Hokkaido University

National Institute of Information and Communications Technology, Incorporated

Optoquest Co., Ltd.

Atsushi Okamoto

Naoya Wada

Tomokazu Oda

Taketoshi Takahata

Shusaku Noda

Jin Nozawa

Yuta Wakayama

Keisuke Kunori

Masanori Takabayashi

Kazuyuki Morita

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.

Optical communication system and optical communication method

The present invention relates to an optical phase measuring method and an optical phase measuring device which can measure phase information contained in an object beam with high accuracy. Intensity distributions of a test object beam, a first reference beam and a first hologram made from the object beam and the first reference beam are detected by the first light intensity detection section. Intensity distributions of the test object beam, a second reference beam and a second hologram made from the object beam and the second reference beam are detected in the second light intensity detection section. Phase information contained in the object beam is computed on the basis of the intensity distributions detected in the first light intensity detection section and the intensity distributions detected in the second light intensity detection section.

Method for measuring optical phase, device for measuring optical phase, and optical communication device

The present invention relates to a reproduction device of a holographic memory capable of precisely reproducing multi-value phase information without being influenced by noise. This holographic memory reproduction device comprises: a hologram diffraction ray generation unit which irradiates a first reference ray to the holographic memory and generates a diffraction ray of the first hologram; a hologram generation unit which changes the phase of a second reference ray which may interfere with the diffraction ray of the first hologram and generates a second hologram from the diffraction ray of the first hologram and the second reference ray to which the phase has been changed; a detection unit which detects the intensity distribution of the second hologram; and a processing unit which demodulates the phase modulation signal or the space quadrature amplitude modulation signal on the basis of the intensity distribution.

Holographic memory reproduction device and holographic memory reproduction method, demodulation device and demodulation method, and observation device and observation method

The present invention causes spatial-mode light emitted from an optical fiber (), which is a multimode fiber, to pass through a photorefractive medium (). The photorefractive medium () includes holograms for signal separation that are written by irradiation of the photorefractive medium with (i) guide light having a wave front identical to the wave front of signal light having a particular spatial mode and (ii) control light. The photorefractive medium includes holograms recorded in a multiplex manner with use of control light having different incidence angles in correspondence with respective spatial modes. For signal separation, irradiating the photorefractive medium () with control light () having a particular angle separates signal light having a spatial mode corresponding to the incidence angle of the control light ().

Optical communication system

Growing community of inventors

Sapporo, Japan

Atsushi Okamoto