Optical modulation system

• US 5,815,610 A
• Filed: 03/03/1997
• Issued: 09/29/1998
• Est. Priority Date: 07/07/1993
• Status: Expired due to Fees

• Current Assignee: Seikoh Giken Company Limited
• Original Assignee: Tokin Corporation (Yageo Corporation)
• Inventors: Tokano, Yuichi, Muramatsu, Ryoji, Tanabe, Takanobu, Takeda, Tsugio
• Primary Examiner(s): Bovernick, Rodney B.
• Assistant Examiner(s): Wise, Robert E.
• Application Number:
  US08/810,557
• Time in Patent Office: 575 Days
• Field of Search: 385/2, 385/3, 385/14, 385/901
• US Class Current: 385/2
• CPC Class Codes: G02F 1/212 Mach-Zehnder type
• CPC Class Codes: G02F 1/225 in an optical waveguide structure
• CPC Class Codes: G02F 1/2255 controlled by a high-frequency electromagnetic component in an electric waveguide structure
• CPC Class Codes: G02F 2201/07 buffer layer
• CPC Class Codes: G02F 2202/07 poled
• CPC Class Codes: G02F 2203/20 Intrinsic phase difference, i.e. optical bias, of an optical modulator; Methods for the pre-set thereof
• CPC Class Codes: G02F 2203/21 Thermal instability, i.e. DC drift, of an optical modulator; Arrangements or methods for the reduction thereof

Abstract

A system comprises a substrate 4, an incident optical waveguide 5 formed on the substrate for receiving a light beam incident thereto, two phase-shift optical waveguides 6 formed on the substrate 4 to be branched from the incident optical waveguide 4 for varying a phase of a transmitted light beam in response to an electric field intensity, an outgoing optical waveguide 7 formed on the substrate 4 to join the phase-shift optical waveguides 6. At least one of the phase-shift optical waveguides 6 has a reversely polarized portion 8 reversely polarized. A light transmission film may be formed at one or a plurality of portions on the phase-shift optical waveguides 6. A buffer layer 14 may be formed on a part on or in the vicinity of the phase-shift optical waveguides 6. A transparent substance film for imparting a stress to one of the phase-shift optical waveguides 6 may be formed on a part or a whole of a portion without the buffer layer 14. A stress imparting member may be formed to impart a stress to a part of one of the phase-shift optical waveguides 6. A light irradiation unit 26 may be formed to irradiate a light beam onto a part or a whole of one of the phase-shift optical waveguides 6.

Claims

1. An optical modulation system comprising:

a substrate;

an incident optical waveguide formed on said substrate for receiving a light beam incident thereto;

two phase-shift optical waveguides formed on said substrate and being branched from said incident optical waveguide for varying a phase of a transmitted light beam in response to an electric field intensity;

an outgoing optical waveguide formed on said substrate and joined to said two phase-shift optical waveguides; and

a light transmission film formed at one or a plurality of portions on one of said two phase-shift optical waveguides.

2. The optical modulation system of claim 1, wherein said light transmission film comprises an SiO₂ film and is formed by a sputtering process.

3. The optical modulation system of claim 2, further comprising two modulation electrodes formed on said substrate and located in the vicinity of said two phase-shift optical waveguides.

4. The optical modulation system of claim 1, wherein said light transmission film is an SiO₂ film.

5. The optical modulation system of claim 1, further comprising two modulation electrodes formed on said substrate and located in the vicinity of said two phase-shift optical waveguides.

6. The optical modulation system of claim 1, further comprising two modulation electrodes formed on said substrate and located in the vicinity of said two phase-shift optical waveguides.