CA2386309A1 - Compact design of 1xn fiber-optic switch using leman prism and step-motor - Google Patents
Compact design of 1xn fiber-optic switch using leman prism and step-motor Download PDFInfo
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- CA2386309A1 CA2386309A1 CA 2386309 CA2386309A CA2386309A1 CA 2386309 A1 CA2386309 A1 CA 2386309A1 CA 2386309 CA2386309 CA 2386309 CA 2386309 A CA2386309 A CA 2386309A CA 2386309 A1 CA2386309 A1 CA 2386309A1
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- 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
- G02B6/3524—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being refractive
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- 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
- G02B6/3524—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being refractive
- G02B6/3528—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being refractive the optical element being a prism
-
- 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
- G02B6/3548—1xN switch, i.e. one input and a selectable single output of N possible outputs
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
- H04Q2011/0007—Construction
- H04Q2011/0035—Construction using miscellaneous components, e.g. circulator, polarisation, acousto/thermo optical
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
- H04Q2011/0037—Operation
- H04Q2011/0049—Crosstalk reduction; Noise; Power budget
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- Optics & Photonics (AREA)
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Abstract
A 1×N (or N×1) fiber-optic switch using a Leman prism driven by a step-motor is proposed in this invention. In the optical matrix switches based on various opto-mechanical designs, 1×N (or N×1) optical switches are generally building units and the operating speed, the complexity, the size, the insertion loss, repeatability and the blocking are main problems. In this invention, the 1×N (or N×1) fiber-optic switch uses a Leman prism directly driven by a step-motor. This configuration can let one fixed input optical beam have different positions for the output by choosing different prism locations with a step-motor without changing the length of optical path and the prism movement is much less than the shift of the output beam for one operation. So, the 1×N
optical switch based on present invention can be improved in the operation speed, the device size and the complexity without impacting other parameters. With the 1×N (and N×1) fiber-optic switches, a nonblocking N×N optical matrix switches can be directly built through a cross-connection. As a result, the complexity, the repeatability, the operating speed, device size and the power consumption can be significantly improved.
optical switch based on present invention can be improved in the operation speed, the device size and the complexity without impacting other parameters. With the 1×N (and N×1) fiber-optic switches, a nonblocking N×N optical matrix switches can be directly built through a cross-connection. As a result, the complexity, the repeatability, the operating speed, device size and the power consumption can be significantly improved.
Description
Compact Design of 1xN Fiber-Optic Switch Using Leman Prism and Step-Motor Technical Field The present invention is a 1xN (or Nxl) fiber-optic matrix switch using a Leman prism driven by a step-motor. The optical switch is based on opto-mechanical design because the technologies used inside have been mature and the design based on the Leman prism can overcome some inherent problems existing in all other designs for the fiber-optic switches. It relates to a high-isolation, low systematic loss, and low-power-consumption optical switch for an optical communication system, optical interconnects, optical cross-connect, and a large-scale fiber-optic network system.
Background of the Invention Optical matrix switches have wide applications in two main aspects. One is optical communications. This capability provides an expected controllable possibility and effective switching in the high capacity optical communication systems, especially in the modern dense wavelength division multiplexing (DWDM) and optical cross-connect (OXC) systems. Other one is the simultaneous testing of multiple parameters of one or more devices without repeated physical reconnections. This capability produces consistent results and makes laboratory and manufacturing testing systems more efficient and cost-effective. In the field of matrix optical switches, conventional products are opto-mechanical design and have been used for tens of years in both optical networks and simultaneous measurements of multiple parameters. JDS Uniphase and Dicon are two main producers in the past decade and their main customers are typically the Nortel Networks, Lucent Technologies, Cisco Networks and so on in the area of optical networks, and the NTT of Japan, the Agilent and the Lucent of the United States, the EXFO of Canada etc. for other uses such as packaging switch modules. So, demand for a variety of reliable. optical switches is strongly driven by the fast growing of optical networks and multi-channel testing systems.
In long-haul transport networks, a hybrid technology is employed and traffic is transported optically, but most of operations are implemented as electronic systems. The switching and communication need to convert optical streams to electronic signals and then convert these signals to optical streams. The optical-electrical-optical (0E0) conversion based networks suffer from several inherent deficiencies such as high cost, lack of scalability and performance limitation. In local area networks, optical switching is an attractive candidate switching and communication. The optical matrix switches together with the variable optical attenuators are the central components in constructing the photonic switching systems such as the optical DWDM networks, the OXCs and simultaneous testing systems of multiple parameters. The maximum number of subscribers will strongly depend on the properties of the individual matrix switches. In the simultaneous measurements of multiple parameters, matrix switches together with the variable optical attenuators are indispensable unless there are enough signal sources and detecting systems. The requirements for the implementation of such optical components in a system are compact size, relatively fast operation, low loss, low power consumption and low crosstalk. Furthermore, the optical matrix switches should have uniform switching characteristics and stable operating characteristics.
