This disclosure relates to an optical fiber cross-connect system. Specifically, this disclosure relates to an optical fiber circuit switching system with latching using stacked rotor plates and a moving robot for optical fiber cross-connect.
The world is more and more connected with optical fibers. IT networking innovations have been mostly applied to layers 0 to 6 of the communication networks while the physical interconnects layer remains unchanged for decades. As the IT infrastructure scales to meet the ever-growing application and service demands, the scale of the physical connectivity layer in data centers, telecom central offices and wireless networks is quickly becoming a huge challenge for manual service and management. An emerging need is a “smart” physical connectivity layer which can help IT services with software defined networking to better utilize the resources and achieve lower cost.
The present disclosure describes a robotic fiber switching system. The system uses a sliding robot to insert fiber connectors into adaptors mimicking manual latching-on operations. One of the advantages of the system is in that it uses off-the-counter connectors and adaptors that keep the cost low. By using stackable and modular parts, the system can be easily scaled up or scaled back according to the needs of specific projects. The system also provides a design that allows one side of the patch cords, i.e. the outer patch cords in the disclosure, to be fixedly placed in the system hence reducing the cord entanglement.
According to an embodiment of the present disclosure, the system includes n layers of stacked stators. each stator has m slots among m stator posts, providing n×m ports. The system further includes n layers of stacked rotors configured to turn inside of the stacked stators, each layer corresponding to a layer of the stacked stators and including a first connector. The system further includes m second connectors disposed of outside of the stacked stators, each corresponding to a slot of the stator. The system further includes a robotic head configured to move on a rail surrounding the n stacked stators, wherein a robotic arm located on a top of the robotic head is configured to connect the first connector and the second connector at a port of the robotic fiber switching system and wherein m and n are natural numbers.
According to another embodiment of the present disclosure, a method of a robotic fiber switching system is disclosed. The method includes the steps of determining to establish a connection between an ith first connector of n first connectors to a P second connector of m second connectors, wherein each of the n first connectors is disposed of on a corresponding layer of stacked rotors and each of the m second connectors are disposed of in a corresponding slot outside of n layers of stacked stators; turning a stacked rotor in the ith layer to the jth slot of the stacked stator; moving a robotic head on a rail to the j slot; and connecting the jth second connector to the ith first connector.
According to yet another embodiment of the present disclosure a fiber switching system is disclosed. The system includes n layers of stackable rotors, each stackable rotor comprising a first connector connected with a first patch cord; n layers of stackable stator, each stackable stator comprising: a second connector connected to a second patch cord; and m slots; and a robotic arm configured to access the m slots by moving on a rail horizontally and to the n layers vertically, wherein the robotic arm latches the second connector to the first connector via an adaptor to establish connection between the first patch cords and the second patch cords.
Additional features and advantages will be set forth in the detailed description that follows, and in part will be readily apparent to people skilled in the art from the description or recognized by practicing the condiments as described in the written description and claims hereof, as well as the accompanying drawings.
It is to be understood that the foregoing general description, the following detailed description, and the accompanying drawings are merely exemplary and intended to provide an overview or framework to understand the nature and character of the claims.
The above-mentioned advantages and other features of the present invention will become more apparent to and the invention will be better understood by people skilled in the art with reference to the following description of the preferred embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
FIG. illustrates a stackable rotor according to an embodiment according to an embodiment of the present disclosure;
FIG. illustrates a stackable stator according to an embodiment of the present disclosure;
Several embodiments of the present disclosure are illustrated by the accompanying drawings and described in detail below. In the figures of the accompanying drawings, elements having the same reference numeral designations represent like elements throughout. The drawings are not to scale, unless otherwise noted. The embodiments are described by way of example, and not by limitation. All terminologies and phraseology used herein are for the purpose of illustrating only and should not be understood as limiting. The phrases such as “including”, “comprising”, “having” and other variations thereof are meant to encompass the items as described and their equivalents without excluding any additional items thereof.
Those skilled in the art will understand that the principles of the present disclosure may be implemented with a number of suitably arranged systems and devices that may vary from the embodiments but are within the scope of the present disclosure.
Optical fiber cross-connect systems, e.g. systems connecting two different termination locations using physical and hardwired cable within a datacenter, is the key element to realize a “smart” physical connectivity layer. Over the past couple of decades, various optical switches have been developed for automated fiber cross-connect. But few meets the performance requirements of all the applications in terms of optical loss, switching time and port count. For active networking, circuit switching time in milliseconds and below is a must. The optical loss is also preferred to be less than 3 dB as the standard transceivers are typically made for a link loss budget not considering the additional loss from the insertion of a fiber cross-connect element. 3D MEMS and collimator steering switching technologies are more suitable as they have reasonably fast switching on the order of a few 10s of milliseconds, and reasonably low loss on the order of 2-3 dB. See X. Zheng et al., “Three-Dimensional MEMS Photonic Cross-Connect,” IEEE J. Sel. Top. Quantum Electron., vol. 9, no. 2, pp. 571-578, 2003; See also Hagood et al, “Beam-steering optical switching apparatus,” U.S. Pat. No. 7,095,916 B2, 2006.
