Patent US5247594A successfully refreshed from Google Patents.
US5247594A
Expired / Lapsed
US
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Waveguide-type optical matrix switch
Assignee: NTT Inc
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Filing: 1992-03-20
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Granted: 1993-09-21
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Expires: 2012-03-20
Abstract
Abstract A waveguide-type optical matrix switch including as its switching element a Mach-Zehnder interferometer which includes two directional couplers and an optical phase shifter. The two directional couplers are arranged by placing two optical waveguides in close proximity at two positions on a substrate, and have an identical coupling ratio. The optical phase shifter is disposed over at least one of the two optical waveguides between the directional couplers. The two optical waveguides have an effective optical path length difference of half a wavelength of a light signal between the two directional couplers, and are intersected in the optical switch element. The waveguide-type optical matrix switch is little affected by fabrication errors in the coupling ratio of the directional couplers, and superior in the extinction ratio.
Inventors
- 👤 Masayuki Okuno
- 👤 Kuniharu Kato
- 👤 Katsumi Katoh
- 👤 Masao Kawachi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:36
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/3136; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/122; G02B6/125; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2821; G02B2006/12133; G02B2006/12145; G02B2006/12159; G02F1/01; G02F1/011; G02F1/0113; G02F1/0147
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
113 words
A waveguide-type optical switch for switching a light signal inputted thereto, comprising: a substrate; two directional couplers arranged by placing two optical waveguides in close proximity at two positions on said substrate, and having an identical coupling ratio, said two optical waveguides having an effective optical path length difference of half a wavelength of the light signal between said two directional couplers; optical path length switching means disposed over at least one of said two optical waveguides between said two directional couplers for switching said effective optical path length difference to an integral multiple of the wavelength of the light signal; and a cross portion at which said two optical waveguides are intersected.
Claim 2
Dependent Claim
113 words
A waveguide-type optical switch for switching a light signal inputted thereto, comprising: a substrate; two directional couplers arranged by placing two optical waveguides in close proximity at two positions on said substrate, and having an identical coupling ratio, said two optical waveguides having an effective optical path length difference of half a wavelength of the light signal between said two directional couplers; optical path length switching means disposed over at least one of said two optical waveguides between said two directional couplers for switching said effective optical path length difference to an integral multiple of the wavelength of the light signal; and a cross portion at which said two optical waveguides are intersected.
Claim 3
Dependent Claim
21 words
A waveguide-type optical switch as claimed in claim 1, wherein said optical path length switching means is an optical phase shifter.
Claim 4
Dependent Claim
26 words
A waveguide-type optical switch as claimed in claim 2, wherein said optical phase shifter is a thermooptic effect phase shifter consisting of a thin film heater.
Claim 5
Dependent Claim
39 words
A waveguide-type optical switch as claimed in claim 1, wherein said optical path length switching means is two optical phase shifters each of which is disposed over each one of said two optical waveguides between said two directional couplers.
Claim 6
Dependent Claim
42 words
A waveguide-type optical switch as claimed in claim 4, wherein one of said optical phase shifters compensates for an offset of said effective optical path length difference when said effective path length difference deviates from half a wavelength of the light signal.
Claim 7
Dependent Claim
48 words
A waveguide-type optical switch as claimed in claim 2, wherein said optical phase shifter is disposed over a longer waveguide of said two optical waveguides so that said effective optical path length difference is made one wavelength of the light signal when said optical phase shifter is driven.
Claim 8
Dependent Claim
43 words
A waveguide-type optical switch as claimed in claim 2, wherein said optical phase shifter is disposed over a shorter waveguide of said two optical waveguides so that said effective optical path length difference is made zero when said optical phase shifter is driven.
Claim 9
Dependent Claim
20 words
A waveguide-type optical switch as claimed in claim 1, wherein said cross portion is disposed between said two directional couplers.
Claim 10
Dependent Claim
28 words
A waveguide-type optical switch as claimed in claim 1, wherein said two optical waveguides intersect at said cross portion with a cross angle of at least 15 degrees.
Claim 11
Dependent Claim
25 words
A waveguide-type optical switch as claimed in claim 1, wherein said two optical waveguides have tapered geometry in sections before and after said cross portion.
Claim 12
Dependent Claim
21 words
A waveguide-type optical switch as claimed in claim 1, wherein said two optical waveguides have tapered geometry at said cross portion.
Claim 13
Dependent Claim
33 words
A waveguide-type optical switch as claimed in claim 1, wherein each one of said two optical waveguides is any one of a plastic waveguide, an ion-diffused glass waveguide, and a lithium niobate waveguide.
Claim 14
Dependent Claim
216 words
A waveguide-type optical matrix switch having a plurality of input ports, and a plurality of output ports, and switching a light signal inputted to one the input ports to be produced from one of the output ports, said waveguide-type optical matrix switch comprising: a plurality of input optical waveguides each of which is connected to each one of the input ports; a plurality of output optical waveguides each of which is connected to each one of the output ports; and a plurality of optical switch elements each of which is disposed at each one of intersections of said input optical waveguides and said output optical waveguides; wherein each of said plurality of optical switch elements including: a substrate; two directional couplers arranged by placing two optical waveguides in close proximity at two positions on said substrate, and having an identical coupling ratio, said two optical waveguides having an effective optical path length difference of half a wavelength of the light signal between said two directional couplers; optical path length switching means disposed over at least one of said two optical waveguides between said directional couplers for switching said effective optical path length difference to an integral multiple of the wavelength of the light signal; and a cross portion at which said two optical waveguides are intersected.