To date, most of optical switching devices in production today use an opto-mechanical means to implement optical steering. This is accomplished through the separation, or the alignment, or the reflection of the light beam by an opto-mechanical driven mechanism.
These designs offer good optical performance typically such as low insertion loss, low power consumption and low crosstalk, but have two typical drawbacks. One is slow operating speed. The typical settling times for switching are from lOms to 100ms. Even for some large-scale optical matrix switches, the setting times for switching are from 100's of milliseconds to 1 second. The other disadvantage is the big size.
Although the opto-mechanical matrix switches have so many disadvantages in their switching operations, a serial of fiber-optic switch products can still have wide uses in the simultaneous testing of multiple parameters and mufti-channel lightwave systems. These disadvantages, in other words, could be acceptable in the conventional small-scale photonics networks today, but future's high capacity communications really could not continue to suffer from these out-of-age properties from the view point of the long term benefits. To overcome some of these limitations, the optical matrix switches aiming at small size and high operating speed must be based on radically different designing concepts and manufacturing technologies from the currently used opto-mechanical approach.
Today, research and development of optical matrix switches have shown that planar optical waveguide technology and micro-electro-mechanical system (MEMS) are typically two promising approaches. The former is based on the thermo-optic (TO) waveguides or the electro-optic (EO) waveguides. The TO waveguide devices using silica-on-silicon waveguides have shown an exciting advantage over the currently used other waveguide devices in fiber-optic communications because of their great flexibility in fabrication and processing as well as speedy operations than the mechanical ones. The EO waveguide devices using diffused LiNb03-based waveguides have also presented a promising application in the future with its high-speed operation, low loss and mature manufacturing technology. But, so far no commercially acceptable products have been widely applied in industry yet because some technical problems still need much more work. The latter, MEMS really presents an attractive potential in research and development of highly mufti-port optical matrix switches, and has been receiving much attention in the past several years. But, due to the very difficult process and packaging on the large-scale matrix switches (>8x8), no commercial products have been developed successfully so far.
As mentioned above, the conventional matrix optical switches based on the opto-mechanical approach really have some important advantages such as low insertion loss, reliable operation and low power consumption as well as mature technologies for both designing and manufacturing. Although this type of matrix optical switches has low operating speed and big device size, they are also acceptable for the environments of applications that do not require high speed and large-scale operations, but only emphasize the low insertion loss and reliable operations. In particular, if the above two drawbacks were improved much with new design, this type of optical switches will also have a relatively strong ability to compete market with the other similar optical switches that are based on the new technologies now and in the near future. Therefore, manufacturing the conventional matrix optical switches based on the opto-mechanical design and developing new matrix optical switches based on currently available reliable advanced technologies in parallel is an appropriate moment in this important technical field.
Summary of the Invention Matrix optical switches are dispensable in both optical communications and simultaneous measurement of multiple parameters in industries. In the former field, the capability of matrix optical switches provides an expected controllable possibility and effective switching in the high capacity optical communication systems, and in the later field their capability produces consistent results and makes laboratory and manufacturing testing systems more efficient and cost-effective. Most of matrix optical switches in production today are fiber-optic switches based on opto-mechanical technology.
This is accomplished through the separation, or the alignment, or the reflection of the light beam by an opto-mechanical driven mechanism. In an NxN matrix fiber-optic switch based on opto-mechanical technology, the 1xN (or Nxl) switches are basic building units. A 1xN
(or Nxl) fiber-optic switch using a Leman prism driven by a step-motor is proposed in this invention. In the matrix optical switches based on various opto-mechanical designs, the operating speed, the complexity, the size, the insertion loss, repeatability and the blocking are main problems. In this invention, the 1xN (or Nxl) fiber-optic switch uses a Leman prism directly driven by a step-motor. This configuration can let one fixed input optical beam have different positions for the output by choosing different prism locations with a step-motor without changing the length of optical path and the prism movement is much less than the shift of the output beam for one operation. So, the 1xN
fiber-optic switch based on present invention can be improved in the operation speed, the device size and the complexity without impacting other parameters. With the 1xN (and Nxl) fiber-optic switches, a nonblocking NxN optical matrix switches can be directly built through a complete cross-connection. As a result, the operating speed, the complexity, the repeatability, the operating speed, device size and the power consumption can be significantly improved. If the precision optical alignment is employed in packaging, the insertion loss of the whole device can be depressed. Therefore, the final performance of the compact NxN optical matrix switch also becomes low insertion loss, high repeatability, relatively fast operating speed and nonblocking.
