WO2000062353A2 - Protection for mems cross-bar switch - Google Patents
Protection for mems cross-bar switch Download PDFInfo
- Publication number
- WO2000062353A2 WO2000062353A2 PCT/US2000/007571 US0007571W WO0062353A2 WO 2000062353 A2 WO2000062353 A2 WO 2000062353A2 US 0007571 W US0007571 W US 0007571W WO 0062353 A2 WO0062353 A2 WO 0062353A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- switch elements
- matrix
- protection
- optical
- elements
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/354—Switching arrangements, i.e. number of input/output ports and interconnection types
- G02B6/3562—Switch of the bypass type, i.e. enabling a change of path in a network, e.g. to bypass a failed element in the network
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/351—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
- G02B6/3512—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being reflective, e.g. mirror
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/354—Switching arrangements, i.e. number of input/output ports and interconnection types
- G02B6/3544—2D constellations, i.e. with switching elements and switched beams located in a plane
- G02B6/3546—NxM switch, i.e. a regular array of switches elements of matrix type constellation
Definitions
- the present invention relates generally to optical matrix switches, and more specifically, to protection mechanisms for micro electro-mechanical system (MEMS) cross-bar switches.
- MEMS micro electro-mechanical system
- Fiber optic technology has continued to expand across today's data communication networks. Having replaced many of the long-haul connections and other inter-office facilities, fiber optics technology has begun to replace transmission facilities and network elements used in intra-office communication.
- One of the primary network elements used in intra-office communication is the digital cross-connect.
- digital cross-connects link any of several incoming lines to any of several outgoing lines.
- Optical cross-connects are envisioned as the replacement for the conventional digital cross-connect.
- Optical cross-connects switch signals at the optical level and therefore obviate the need for optical-to-electrical conversions.
- the elimination of unnecessary components can lower the overall cost of the network while also increasing the reliability of the network. Reliability is a paramount concern to network planners and bandwidth providers.
- the reliability of the optical cross-connects must meet reasonable reliability expectations.
- the present invention addresses reliability concerns of micro electro- mechanical system (MEMS) cross-bar switches by providing alternative protection paths for optical signals that are cross-connected by a N x N MEMS cross-bar switch.
- the N x N optical cross-bar switch receives, on a first side, input optical signals from an array of one or more input lines (i), and outputs, on a second side, output optical signals to an array of one or more output lines (j). Because of the physical distance the light must propagate between the input and output lines, the input lines are typically provided with lenses to convert the signal on an input fiber into a collimated beam, and the output lines are similarly provided with lenses to focus the output collimated beam onto the output fiber.
- MEMS micro electro- mechanical system
- the design of such collimating and focusing lenses is critically dependent on the required optical path length between the two lenses.
- Cross connection within the N x N switch matrix is effected through the activation of selected switch elements.
- input line (i) can be connected to output line (j) by activating switch element (i,j) in the N x N cross-bar switch.
- the MEMS cross-bar switch of the present invention includes a N x M matrix of protection switch elements, a M x N matrix of protection switch elements, and a set of at least M protection switch elements.
- the N x M matrix of protection switch elements is positioned between the array of input lines (i) and the first side of the N x N optical cross-bar switch such that the N rows of the N x M matrix of protection switch elements are aligned with the N rows of the N x N optical cross-bar switch.
- the M x N matrix of protection switch elements is positioned between the second side of the N x N optical cross-bar switch and the array of one or more output lines (j) such that the N columns of the M x N matrix of protection switch elements are aligned with the N columns of the N x N optical cross-bar switch.
- each of the M protection switch elements in the set of at least M protection switch elements is aligned with one of the M columns of the N x M matrix of protection switch elements and one of the M rows of the M x N matrix of protection switch elements.
