US5889898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Crosstalk-reduced integrated digital optical switch
Assignee: Nokia of America Corp
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Filing: 1997-02-10
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Granted: 1999-03-30
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Expires: 2017-02-10
Abstract
Abstract Methods and apparatus for performing optical signal switching or other optical routing functions in an optical device or system, in which crosstalk induced by modal interference is suppressed by providing appropriate loss, gain and/or refractive index changes in different parts of a switch structure. An exemplary optical signal switch includes first and second branches each having a refraction-controlled section and an absorption-controlled section. An optical signal path over which an optical signal propagates in passing through the switch is selected to include a portion of at least one of the first and second branches, such that one of the first and second branches is a selected branch and the other branch is a non-selected branch. The refraction-controlled section of the selected branch is configured in a high effective refractive index state which allows the optical signal to propagate along at least a portion of the selected branch, while the refraction-controlled section of the non-selected branch is configured in a low effective refractive index state. The absorption-controlled section of the selected branch is configured in a low absorption state, while the absorption-controlled section of the non-selected branch is configured in a high absorption state to reduce crosstalk within the optical switch. An effective refractive index in a given refraction-controlled section may be provided using electro-refractive techniques such as the quantum-confined Stark effect (QCSE) or the Franz-Keldysh effect, or by carrier-induced effects such as carrier injection or carrier depletion. An absorption change in a given absorption-controlled section may be provided using electro-absorptive techniques or a gain-switching technique. The switch may be configured as a Y-branch switch, a directional coupler, or in other suitable configurations, and may be interconnected with other similar switches to construct 1×N, N×1, N×M and N×N switch arrays.
Inventors
- 👤 Uziel Koren
- 👤 Anat Sneh
- 👤 Jane Elisa Zucker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:19
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/3132; G02F1/3133; G02F1/3137; G02F1/3138; G02F1/01; G02F1/015; G02F1/0151; G02F1/0152; G02F1/0153; G02F1/0155; G02F1/0157; H; H01; H01S; H01S5/00; H01S5/50
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
131 words
A method of reducing crosstalk in an optical switch having a first branch and a second branch, each of the first and second branches including a refraction-controlled section and an absorption-controlled section, the method including the steps of: selecting one of the first and second branches as part of a desired optical signal path through the switch, such that one of the first and second branches is a selected branch and the other is a non-selected branch; configuring the absorption-controlled section of the selected branch into a first absorption state providing a first level of absorption and no substantial gain for the optical signal; and configuring the absorption-controlled section of the non-selected branch into an second absorption state providing a second level of absorption greater than the first level of absorption.
Claim 2
Independent Claim
131 words
A method of reducing crosstalk in an optical switch having a first branch and a second branch, each of the first and second branches including a refraction-controlled section and an absorption-controlled section, the method including the steps of: selecting one of the first and second branches as part of a desired optical signal path through the switch, such that one of the first and second branches is a selected branch and the other is a non-selected branch; configuring the absorption-controlled section of the selected branch into a first absorption state providing a first level of absorption and no substantial gain for the optical signal; and configuring the absorption-controlled section of the non-selected branch into an second absorption state providing a second level of absorption greater than the first level of absorption.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein the optical switch operates as a Y-branch switch.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein the optical switch operates as a directional coupler, and the first and second branches each include first and second absorption-controlled sections.
Claim 5
Dependent Claim
50 words
The method of claim 3 wherein the step of configuring the absorption-controlled section of the selected branch into a first absorption state providing a first level of absorption further includes the step of configuring both the first and second absorption-controlled sections of the selected branch into the first absorption state.
Claim 6
Dependent Claim
72 words
The method of claim 3 wherein the step of configuring the absorption-controlled section of the non-selected branch into a second absorption state providing a second level of absorption greater than the first level of absorption further includes the step of configuring one of the first and second absorption-controlled sections in the non-selected branch into the first absorption state and the other absorption-controlled section in the non-selected branch into the second absorption state.
Claim 7
Dependent Claim
31 words
The method of claim 1 wherein the steps of configuring the absorption-controlled sections further include the step of configuring at least one of the absorption-controlled sections using a gain switching technique.