In a desirable embodiment according to the present invention, the strategy for the fiber-optic switches based on the present invention lies in the compact structure design, the lens alignment technology and the precision mechanical controlling to provide low insertion loss, excellent repeatability, small size/weight and relatively fast switching speed based on our own proprietary optical designs. The size of our products will be about a quarter of the same kind of products currently existing in market, and the cost of each individual product will a half of the same level product currently existing in market.
The fiber-optic switches will be fully-bidirectional and can be suitable for a wide range of applications, including fiber-optic component testing, remote fiber-optic system testing in telecommunication networks, transmitter/receiver measurements, reconfiguration and restoration in broadband fiber-optic telecommunication systems, and sampling education, research and development according to current invention.
Brief Description of the Drawing FIG. 1 is the configuration of a 1xN optical matrix switch using a Leman prism driven by a step-motor: (a) the top view and the construction of the 1xN optical matrix switch and (b) the cross-section view.
FIG. 2 (a) is the construction of the Leman prism and {b) the operation principle of a 1xN (or Nxl) optical matrix switch using a Leman prism driven by a step-motor.
FIG. 3 (a) is the physical analysis for the Leman prism operation where the relationship between input beam and output beam can be calculated and (b) the unfolded principle of the Leman prism where the effective optical path can be calculated.
FIG. 4 is the detailed configuration of the nonblocking NxN matrix switch using the 1xN (or Nxl) matrix switches and cross-connection based on present invention.
Detailed Descriution of the Invention The matrix switches must be nonblocking, that means every input must have the possibility to be interconnected to every output without impacting the connection of any other pair of input and output. A nonblocking optical matrix switch is actually a communication network between N input ports and N output ports. For the fiber-optic switches, the nonblocking networks can be implemented with the switching units:
1xN/Nxl switches and the cross-connection between the input (1xN) switching units and output (1xN) switching units. Thus, for building a nonblocking NxN matrix optical switch with the fiber-optic technology, the 1xN (or Nxl) optical switch is a central part because it is basic building unit.
Figure 1 is the 1xN fiber-optic switch built with a movable Leman prism and aligned fibers where Fig. 1(a) is the top view and Fig. 1(b) the cross-section view.
This 1xN
fiber-optic switch comprises an amount 20, prism-carrier 22 which can be moved along two straight-line rails 24 driven by a step-motor, a Leman prism 26 put on the prism carrier 22, an input optical signal 28 and output signal 30 comes from the input fiber 32, after three reflections of the Leman prism, enters one of the output fibers 34. This construction can be inversely used as Nxl switch by using the fibers 34 as input fibers and fiber 32 as output fiber. The Leman prism is the core part of the 1xN
fiber-optic switch based on the present invention, so, as shown in Fig. 2, the detailed description of the optical switch should be strongly related to the physical characteristics of the Leman prism 26. As shown in Fig. 2(a), the Leman prism is composed of two typical prisms: one is equal-angle triangle and one is 30°-60°-90° triangle.
An optical beam is input at the direction perpendicular to one surface of the Leman prism, then it is through three total-internal-reflections and final comes out at the direction perpendicular to another surface of the Leman prism. In accordance with the geometrical optics, if the prism is moved along the direction perpendicular to the incident optical beam, the output optical beam will be at different positions for the same input optical beam. As shown in Fig. 2(b), when the Leman prism is located at three different positions called No. 1, No.
i and No.
N, the input optical beams corning from the same input fiber can come out at three different positions and enter three different output fibers. In the similar manner, an inverse process can also be performed. Therefore, with this construction using step-motor driven moving of Leman prism, a 1 xN (or Nx 1 ) optical switch can be implemented.
