Abstract: [Object] To provide an interferometric optical fiber gyroscope that can perform higher-accuracy measurement and can be produced at a low cost. [Solving Means] An interferometric optical fiber gyroscope is an interferometric optical fiber gyroscope that detects angular velocity by optical interference between counterclockwise light and clockwise light. In such an interferometric optical fiber gyroscope that detects angular velocity by optical interference between counterclockwise light and clockwise light, the interferometric optical fiber gyroscope includes: a sensing coil mechanism including a multicore fiber that includes a plurality of transmission cores, and a multicore fiber optical path junction that optically couples at least a first transmission core and a second transmission core, of the plurality of transmission cores.

Abstract: An optical communication system is arranged to bring out potential capabilities of mode-division multiplexing (MDM). The optical communication system includes a hologram medium in which holograms are multiplex-recorded so as to correspond to respective spatial modes of signal light transmitted by a multi-mode fiber (MMF). A phase plate modulates phases of the respective spatial modes so as to reduce a spatial overlap between the spatial modes, and is provided on a side of the hologram medium on which signal light enters the hologram medium.

Abstract: An object of the present invention is to bring out potential capabilities of mode-division multiplexing (MDM). An optical communication system includes a hologram medium (1) in which holograms are multiplex-recorded so as to correspond to respective spatial modes of signal light transmitted by a multi-mode fiber (MMF) (2). A phase plate (4) which modulates phases of the respective spatial modes so as to reduce a spatial overlap between the spatial modes is provided on a side of the hologram medium (1) on which side the signal light enters the hologram medium (1).

Abstract: A device for coupling a multicore/multimode fiber that can transmit a large quantity of information. This multicore/multimode fiber coupling device has a first fiber group (11), a first light converging system (13), a first mode converter (15), a second fiber group (21), a second light converging system (23), and light converging system (33) for multicore fibers. By means of the first mode converter (15), light from the first fiber group (11) is subjected to mode conversion en masse. A space coupling system (33) for multicore fibers transmits light derived from the second fiber group (21) and light derived from the first fiber group (11) subjected to mode conversion to the multicore fibers (31).