Claim 8
Dependent Claim
39 words
The method of claim 6 wherein the step of configuring at least one of the absorption-controlled sections using a gain switching technique further includes the step of injecting current into a forward-biased diode structure corresponding to the absorption-controlled section.
Claim 9
Dependent Claim
42 words
The method of claim 1 wherein the steps of configuring the absorption-controlled sections further include the step of configuring at least one of the absorption-controlled sections using an electro-absorptive technique which involves reverse biasing a diode structure corresponding to the absorption-controlled section.
Claim 10
Dependent Claim
54 words
The method of claim 1 further including the step of configuring the refraction-controlled sections of the selected branch and the non-selected branch into a state which allows an optical signal to propagate through at least a portion of the selected branch, wherein at least one of the refraction-controlled sections a configured using carrier-induced effects.
Claim 11
Dependent Claim
37 words
The method of claim 9 wherein the step of configuring at least one of the refraction-controlled sections using carrier-induced effects further includes the step of injecting carriers into a forward-biased diode structure corresponding to the refraction-controlled section.
Claim 12
Dependent Claim
37 words
The method of claim 9 wherein the step of configuring at least one of the refraction-controlled sections using carrier-induced effects further includes the step of depleting carriers from a reverse-biased diode structure corresponding to the refraction-controlled section.
Claim 13
Dependent Claim
60 words
The method of claim 1 wherein the step of configuring the refraction-controlled sections of the selected branch and the non-selected branch into a state which allows an optical signal to propagate further includes the step of configuring at least one of the refraction-controlled sections using an electro-refractive technique which involves reverse biasing a diode structure corresponding to the refraction-controlled section.
Claim 14
Dependent Claim
57 words
The method of claim 1 wherein the step of configuring the absorption-controlled section of the selected branch into a first absorption state providing a first level of absorption and no substantial gain for the optical signal further includes configuring the absorption-controlled section of the selected branch such that it is effectively transparent at the optical signal wavelength.
Claim 15
Dependent Claim
128 words
An optical switch comprising: first and second branches each having a refraction-controlled section and an absorption-controlled section; and an optical signal path over which an optical signal propagates in passing through the switch, the optical signal path including a portion of at least one of the first and second branches, such that one of the first and second branches is a selected branch and the other branch is a non-selected branch, wherein the absorption-controlled section of the selected branch is configured in a first absorption state providing a first level of absorption and no substantial gain for the optical signal, and the absorption-controlled section of the non-selected branch is configured in a second absorption state providing a second level of absorption greater than the first level of absorption.
Claim 16
Dependent Claim
128 words
An optical switch comprising: first and second branches each having a refraction-controlled section and an absorption-controlled section; and an optical signal path over which an optical signal propagates in passing through the switch, the optical signal path including a portion of at least one of the first and second branches, such that one of the first and second branches is a selected branch and the other branch is a non-selected branch, wherein the absorption-controlled section of the selected branch is configured in a first absorption state providing a first level of absorption and no substantial gain for the optical signal, and the absorption-controlled section of the non-selected branch is configured in a second absorption state providing a second level of absorption greater than the first level of absorption.
Claim 17
Dependent Claim
14 words
The apparatus of claim 14 wherein the optical switch operates as a Y-branch switch.
Claim 18
Dependent Claim
27 words
The apparatus of claim 14 wherein the optical switch operates as a directional coupler, and the first and second branches each include first and second absorption-controlled sections.
Claim 19
Dependent Claim
24 words
The apparatus of claim 16 wherein both the first and second absorption-controlled sections of the selected branch are configured in the first absorption state.
Claim 20
Dependent Claim
41 words
The apparatus of claim 16 wherein one of the first and second absorption-controlled sections in the non-selected branch is configured in the first absorption state and the other absorption-controlled section in the non-selected branch is configured in the second absorption state.
Claim 21
Dependent Claim
20 words
The apparatus of claim 14 wherein at least one of the absorption-controlled sections is configured using a gain switching technique.
Claim 22
Dependent Claim
33 words
The apparatus of claim 19 wherein at least one of the absorption-controlled sections is configured using a gain switching technique by injecting current into a forward-biased diode structure corresponding to the absorption-controlled section.
Claim 23
Dependent Claim
31 words
The apparatus of claim 14 wherein at least one of the absorption-controlled sections is configured using an electro-absorptive technique which involves reverse biasing a diode structure corresponding to the absorption-controlled section.