In general, the operation of prism for an optical beam can be analyzed with vectors. As shown in Fig. 3(a), the incident optical beam is determined as the left-hand principle and the propagating direction of the incident optical beam is defined as z coordinate, x coordinate is perpendicular to the operating plane of optical beams and y coordinate is in the operating plane of optical beams and perpendicular to the propagating direction of the incident optical beam, and the unit vectors in x, y, and z coordinates are i , j and k , respectively. We define the incident beam vector as Ac°~ , the first reflected, the second reflected and the third reflected beams as Ac's , Acz~ and Ac3~ , respectively. Thus the unit vector of the incident beam can be represented as Ac°' = k (1) At the first reflection point, the normal line vector of the reflection plane can be represented as Nc'~ = cos(60° ) j + (sin 60° )k (2) So, the unit vector of the reflected beam at the first reflection point can be analyzed by Acr> _ Aio> _ 2(Na> , Aco~)Nm (3) Substituting Eqs. (1) and (2) into Eq. (3), we obtain Ac's = 2 j - 2 k (4) At the second reflection point, the normal line vector of the reflection plane can be represented as Ncz> - k (5) So, the unit vector of the reflected beam at the second reflection point can be analyzed by AWz> = Aa> _ 2(Ncz~ ~ AW>)Ncz> (6) Substituting Eqs. (4) and (5) into Eq. (6), we obtain AWz> -_ _ 2 j + 2 k (7) At the third reflection point, the normal line vector of the reflection plane can be represented as N~'~ = -sin(30°) j -cos(30")k (8) So, the unit vector of the reflected beam at the third reflection point can be analyzed by Ais~ _ Acz~ _ 2(N(3> ~ A(2))N(3) (9) Substituting Eqs. (7) and (8) into Eq. (9), we obtain A(3' = k (10) Note from Eqs. (1) and (10) that the propagation direction of the third reflected beam is the same as the direction of the incident beam, which is one of important characteristics of the Leman prism in this invention. As shown in Fig. 3(a), from the incident beam to the output beam, the shifted distance of the optical beam is S after it is reflected three times by the Lamen prism at the vertical direction (y direction). Assuming the lowest point of input aperture is the starting point at the height direction (y=0) and the height of the incident beam is yo, then we have S =(y~,+2yo)x2=6yo (11) Taking a look at Eq. (11), the shifted distance of the optical beam at the height direction certainly depends on the height of the incident beam yo . Then, assuming that the input optical beam does not move and the Lamen prism moves to lower direction by Dy , namely, the height of the incident beam is yo + ~y , we have S =~(Yo'~'DY)+2(Yo+DY)~x2 (12) =6(Yo+DY) Therefore, if the matrix optical switch is 1xN and the center-to-center distance of two adjacent fibers is do, the longest distance for one switching operation is the moving distance of the output optical beam from the OFF-position to the furthest fiber, i.e., Ndo, while the moving distance of the Leman prism is only Ndol6. Accordingly, the operating time for one switching is less 6 times than that of the opto-mechanical approaches.
In order to analyze the propagating process of optical beam within the Leman prism in this invention, unfolding prism is a good method. Especially, through unfolding the prism, both the propagating distance of optical beam within the prism and the characteristic parameter, which is an important parameter in studying a prism, are easy to be determined. Figure 3(b) is the schematic of the unfolded prism, so the propagating distance L and the characteristic parameter K can be calculated as follows.
L = D ~ tan(60°) + 2D ~ tan(60°) (13) = 3~D
So, we have the characteristic parameter of the Leman prism as K=LlD=3~ (14) For the 1xN fiber-optic switches based on the present invention, the design for the whole system, the design for the detailed structure of the Leman prism, the design for the optical alignment system including the grin lenses or micro-optic lenses, and the packaging of the: whole system are critical issues. These two parameters L and K are very helpful for all above issues. As mentioned above, 1 xN (or Nx 1 ) optical switches can be not only usf:d as individual components and have wide applications, but they are also basic units for building the NxN matrix optical switches. Especially, the nonblocking matrix optical switches are core components in both fiber-optic communications and simultaneous measurements of multiple parameters. With these 1xN (or Nxl) optical switches and a full cross-connect of fibers, a nonblocking NxN matrix optical switch can be built as shown in Fig. 4 where input fibers 36 and output fibers 38 are connected to the input (1~;N) switches 40 and the output (Nxl) switches 42, respectively, and then the input switches and the output switches are communicated with a cross-connection 44 of fibers.
This configuration of NxN nonblocking matrix optical switches is a full-bidirectional. Of course, other connection methods of fibers can also be used for building the NxN matrix optical switches with the 1xN (or Nx L) fiber-optic switches based on the present invention.
