Tdk Corporation

Hiroshi Take

Kenji Nagase

Anthony Reymund Melad Binarao

Cheng Bu Heng

Hiroki Hara

Shinji Iwatsuka

Takashi Kikukawa

Atsushi Shimura

Shuntaro Kodama

An optical modulator, including: a substrate; a plurality of electro-optic material layers formed on the substrate; and an electrode formed on the electro-optic material layer; wherein the electro-optic material layer has a patterned RF portion waveguide that applies a modulated signal and a patterned DC portion waveguide that applies a direct current bias signal; and on a section perpendicular to a light propagation direction, the sectional area of the DC portion waveguide is greater than the sectional area of the RF portion waveguide.

Optical modulator

An optical device and an optical modulator, the optical device includes 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.

Optical device and optical modulator

An optical modulation element is provided with a substrate, a waveguide layer formed on the substrate, a dielectric layer formed on the waveguide layer, and an electrode formed on the dielectric layer. An outer peripheral end portion of the dielectric layer has an offset area positioned inside an outer peripheral end portion of the substrate. In at least a part of the offset area, a distance from the outer peripheral end portion of the substrate to the outer peripheral end portion of the dielectric layer is equal to or less than a distance from the outer peripheral end portion of the substrate to the outer peripheral end portion of the electrode.

Optical modulation element

An optical device, including a substrate; an optical waveguide provided in a predetermined region of the substrate and formed of an electro-optic material film; a protective layer formed adjacent to the optical waveguide; and a non-light-propagation optical waveguide provided outside the predetermined region, wherein the surface roughness of the non-light-propagation optical waveguide is RMS 0.5 nm or more. According to the optical device, the occurrence of micro-cracks on the optical waveguide can be suppressed, thereby reducing the light propagation loss.

Optical device

An electro-optical device includes a substrate, an optical waveguide formed on the substrate, a buffer layer formed on the substrate which is provided so as to cover the optical waveguide and an electrode formed on the buffer layer, when viewed in a propagation direction of light, a side surface of the optical waveguide has at least one slope change point. An electro-optical device can reduce the driving voltage and the propagation loss of light.

Electro-optical device including optical waveguide with slope change point

The optical device includes a substrate and an optical waveguide formed on the substrate, a protrusion portion is formed on the substrate adjacent to the optical waveguide. Accordingly, an optical device which can achieve further suppression of the light propagation loss and higher reliability is provided.

An optical modulators is disclosed. The optical modulator includes a substrate, an optical waveguide formed on the substrate, a signal electrode formed on the optical waveguide via a first buffer layer and applying a modulation signal to the optical waveguide, and a bias electrode formed on the optical waveguide via a second buffer layer and applying a DC bias to the optical waveguide, the first buffer layer and the second buffer layer are formed in such a way that either one of the first buffer layer and the second buffer layer covers an end surface of the other one of the first buffer layer and the second buffer layer at a boundary part of the first buffer layer and the second buffer layer. Accordingly, an optical modulator with high reliability can be provided.

An optical modulator includes a substrate; an electro-optical material layer formed on a predetermined region of the substrate; a buffer layer formed on the substrate which is provided so as to cover the electro-optical material layer; and an electrode formed on the buffer layer. The electro-optical material layer has a RF portion optical waveguide which is applied with a modulation signal and is patterned, and a DC portion optical waveguide which is applied with a DC voltage and is patterned. The electrode has an RF portion electrode formed on the buffer layer where the RF portion optical waveguide is located and a DC portion electrode formed on the buffer layer where the DC portion optical waveguide is located. The film thickness of the DC portion electrode is smaller than the film thickness of the RF portion electrode.

To provide an optical modulation element whereby reduced drive voltage and suppression of DC drift can be obtained at the same time. An optical modulation element includes: a substrate; and an optical waveguide formed of an electrooptic material film formed on the substrate and having a ridge part which is a protruding portion, and a slab part having a smaller film thickness than the ridge part. The optical waveguide includes a first waveguide part having a first ridge width and a first slab film thickness and to which an RF signal is applied, and a second waveguide part having a second ridge width and a second slab film thickness different from the first slab film thickness and to which a DC bias is applied.

An optical waveguide element includes: an optical waveguide having a ridge part and a slab part having a thickness less than the ridge part. The optical waveguide includes: a first waveguide having a first ridge with and a first slab film thickness; a second waveguide having a second ridge width and a second slab film thickness; a first intermediate waveguide connected to the first waveguide and having a third ridge width and the first slab film thickness; and a second intermediate waveguide connected to the second waveguide and having a fourth ridge width and the second slab film thickness. The first waveguide, the first intermediate waveguide, the second intermediate waveguide, and the second waveguide are arranged in this order; the second slab film thickness is larger than the first slab film thickness; and the third ridge width is larger than the fourth ridge width.

Optical waveguide element and optical modulation element

An optical device including: a substrate; an optical waveguide formed at the substrate; and a protective layer formed adjacent to the optical waveguide, wherein the optical waveguide includes multiple side surfaces that intersect the substrate, at least one side surface of the optical waveguide is provided with a rough surface. According to the optical device of the present invention, the light propagation loss can be reduced.

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Hong Kong, China

Hiroshi Take