Abstract: In an electro-optic device, a stack structure including a first silicon layer of a first conductivity type and a second silicon layer of a second conductivity type has a rib waveguide shape so as to form an optical confinement area, and a slab portion of a rib waveguide includes an area to which a metal electrode is connected. The slab portion in the area to which the metal electrode is connected is thicker than a surrounding slab portion. The area to which the metal electrode is connected is set so that a range of a distance from the rib waveguide to the area to which the metal electrode is connected is such that when the distance is changed, an effective refractive index of the rib waveguide in a zeroth-order mode does not change.

Abstract: An optical modulation structure includes a lower cladding layer (102), a first silicon layer (103) integrally formed from silicon of a first conductivity type on the lower cladding layer (102) while including a core (104) and slab regions (105) arranged on both sides of the core (104) and connected to the core, a concave portion (104a) formed in an upper surface of the core (104), and a second silicon layer (109) of a second conductivity type formed on a dielectric layer (108) in the concave portion (104a) so as to fill the concave portion (104a).

Abstract: In a waveguide path coupling-type photodiode, a semiconductor light absorbing layer and an optical waveguide path core are adjacently arranged. An electrode formed of at least one layer is installed in a boundary part of the semiconductor light absorbing layer and the optical waveguide path core. The electrodes are arranged at an interval of (1/100)? to ? [?: wavelength of light transmitted through optical waveguide path core]. At least a part of the electrodes is embedded in the semiconductor light absorbing layer. Embedding depth from a surface of the semiconductor light absorbing layer is a value not more than ?/(2 ns) [ns: refractive index of semiconductor light absorbing layer]. At least one layer of the electrode is constituted of a material which can surface plasmon-induced.

Abstract: Provided is a high-speed and highly efficient semiconductor light-receiving element with small dependence on an incident light polarization direction. A semiconductor light-receiving element according to one aspect of the present invention includes a semiconductor layer including a light-absorbing layer 4, an MSM electrode 1 that is provided over the semiconductor layer, forms a Schottky junction with the semiconductor layer, and includes a slit-like opening, an anti-reflective film 2 formed over the semiconductor layer and the MSM electrode 1, and a Bragg reflection multilayer film 6 provided to a lower part of the semiconductor layer. The MSM electrode 1 includes a period capable of exciting surface plasmon to incident light of TM polarization, and obtains sufficient transmittance to the incident light of TE polarization.

Abstract: The present invention provides a photodetector which solves the problem of low sensitivity of a photodetector, an optical communication device equipped with the same, and a method for making the photodetector, and a method for making the optical communication device. The photodetector includes a substrate, a lower cladding layer arranged on the substrate, an optical waveguide arranged on the lower cladding layer, an intermediate layer arranged on the optical waveguide, a optical absorption layer arranged on the intermediate layer, a pair of electrodes arranged on the optical absorption layer, and wherein the optical absorption layer includes a IV-group or III-V-group single-crystal semiconductor, and the optical absorption layer absorbs an optical signal propagating through the optical waveguide.

Abstract: A semiconductor device comprises a semiconductor layer having a semiconductor integrated circuit, which is for processing an electrical signal, on a semiconductor substrate and an optical interconnect layer for transmitting an optical signal are joined. Control of modulation of the optical signal transmitted in the optical interconnect layer is performed by an electrical signal from the semiconductor layer, and an electrical signal generated by reception of light in the optical interconnect layer is transmitted to the semiconductor layer. The optical interconnect layer is disposed on the underside of the semiconductor substrate.

Abstract: To provide an optical modulator having a reduced size and reduced power consumption and capable of being easily connected to a waveguide and a method of manufacturing the optical modulator. The optical modulator has at least semiconductor layer (8) having a rib-shaped portion and doped so as to be of a first conduction type, dielectric layer (11) laid on first-conduction-type semiconductor layer (8), and semiconductor layer (9) laid on dielectric layer (11), having the width at the side opposite from dielectric layer (11) increased relative to the width of the rib-shaped portion, and doped so as to be of a second conduction type.

