Optical waveguide device

• US 4,871,221 A
• Filed: 12/15/1988
• Issued: 10/03/1989
• Est. Priority Date: 12/25/1987
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Imoto, Katsuyuki
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Ullah, Akm E.
• Application Number:
  US07/284,633
• Time in Patent Office: 292 Days
• Field of Search: 350/96.11, 350/96.12, 350/96.13, 350/96.14, 350/96.15, 350/96.29, 350/96.30, 350/96.33, 350/96.34
• US Class Current: 385/130
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/2808 using a mixing element which evenly distributes an input signal over a number of outputs
• CPC Class Codes: G02B 6/29332 Wavelength selective couplers, i.e. based on evanescent coupling between light guides, e.g. fused fibre couplers with transverse coupling between fibres having different propagation constant wavelength dependency non wavelength-selective light guide couplers G02B6/28
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: G02F 1/3132 of directional coupler type

Abstract

An optical waveguide device comprises a low refractive index layer having a refractive index n_b, a core layer having a refractive index n_c (where n_c >n_b) and a cladding layer having a refractive index n_c1 (where n_c1 <n_c) formed on a substrate. Thermal expansion coefficients of the low refractive index layer, the core layer and the cladding layers, respectively, are made substantially equal to each other at respective boundaries.

Claims

1. An optical waveguide device, comprising a low refractive index layer having a refractive index n_b, a core layer having a refractive index n_c (where n_c >

n_b) and a cladding layer having a refractive index n_cl (where n_cl <

n_c) formed on a substrate, wherein thermal expansion coefficients of said low refractive index layer, said core layer and said cladding layers, respectively, are made substantially equal to each other at respective boundaries.

2. An optical waveguide device according to claim 1, wherein the thermal expansion coefficient of said low refractive index layer is varied substantially continuously in the direction thicknesswise of said layer.

3. An optical waveguide device according to claim 1, wherein said substrate is formed of SiO₂ -glass.

4. An optical waveguide device according to claim 1, wherein said core layer is constituted by a pair of rectangular layers disposed in parallel with each other so that said rectangular layers are distributively coupled to each other.

5. An optical waveguide device according to claim 1, said core layer being of a rectangular form, wherein one end of a waveguide formed by said rectangular core layer is connected to at least two waveguides each formed by a rectangular core layer.

6. An optical waveguide device according to claim 1, said core layer being of a rectangular form, wherein each of two ends of a waveguide formed by said core layer is connected to at least two waveguides formed by rectangular core layers, respectively.