Claim 15
Dependent Claim
216 words
A waveguide-type optical matrix switch having a plurality of input ports, and a plurality of output ports, and switching a light signal inputted to one the input ports to be produced from one of the output ports, said waveguide-type optical matrix switch comprising: a plurality of input optical waveguides each of which is connected to each one of the input ports; a plurality of output optical waveguides each of which is connected to each one of the output ports; and a plurality of optical switch elements each of which is disposed at each one of intersections of said input optical waveguides and said output optical waveguides; wherein each of said plurality of optical switch elements including: a substrate; two directional couplers arranged by placing two optical waveguides in close proximity at two positions on said substrate, and having an identical coupling ratio, said two optical waveguides having an effective optical path length difference of half a wavelength of the light signal between said two directional couplers; optical path length switching means disposed over at least one of said two optical waveguides between said directional couplers for switching said effective optical path length difference to an integral multiple of the wavelength of the light signal; and a cross portion at which said two optical waveguides are intersected.
Claim 16
Dependent Claim
22 words
A waveguide-type optical matrix switch as claimed in claim 13, wherein said optical path length switching means is an optical phase shifter.
Claim 17
Dependent Claim
27 words
A waveguide-type optical matrix switch as claimed in claim 14, wherein said optical phase shifter is a thermooptic effect phase shifter consisting of a thin film heater.
Claim 18
Dependent Claim
44 words
A waveguide-type optical matrix switch as claimed in claim 14, wherein said optical phase shifter is disposed over a shorter waveguide of said two optical waveguides so that said effective optical path length difference is made zero when said optical phase shifter is driven.
Claim 19
Dependent Claim
49 words
A waveguide-type optical matrix switch as claimed in claim 14, wherein said optical phase shifter is disposed over a longer waveguide of said two optical waveguides so that said effective optical path length difference is made one wavelength of the light signal when said optical phase shifter is driven.
Claim 20
Dependent Claim
40 words
A waveguide-type optical matrix switch as claimed in claim 13, wherein said optical path length switching means is two optical phase shifters each of which is disposed over each one of said two optical waveguides between said two directional couplers.
Claim 21
Dependent Claim
43 words
A waveguide-type optical matrix switch as claimed in claim 18, wherein one of said optical phase shifters compensates for an offset of said effective optical path length difference when said effective path length difference deviates from half a wavelength of the light signal.
Claim 22
Dependent Claim
21 words
A waveguide-type optical matrix switch as claimed in claim 13, wherein said cross portion is disposed between said two directional couplers.
Claim 23
Dependent Claim
29 words
A waveguide-type optical matrix switch as claimed in claim 13, wherein said two optical waveguides intersect at said cross portion with a cross angle of at least 15 degrees.
Claim 24
Dependent Claim
26 words
A waveguide-type optical matrix switch as claimed in claim 13, wherein said two optical waveguides have tapered geometry in sections before and after said cross portion.
Claim 25
Dependent Claim
22 words
A waveguide-type optical matrix switch as claimed in claim 13, wherein said two optical waveguides have tapered geometry at said cross portion.
Claim 26
Dependent Claim
34 words
A waveguide-type optical matrix switch as claimed in claim 13, wherein each one of said two optical waveguides is any one of a plastic waveguide, an ion-diffused glass waveguide, and a lithium niobate waveguide.
Claim 27
Dependent Claim
26 words
A waveguide-type optical matrix switch as claimed in claim 13, wherein said optical switch elements are connected by curved waveguide bundles to form a serpentine layout.
Claim 28
Dependent Claim
53 words
A waveguide-type optical switch as claimed in claim 25, wherein centers of said optical waveguides are offset at portions where each of said optical waveguides changes its geometry from a straight to a curve, and where each of said optical waveguides changes its radius of curvature, or changes its direction of a curve.
Claim 29
Dependent Claim
26 words
A waveguide-type optical matrix switch as claimed in claim 25, wherein a radius of curvature of a curve of said waveguides is at least 4 mm.
Claim 30
Dependent Claim
28 words
A waveguide-type optical matrix switch as claimed in claim 13, further comprising inactive switch elements placed at positions corresponding to said optical switch elements on said optical waveguides.
Claim 31
Dependent Claim
78 words
A waveguide-type optical matrix switch as claimed in claim 28, wherein each of said inactive switch element comprising: two directional couplers arranged by placing two optical waveguides in close proximity at two positions on said substrate, and having an identical coupling ratio, said two optical waveguides having an effective optical path length difference of half a wavelength of the light signal between said two directional couplers; and a cross portion at which said two optical waveguides are intersected.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-20 | 1997-03-22 | 1997-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-20 | 2001-03-22 | 2001-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-20 | 2005-03-22 | 2005-09-21 | $7700.00 | Window Closed / Lapsed |