Nippon Telegraph and Telephone Corporation

Masaya Notomi

Akihiko Shinya

Shota Kita

Kengo Nozaki

Eiichi Kuramochi

Kenta Takata

Masato Takiguchi

Masaaki Ono

Hideaki Taniyama

Satoshi Sasaki

Koji Yamada

Junichi Takahashi

Shinji Matsuo

Takaaki Kakitsuka

Itaru Yokohama

Guoqiang Zhang

Tetsuya Mukai

Naotomo Takemura

Kota Tateno

Atsushi Yokoo

Sergent Sylvain

Katsumasa Yoshioka

Chiharu Takahashi

Hisashi Sumikura

A nanowire optical device includes: a photonic crystal body having a planar shape and provided on a base part; an optical waveguide by a line defect in which a plurality of defects including a part without grating elements of the photonic crystal body are linearly arrayed; a trench formed in a waveguide direction in the optical waveguide; a nanowire made of a semiconductor and arranged in the trench; an n-type region formed on one end side of the nanowire; a p-type region formed on the other end side of the nanowire; an active region provided to be interposed between the n-type region and the p-type region in the nanowire; a first electrode connected to the n-type region; and a second electrode connected to the p-type region.

Nanowire optical device

A photonic crystal device to be used for trapping an atom and including a photonic crystal body, a slot waveguide, and an attractive force trap light laser. The photonic crystal body includes a base and a plurality of lattice elements periodically provided on the base, the slot waveguide is arranged between periodic lattice rows and includes an opening on one side face of the photonic crystal body, and the attractive force trap light laser is excited by excitation light incident from the opening and oscillates at a wavelength being longer than a wavelength of an absorption edge of the atom.

Photonic crystal device and atom trapping device

The output computing unit includes cascade-connected N number of Y coupling elements having two inputs and one output, and N number of optical intensity modulators. The N number of light intensity modulators individually modulate the intensity of a continuous light to a second optical input port, which is different from a first optical input port to which no light is input or to which a signal light from an optical output port of a Y coupling element in a previous stage, out of two optical input ports of each of the cascade-connected N number of Y coupling elements, in accordance with corresponding bits of an N-bit electric digital signal. The output light acquired from the Y coupling element 1-N in the final stage is regarded as the N-bit digital analog computing result.

Optical arithmetic unit

A photodetector includes a substrate, a material layer, a first electrode made of a metal, a core, a second electrode and a light absorption layer made of graphene. The first electrode, the core, and the material layer constitute a hybrid plasmonic waveguide, and the light absorption layer is disposed thereon. Light guided in the hybrid plasmonic waveguide is absorbed by the light absorption layer, photoelectrically converted by the PTE effect, and extracted as an electric signal from the first electrode and the second electrode.

Photo-detector

Each of six first lattice elements adjacent to a light confinement portion shifts from a lattice point in a direction of separating from the light confinement portion, and each of twelve second lattice elements shifts from a lattice point in a direction of separating from the light confinement portion. The second lattice elements are lattice elements arranged to be adjacent to the first lattice elements on a side of separating from the light confinement portion. Moreover, each of the first lattice elements has a smaller diameter than other lattice elements arranged on lattice points.

Photonic crystal optical resonator and method for fabricating same

An optical DAC includes a 1:N splitter that splits a single light beam into N light beams corresponding to bits of an N-bit electrical digital signal (where N is an integer of 2 or more) and makes the N light beams different in optical intensities such that (N−1) light beams corresponding to bits except a least significant bit of the N-bit electrical digital signal each have an optical intensity which is four times as large as an optical intensity of a light beam corresponding to a next less significant bit, an optical intensity modulator that individually intensity-modulates the N light beams, an N:1 combiner that combines the N output light beams intensity-modulated by the optical intensity modulator and outputs the combined light, and a phase shifter that is adjustable such that the light beams that are combined by the N:1 combiner are made in phase.

Optical digital/analog converter

An optical IQ modulator includes: Y branching elements, which are cascade-connected, each of which has one input and two outputs; QPSK modulators configured to perform QPSK modulation on continuous light branched by the Y branching elements to generate signal light; and Y combining elements, which are cascade-connected, each of which has two inputs and one output.

Optical IQ modulator

First lattice elements shift away from a light confinement portion in a second direction. Second lattice elements shift away from the light confinement portion in the second direction. Third lattice elements shift away from the light confinement portion in the second direction. A shift amount of the first lattice elements is 0.05 to 0.5 times as large as a crystal period. A shift amount of the second lattice elements is 0.02 to 0.5 times as large as the crystal period. A shift amount of the third lattice elements is 0.01 to 0.5 times as large as the crystal period.

Photonic crystal optical resonator

The amount of outward shift of a lattice element () and a lattice element (), the outward shift being symmetrical with respect to a resonator center on a straight line, is 0.42 to 0.5 times a lattice constant of a photonic crystal. The amount of outward shift of a lattice element () and a lattice element (), the outward shift being symmetrical with respect to the resonator center on the straight line, is 0.26 to 0.38 times the lattice constant of the photonic crystal. The amount of outward shift of a lattice element () and a lattice element (), the outward shift being symmetrical with respect to the resonator center on the straight line, is 0.13 to 0.19 times the lattice constant of the photonic crystal. The amount of outward shift of a lattice element () and a lattice element (), the outward shift being symmetrical with respect to the resonator center on the straight line, is &#x2212;0.1 to 0 times the lattice constant of the photonic crystal.

Photonic crystal optical element having an active medium in a light confinement portion

An active medium piece (), which has been taken out using a nanoprobe (), is processed so as to match the shape of a nanoslot (), and thus an active medium small piece () that is smaller than the active medium piece () is formed (a fourth step). For example, irradiation with an ion beam () is performed so that the active medium piece () is shaped (processed) into an active medium small piece () that has a three-dimensional shape suitable for being placed in the nanoslot (). The active medium piece () is processed into the active medium small piece () in the state of being held by the nanoprobe ().

Method for manufacturing optical device

The objective of the invention is to provide a photonic crystal device which enables efficient confinement of carriers while preventing the deterioration of device characteristics. Specifically a photonic crystal device has a photonic crystal in which media with different refractive indexes are regularly arranged, wherein an active region () includes an active layer () and carrier confinement layers () provided on the top and bottom of the active layer () respectively for confining carriers. The photonic crystal is formed by a buried growth layer () with a larger bandgap than that of the active region ().

Photonic crystal device

A two-dimensional photonic crystal slab waveguide is provided in which a line defect is formed, wherein a first width which is a distance between centers of nearest two lattice points located on both sides of the line defect is different from a second width which is a corresponding distance in a normal two-dimensional photonic crystal slab waveguide. In addition, a two-dimensional photonic crystal slab waveguide is provided in which low refractive index columns in a optical waveguide part are placed at positions shifted from normal positions in a normal two-dimensional photonic crystal slab.

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Tokyo, Japan

Masaya Notomi