Abstract: The invention relates to a wavelength division multiplexing optical receiver that is provided with a polarization splitting grating coupler and a driving method for the same, where the power consumption is reduced, and at the same time, a degradation in the receiver sensitivity is suppressed. Two monitor photodetectors configured to monitor the light intensity of a first polarization component and a second polarization component separated by a polarization splitting optical coupler are provided, and a control circuit is provided in order to allow a semiconductor optical amplifier that amplifies the first polarization component and another semiconductor optical amplifier that amplifies the second polarization component in accordance with the signal intensity ratio of the two monitor photodetectors to amplify light with different light gains.

Abstract: Provided is a wavelength filter including: an optical waveguide core that includes n (n is an integer greater than or equal to 2) number of mode conversion parts and n?1 number of cavity parts that are alternately connected to each other in series; and cladding that surrounds the optical waveguide core. The mode conversion parts convert light having a specific wavelength of a p-order mode (p is an integer satisfying p?0) into light of a q-order mode (q is an integer satisfying q>p) and reflect the light. The cavity parts match phases of the light having the specific wavelength of the p-order mode propagating through the cavity part.

Abstract: An electro-optic device includes a first semiconductor layer including the rib-type waveguide, which includes a rib part and a first slab part, which extends in a first direction from the rib part; a dielectric layer, which is formed on the rib part; a second semiconductor layer, which extends in a second direction, which is opposite to the first direction, from an upper surface of the dielectric layer; a first high-concentration impurity region, which is formed in the first semiconductor layer to be in contact with the first slab part on the first direction side; and a second high-concentration impurity region, which is formed in a region of the second semiconductor layer on the second direction side. The second high-concentration impurity region is formed in a region other than a region overlapping the first semiconductor layer in a lamination direction.

Abstract: The invention relates to an optical fiber mounted photonic integrated circuit device, wherein the tolerance for positioning in terms of the coupling between the single mode optical fibers and the optical waveguides provided on the photonic integrated circuit device is increased. An optical waveguide core group is provided in such a manner where a plurality of optical waveguide cores having a portion that is tapered in the direction of the width within a plane are aligned parallel to each other at intervals that allow for mutual directional coupling and that are narrower than the width of the core of the single mode optical fiber, and the inclined connection end surface of the single mode optical fiber and the upper surface of an end portion of the optical waveguide cores face each other for coupling.

Abstract: An optical end coupling type silicon optical integrated circuit is provided using an SOI substrate. This optical integrated circuit is constituted so as to connect with an external optical circuit at an end coupling part and have signal light incident to an optical circuit that includes a curved part. In the plane of the optical integrated circuit, the position of one end coupling part selected from among any thereof and the position of any multimode optical waveguide element to which a respective optical waveguide is connected via a respective curved part satisfy a positional relationship defined on the basis of a beam divergence angle [theta] of stray light.

Abstract: The invention relates to an optical fiber mounted photonic integrated circuit device where the tolerance in the positioning of the coupling between a single mode optical fiber and an optical waveguide provided in the photonic integrated circuit device is increased. A second optical waveguide of which the cross-section of the core is in the form of a slab having a width that is greater than the mode diameter of the single mode optical fiber, and which is tapered in such a manner that the thickness of the core is reduced as the location is closer to the connection portion with the single mode optical fiber, is provided on the input/output end side of the first optical waveguide through which light propagates in such a manner that the inclined connection end surface of the single mode optical fiber is coupled to the upper surface of the second optical waveguide.

Abstract: An optical wiring module includes an optical wiring substrate on which an optical waveguide having a light input/output part is formed, and a fiber holder mounted on the optical wiring substrate, the fiber holder being configured to hold an optical fiber. The optical wiring substrate includes a hydrophobic film having an opening at a position corresponding to the light input/output part and a first adhesive layer disposed within the opening, and the optical fiber is optically coupled to the light input/output part via the first adhesive layer.

Abstract: An optical modulation device includes: an optical waveguide formed above a substrate; a phase modulator disposed on part of the optical waveguide; a capacitor connected to the phase modulator and including a lower electrode and an upper electrode; a resistor connected in parallel to the capacitor; and an appended part integrated with the upper electrode and electrically connected to the resistor, wherein the appended part is smaller in area than the capacitor (upper electrode).

Abstract: An optical functional device includes: a photodetector; a first optical waveguide which is connected to one end face of the photodetector; and a second optical waveguide which is connected to the other end face of the photodetector. The photodetector is formed in a multi-mode interferometer and has electrodes. Light input from the first optical waveguide to the photodetector focuses image at a position physically away from the second optical waveguide, and light input from the second optical waveguide to the photodetector focuses image at a position physically away from the first optical waveguide.

Abstract: An optical device includes an optical waveguide provided on a principal surface of a substrate. The optical waveguide includes a core and a cladding provided around the core. The cladding is configured by a substance having a refractive index smaller than 71.4% of the refractive index of the core. The core has constituent atoms substantially forming a diamond lattice structure. The optical waveguide has a light input/output part through which a light beam is input and/or output. The light input/output part decreases stepwise in thickness towards an output end while tapering down in its width. The core is provided in the light input/output part to have a (111) plane or an equivalent plane to the (111) plane exposed on a face of a riser of the stepwise thickness of the light input/output part.

