Waveguide-type optical diffraction grating and optical wavelength filter

Patent metadata

Field	Value
Publication number	US-9823418-B2
Application number	US-201615179098-A
Country	US
Kind code	B2
Filing date	Jun 10, 2016
Priority date	Aug 25, 2015
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

Provided is a waveguide-type optical diffraction grating. A waveguide core includes a waveguide core that is asymmetric with respect to a thickness direction perpendicular to a light propagating direction. In the waveguide core, a phase adjustment portion is configured to adjust a phase difference between a forward wave traveling in an input direction and a reflected wave traveling in a direction reverse to the input direction in the waveguide-type optical diffraction grating, and the phase adjustment portion is provided in a manner that a sum of a phase of the forward wave and a phase of the reflected wave which are generated in the phase adjustment portion becomes a constant value irrespective of a polarization state of input light to the waveguide-type optical diffraction grating.

First claim

What is claimed is:

1. A waveguide-type optical diffraction grating comprising:
a waveguide core that is asymmetric with respect to a thickness direction perpendicular to a light propagating direction,
wherein
in the waveguide core, a phase adjustment portion is configured to adjust a phase difference between a forward wave traveling in an input direction and a reflected wave traveling in a direction reverse to the input direction in the waveguide-type optical diffraction grating, and
the phase adjustment portion is provided in a manner that a sum of a phase of the forward wave and a phase of the reflected wave which are generated in the phase adjustment portion becomes a constant value irrespective of a polarization state of input light to the waveguide-type optical diffraction grating, wherein
a phase shift portion configured to break a periodic structure is provided in the waveguide core, and
the phase adjustment portion includes the phase shift portion.

2. A waveguide-type optical diffraction grating comprising:
a waveguide core that is asymmetric with respect to a thickness direction perpendicular to a light propagating direction,
wherein
in the waveguide core, a phase adjustment portion is configured to adjust a phase difference between a forward wave traveling in an input direction and a reflected wave traveling in a direction reverse to the input direction in the waveguide-type optical diffraction grating, and
the phase adjustment portion is provided in a manner that a sum of a phase of the forward wave and a phase of the reflected wave which are generated in the phase adjustment portion becomes a constant value irrespective of a polarization state of input light to the waveguide-type optical diffraction grating, wherein
in the waveguide core, a plurality of unit regions are provided continuously in a waveguide direction of the waveguide core, the unit region including a non-optical diffraction grating region in which a periodic structure is not formed and an optical diffraction grating region in which a periodic structure provided adjacently to the non-optical diffraction grating region is formed, and
the phase adjustment portion is provided in the non-optical diffraction grating region.

3. A waveguide-type optical diffraction grating comprising:
a waveguide core that is asymmetric with respect to a thickness direction perpendicular to a light propagating direction,
wherein
in the waveguide core, a phase adjustment portion is configured to adjust a phase difference between a forward wave traveling in an input direction and a reflected wave traveling in a direction reverse to the input direction in the waveguide-type optical diffraction grating, and
the phase adjustment portion is provided in a manner that a sum of a phase of the forward wave and a phase of the reflected wave which are generated in the phase adjustment portion becomes a constant value irrespective of a polarization state of input light to the waveguide-type optical diffraction grating, wherein
in the waveguide core, a plurality of groups of chirped diffraction gratings are provided continuously in a waveguide direction of the waveguide core, and
the phase adjustment portion is provided with a boundary of adjacent groups of the chirped diffraction gratings as a center.

4. The waveguide-type optical diffraction grating according to claim 1 , wherein
a left-side waveguide area, a center waveguide area, and a right-side waveguide area are provided along a waveguide direction in the waveguide core,
a width of the left-side waveguide area and a width of the right-side waveguide area are equal,
each of optical diffraction grating regions is formed in the left-side waveguide area and the right-side waveguide area respectively,
in the optical diffraction grating region, first portion in which a thickness is equal to a thickness of the center waveguide area and second portion in which the waveguide core is gouged to be thinner than the thickness of the center waveguide area and is made to be asymmetric with respect to a thickness direction are provided alternately, and
the first portion and the second portion are arranged in laterally antisymmetric positions with the center waveguide area as a center, in the left-side waveguide area and the right-side waveguide area.

5. The waveguide-type optical diffraction grating according to claim 1 , wherein
a waveguide core is formed of silicon material, and
a clad layer which encloses the waveguide core is formed of silicon oxide material.

Assignees

• Oki Electric Ind Co Ltd
• Photonics Electronics Technology Res Ass

Inventors

• Okayama Hideaki

Classifications

• G02B6/29397 Primary

  Polarisation insensitivity · CPC title

• G02B2006/12061

  Silicon · CPC title

• G02B6/2766

  Manipulating the plane of polarisation from one input polarisation to another output polarisation, e.g. polarisation rotators, linear to circular polarisation converters · CPC title

• G02B6/29325

  of the slab or planar or plate like form, i.e. confinement in a single transverse dimension only (integrated circuit planar waveguide arrangements G02B6/12007; specially adapted for lighting G02B6/0011) · CPC title

• G02B6/124 Primary

  Geodesic lenses or integrated gratings · CPC title