Claim 24
Dependent Claim
18 words
The apparatus of claim 14 wherein at least one of the refraction-controlled sections is configured using carrier-induced effects.
Claim 25
Dependent Claim
22 words
The apparatus of claim 22 wherein the carrier-induced effects include injecting carriers into a forward-biased diode structure corresponding to the refraction-controlled section.
Claim 26
Dependent Claim
22 words
The apparatus of claim 22 wherein the carrier-induced effects include depleting carriers from a reverse-biased diode structure corresponding to the refraction-controlled section.
Claim 27
Dependent Claim
31 words
The apparatus of claim 14 wherein at least one of the refraction-controlled sections is configured using an electro-refractive technique which involves reverse biasing a diode structure corresponding to the refraction-controlled section.
Claim 28
Dependent Claim
24 words
The apparatus of claim 14 wherein the absorption-controlled section of the selected branch such that it is effectively transparent at the optical signal wavelength.
Claim 29
Dependent Claim
142 words
An optical switch comprising: a region of refraction-control material formed on a substrate; a region of absorption-control material formed on the substrate adjacent to the region of refraction-control material; and first and second switch branches, each having a refraction-controlled section associated with the refraction-control material region and an absorption-controlled section associated with the absorption-control material region, such that in configuring a given optical path through at least a portion of the switch, one of the first and second branches is configured as a selected branch and the other branch as a non-selected branch, wherein the absorption-controlled section of the selected branch is configured to provide a first level of absorption and no substantial gain for the optical signal, and the absorption-controlled section of the non-selected branch is configured to provide a second level of absorption greater than the first level of absorption.
Claim 30
Dependent Claim
142 words
An optical switch comprising: a region of refraction-control material formed on a substrate; a region of absorption-control material formed on the substrate adjacent to the region of refraction-control material; and first and second switch branches, each having a refraction-controlled section associated with the refraction-control material region and an absorption-controlled section associated with the absorption-control material region, such that in configuring a given optical path through at least a portion of the switch, one of the first and second branches is configured as a selected branch and the other branch as a non-selected branch, wherein the absorption-controlled section of the selected branch is configured to provide a first level of absorption and no substantial gain for the optical signal, and the absorption-controlled section of the non-selected branch is configured to provide a second level of absorption greater than the first level of absorption.
Claim 31
Dependent Claim
25 words
The apparatus of claim 27 wherein the refraction-controlled and absorption-controlled sections are formed as ridge waveguide structures overlying the respective refraction-control and absorption-control material regions.
Claim 32
Dependent Claim
26 words
The apparatus of claim 27 wherein the refraction-controlled and absorption-controlled sections are formed as waveguide structures which are at least partially buried in an underlying region.
Claim 33
Dependent Claim
66 words
The apparatus of claim 27 wherein the refraction-controlled section of the selected branch is configured in a state providing a first effective refractive index which allows an optical signal to propagate along at least a portion of the selected branch, and the refraction-controlled section of the non-selected branch is configured in a state providing a second effective refractive index lower than the first effective refractive index.
Claim 34
Dependent Claim
33 words
The apparatus of claim 27 wherein at least one of the absorption-controlled sections is configured using a gain switching technique by injecting current into a forward-biased diode structure corresponding to the absorption-controlled section.
Claim 35
Dependent Claim
31 words
The apparatus of claim 27 wherein at least one of the absorption-controlled sections is configured using an electro-absorptive technique which involves reverse biasing a diode structure corresponding to the absorption-controlled section.
Claim 36
Dependent Claim
18 words
The apparatus of claim 27 wherein at least one of the refraction-controlled sections is configured using carrier-induced effects.
Claim 37
Dependent Claim
22 words
The apparatus of claim 33 wherein the carrier-induced effects include injecting carriers into a forward-biased diode structure corresponding to the refraction-controlled section.
Claim 38
Dependent Claim
22 words
The apparatus of claim 33 wherein the carrier-induced effects include depleting carriers from a reverse-biased diode structure corresponding to the refraction-controlled section.