Background of the Invention Optical matrix switches have wide applications in two main aspects. One is optical communications. This capability provides an expected controllable possibility and effective switching in the high capacity optical communication systems, especially in the modern dense wavelength division multiplexing (DWDM) and optical cross-connect (OXC) systems. Other one is the simultaneous testing of multiple parameters of one or more devices without repeated physical reconnections. This capability produces consistent results and makes laboratory and manufacturing testing systems more efficient and cost-effective. In the field of matrix optical switches, conventional products are opto-mechanical design and have been used for tens of years in both optical networks and simultaneous measurements of multiple parameters. JDS Uniphase and Dicon are two main producers in the past decade and their main customers are typically the Nortel Networks, Lucent Technologies, Cisco Networks and so on in the area of optical networks, and the NTT of Japan, the Agilent and the Lucent of the United States, the EXFO of Canada etc. for other uses such as packaging switch modules. So, demand for a variety of reliable. optical switches is strongly driven by the fast growing of optical networks and multi-channel testing systems.
In long-haul transport networks, a hybrid technology is employed and traffic is transported optically, but most of operations are implemented as electronic systems. The switching and communication need to convert optical streams to electronic signals and then convert these signals to optical streams. The optical-electrical-optical (0E0) conversion based networks suffer from several inherent deficiencies such as high cost, lack of scalability and performance limitation. In local area networks, optical switching is an attractive candidate switching and communication. The optical matrix switches together with the variable optical attenuators are the central components in constructing the photonic switching systems such as the optical DWDM networks, the OXCs and simultaneous testing systems of multiple parameters. The maximum number of subscribers will strongly depend on the properties of the individual matrix switches. In the simultaneous measurements of multiple parameters, matrix switches together with the variable optical attenuators are indispensable unless there are enough signal sources and detecting systems. The requirements for the implementation of such optical components in a system are compact size, relatively fast operation, low loss, low power consumption and low crosstalk. Furthermore, the optical matrix switches should have uniform switching characteristics and stable operating characteristics.
To date, most of optical switching devices in production today use an opto-mechanical means to implement optical steering. This is accomplished through the separation, or the alignment, or the reflection of the light beam by an opto-mechanical driven mechanism.
These designs offer good optical performance typically such as low insertion loss, low power consumption and low crosstalk, but have two typical drawbacks. One is slow operating speed. The typical settling times for switching are from lOms to 100ms. Even for some large-scale optical matrix switches, the setting times for switching are from 100's of milliseconds to 1 second. The other disadvantage is the big size.
Although the opto-mechanical matrix switches have so many disadvantages in their switching operations, a serial of fiber-optic switch products can still have wide uses in the simultaneous testing of multiple parameters and mufti-channel lightwave systems. These disadvantages, in other words, could be acceptable in the conventional small-scale photonics networks today, but future's high capacity communications really could not continue to suffer from these out-of-age properties from the view point of the long term benefits. To overcome some of these limitations, the optical matrix switches aiming at small size and high operating speed must be based on radically different designing concepts and manufacturing technologies from the currently used opto-mechanical approach.
Today, research and development of optical matrix switches have shown that planar optical waveguide technology and micro-electro-mechanical system (MEMS) are typically two promising approaches. The former is based on the thermo-optic (TO) waveguides or the electro-optic (EO) waveguides. The TO waveguide devices using silica-on-silicon waveguides have shown an exciting advantage over the currently used other waveguide devices in fiber-optic communications because of their great flexibility in fabrication and processing as well as speedy operations than the mechanical ones. The EO waveguide devices using diffused LiNb03-based waveguides have also presented a promising application in the future with its high-speed operation, low loss and mature manufacturing technology. But, so far no commercially acceptable products have been widely applied in industry yet because some technical problems still need much more work. The latter, MEMS really presents an attractive potential in research and development of highly mufti-port optical matrix switches, and has been receiving much attention in the past several years. But, due to the very difficult process and packaging on the large-scale matrix switches (>8x8), no commercial products have been developed successfully so far.
As mentioned above, the conventional matrix optical switches based on the opto-mechanical approach really have some important advantages such as low insertion loss, reliable operation and low power consumption as well as mature technologies for both designing and manufacturing. Although this type of matrix optical switches has low operating speed and big device size, they are also acceptable for the environments of applications that do not require high speed and large-scale operations, but only emphasize the low insertion loss and reliable operations. In particular, if the above two drawbacks were improved much with new design, this type of optical switches will also have a relatively strong ability to compete market with the other similar optical switches that are based on the new technologies now and in the near future. Therefore, manufacturing the conventional matrix optical switches based on the opto-mechanical design and developing new matrix optical switches based on currently available reliable advanced technologies in parallel is an appropriate moment in this important technical field.