- This configuration of protection switch elements in combination with the N x N optical cross-bar switch enables a portion of an original path of an optical signal from an input line (i) that is connected to an output line (j) via switch element (i,j) in the N x N optical cross-bar switch to be switched to an alternative protection path that traverses a path between a first protection switch element in row (i) of the N x M matrix of protection switch elements, a second protection switch element in column (j) of the M x N matrix of protection switch elements, and a protection switch element in the set of at least M protection switch elements that is aligned with the first and second protection switch elements. It is a feature of the present invention that the path length of the alternative protection path is the same as the original path of the optical signal.
- Fig. 1 illustrates a micro electro-mechanical systems (MEMS) cross-bar switch
- Fig. 2 illustrates a protection mechanism for a MEMS cross-bar switch.
- MEMS micro electro-mechanical systems
- MEMS will provide the advantages of small size, low power, low mass, low-cost and high-functionality to integrated electro-mechanical systems.
- MEMS cross-bar switches are envisioned as playing a key role in the evolution of data communication networks.
- electrical digital signal cross-connects are used to link a set of incoming lines to a set of outgoing lines. This type of electrical cross-connection requires additional optical-to-electrical and electrical-to-optical conversion components between a set of network elements. Fiberoptic cross-bar switches would obviate the need for these conversion elements.
- An example of a MEMS cross-bar switch is illustrated in Fig. 1.
- MEMS cross-bar switch 110 is a silicon wafer based fabricated structure that includes a 4 x 4 matrix of switch elements.
- Each of the switch elements represents a mirror that is operatively moved into the center of the optical path junction at a 45 angle.
- the switch When the mirror is moved into the optical path, the switch operates in the "reflection” mode; and when the mirror is moved out of the optical path, the switch operates in the "through” mode.
- Various micro electro-mechanical structures can be used to effect a movement of the mirror into and out of the optical path.
- the mirror is pushed into or pulled out of the optical path.
- the mirror is moved into and out of the optical path through a pivot mechanism. The movement of the mirror into the optical path is referred to below as the activation of the switch element.
- the switch elements serve to connect input optical lines 102A-102D to output optical lines 104A-104D.
- the input lines are typically provided with lenses (not shown) to convert the signal on an input fiber into a collimated beam
- the output lines are similarly provided with lenses (not shown) to focus the output collimated beam onto the output fiber.
- the design of such collimating and focusing lenses is critically dependent on the required optical path length between the two lenses.
- input line 102A is connected to output line 104B
- input line 102B is connected to output line 104C
- input line 102C is connected to output line 104D
- input line 102D is connected to output line 104A.
- switch element (1,2), switch element (2,3), switch element (3,4), and switch element (4,1) respectively, where switch element (i,j) refers to the switch element in row i, column j of the 4 x 4 MEMS cross-bar switch 110.
- switch element (i,j) refers to the switch element in row i, column j of the 4 x 4 MEMS cross-bar switch 110.
- One of the key concerns regarding the adoption and use of MEMS cross-bar switches is the reliability of the switching mechanisms. Once a mirror is stuck in either the activated or inactivated position, the entire MEMS cross-bar switch must be replaced because there is no way to do an in-service repair of the defective actuator that controls the faulty switch element.
- the effect of a faulty switch element is dependent upon whether the switch element is stuck in either the activated or inactivated position. If the switch element is stuck in the inactivated position (i.e., the mirror is stuck outside the optical path), only one connection will be affected. For example, if switch element (1,2) was stuck in an inactivated position, input line 102A would not be able to be connected to output line
- Fig. 1 illustrates a potential fault in switch element (3,3). If this switch element is stuck in an activated position, the connection between input line 102B and output line 104C and the connection between input line 102C and output line 104D would both be disrupted.
- MEMS cross-bar switch 110 would have to be replaced in its entirety should switch element (3,3) fail.
- the replacement of MEMS cross-bar switch 110 would cause a significant disruption in the data communications network.
- all optical signals that traverse MEMS cross-bar switch 110 would either have to be transferred to an external protection path or taken off line, thereby leaving a substantial part of the network either unprotected or in a failed state.
- the present invention addresses the potential reliability issues of MEMS cross-bar switches by incorporating internal protection paths within the MEMS cross-bar switch.