Claim 39
Dependent Claim
31 words
The apparatus of claim 27 wherein at least one of the refraction-controlled sections is configured using an electro-refractive technique which involves reverse biasing a diode structure corresponding to the refraction-controlled section.
Claim 40
Dependent Claim
26 words
The apparatus of claim 27 wherein the absorption-controlled section of the selected branch is configured so as to be effectively transparent at the optical signal wavelength.
Claim 41
Dependent Claim
165 words
An optical switch array comprising: a plurality of optical switches, at least a subset of the optical switches each having first and second branches, with each of the first and second branches having a refraction-controlled section and an absorption-controlled section; and an optical signal path over which an optical signal propagates in passing through at least a portion of the switch array, the optical signal path including a portion of at least one of the first and second branches of a given switch, such that one of the first and second branches of the given switch is a selected branch and the other branch is a non-selected branch, wherein the absorption-controlled section of the selected branch is configured in a first absorption state providing a first level of absorption and no substantial gain for the optical signal, and the absorption-controlled section of the non-selected branch is configured in a second absorption state providing a second level of absorption greater than the first level of absorption.
Claim 42
Dependent Claim
165 words
An optical switch array comprising: a plurality of optical switches, at least a subset of the optical switches each having first and second branches, with each of the first and second branches having a refraction-controlled section and an absorption-controlled section; and an optical signal path over which an optical signal propagates in passing through at least a portion of the switch array, the optical signal path including a portion of at least one of the first and second branches of a given switch, such that one of the first and second branches of the given switch is a selected branch and the other branch is a non-selected branch, wherein the absorption-controlled section of the selected branch is configured in a first absorption state providing a first level of absorption and no substantial gain for the optical signal, and the absorption-controlled section of the non-selected branch is configured in a second absorption state providing a second level of absorption greater than the first level of absorption.
Claim 43
Dependent Claim
32 words
The apparatus of claim 38 wherein the refraction-controlled and absorption-controlled sections of the plurality of optical switches in the switch array are configured to provide a routing function for the optical signal.
Claim 44
Dependent Claim
32 words
The apparatus of claim 38 wherein the refraction-controlled and absorption-controlled sections of the plurality of optical switches in the switch array are configured to provide a broadcasting function for the optical signal.
Claim 45
Dependent Claim
32 words
The apparatus of claim 38 wherein the refraction-controlled and absorption-controlled sections of the plurality of optical switches in the switch array are configured to provide a no-connection function for the optical signal.
Claim 46
Dependent Claim
26 words
The apparatus of claim 38 wherein the absorption-controlled section of the selected branch is configured so as to be effectively transparent at the optical signal wavelength.
Claim 47
Independent Claim
142 words
A method of reducing crosstalk in an optical switch having a first branch and a second branch, each of the first and second branches including a refraction-controlled section and an absorption-controlled section, the method including the steps of: selecting one of the first and second branches as part of a desired optical signal path through the switch, such that one of the first and second branches is a selected branch and the other is a non-selected branch; configuring the absorption-controlled section of the selected branch into a first absorption state providing a first level of absorption; and configuring the absorption-controlled section of the non-selected branch into an second absorption state providing a second level of absorption greater than the first level of absorption, wherein at least one of the absorption-controlled sections of the selected and non-selected branches operates using an electro-absorptive technique.
Claim 48
Independent Claim
142 words
A method of reducing crosstalk in an optical switch having a first branch and a second branch, each of the first and second branches including a refraction-controlled section and an absorption-controlled section, the method including the steps of: selecting one of the first and second branches as part of a desired optical signal path through the switch, such that one of the first and second branches is a selected branch and the other is a non-selected branch; configuring the absorption-controlled section of the selected branch into a first absorption state providing a first level of absorption; and configuring the absorption-controlled section of the non-selected branch into an second absorption state providing a second level of absorption greater than the first level of absorption, wherein at least one of the absorption-controlled sections of the selected and non-selected branches operates using an electro-absorptive technique.
Claim 49
Dependent Claim
141 words
An optical switch comprising: first and second branches each having a refraction-controlled section and an absorption-controlled section; and an optical signal path over which an optical signal propagates in passing through the switch, the optical signal path including a portion of at least one of the first and second branches, such that one of the first and second branches is a selected branch and the other branch is a non-selected branch, wherein the absorption-controlled section of the selected branch is configured in a first absorption state providing a first level of absorption, and the absorption-controlled section of the non-selected branch is configured in a second absorption state providing a second level of absorption greater than the first level of absorption, and further wherein at least one of the absorption-controlled sections of the selected and non-selected branches operates using an electro-absorptive technique.
