An integrated structure and method of formation provide a lower level waveguide having a core of a first material and a higher level waveguide having a core of a second material and a coupling region for coupling the two waveguides together. The different core materials provided different coupled waveguides having different light loss characteristics.

The present invention discloses a TMOS with a high extinction ratio based on slab PhCs which comprises an upper slab PhC and a lower slab PhC connected as a whole; the upper slab PhC is called as a first square-lattice slab PhC, wherein the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three first flat dielectric pillars and a background dielectric, and the first flat dielectric pillars includes a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or of 1 to 3 high-refractive-index flat films, or of a low-refractive-index dielectric; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three second flat dielectric pillars and a background dielectric is a low-refractive-index dielectric and an normalized operating frequency of the TMOS is 0.4057 to 0.406.

The present invention discloses a TEOS based on slab PhCs with a high DOP and large EXR, which comprises an upper slab PhC and a lower slab PhC; the upper slab PhC is a first square-lattice slab PhC with a TM bandgap and a complete bandgap, wherein the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single first flat dielectric pillar and a background dielectric, the first flat dielectric pillar includes a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or a high-refractive-index flat film, or a low-refractive-index dielectric; the lower slab PhC is a second square lattice slab PhC with a TM bandgap and complete bandgap, wherein the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single second flat dielectric pillar and a background dielectric, and an normalized operating frequency of the TEOS is 0.453 to 0.458.

This photonic transmitter includes a layer made of dielectric material, a sublayer made of doped III-V crystalline material extending directly over the layer made of dielectric material, a laser source including the sublayer made of doped III-V crystalline material, a modulator including a waveguide formed by proximal ends facing first and second electrodes and that segment of the layer made of dielectric material which is interposed between these proximal ends, and a zone composed only of one or more solid dielectric materials, which extends from a distal end of the second electrode to a substrate, and under the entirety of the distal end of the second electrode.

This slow light waveguide includes an initial region which extends, along an optical axis, from a start starting from which the width of a central waveguide begins to continuously decrease up to an end beyond which the width of the central waveguide no longer decreases up to the end of a slowing section, this initial region overlapping a broadening region where the length of lateral teeth continuously increases, a final region which extends, along the optical axis, from a start starting from which the width of the central waveguide begins to continuously increase up to an end beyond which the width of the central waveguide no longer increases, this final region overlapping a narrowing region where the length of the lateral teeth continuously decreases.

An optical integrated circuit includes: a mode conversion and branching section that launches light from a first optical waveguide to a second optical waveguide, converts light from the first optical waveguide into converted light, and launches the converted light to a third optical waveguide; an optical multiplexing and branching section that multiplexes lights from the second and third optical waveguides into one multiplexed light component, and branches the multiplexed light component into a light component to be input to a fourth optical waveguide and a light component to be input to a fifth optical waveguide; a phase modulation section that is provided in at least one of the fourth and fifth optical waveguides and modulates a phase of guided light; and an optical multiplexing section that multiplexes light components from the fourth and fifth optical waveguides into one light component.

An optical modulator for switching an optical signal of wavelength λ from one waveguide-electrode to another requires that both waveguide-electrodes be made of an electrically conducting material. Also, a non-conducting cross-coupling material fills a slot along a length L between the waveguide-electrodes. Importantly, cross-coupling material in the slot provides a separation distance x.sub.c between the waveguide-electrodes that is less than 0.35 microns. When a switching voltage V.sub.π is selectively applied to the waveguide-electrodes, a strong uniform electric field E is created within the cross-coupling material. Thus, E modulates the cross-coupling length of the optical signal by an increment ±Δ each time it passes back and forth through the cross-coupling material along the length L. Thus, after an N number of cross-coupling length cycles along the length L, when NΔ equals one cross-coupling length, the optical signal is switched from one waveguide-electrode to the other.

An integrated optical beam steering device includes a planar dielectric lens that collimates beams from different inputs in different directions within the lens plane. It also includes an output coupler, such as a grating or photonic crystal, that guides the collimated beams in different directions out of the lens plane. A switch matrix controls which input port is illuminated and hence the in-plane propagation direction of the collimated beam. And a tunable light source changes the wavelength to control the angle at which the collimated beam leaves the plane of the substrate. The device is very efficient, in part because the input port (and thus in-plane propagation direction) can be changed by actuating only log.sub.2 N of the N switches in the switch matrix. It can also be much simpler, smaller, and cheaper because it needs fewer control lines than a conventional optical phased array with the same resolution.

A device includes an optical splitter comprising a plurality of splitter outputs. The splitter outputs are out of phase and include a non-uniform phase front. The device includes a one-dimensional phase compensation array communicating with the optical splitter. The phase compensation array receives the non-uniform phase front and outputs a uniform phase front. The phase compensation array includes a plurality of array outputs. The device includes a tunable linear gradient phase shifter communicating with said phase compensation array to impart a linearly-varying phase shift across said plurality of array outputs, thereby steering a beam along a first angle in a first plane. The device includes a waveguide grating out-coupler communicating with said linear gradient phase shifter, and a uniform phase shifter communicating with the waveguide grating out-coupler. The uniform phase shifter steers the flat phase front along a second angle in a second plane perpendicular to said first plane.

An optical waveguide device includes a substrate on which an optical waveguide is formed, and an object that is disposed on the substrate. The optical waveguide includes a mode conversion/branching portion that converts a mode of a light wave propagating through the optical waveguide and branches the light wave, and the object is disposed to cover a part or the whole of the mode conversion/branching portion or not to cover the mode conversion/branching portion when the substrate is viewed in a plan view. In a case where the object is disposed to cover a part of the mode conversion/branching portion, the object is disposed not to consecutively cover a section over a length of a predetermined value or higher in an advancing direction of a light wave.