- the protection paths are included as part of the silicon wafer based fabricated structure that forms the MEMS cross-bar switch.
- MEMS cross-bar switch 200 includes the 4 x 4 matrix of switch elements that formed MEMS cross-bar switch 110. Additionally, MEMS cross-bar switch 200 includes protection switch element sections 210, 220, and 230. In this particular example, protection switch element section 210 is a 2 x 4 switch matrix, protection switch element section 220 is a 2 x 2 switch matrix, and protection switch element section 230 is a 2 x 4 switch matrix. As described below, protection switch element sections 210, 220, and 230, in combination, enable MEMS cross-bar switch 200 to recover from failures in switch elements of the original 4 x 4 matrix of switch elements 110.
- Fig. 2 focuses on the connection between input line 102B and output line 104C and the connection between input line 102C and output line 104D. As noted, both of these connections would be disrupted if switch element (3,3) in matrix switch section 110 became stuck in an activated position.
- switch elements in protection switch element sections 210, 220, and 230 can be selectively activated to re-route the failed connections. This re- routing is handled internally by MEMS cross-bar switch 200. Accordingly, one or more failures in matrix switch section 110 would not require the replacement of MEMS crossbar switch 200.
- a portion of the original path of the connection between input line 102B and output line 104C is re-routed using switch element (2,2) in protection switch element section 210, switch element (1,2) in protection switch element section 220, and switch element (1,3) in protection switch element section 230; and a portion of the original path of the connection between input line 102C and output line 104D is re-routed using switch element (3,1) in protection switch element section 210, switch element (2,1) in protection switch element section 220, and switch element (2,4) in protection switch element section 230.
- each of the protection paths that are set up to replace a portion of the failed connection does not change the total path length of the connection between the input and output lines.
- the path length between switch element (2,2) in protection switch element section 210, switch element (1,2) in protection switch element section 220, and switch element (1,3) in protection switch element section 230 would be equivalent to the path length between switch element (2,2) in protection switch element section 210, switch element (2,3) in matrix switch section, and switch element (1,3) in protection switch element section 230.
- This feature of the present invention eliminates the need for compensating lenses in the protection path. More importantly, the inclusion of a protection mechanism within the MEMS cross-bar switch itself reduces the likelihood and immediacy of replacement of the entire MEMS cross-bar switch 200.
- MEMS cross-bar switch 200 can be configured to accommodate any amount of protection paths. In the example of Fig. 2, MEMS cross-bar switch 200 is capable of accommodating two protection paths. Conversely, if protection switch element sections 210, 220, and 230 are each configured as a 4 x 4 matrix of switch elements, then MEMS cross-bar switch 200 could accommodate four protection paths, one each for the four connections that can be cross-connected through matrix switch section 110.
- the switch elements in protection switch element section 220 are switchable based on some form of system control.
- selective switch elements in protection switch element section 220 can be fixed in an activated position.
- switch elements (1,2) and (2,1) of protection switch element section 220 can be fixed in an activated position to accommodate the two illustrated protection paths.
- switch elements (1,1) and (2,2) of protection switch element section 220 can be fixed in an activated position.
- the original path of the connection between input line 102B and output line 104C is re-routed using switch element (1,2) in protection switch element section 210, switch element (1,1) in protection switch element section 220, and switch element (1,3) in protection switch element section 230; and a portion of the original path of the connection between input line 102C and output line 104D is re-routed using switch element (3,2) in protection switch element section 210, switch element (2,2) in protection switch element section 220, and switch element (2,4) in protection switch element section 230.
- each output port is replaced by a pair of output ports.
