). Upon receiving the second signal, the drive circuit (2) turns OFF the switching element (B).

Abstract: The invention provides a module for electronic musical instruments and an electronic musical instrument that is easy to use during drinking and allow a user to know the alcohol concentration in their exhaled breath in a timely manner. The electronic musical instrument of the present invention can easily be used by a user while drinking. Accordingly, the user and the audience can know the alcohol concentration in the user's exhaled breath in timely manner.