Polarization beam splitter and optical device

Patent metadata

Field	Value
Publication number	US-2016103281-A1
Application number	US-201414786956-A
Country	US
Kind code	A1
Filing date	Jan 10, 2014
Priority date	Apr 24, 2013
Publication date	Apr 14, 2016
Grant date	—

Abstract

A polarization beam splitter according to an exemplary embodiment of the present invention includes: a demultiplexer ( 11 ); a multiplexer ( 14 ); a first arm waveguide ( 12 ), at least a part of which is formed of a rib waveguide; and a second arm waveguide ( 13 ), at least a part of which is formed of a channel waveguide. The first and second arm waveguides are formed with a waveguide width at which, in one of linear polarization components orthogonal to each other, a refractive index of the first arm waveguide ( 12 ) with respect to input light is the same as a refractive index of the second arm waveguide ( 13 ) with respect to the input light and a refractive index change of the first arm waveguide with respect to a change in the waveguide width is the same as a refractive index change of the second arm waveguide with respect to a change in the waveguide width. In the other one of the orthogonal polarization components, a phase difference is generated between the first input light propagating through the first arm waveguide ( 12 ) and the second input light propagating through the second arm waveguide ( 13 ).

First claim

1 . A polarization beam splitter comprising:
a demultiplexer that demultiplexes input light into first input light and second input light; a multiplexer that multiplexes the first input light and the second input light, the first input light and the second input light being obtained by demultiplexing the input light by the demultiplexer; a first arm waveguide that guides the first input light to the multiplexer, at least a part of the first arm waveguide being formed of a rib waveguide; and a second arm waveguide that guides the second input light to the multiplexer, at least a part of the second arm waveguide being formed of a channel waveguide, wherein the first and second arm waveguides are formed with a waveguide width at which, in one of linear polarization components orthogonal to each other, a refractive index of the first arm waveguide with respect to the input light is the same as a refractive index of the second arm waveguide with respect to the input light and a refractive index change of the first arm waveguide with respect to a change in the waveguide width is the same as a refractive index change of the second arm waveguide with respect to a change in the waveguide width, and in the other one of the orthogonal polarization components, a phase difference is generated between the first input light propagating through the first arm waveguide and the second input light propagating through the second arm waveguide.

2 . The polarization beam splitter according to claim 1 , wherein the first and second arm waveguides have a waveguide width in a range from 1 to 4 μm.

3 . The polarization beam splitter according to claim 1 , wherein the first and second arm waveguides have substantially the same length.

4 . An optical device comprising:
polarization beam splitters according to claim 1 , the polarization beam splitters being connected in multiple stages.

5 . The optical device according to claim 4 , wherein
the multiplexer of the polarization beam splitter at a preceding stage outputs first polarized light and second polarized light separately, the first polarized light and the second polarized light being linear polarization components orthogonal to each other, the demultiplexer of the polarization beam splitter at a subsequent stage receives the first polarized light as the input light, and the first and second arm waveguides of the polarization beam splitter at the subsequent stage are formed with a waveguide width at which, in the first polarized light, a refractive index of the first arm waveguide with respect to the input light is the same as a refractive index of the second arm waveguide with respect to the input light and a refractive index change of the first arm waveguide with respect to a change in the waveguide width is the same as a refractive index change of the second arm waveguide with respect to a change in the waveguide width.

Assignees

• Nec Corp

Inventors

• Matsumoto Takashi

Classifications

• G02B2006/12097

  Ridge, rib or the like · CPC title

• G02B6/2938

  for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM · CPC title

• G02B6/126

  using polarisation effects {(G02B6/1226 takes precedence)} · CPC title

• G02B6/2726 Primary

  in or on light guides, e.g. polarisation means assembled in a light guide · CPC title

• G02B6/12004 Primary

  Combinations of two or more optical elements · CPC title