Optical modulator and optical transmission device using the same

• US 10,642,124 B2
• Filed: 11/30/2018
• Issued: 05/05/2020
• Est. Priority Date: 11/30/2017
• Status: Active Grant

• Current Assignee: Sumitomo Osaka Cement Company Limited
• Original Assignee: Sumitomo Osaka Cement Company Limited
• Inventors: Miyazaki, Norikazu, Sugamata, Toru
• Primary Examiner(s): Smith, Chad H
• Application Number:
  US16/205,243
• Publication Number:
  US 20190163028A1
• Time in Patent Office: 522 Days
• Field of Search: None
• CPC Class Codes: G02F 1/035 in an optical waveguide structure
• CPC Class Codes: G02F 1/212 Mach-Zehnder type
• CPC Class Codes: G02F 1/225 in an optical waveguide structure
• CPC Class Codes: G02F 2203/21 Thermal instability, i.e. DC drift, of an optical modulator; Arrangements or methods for the reduction thereof
• CPC Class Codes: H04B 10/25891 Transmission components H04B10/40 takes precedence
• CPC Class Codes: H04B 10/5161 Combination of different modulation schemes
• CPC Class Codes: H04B 10/532 Polarisation modulation
• CPC Class Codes: H04B 10/5561 Digital phase modulation

Abstract

A small and inexpensive optical modulator having suppressed temperature drift and high reliability and an optical transmission device using the same are provided. The optical modulator includes an optical waveguide substrate where an optical waveguide is formed; a control electrode that is provided on the optical waveguide substrate and applies an electric field to the optical waveguide; and a relay substrate that is disposed in the vicinity of the optical waveguide substrate and includes electrical wirings that relay electrical signals from the outside to the control electrode. The control electrode includes a signal electrode. The optical modulator comprises terminating units that include terminal resistors that terminate the signal electrode. At least a part of the terminating units are provided on the relay substrate.

Claims

1. An optical modulator, comprising:

an optical waveguide substrate in which an optical waveguide is formed;

a control electrode, provided on the optical waveguide substrate and applying an electric field to the optical waveguide;

a relay substrate, disposed in the vicinity of the optical waveguide substrate and including electrical wirings for relaying electrical signals from an outside to the control electrode;

light receiving elements, receiving a part of light waves that propagates through the optical waveguide or a part of emission light emitted from the optical waveguide and

a housing, where the optical waveguide substrate and the relay substrate are mounted,

wherein the control electrode includes a signal electrode,

the optical modulator comprises terminating units that include terminal resistors that are provided at a terminal of the signal electrode,

at least a part of the terminating units are provided on the relay substrate, and

electrical wirings for light reception for guiding light receiving signals from the light receiving elements to the outside is not disposed on the relay substrate in which the terminating unit is provided, and

a thickness of the relay substrate is formed to be thinner than that of the optical waveguide substrate, and

a step is formed between a first mounting surface of the housing where the relay substrate is mounted and a second mounting surface of the housing where the optical waveguide substrate is mounted.

2. The optical modulator according to claim 1, wherein at least two or more terminal resistors are provided in one terminating unit.

3. The optical modulator according to claim 1, wherein the control electrode includes the signal electrode and a DC bias electrode, and

on the relay substrate, at least electrical wirings for relaying a DC bias voltage to the DC bias electrode are provided.

4. An optical transmission device, comprising:

the optical modulator according to claim 1;

a data generating part, generating data signals that are applied to the optical modulator; and

a light source, inputting light waves to the optical modulator.

5. The optical transmission device according to claim 4, wherein at least two or more terminal resistors are provided in one terminating unit.

6. The optical transmission device according to claim 4, wherein the control electrode includes the signal electrode and a DC bias electrode, and

on the relay substrate, at least electrical wirings for relaying a DC bias voltage to the DC bias electrode are provided.

7. The optical transmission device according to claim 4, wherein at least one of an electrical wiring for relaying a DC bias voltage, a ground electrode, and a groove formed on the relay substrate is provided between the terminating unit provided on the relay substrate and the electrical wirings for light reception.

8. An optical modulator, comprising:

an optical waveguide substrate in which an optical waveguide is formed;

a control electrode, provided on the optical waveguide substrate and applying an electric field to the optical waveguide;

a relay substrate, disposed in the vicinity of the optical waveguide substrate and including electrical wirings for relaying electrical signals from an outside to the control electrode;

light receiving elements, receiving a part of light waves that propagates through the optical waveguide or a part of emission light emitted from the optical waveguide and

a housing, where the optical waveguide substrate and the relay substrate are mounted,

wherein the control electrode includes a signal electrode,

the optical modulator comprises terminating units that include terminal resistors that are provided at a terminal of the signal electrode,

at least a part of the terminating units are provided on the relay substrate, and

electrical wirings for light reception for guiding light receiving signals from the light receiving elements to the outside is provided on the relay substrate,

at least one of an electrical wiring for relaying a DC bias voltage, a ground electrode, and a groove formed on the relay substrate is provided between the terminating unit provided on the relay substrate and the electrical wirings for light reception, and

a thickness of the relay substrate is formed to be thinner than that of the optical waveguide substrate, and

a step is formed between a first mounting surface of the housing where the relay substrate is mounted and a second mounting surface of the housing where the optical waveguide substrate is mounted.

9. An optical transmission device, comprising:

the optical modulator according to claim 8;

a data generating part, generating data signals that are applied to the optical modulator; and

a light source, inputting light waves to the optical modulator.