公开(公告)号：US20220276513A1

公开(公告)日：2022-09-01

申请号：US17678096

申请日：2022-02-23

Applicant: TDK Corporation

Inventor： Hajime UTSUNOMIYA ,  Takashi KIKUKAWA

IPC: G02F1/035 ,  G02F1/21 ,  G02F1/03 ,  G02F1/225

Abstract: A optical modulation element includes a substrate made of a material different from lithium niobate, a lithium niobate film formed on a main surface of the substrate, the lithium niobate film including a Mach-Zehnder-type optical waveguide having a first ridge and a second ridge that function as a first optical waveguide and a second optical waveguide, respectively, wherein both the first ridge and the second ridge having a cross-sectional shape fixed portion, at least one of the first ridge and the second ridge having a cross-sectional shape non-fixed portion in which the cross-sectional shape is different from that of the cross-sectional shape fixed portion, and the optical output obtained when the DC bias voltage applied between the first electrode and the second electrode is 0 (V) is smaller than the maximum of the optical output obtained when the DC bias voltage is changed in a predetermined voltage range.

公开(公告)号：US20240126015A1

公开(公告)日：2024-04-18

申请号：US18377602

申请日：2023-10-06

Applicant: TDK CORPORATION

Inventor： Hajime UTSUNOMIYA ,  Yasuhiro TAKAGI ,  Hiroki HARA ,  Atsushi SHIMURA ,  Jiro YOSHINARI ,  Takashi KIKUKAWA ,  Tsuyoshi KOMAKI ,  Hideaki FUKUZAWA

IPC: G02B6/293

CPC classification number: G02B6/29344

Abstract: This optical coupler for coupling a plurality of visible light beams having different wavelengths includes: a substrate made of a material different from lithium niobate; and an optical coupling function layer formed on a main surface of the substrate. The optical coupling function layer includes: two multimode-interference-type optical coupling parts; optical-input-side waveguides and an optical-output-side waveguide connected to one multimode-interference-type optical coupling part, and optical-input-side waveguides and an optical-output-side waveguide connected to the other multimode-interference-type optical coupling part. The multimode-interference-type optical coupling parts, the optical-input-side waveguides, and the optical-output-side waveguides are made of a lithium niobate film.

公开(公告)号：US20230229030A1

公开(公告)日：2023-07-20

申请号：US17924533

申请日：2021-07-13

Applicant: TDK CORPORATION

Inventor： Hajime UTSUNOMIYA ,  Takashi KIKUKAWA

IPC: G02F1/035 ,  G02F1/21 ,  G02F1/225

CPC classification number: G02F1/035 ,  G02F1/212 ,  G02F1/225 ,  G02F2202/20

Abstract: This optical modulator includes an optical modulation element having a first optical waveguide, a second optical waveguide, a first electrode configured to apply an electric field to the first optical waveguide, and a second electrode configured to apply an electric field to the second optical waveguide; and a control unit configured to control an applied voltage between the first electrode and the second electrode. The control unit sets Vpp to 0.06×Vπ≤Vpp≤0.4×Vπ when a half-wavelength voltage of the optical modulation element is Vπ and an applied voltage width that is an amplitude of an applied voltage applied to the optical modulation element is Vpp, and sets Vn≤Vmin≤Vn+0.29×Vπ or Vn−0.29×Vπ≤Vmax≤Vn when a minimum value and a maximum value of a voltage applied to the optical modulation element are respectively Vmin and Vmax and a null point voltage of the optical modulation element is Vn.

公开(公告)号：US20230176403A1

公开(公告)日：2023-06-08

申请号：US17924517

申请日：2021-07-13

Applicant: TDK CORPORATION

Inventor： Hajime UTSUNOMIYA ,  Takashi KIKUKAWA

IPC: G02F1/035 ,  G02F1/21 ,  G02F1/225

CPC classification number: G02F1/035 ,  G02F1/212 ,  G02F1/225 ,  G02F2202/20 ,  G02F2203/50

Abstract: This optical modulation element includes a first optical waveguide, a second optical waveguide, a first electrode for applying an electric field to the first optical waveguide, and a second electrode for applying an electric field to the second optical waveguide. The first optical waveguide and the second optical waveguide each include a ridge-shaped portion protruding from a first surface of a lithium niobate film. A first interaction length L1 that is a length of a part of the first electrode overlapping the first optical waveguide in a longitudinal direction is 0.9 mm or more and 20 mm or less. A second interaction length L2 that is a length of a part of the second electrode overlapping the second optical waveguide in the longitudinal direction is 0.9 mm or more and 20 mm or less.

公开(公告)号：US20230213791A1

公开(公告)日：2023-07-06

申请号：US17928386

申请日：2021-06-18

Applicant: TDK CORPORATION

Inventor： Hajime UTSUNOMIYA ,  Takashi KIKUKAWA

IPC: G02F1/035 ,  G02F1/01

CPC classification number: G02F1/035 ,  G02F1/0123

Abstract: The optical modulator includes an optical modulation element having a first optical waveguide, a second optical waveguide, a first electrode which applies an electric field to the first optical waveguide, and a second electrode which applies an electric field to the second optical waveguide, and a control unit configured to control an applied voltage between the first electrode and the second electrode. When a half-wave voltage of the optical modulation element is Vπ and a null point voltage of the optical modulation element is Vn, the control unit sets an operating point Vd in a range of Vn+0.50Vπ≤Vd≤Vn+0.75Vπ or Vn−0.75Vπ≤Vd≤Vn−0.50Vπ and sets an applied voltage width Vpp, which is an amplitude of an applied voltage applied to the optical modulation element, in a range of 0.22Vπ≤Vpp≤0.50Vπ.