Summary of the Invention Matrix optical switches are dispensable in both optical communications and simultaneous measurement of multiple parameters in industries. In the former field, the capability of matrix optical switches provides an expected controllable possibility and effective switching in the high capacity optical communication systems, and in the later field their capability produces consistent results and makes laboratory and manufacturing testing systems more efficient and cost-effective. Most of matrix optical switches in production today are fiber-optic switches based on opto-mechanical technology.
This is accomplished through the separation, or the alignment, or the reflection of the light beam by an opto-mechanical driven mechanism. In an NxN matrix fiber-optic switch based on opto-mechanical technology, the 1xN (or Nxl) switches are basic building units. A 1xN
(or Nxl) fiber-optic switch using a Leman prism driven by a step-motor is proposed in this invention. In the matrix optical switches based on various opto-mechanical designs, the operating speed, the complexity, the size, the insertion loss, repeatability and the blocking are main problems. In this invention, the 1xN (or Nxl) fiber-optic switch uses a Leman prism directly driven by a step-motor. This configuration can let one fixed input optical beam have different positions for the output by choosing different prism locations with a step-motor without changing the length of optical path and the prism movement is much less than the shift of the output beam for one operation. So, the 1xN
fiber-optic switch based on present invention can be improved in the operation speed, the device size and the complexity without impacting other parameters. With the 1xN (and Nxl) fiber-optic switches, a nonblocking NxN optical matrix switches can be directly built through a complete cross-connection. As a result, the operating speed, the complexity, the repeatability, the operating speed, device size and the power consumption can be significantly improved. If the precision optical alignment is employed in packaging, the insertion loss of the whole device can be depressed. Therefore, the final performance of the compact NxN optical matrix switch also becomes low insertion loss, high repeatability, relatively fast operating speed and nonblocking.
In a desirable embodiment according to the present invention, the strategy for the fiber-optic switches based on the present invention lies in the compact structure design, the lens alignment technology and the precision mechanical controlling to provide low insertion loss, excellent repeatability, small size/weight and relatively fast switching speed based on our own proprietary optical designs. The size of our products will be about a quarter of the same kind of products currently existing in market, and the cost of each individual product will a half of the same level product currently existing in market.
The fiber-optic switches will be fully-bidirectional and can be suitable for a wide range of applications, including fiber-optic component testing, remote fiber-optic system testing in telecommunication networks, transmitter/receiver measurements, reconfiguration and restoration in broadband fiber-optic telecommunication systems, and sampling education, research and development according to current invention.
Brief Description of the Drawing FIG. 1 is the configuration of a 1xN optical matrix switch using a Leman prism driven by a step-motor: (a) the top view and the construction of the 1xN optical matrix switch and (b) the cross-section view.
FIG. 2 (a) is the construction of the Leman prism and {b) the operation principle of a 1xN (or Nxl) optical matrix switch using a Leman prism driven by a step-motor.
FIG. 3 (a) is the physical analysis for the Leman prism operation where the relationship between input beam and output beam can be calculated and (b) the unfolded principle of the Leman prism where the effective optical path can be calculated.
FIG. 4 is the detailed configuration of the nonblocking NxN matrix switch using the 1xN (or Nxl) matrix switches and cross-connection based on present invention.
Detailed Descriution of the Invention The matrix switches must be nonblocking, that means every input must have the possibility to be interconnected to every output without impacting the connection of any other pair of input and output. A nonblocking optical matrix switch is actually a communication network between N input ports and N output ports. For the fiber-optic switches, the nonblocking networks can be implemented with the switching units:
1xN/Nxl switches and the cross-connection between the input (1xN) switching units and output (1xN) switching units. Thus, for building a nonblocking NxN matrix optical switch with the fiber-optic technology, the 1xN (or Nxl) optical switch is a central part because it is basic building unit.
Figure 1 is the 1xN fiber-optic switch built with a movable Leman prism and aligned fibers where Fig. 1(a) is the top view and Fig. 1(b) the cross-section view.
This 1xN
fiber-optic switch comprises an amount 20, prism-carrier 22 which can be moved along two straight-line rails 24 driven by a step-motor, a Leman prism 26 put on the prism carrier 22, an input optical signal 28 and output signal 30 comes from the input fiber 32, after three reflections of the Leman prism, enters one of the output fibers 34. This construction can be inversely used as Nxl switch by using the fibers 34 as input fibers and fiber 32 as output fiber. The Leman prism is the core part of the 1xN
fiber-optic switch based on the present invention, so, as shown in Fig. 2, the detailed description of the optical switch should be strongly related to the physical characteristics of the Leman prism 26. As shown in Fig. 2(a), the Leman prism is composed of two typical prisms: one is equal-angle triangle and one is 30°-60°-90° triangle.