- the physical size of the switch matrix would need to be increased to accommodate the additional collimators, but the total number of switch elements (and protection switch elements) is unchanged.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000611324A JP2002541530A (en) | 1999-03-24 | 2000-03-23 | MEMS crossbar switch protection |
CA002366438A CA2366438A1 (en) | 1999-03-24 | 2000-03-23 | Protection for mems cross-bar switch |
EP00950200A EP1166372A2 (en) | 1999-03-24 | 2000-03-23 | Protection for mems cross-bar switch |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/275,414 | 1999-03-24 | ||
US09/275,414 US6292281B1 (en) | 1999-03-24 | 1999-03-24 | Protection for MEMS cross-bar switch |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2000062353A2 true WO2000062353A2 (en) | 2000-10-19 |
WO2000062353A3 WO2000062353A3 (en) | 2001-02-01 |
Family
ID=23052189
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2000/007571 WO2000062353A2 (en) | 1999-03-24 | 2000-03-23 | Protection for mems cross-bar switch |
Country Status (5)
Country | Link |
---|---|
US (1) | US6292281B1 (en) |
EP (1) | EP1166372A2 (en) |
JP (1) | JP2002541530A (en) |
CA (1) | CA2366438A1 (en) |
WO (1) | WO2000062353A2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1239309A1 (en) * | 2001-03-02 | 2002-09-11 | Fujitsu Limited | Optical switch matrix |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9432172B2 (en) | 1997-12-05 | 2016-08-30 | Rembrandt Wireless Technologies, Lp | System and method of communication using at least two modulation methods |
US7248626B2 (en) | 1997-12-05 | 2007-07-24 | Paradyne Corporation | System and method of communication via embedded modulation |
US6160928A (en) * | 1999-04-16 | 2000-12-12 | Agilent Technologies, Inc. | Fault tolerant optical switch |
US6507421B1 (en) * | 1999-10-08 | 2003-01-14 | Lucent Technologies Inc. | Optical monitoring for OXC fabric |
US6477290B1 (en) * | 2000-02-15 | 2002-11-05 | Optic Net, Inc. | Fiber optic switch using MEMS |
GB0007552D0 (en) * | 2000-03-28 | 2000-05-17 | Iltron Limited | A fully reconfigurable regenerative optical add-drop multiplexer |
US6366716B1 (en) * | 2000-06-15 | 2002-04-02 | Nortel Networks Limited | Optical switching device |
US6850662B1 (en) | 2000-07-31 | 2005-02-01 | Tellabs Operations, Inc. | Optical switch for reciprocal traffic |
US6363182B2 (en) | 2000-07-31 | 2002-03-26 | James D. Mills | Optical switch for reciprocal traffic |
US6819824B1 (en) * | 2001-05-21 | 2004-11-16 | Calient Networks | Optical switch package |
US6937783B2 (en) * | 2002-06-07 | 2005-08-30 | Charles Chu | 2-D optical switch with lens mount |
CN1222821C (en) * | 2002-07-01 | 2005-10-12 | 华为技术有限公司 | Optical channel protector and method based on WDM layer |
US7242860B2 (en) * | 2002-10-18 | 2007-07-10 | Hitachi America, Ltd | Optical protection switching using 2 by 2 switching functions |
US7162116B1 (en) * | 2003-06-18 | 2007-01-09 | Nortel Networks Limited | Depopulated switchable micro electro-mechanical systems (MEMS) based module for photonic fabric verification and protection |
US8942644B2 (en) | 2011-11-11 | 2015-01-27 | Apple Inc. | Systems and methods for protecting microelectromechanical systems switches from radio-frequency signals using switching circuitry |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5325224A (en) * | 1993-03-09 | 1994-06-28 | California Institute Of Technology | Time-multiplexed, optically-addressed, gigabit optical crossbar switch |
US5960133A (en) * | 1998-01-27 | 1999-09-28 | Tellium, Inc. | Wavelength-selective optical add/drop using tilting micro-mirrors |
US5960132A (en) * | 1997-09-09 | 1999-09-28 | At&T Corp. | Fiber-optic free-space micromachined matrix switches |
US6038044A (en) * | 1998-02-20 | 2000-03-14 | Mci Communications Corporation | Ring/mesh optical network |