Abstract: An optical element includes a gain chip, a ring modulator, which is a band-pass filter, a first optical waveguide and a second optical waveguide that are optically connected to the ring modulator, and a heater, wherein the first optical waveguide and the second optical waveguide are formed to be equal in optical path length (have no difference in optical path length) between a first light coupling point and a second light coupling point and equal in shape and length between the first light coupling point and the second light coupling point (to be symmetrical with the ring modulator interposed therebetween (with respect to the ring modulator)).

Abstract: An alignment optical measurement element includes a grating coupler, and a reflector coupled to the grating coupler. The alignment optical measurement element is arranged so that: the grating coupler diffracts an incident light in a first direction into a first diffracted light to propagate the first diffracted light as a first propagating light in a second direction, the reflector reflects the first propagating light into a second propagating light in a third direction opposite to the second direction; and the grating coupler diffracts the second propagating light into a second diffracted light to emit the second diffracted light as an emitted light in a fourth direction opposite to the first direction.

Abstract: An optical circuit module comprises a substrate with a first optical coupler connected to a first optical waveguide and a second optical coupler connected to a second optical waveguide on a substrate surface side; and a semiconductor photonic device mounted on the substrate, wherein the semiconductor photonic device has a third optical waveguide and a fourth optical waveguide extending to a first end face that faces the substrate surface, and wherein the third optical waveguide is optically connected to the first optical coupler and the fourth optical waveguide is optically connected to the second optical coupler.

Abstract: Provided is a light receiving element with high light receiving sensitivity. The light receiving element comprises: a light absorbing layer that absorbs light to generate a carrier; and a diffraction element that converts the optical path of first polarized light, which is obliquely incident on a plane formed by the light absorbing layer, so that the first polarized light propagates in a first direction along the light absorbing layer, and that converts the optical path of second polarized light incident from the same direction as the first polarized light so that the second polarized light propagates in a second direction, opposite the first direction, along the light absorbing layer.

Abstract: An electro-optical modulator includes a substrate 201; an optical waveguide formed of a silicon-containing i-type amorphous semiconductor 204 on the substrate; and a silicon-containing p-type semiconductor layer 203 and a silicon-containing n-type semiconductor layer 205 arranged apart from each other with the silicon-containing optical waveguide formed of an i-type amorphous semiconductor 204 interposed therebetween and constituting optical waveguides together with the silicon-containing optical waveguide formed of an i-type amorphous semiconductor. The silicon-containing p-type semiconductor layer 203 and/or silicon-containing n-type semiconductor layer 205 area crystalline semiconductor layer.

Abstract: Provided is a waveguide-type optical diffraction grating. A waveguide core includes a waveguide core that is asymmetric with respect to a thickness direction perpendicular to a light propagating direction. In the waveguide core, a phase adjustment portion is configured to adjust a phase difference between a forward wave traveling in an input direction and a reflected wave traveling in a direction reverse to the input direction in the waveguide-type optical diffraction grating, and the phase adjustment portion is provided in a manner that a sum of a phase of the forward wave and a phase of the reflected wave which are generated in the phase adjustment portion becomes a constant value irrespective of a polarization state of input light to the waveguide-type optical diffraction grating.

Abstract: There is provided an optical multiplexing and de-multiplexing element which is provided with a slab waveguide and a waveguide structure and can reduce radiation loss caused in a connection part between the slab waveguide and the waveguide structure. The waveguide structure includes a multimode interference (MMI) waveguide coupler and a narrow-width waveguide, the MMI waveguide coupler and the narrow-width waveguide are connected to each other in this order from a connection position with the slab waveguide along the waveguide direction, step portions are formed on both sides of the MMI waveguide coupler along the waveguide direction, and the thickness of the step portion is smaller than the thickness of the MMI waveguide coupler.

Abstract: An optical modulation device includes: an optical waveguide formed above a substrate; a phase modulator disposed on part of the optical waveguide; a capacitor connected to the phase modulator and including a lower electrode and an upper electrode; a resistor connected in parallel to the capacitor; and an appended part integrated with the upper electrode and electrically connected to the resistor, wherein the appended part is smaller in area than the capacitor (upper electrode).

Abstract: The invention relates to a wavelength division multiplexing optical receiver that is provided with a polarization splitting grating coupler and a driving method for the same, where the power consumption is reduced, and at the same time, a degradation in the receiver sensitivity is suppressed. Two monitor photodetectors configured to monitor the light intensity of a first polarization component and a second polarization component separated by a polarization splitting optical coupler are provided, and a control circuit is provided in order to allow a semiconductor optical amplifier that amplifies the first polarization component and another semiconductor optical amplifier that amplifies the second polarization component in accordance with the signal intensity ratio of the two monitor photodetectors to amplify light with different light gains.

Abstract: The invention relates to an optical fiber mounted photonic integrated circuit device where the tolerance in the positioning of the coupling between a single mode optical fiber and an optical waveguide provided in the photonic integrated circuit device is increased. A second optical waveguide of which the cross-section of the core is in the form of a slab having a width that is greater than the mode diameter of the single mode optical fiber, and which is tapered in such a manner that the thickness of the core is reduced as the location is closer to the connection portion with the single mode optical fiber, is provided on the input/output end side of the first optical waveguide through which light propagates in such a manner that the inclined connection end surface of the single mode optical fiber is coupled to the upper surface of the second optical waveguide.