WAVEGUIDE STRUCTURE AND ARRAYED WAVEGUIDE GRATING STRUCTURE

• US 20090252457A1
• Filed: 08/27/2008
• Published: 10/08/2009
• Est. Priority Date: 04/04/2008
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Pyo, Junghyung, Kim, Gyung-Ock, Song, Jung-Ho, Lee, Jong-Moo, KIM, Duk-Jun
• Granted Patent: US 7,848,602 B2
• Time in Patent Office: Days
• US Class Current: 385/46
• CPC Class Codes: G02B 2006/12119 Bend
• CPC Class Codes: G02B 6/12011 characterised by the arrayed waveguides, e.g. comprising a filled groove in the array section

Abstract

Provided are a waveguide structure and an arrayed waveguide grating structure. The arrayed waveguide grating structure includes an input star coupler, an output star coupler, and a plurality of arrayed waveguides optically connecting the input star coupler and the output star coupler. Each of the arrayed waveguides includes at least one section having a high confinement factor and at least two sections having a relatively low confinement factor. The sections of the arrayed waveguides having a high confinement factor have the same structure.

Claims

1. An arrayed waveguide grating structure comprising:

an input star coupler;

an output star coupler; and

a plurality of arrayed waveguides optically connecting the input star coupler and the output star coupler,

wherein each of the arrayed waveguides comprises at least one first section having a high confinement factor and at least two second sections having a relatively low confinement factor,

wherein the first sections of the arrayed waveguides have the same structure.

2. The arrayed waveguide grating structure of claim 1, wherein each of the arrayed waveguides comprises:

at least two approximately linear sections; and

at least one bending section having a radius of curvature smaller than the minimal radius of curvature of the approximately linear sections.

3. The arrayed waveguide grating structure of claim 2, wherein the bending section forms the first section, and the approximately linear sections form the second sections.

4. The arrayed waveguide grating structure of claim 2, wherein the arrayed waveguides have different lengths,

wherein the approximately linear sections of the arrayed waveguides have different lengths, and the bending sections of the arrayed waveguides have substantially the same radius of curvature and length.

5. The arrayed waveguide grating structure of claim 2, wherein at least one of the approximately linear sections comprises:

at least one linear section having a low confinement factor; and

a gently curved section having a radius of curvature greater than that of the bending section,

wherein the linear sections of the arrayed waveguides have different lengths, and the gently curved sections of the arrayed waveguides have substantially the same radius of curvature and different lengths.

6. The arrayed waveguide grating structure of claim 5, wherein the at least one of the approximately linear sections further comprises at least one linear section having a high confinement factor,

wherein the linear sections of the arrayed waveguides have different lengths.

7. The arrayed waveguide grating structure of claim 1, wherein the arrayed waveguides comprise a core pattern and an auxiliary pattern disposed beside the core pattern,

wherein the auxiliary pattern is thinner than the core pattern and extends from the core pattern,

wherein the auxiliary pattern covers a lower portion of a sidewall of the core pattern at the second sections and is spaced apart from the core pattern at the first section so as to expose the sidewall of the core pattern at the first section.

8. The arrayed waveguide grating structure of claim 7, wherein the auxiliary pattern is formed of the same material as that used for forming the core pattern.

9. The arrayed waveguide grating structure of claim 1, wherein the arrayed waveguides comprise a highly refractive pattern and a low refractive pattern,

wherein the highly refractive pattern is used as a core layer at the first section, and the low refractive pattern is used as the core layer at the second sections.

10. The arrayed waveguide grating structure of claim 9, wherein the second sections comprise a transition section to allow guided mode propagation between the highly refractive pattern and the low refractive pattern,

wherein the highly refractive pattern has a tapered shape at the transition section, and the low refractive pattern is used as a clad pattern covering the highly refractive pattern at the transition section and the first section.

11. The arrayed waveguide grating structure of claim 1, further comprising:

at least one input waveguide facing the arrayed waveguides and optically connected to the input star coupler; and

a plurality of output waveguides facing the arrayed waveguides and optically connected to the output star coupler.

12. A waveguide structure comprising at least one waveguide pattern disposed on a lower clad, the waveguide pattern comprising a core pattern and an auxiliary pattern thinner than the core pattern,

wherein the core pattern comprises a bending section and an approximately linear section having a radius of curvature greater than that of the bending section,

wherein the auxiliary pattern is spaced apart from the bending section of the core pattern so as to expose the lower clad and covers at least a portion of a lower sidewall of the approximately linear section of the core pattern.

13. The waveguide structure of claim 12, wherein the at least one waveguide pattern is configured to form a plurality of arrayed waveguide patterns optically connected between an input star coupler and an output star coupler,

wherein bending sections of the arrayed waveguide patterns have substantially the same radius of curvature and length.

14. The waveguide structure of claim 12, wherein the auxiliary pattern is formed of the same material as that used for forming the core pattern, and the auxiliary pattern has a thickness in a range from about 40% to about 85% of a thickness of the core pattern.

15. The waveguide structure of claim 12, further comprising an upper clad covering the waveguide pattern, wherein the upper clad is formed of at least one of materials having a refractive index lower than that of the waveguide pattern.

16. The waveguide structure of claim 12, wherein the auxiliary pattern is spaced apart from at least a portion of the approximately linear section of the core pattern so as to expose the lower clad.

17. A waveguide structure comprising a highly refractive pattern and a low refractive pattern covering the highly refractive pattern,

wherein the highly refractive pattern is locally disposed at a section of a light propagation path having a small radius of curvature so as to be used as a core layer of a waveguide, and

the low refractive pattern is used as a clad of the waveguide at a section of the light propagation path having a small radius of curvature and as the core layer of the waveguide at a section of the light propagation path having a large radius of curvature.

18. The waveguide structure of claim 17, further comprising an upper clad configured to cover the low refractive pattern,

wherein a refractive index difference between the highly refractive pattern and the low refractive pattern is greater than a refractive index difference between the upper clad and the low refractive pattern.

19. The waveguide structure of claim 17, wherein the highly refractive pattern and the low refractive pattern are used as arrayed waveguide patterns for optically connecting an input star coupler and an output star coupler.