Claim 50
Dependent Claim
141 words
An optical switch comprising: first and second branches each having a refraction-controlled section and an absorption-controlled section; and an optical signal path over which an optical signal propagates in passing through the switch, the optical signal path including a portion of at least one of the first and second branches, such that one of the first and second branches is a selected branch and the other branch is a non-selected branch, wherein the absorption-controlled section of the selected branch is configured in a first absorption state providing a first level of absorption, and the absorption-controlled section of the non-selected branch is configured in a second absorption state providing a second level of absorption greater than the first level of absorption, and further wherein at least one of the absorption-controlled sections of the selected and non-selected branches operates using an electro-absorptive technique.
Claim 51
Dependent Claim
155 words
An optical switch comprising: a region of refraction-control material formed on a substrate; a region of absorption-control material formed on the substrate adjacent to the region of refraction-control material; and first and second switch branches, each having a refraction-controlled section associated with the refraction-control material region and an absorption-controlled section associated with the absorption-control material region, such that in configuring a given optical path through at least a portion of the switch, one of the first and second branches is configured as a selected branch and the other branch as a non-selected branch, wherein the absorption-controlled section of the selected branch is configured to provide a first level of absorption, and the absorption-controlled section of the non-selected branch is configured to provide a second level of absorption greater than the first level of absorption, and further wherein at least one of the absorption-controlled sections of the selected and non-selected branches operates using an electro-absorptive technique.
Claim 52
Dependent Claim
155 words
An optical switch comprising: a region of refraction-control material formed on a substrate; a region of absorption-control material formed on the substrate adjacent to the region of refraction-control material; and first and second switch branches, each having a refraction-controlled section associated with the refraction-control material region and an absorption-controlled section associated with the absorption-control material region, such that in configuring a given optical path through at least a portion of the switch, one of the first and second branches is configured as a selected branch and the other branch as a non-selected branch, wherein the absorption-controlled section of the selected branch is configured to provide a first level of absorption, and the absorption-controlled section of the non-selected branch is configured to provide a second level of absorption greater than the first level of absorption, and further wherein at least one of the absorption-controlled sections of the selected and non-selected branches operates using an electro-absorptive technique.
Claim 53
Dependent Claim
178 words
An optical switch array comprising: a plurality of optical switches, at least a subset of the optical switches each having first and second branches, with each of the first and second branches having a refraction-controlled section and an absorption-controlled section; and an optical signal path over which an optical signal propagates in passing through at least a portion of the switch array, the optical signal path including a portion of at least one of the first and second branches of a given switch, such that one of the first and second branches of the given switch is a selected branch and the other branch is a non-selected branch, wherein the absorption-controlled section of the selected branch is configured in a first absorption state providing a first level of absorption, and the absorption-controlled section of the non-selected branch is configured in a second absorption state providing a second level of absorption greater than the first level of absorption, and further wherein at least one of the absorption-controlled sections of the selected and non-selected branches operates using an electro-absorptive technique.
Claim 54
Dependent Claim
178 words
An optical switch array comprising: a plurality of optical switches, at least a subset of the optical switches each having first and second branches, with each of the first and second branches having a refraction-controlled section and an absorption-controlled section; and an optical signal path over which an optical signal propagates in passing through at least a portion of the switch array, the optical signal path including a portion of at least one of the first and second branches of a given switch, such that one of the first and second branches of the given switch is a selected branch and the other branch is a non-selected branch, wherein the absorption-controlled section of the selected branch is configured in a first absorption state providing a first level of absorption, and the absorption-controlled section of the non-selected branch is configured in a second absorption state providing a second level of absorption greater than the first level of absorption, and further wherein at least one of the absorption-controlled sections of the selected and non-selected branches operates using an electro-absorptive technique.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-03-29 | 2002-09-28 | 2003-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-29 | 2006-09-28 | 2007-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-29 | 2010-09-28 | 2011-03-30 | $7700.00 | Window Closed / Lapsed |