Abstract: Provided is a semiconductor optical interconnection device capable of transmitting signals between laminated semiconductor chips in a structure where semiconductor chips highly functionalized by being bonded to an optical interconnection chip are laminated. The semiconductor optical interconnection device includes a semiconductor chip 1 and an optical interconnection chip 2. The optical interconnection chip 2 includes an optical element formed thereon (for instance, a photo-sensitive element, a luminous element, or an optical modulator) which has a function relating to signal conversion between light and electricity. The semiconductor chip 1 includes a transmission section 3 (for instance, a coil or an inductor) to transmit signals in a non-contact manner, and a connection section 4 (for instance, a bump) to electrically connect with the optical element.

Abstract: The Si waveguide 305 includes a first conductivity-type Si layer 301 and an intrinsic Si layer 302, and a second conductivity-type light-absorption layer 303 is partially formed on an area thereof. During operation, a reverse bias is applied between the first conductivity-type Si layer 301 and the light-absorption layer 303. Since the light-absorption layer 303 has a conductivity type, it is not depleted when a voltage is applied, but the intrinsic Si layer 302 forming the Si waveguide 305 is depleted. Therefore, it is possible to reduce a CR time constant. Furthermore, since the intrinsic Si layer 302 can be formed on the first conductivity-type Si layer 301 in a continuous manner, it is possible to reduce lattice defects. As a result, it is possible to suppress the dark current generated in the light-receiving element.

Abstract: A downsized, low-power electro-optical modulator that achieves reducing both of the additional resistance in the modulation portion and the optical loss each caused by electrodes at the same time is provided. The electro-optical modulator includes a rib waveguide formed by stacking a second semiconductor layer 9 having a different conductivity type from a first semiconductor layer 8 on the first semiconductor layer 8 via a dielectric film 11, and the semiconductor layers 8 and 9 are connectable to an external terminal via highly-doped portions 4 and 10, respectively. In a region in the vicinity of contact surfaces of the semiconductor layers 8 and 9 with the dielectric film 11, a free carrier is accumulated, removed, or inverted by an electrical signal from the external terminal, and whereby a concentration of the free carrier in an electric field region of an optical signal is modulated, so that a phase of the optical signal can be modulated.

Abstract: The lattice mismatching between a Ge layer and a Si layer is as large as about 4%. Thus, when the Ge layer is grown on the Si layer, penetration dislocation is introduced to cause leakage current at the p-i-n junction. Thereby, the photo-detection sensitivity is reduced, and the reliability of the element is also lowered. Further, in the connection with a Si waveguide, there are also problems of the reflection loss due to the difference in refractive index between Si and Ge, and of the absorption loss caused by a metal electrode.

Abstract: Provided is a connecting channel that has manufacturing tolerance, can suppress light loses, improves reliability of the connecting channel, and connects an optical device and an optical waveguide. The connecting channel includes first silicon layer (3) that has rib-shaped part (3?) extending in a longitudinal direction of the connecting channel, and second silicon layer (6) that is stacked on first silicon layer (3) to partially overlap rib-shaped part 3?, and extends in the longitudinal direction. Second silicon layer (6) has tapered part (W) tapered toward one end in the longitudinal direction, and is located away from an upper portion of rib-shaped part (3?) at an end surface of one end in the longitudinal direction.

Abstract: A photodiode includes: an upper spacer layer including a semiconductor transparent to incident light; a metal periodic structure provided on the upper spacer layer and arranged to induce surface plasmon, the metal periodic structure including first and second electrodes including portions arranged alternately on the upper spacer layer; a light absorption layer formed under the upper spacer layer and including a semiconductor having a refractive index higher than that of the upper spacer layer; and a lower spacer layer formed under the light absorption layer and having a refractive index smaller than that of the light absorption layer. Each of the first and second electrodes forms a Schottky barrier junction with the upper spacer layer.

