A fiber-to-fiber system for multi-layer ferroelectric on insulator waveguide devices is described. The system comprises a fiber-to-chip coupler that couples light from a standard optical fiber to multi-layer ferroelectric on insulator waveguides. The multi-layer ferroelectric on insulator waveguides are integrated with electrodes to implement an optical device, an electro-optical device, or a non-linear optical device, such as an electro-optical modulator, with microwave and optical waveguide crossings compatible with packaging. A second fiber-to-chip coupler outputs the light from the multi-layer ferroelectric on insulator device to a standard optical fiber.

In an example, an integrated optical circuit (IOC) includes a first substrate formed of a first material and a first waveguide formed of a second material and positioned on the first substrate. The first waveguide includes a plurality of branches and is configured to polarize light beams that propagate through the first waveguide. The IOC further includes a second substrate formed of a third material, the second substrate coupled to or positioned on the first substrate. The IOC further includes a plurality of straight waveguides formed in the second substrate, each of the plurality of straight waveguides optically coupled to a respective branch of the plurality of branches of the first waveguide. The IOC further includes a plurality of electrodes positioned proximate to the plurality of straight waveguides, the plurality of electrodes configured to modulate the phase of light beams that propagate through the plurality of straight waveguides.

An optical waveguide element includes an optical waveguide which is formed on one surface of a substrate, an incidence part for light to be incident on the optical waveguide or an emission part for emitting light from the optical waveguide which is disposed in an end portion of the substrate, and a dielectric film which is formed on the optical waveguide of at least one of the incidence part and the emission part, and the vicinity thereof. Regarding the dielectric film, dielectric films including a dielectric film formed of a first material having an index of refraction higher than an index of refraction of the substrate and a dielectric film formed of a second material having an index of refraction lower than the index of refraction of the substrate are alternately laminated.

A fiber-to-fiber system for multi-layer ferroelectric on insulator waveguide devices is described. The system comprises a fiber-to-chip coupler that couples light from a standard optical fiber to multi-layer ferroelectric on insulator waveguides. The multi-layer ferroelectric on insulator waveguides are integrated with electrodes to implement an optical device, an electro-optical device, or a non-linear optical device, such as an electro-optical modulator, with microwave and optical waveguide crossings compatible with packaging. A second fiber-to-chip coupler outputs the light from the multi-layer ferroelectric on insulator device to a standard optical fiber.

The present invention provides an optical device and an optical modulator, the optical device comprises an optical waveguide, at an surface of plate-like or film-like electro-optic material forming the optical waveguide, 3 locations are selected in the extension direction of the optical waveguide, and 2 locations are selected in the width direction of the optical waveguide in a range of a region of 0.1×0.1 μm, and for a total of 6 locations, an surface roughness RMS is measured with Atomic Force Microscope, and an average of the RMS is 5.1 nm or less. According to the optical device in the present invention, the occurrence of micro-cracks at the optical waveguide can be suppressed, thereby reducing the light propagation loss.

A device comprises first, second and third elements fabricated on a common substrate. The first element comprises an active waveguide structure supporting a first optical mode and at least one of the modal gain control structures. The second element comprises a passive waveguide structure supporting a second optical mode. The third element, at least partly butt-coupled to the first element, comprises an intermediate waveguide structure supporting intermediate optical modes. If the first optical mode differs from the second optical mode by more than a predetermined amount, a tapered waveguide structure in at least one of the second and third elements facilitate efficient adiabatic transformation between the second optical mode and one of the intermediate optical modes. No adiabatic transformation occurs between any of the intermediate optical modes and the first optical mode. Mutual alignments of the first, second and third elements are defined using lithographic alignment marks.

The present invention concerns an optical coupling device including at least one supporting layer comprising a first support wall and a second support wall. The at least one supporting layer comprises at least one bridging waveguide for coupling electromagnetic radiation to and from an optical resonator or optical device, the at least one bridging waveguide extending between the first support wall and the second support wall.

A fully integrated photonic coherent microwave generator includes an external laser cavity on a suitable material waveguide platform (e.g., LiNbO3) operationally integrated with a III-V gain element. Operational components include a tunable high-Q resonator (e.g., LiNbO3 microresonator) and one or more end mirrors to form an integrated semiconductor external-cavity laser. Operationally coupled electrical components enable coherent microwave and phase-locked laser comb outputs as follows. An optical detector converts the beating of generated laser-comb modes into microwaves with a fundamental frequency equal to the free-spectral range f.sub.R of the microresonator. The external laser cavity enables high-speed electro-optic modulation of laser modes directly inside the laser cavity. Phase locking of the lasing modes is accomplished via electro-optic modulation and electro-optic comb generation directly inside the laser cavity. Highly coherent microwaves are generated via phase-locked comb-like lasing modes.

With a wavelength conversion device based on a nonlinear optical effect, when arrayed waveguides including an intended nonlinear waveguide are fabricated, unwanted slab waveguides are inevitably formed. The slab waveguides can cause an erroneous measurement in the selection of a waveguide having desired characteristics from the arrayed waveguides. The erroneous measurement can lead to redoing steps for fabricating the wavelength conversion device and a decrease in the yield and inhibit the evaluation of the characteristics in selection of the waveguide and the subsequent fabrication of the wavelength conversion device from being efficiently performed. A wavelength conversion device according to the present invention includes a plurality of waveguides formed on a substrate, and a plurality of slab waveguides that are arranged substantially in parallel with and spaced apart from the plurality of waveguides, and a guided light attenuator is formed in each of the slab waveguides. The guided light attenuators allow efficient selection of a waveguide having desired optical characteristics from the plurality of waveguides. The light attenuation by the guided light attenuators can be changed in steps for fabricating the wavelength conversion device.

Provided is an optical waveguide element that prevents leaked light generated at a forking section from entering a downstream optical waveguide such as another forking section, thereby affording minimal degradation of optical characteristics. The optical waveguide is characterized in that: at least one of two fork waveguides (20a, 20b) forking from a first forking section (20) comprises a second forking section (21, 22); slab waveguides (3c-1 to 3c-3) are formed between the two fork waveguides; and between the first forking section and the second forking section, slits (41, 42) are formed that partition the slab waveguides into a first slab waveguide area (3c-1) close to the first forking section and second slab waveguide areas (3c-2, 3c-3) close to the second forking section(s).