US6097859A (en) * | 1998-02-12 | 2000-08-01 | The Regents Of The University Of California | Multi-wavelength cross-connect optical switch |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6075239A (en) * | 1997-09-10 | 2000-06-13 | Lucent Technologies, Inc. | Article comprising a light-actuated micromechanical photonic switch |
-
1999
- 1999-03-24 US US09/275,414 patent/US6292281B1/en not_active Expired - Fee Related
-
2000
- 2000-03-23 JP JP2000611324A patent/JP2002541530A/en active Pending
- 2000-03-23 EP EP00950200A patent/EP1166372A2/en not_active Withdrawn
- 2000-03-23 WO PCT/US2000/007571 patent/WO2000062353A2/en not_active Application Discontinuation
- 2000-03-23 CA CA002366438A patent/CA2366438A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5325224A (en) * | 1993-03-09 | 1994-06-28 | California Institute Of Technology | Time-multiplexed, optically-addressed, gigabit optical crossbar switch |
US5960132A (en) * | 1997-09-09 | 1999-09-28 | At&T Corp. | Fiber-optic free-space micromachined matrix switches |
US5960133A (en) * | 1998-01-27 | 1999-09-28 | Tellium, Inc. | Wavelength-selective optical add/drop using tilting micro-mirrors |
US6097859A (en) * | 1998-02-12 | 2000-08-01 | The Regents Of The University Of California | Multi-wavelength cross-connect optical switch |
US6038044A (en) * | 1998-02-20 | 2000-03-14 | Mci Communications Corporation | Ring/mesh optical network |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1239309A1 (en) * | 2001-03-02 | 2002-09-11 | Fujitsu Limited | Optical switch matrix |
Also Published As
Publication number | Publication date |
---|---|
US6292281B1 (en) | 2001-09-18 |
WO2000062353A3 (en) | 2001-02-01 |
EP1166372A2 (en) | 2002-01-02 |
CA2366438A1 (en) | 2000-10-19 |
JP2002541530A (en) | 2002-12-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6614953B2 (en) | Modular all-optical cross-connect | |
US6292281B1 (en) | Protection for MEMS cross-bar switch | |
US6707959B2 (en) | Wavelength switch | |
US6307653B1 (en) | Optical matrix protection system | |
US6693926B2 (en) | MEMS-based selectable laser source | |
US6603894B1 (en) | MEMS mirror arrays and external lens system in an optical switch | |
US20090297097A1 (en) | Reconfigurable optical switch | |
US6567576B2 (en) | Optical switch matrix with failure protection | |
US5903686A (en) | Optical switch module | |
EP0898440A2 (en) | Optical switch module | |
US6771852B2 (en) | Two-fiber optical shared protection ring with a bi-directional 4×4 optical switch fabric | |
US6493479B1 (en) | Crosspoint switch protection using additional switching elements to provide alternate paths | |
US6366715B1 (en) | Free space optical switch with lenses for re-collimating the light | |
US6842555B2 (en) | Method and apparatus for optical switching with same side input and outputs | |
US6690849B1 (en) | Optical switch having MEMS array with reduced optical loss | |
US7162118B1 (en) | Dual optical switch | |
CA2245599C (en) | Optical switch module | |
US20030081883A1 (en) | Checker-board optical cross-connect |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A2 Designated state(s): CA JP |
|
AL | Designated countries for regional patents |
Kind code of ref document: A2 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
AK | Designated states |
Kind code of ref document: A3 Designated state(s): CA JP |
|
AL | Designated countries for regional patents |
Kind code of ref document: A3 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
ENP | Entry into the national phase |
Ref document number: 2366438 Country of ref document: CA Ref country code: CA Ref document number: 2366438 Kind code of ref document: A Format of ref document f/p: F |
|
ENP | Entry into the national phase |
Ref country code: JP Ref document number: 2000 611324 Kind code of ref document: A Format of ref document f/p: F |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2000950200 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 2000950200 Country of ref document: EP |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 2000950200 Country of ref document: EP |