Abstract: Provided is a small-size optical phase modulation element and an optical modulator using it. The optical phase modulation element includes a Plasmon waveguide having a clad made of a metal material having a complex dielectric constant having a negative real part in the used wavelength and a core formed by a dielectric metal material having a complex dielectric constant having a positive real part in the used wavelength. The Plasmon waveguide is connected to an optical waveguide including a clad and a core both having a complex dielectric constant having a positive real part. The core of the Plasmon waveguide and the core of the optical waveguide are formed, at least partially, of the same semiconductor material. The Plasmon waveguide has a function to phase-modulate the incident light when voltage is applied.

Abstract: An optical modulator according to the present invention is configured at least by a semiconductor layer subjected to a doping process so as to exhibit a first conductivity type, and a semiconductor layer subjected to a doping process so as to exhibit a second conductivity type. Further, in the optical modulator, at least the first conductivity type semiconductor layer, a dielectric layer, the second conductivity type semiconductor layer, and a transparent electrode optically transparent in at least a near-infrared wavelength region are laminated in order.

Abstract: The components are a lower clad layer (102), a first silicon layer (103) that is formed on the lower clad layer (102) as a single body made of silicon of a first conduction type and has a slab region (105) that is disposed at a core (104) and on both sides of the core (104) and connects to the core, a concave section (104a) that is formed in the top surface of the core (104), and a second silicon layer (109) of a second conduction type that is formed inside the concave section (104a) with an intervening dielectric layer (108) to fill the inside of the concave section (104a).

Abstract: In an electro-optic device, a stack structure including a first silicon layer of a first conductivity type and a second silicon layer of a second conductivity type has a rib waveguide shape so as to form an optical confinement area, and a slab portion of a rib waveguide includes an area to which a metal electrode is connected. The slab portion in the area to which the metal electrode is connected is thicker than a surrounding slab portion. The area to which the metal electrode is connected is set so that a range of a distance from the rib waveguide to the area to which the metal electrode is connected is such that when the distance is changed, an effective refractive index of the rib waveguide in a zeroth-order mode does not change.

Abstract: An optical modulator is formed with at least a portion of a semiconductor layer (8) that has undergone a doping process to exhibit a first conductivity and at least a portion of a semiconductor layer (9) that has undergone a doping process to exhibit a second conductivity overlapping with a dielectric layer (11) interposed. The surface of the semiconductor layer (8) of first conductivity has an uneven form in the portion in which the semiconductor layer (8) that exhibits first conductivity and the semiconductor layer (9) that exhibits second conductivity overlap with the dielectric layer (11) interposed. The dielectric layer (11) is formed on the semiconductor layer (8) of first conductivity that has the uneven form, and the semiconductor layer (9) of second conductivity is formed on the dielectric layer (11).

Abstract: Provided is a high-speed and highly efficient semiconductor light-receiving element with small dependence on an incident light polarization direction. A semiconductor light-receiving element according to one aspect of the present invention includes a semiconductor layer including a light-absorbing layer 4, an MSM electrode 1 that is provided over the semiconductor layer, forms a Schottky junction with the semiconductor layer, and includes a slit-like opening, an anti-reflective film 2 formed over the semiconductor layer and the MSM electrode 1, and a Bragg reflection multilayer film 6 provided to a lower part of the semiconductor layer. The MSM electrode 1 includes a period capable of exciting surface plasmon to incident light of TM polarization, and obtains sufficient transmittance to the incident light of TE polarization.

Abstract: A Schottky photodiode includes a semiconductor layer and a conductive film provided in contact with the semiconductor layer. The conductive film has an aperture and a periodic structure provided around said aperture for producing a resonant state by an excited surface plasmon in a film surface of the conductive film by means of the incident light to the film surface. The photodiode detects near-field light that is generated by at the interface between the conductive film and semiconductor layer the excited surface plasmon. The aperture has a diameter smaller than the wavelength of the incident light.