An optical beam is input at the direction perpendicular to one surface of the Leman prism, then it is through three total-internal-reflections and final comes out at the direction perpendicular to another surface of the Leman prism. In accordance with the geometrical optics, if the prism is moved along the direction perpendicular to the incident optical beam, the output optical beam will be at different positions for the same input optical beam. As shown in Fig. 2(b), when the Leman prism is located at three different positions called No. 1, No.
i and No.
N, the input optical beams corning from the same input fiber can come out at three different positions and enter three different output fibers. In the similar manner, an inverse process can also be performed. Therefore, with this construction using step-motor driven moving of Leman prism, a 1 xN (or Nx 1 ) optical switch can be implemented.
In general, the operation of prism for an optical beam can be analyzed with vectors. As shown in Fig. 3(a), the incident optical beam is determined as the left-hand principle and the propagating direction of the incident optical beam is defined as z coordinate, x coordinate is perpendicular to the operating plane of optical beams and y coordinate is in the operating plane of optical beams and perpendicular to the propagating direction of the incident optical beam, and the unit vectors in x, y, and z coordinates are i , j and k , respectively. We define the incident beam vector as Ac°~ , the first reflected, the second reflected and the third reflected beams as Ac's , Acz~ and Ac3~ , respectively. Thus the unit vector of the incident beam can be represented as Ac°' = k (1) At the first reflection point, the normal line vector of the reflection plane can be represented as Nc'~ = cos(60° ) j + (sin 60° )k (2) So, the unit vector of the reflected beam at the first reflection point can be analyzed by Acr> _ Aio> _ 2(Na> , Aco~)Nm (3) Substituting Eqs. (1) and (2) into Eq. (3), we obtain Ac's = 2 j - 2 k (4) At the second reflection point, the normal line vector of the reflection plane can be represented as Ncz> - k (5) So, the unit vector of the reflected beam at the second reflection point can be analyzed by AWz> = Aa> _ 2(Ncz~ ~ AW>)Ncz> (6) Substituting Eqs. (4) and (5) into Eq. (6), we obtain AWz> -_ _ 2 j + 2 k (7) At the third reflection point, the normal line vector of the reflection plane can be represented as N~'~ = -sin(30°) j -cos(30")k (8) So, the unit vector of the reflected beam at the third reflection point can be analyzed by Ais~ _ Acz~ _ 2(N(3> ~ A(2))N(3) (9) Substituting Eqs. (7) and (8) into Eq. (9), we obtain A(3' = k (10) Note from Eqs. (1) and (10) that the propagation direction of the third reflected beam is the same as the direction of the incident beam, which is one of important characteristics of the Leman prism in this invention. As shown in Fig. 3(a), from the incident beam to the output beam, the shifted distance of the optical beam is S after it is reflected three times by the Lamen prism at the vertical direction (y direction). Assuming the lowest point of input aperture is the starting point at the height direction (y=0) and the height of the incident beam is yo, then we have S =(y~,+2yo)x2=6yo (11) Taking a look at Eq. (11), the shifted distance of the optical beam at the height direction certainly depends on the height of the incident beam yo . Then, assuming that the input optical beam does not move and the Lamen prism moves to lower direction by Dy , namely, the height of the incident beam is yo + ~y , we have S =~(Yo'~'DY)+2(Yo+DY)~x2 (12) =6(Yo+DY) Therefore, if the matrix optical switch is 1xN and the center-to-center distance of two adjacent fibers is do, the longest distance for one switching operation is the moving distance of the output optical beam from the OFF-position to the furthest fiber, i.e., Ndo, while the moving distance of the Leman prism is only Ndol6. Accordingly, the operating time for one switching is less 6 times than that of the opto-mechanical approaches.
In order to analyze the propagating process of optical beam within the Leman prism in this invention, unfolding prism is a good method. Especially, through unfolding the prism, both the propagating distance of optical beam within the prism and the characteristic parameter, which is an important parameter in studying a prism, are easy to be determined. Figure 3(b) is the schematic of the unfolded prism, so the propagating distance L and the characteristic parameter K can be calculated as follows.
