Patent EP0367682A2 successfully refreshed from Google Patents.
EP0367682A2
Expired / Lapsed
EP
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Optical switch
Assignee: Furukawa Electric Co Ltd
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Filing: 1989-11-03
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Granted: —
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Expires: 2009-11-03
Abstract
Abstract An optical switch includes at least one input optical semiconductor waveguide (5); two output optical semiconductor waveguides (3a , 3b) connected at a branch point to the input optical waveguide and diverging from the branch point (2) with a preset angle ϑ (degree) therebetween; and a refractive index controlling section (4) disposed in position on at least one of the output optical waveguides (3a) and apart from the branch point (2), for electrically causing the refractive index of the output optical waveguideto be reduced. A light attenuating layer for preventing radiation mode light leaked from a portion near the branch point to the outside of the optical waveguide from being re-combined with guided mode light in the output optical waveguide is disposed between the two output optical waveguides. The refractive index controlling section (4) is formed so that a length from the physical branch point between said two output optical waveguides to an output end portion of the refractive index controlling section may be set equal to or larger than 100 x ϑ/cos (ϑ/2) µm. A distance between the nearest portions of the refractive controlling sections of the output optical waveguides is set to be equal to or less than twice a spot size so as to improve the extinction ratio and excessive loss.
Inventors
- 👤 Hisaharu The Furukawa Electric Co. Ltd. Yanagawa
- 👤 Yoshiyuki The Furukawa Electric Co. Ltd. Kamata
- 👤 Ken The Furukawa Electric Co. Ltd. Ueki
- 👤 Hidehisa The Furukawa Electric Co. Ltd Miyazawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 19:29
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/3137; G02F1/3138
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
81 words
An optical switch comprising: at least one input optical semiconductor waveguide; two output optical semiconductor waveguides connected at a branch point to said input optical waveguide and diverging from said branch point with a preset angle ϑ (degree) therebetween; and refractive index controlling means disposed in position on at least one of said output optical waveguides and apart from said branch point, for electrically causing the refractive index of said at least one of said output optical waveguides to be reduced.
Claim 2
Dependent Claim
81 words
An optical switch comprising: at least one input optical semiconductor waveguide; two output optical semiconductor waveguides connected at a branch point to said input optical waveguide and diverging from said branch point with a preset angle ϑ (degree) therebetween; and refractive index controlling means disposed in position on at least one of said output optical waveguides and apart from said branch point, for electrically causing the refractive index of said at least one of said output optical waveguides to be reduced.
Claim 3
Dependent Claim
43 words
An optical switch according to claim 1, wherein said refractive index controlling means includes an electrode disposed on said at least one of said output optical waveguides and said output optical waveguides are set electromagnetically asymmetrical by injecting a current via said electrode.
Claim 4
Dependent Claim
43 words
An optical switch according to claim 1, wherein said refractive index controlling means includes an electrode disposed on said at least one of said output optical waveguides and said output optical waveguides are set electromagnetically asymmetrical by applying a voltage to said electrode.
Claim 5
Dependent Claim
68 words
An optical switch according to claim 1, therein said output optical waveguide includes a core portion and clad portions between which said core portion is located, and said refractive index controlling means reduces the refractive index of said output optical waveguide by a value not less than a refractive index difference between the refractive indices of said core portion and said clad portion of said output optical waveguide.
Claim 6
Dependent Claim
33 words
An optical switch according to claim 1, wherein the preset angle between said output optical waveguides which are connected to said input optical waveguide is set to an angle not greater than 3°.
Claim 7
Dependent Claim
51 words
An optical switch according to claim 1, further comprising light attenuation means disposed between said two output optical waveguides, for preventing radiation mode light leaked from a portion near said branch point to the outside of said optical waveguide from being re-combined with guided mode light in said output optical waveguide.
Claim 8
Dependent Claim
23 words
An optical switch according to claim 6, wherein said light attenuation means includes light absorbing means for absorbing the leaked radiation mode light.
Claim 9
Dependent Claim
34 words
An optical switch according to claim 7, wherein said light absorbing means includes a metal layer formed on that portion of a surface of said clad portion which is located between said core portions.
Claim 10
Dependent Claim
23 words
An optical switch according to claim 6, wherein said light attenuation means includes light scattering means for scattering the leaked radiation mode light.
Claim 11
Dependent Claim
35 words
An optical switch according to claim 9, wherein said light scattering means includes an uneven surface pattern formed on that portion of a surface of said clad portion which is located between said core portions.
Claim 12
Dependent Claim
16 words
An optical switch according to claim 10, wherein said uneven surface pattern is a random pattern.
Claim 13
Dependent Claim
17 words
An optical switch according to claim 10, wherein said uneven surface pattern is a diffraction grating pattern.
Claim 14
Dependent Claim
51 words
An optical switch according to claim 1, wherein said refractive index controlling means is formed with a length from the physical branch point between said two output optical waveguides to an output end portion of said refractive index controlling means set to be not less than 100 x ϑ/cos (ϑ/2) µm.
Claim 15
Dependent Claim
39 words
An optical switch according to claim 1, wherein said refractive index controlling means are disposed on each of said two output optical waveguides, for electrically causing the refractive index of each of said output optical waveguides to be reduced.
Claim 16
Dependent Claim
105 words
An optical switch according to claim 14, wherein a distance between the nearest portions of said refractive index controlling means of said respective output optical waveguides is set to be not larger than twice a spot size which is defined as half a distance indicated by a light intensity distribution curve representing the light intensity distribution along the cross section of the optical path of said output optical waveguide, said distance being defined by two points on the light intensity distribution curve at which the light intensity is reduced to 1/e² ( e is the base of the natural logarithms) times the peak value thereof.
Claim 17
Dependent Claim
86 words
An optical switch according to claim 1, wherein two optical waveguides are arranged to intersect at an intersection with an angle ϑ, two optical waveguide portions of said two optical waveguides located on one side with respect to said intersection constitute said input optical waveguide, the other two optical waveguide portions of said two optical waveguides located on the other side with respect to said intersection constitute said output optical waveguides, and said input and output optical waveguides are connected to each other at said intersection.
Claim 18
Dependent Claim
63 words
An optical switch comprising: two optical semiconductor waveguides intersecting at an intersection with an angle ϑ (degree) and diverging from said intersection to have four branches which extend outwardly from said intersection; and refractive index controlling means disposed on at least two of said branches in position apart from said intersection, for electrically causing the refractive index of said branches to be reduced.
Claim 19
Dependent Claim
63 words
An optical switch comprising: two optical semiconductor waveguides intersecting at an intersection with an angle ϑ (degree) and diverging from said intersection to have four branches which extend outwardly from said intersection; and refractive index controlling means disposed on at least two of said branches in position apart from said intersection, for electrically causing the refractive index of said branches to be reduced.
Claim 20
Dependent Claim
43 words
An optical switch according to claim 17, wherein said four branches are grouped into two pairs of branches which make an angle of (180°-ϑ°), and said refractive index controlling means is disposed on each of the branches constituting one of said two pairs.
Claim 21
Dependent Claim
20 words
An optical switch according to claim 17, wherein said refractive controlling means is disposed on each of said four branches.
References Cited (Backward Citations)
No citation records indexed.
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