L = D ~ tan(60°) + 2D ~ tan(60°) (13) = 3~D
So, we have the characteristic parameter of the Leman prism as K=LlD=3~ (14) For the 1xN fiber-optic switches based on the present invention, the design for the whole system, the design for the detailed structure of the Leman prism, the design for the optical alignment system including the grin lenses or micro-optic lenses, and the packaging of the: whole system are critical issues. These two parameters L and K are very helpful for all above issues. As mentioned above, 1 xN (or Nx 1 ) optical switches can be not only usf:d as individual components and have wide applications, but they are also basic units for building the NxN matrix optical switches. Especially, the nonblocking matrix optical switches are core components in both fiber-optic communications and simultaneous measurements of multiple parameters. With these 1xN (or Nxl) optical switches and a full cross-connect of fibers, a nonblocking NxN matrix optical switch can be built as shown in Fig. 4 where input fibers 36 and output fibers 38 are connected to the input (1~;N) switches 40 and the output (Nxl) switches 42, respectively, and then the input switches and the output switches are communicated with a cross-connection 44 of fibers.
This configuration of NxN nonblocking matrix optical switches is a full-bidirectional. Of course, other connection methods of fibers can also be used for building the NxN matrix optical switches with the 1xN (or Nx L) fiber-optic switches based on the present invention.
Claims (5)
1. An opto-mechanical device comprising:
an amount;
a Leman prism, a prism-carrier, which is driven by a step-motor, on said substrate;
an input fiber and multiple output fibers, which are arranged at the two sides of the Leman prism.
an amount;
a Leman prism, a prism-carrier, which is driven by a step-motor, on said substrate;
an input fiber and multiple output fibers, which are arranged at the two sides of the Leman prism.
2. Based on claim 1, the 1×N switching operations based on the present invention are implemented by moving the Leman prism along straight line with the step-motor.
3. Based on claim 1 and claim 2, the Leman prism is mandatory though some other types of prisms can also be employed to implement the opto-mechanical switching operations because the Leman prism has some special characteristics that can implement some main objectives of the devices based on the present invention such as small size, short switching time, low systematic loss and easy packaging.
4. Based on claim 3, the straight-line moving motor is suggested to drive the prism-carrier.
5. The N×N optical matrix switch could be built with the 1×N/N×l opto-mechanical switches based on this invention and a full cross-connect of fibers, and the size of the N×N matrix optical switches can be also pressed some compared with the other designs.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2386309 CA2386309A1 (en) | 2002-05-28 | 2002-05-28 | Compact design of 1xn fiber-optic switch using leman prism and step-motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2386309 CA2386309A1 (en) | 2002-05-28 | 2002-05-28 | Compact design of 1xn fiber-optic switch using leman prism and step-motor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2386309A1 true CA2386309A1 (en) | 2003-11-28 |
Family
ID=29783766
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2386309 Abandoned CA2386309A1 (en) | 2002-05-28 | 2002-05-28 | Compact design of 1xn fiber-optic switch using leman prism and step-motor |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2386309A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7590316B2 (en) | 2005-09-14 | 2009-09-15 | Polatis Limited | Optical switch |
| US7876981B2 (en) | 2004-07-15 | 2011-01-25 | Polatis Ltd. | Optical switch |
| CN108761652A (en) * | 2018-05-30 | 2018-11-06 | 中国科学院半导体研究所 | The multimode optical switching framework with link switching is exchanged for link internal schema |
| CN114448551A (en) * | 2022-01-20 | 2022-05-06 | 中国电子科技集团公司第二十八研究所 | Distributed serial matrix switching system based on passive wavelength division multiplexing |
-
2002
- 2002-05-28 CA CA 2386309 patent/CA2386309A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7876981B2 (en) | 2004-07-15 | 2011-01-25 | Polatis Ltd. | Optical switch |
| US7590316B2 (en) | 2005-09-14 | 2009-09-15 | Polatis Limited | Optical switch |
| CN108761652A (en) * | 2018-05-30 | 2018-11-06 | 中国科学院半导体研究所 | The multimode optical switching framework with link switching is exchanged for link internal schema |
| CN114448551A (en) * | 2022-01-20 | 2022-05-06 | 中国电子科技集团公司第二十八研究所 | Distributed serial matrix switching system based on passive wavelength division multiplexing |
| CN114448551B (en) * | 2022-01-20 | 2023-08-25 | 中国电子科技集团公司第二十八研究所 | Distributed serial matrix switching system based on passive wavelength division multiplexing |
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