However, for applications such as automated fiber patch panel or optical distribution frame (ODF), the switching time is not very critical as the fiber patching is traditionally done manually. But the optical loss of each connection has to be very low, with less than 1 dB preferred. In addition, latching is typically required for this type of applications once a fiber connection is made to guarantee reliable physical connection against power outage, earthquake, etc.
For low cost, low loss fiber switching with latching, robotic fiber switching is an excellent solution. A few robotic fiber switches have been provided and commercialized previously. (See Wave2wave Solution, ROME 500. http://www.wave-2-wave.com/rome-500.html; Mizukami et al., “200×200 automated optical fiber cross-connect equipment using a fiber-handling robot for optical cabling systems,” in OFC/NFOEC 2005-2005 Conference on Optical Fiber Communication/National Fiber Optic Engineers Conference, 2005, p. OFP5; “Telescent G3 NTM.” [Online]. Available: http://www.telescent.com/products/.)
For example, in Wave2wave Solution, supra, two robots connect a pair of LC ferrule based custom optical connectors over a mechanical matrix structure. With the connectors clamped onto the matrix, the connection is latched. The customized connector design has the benefit of achieving reasonably large port count in a compact design. A switch with 256×256 duplex ports is realized fitting in a 19″ rack. But customized fiber connector design also resulted in high cost such as a cost of more than $100 per fiber port.
Low cost robotic fiber switching uses standard optical fiber connectors. Mizukami et. al., supra, built a 200×200 automated optical fiber cross-connect system in 2005 using a fiber-handling robot in 2005, which is illustrated in
A. S. Kewitsch from Telescent Inc. later improved the connection reconfiguration control algorithm based on the Theory of Knots and Braids (see “Telescent G3 NTM.”, supra and Kewitsch, supra) to link a 2-D input array to a 1-D intermediate array, and demonstrated automated cross-connect with reconfigurability in a completely non-blocking fashion and scalable to large port count of 1000×1000. However, the switching time was not improved. On average it would take a few minutes to connect any input to an output port because of the complex control algorithm for minimizing the fiber entangling.
In this disclosure, a low-cost robotic fiber cross-connect system using off-the-shelf standard fiber connectors is provided. Specifically, an apparatus of fiber circuit switching with latching using stacked rotor plates and one moving robot is disclosed. Further, this disclosure provides an advantageous solution by utilizing fiber patch cords with standard connectors commonly used in the art, which further lowers the cost of the overall solution. To realize fiber cross-connect using fiber patch cords with off-the-shelf standard connectors without having to worry about fiber entanglement, a straightforward solution is to have the input and output fiber ports moving orthogonally in two separate planes. This disclosure utilizes a slightly modified implementation of such principle.
The stackable rotor may freely and independently rotate in 360 degrees on the layer it is in with regard to a common axis located in the center of the switch. On the boundary of the circle that the stackable rotors may rotate in, a plurality of ring-shaped stackable stators 110 are concentrically stacked therein, each corresponding to a stackable rotor.
Along the circle of ring-shaped stackable stators 110, there are a plurality of stator posts 115 evenly distributed therein, which will be described in further detail below. According to an embodiment of the present disclosure, the stator posts 115 are periodically raised portions on the stackable stators. According to an embodiment of the present disclosure, each stator post 115 is configured to house a magnet 130. The spaces between neighboring stator posts 115 correspond where the fiber connectors may be latched on for switching. When multiple layers of stators are stacked together as illustrated in
Outside of the stackable stators 110, the robotic switch 100 further includes a robotic head 140 that can freely move around a circular rail 160 located at the outmost edge of the base board 105. A pickup arm 150 is placed on top of and supported by the robotic head 140, which is configured to grab the connectors to latch to and unlatch from the ports of the switch 100. The switch 100 cross-connects by establishing connections between the inner patch cords 170 and the outer patch cords 190. The inner patch cords 170 are connected to inner fiber connectors 180 located on the stackable rotors. The outer patch cords 190 are connected to outer fiber connectors 195 located outside of the stackable stators, configured to be picked up by the pickup arm 150. According to an embodiment of the present disclosure, when establishing a connection at a port, the inner patch cords 170 and outer patch cords 190 are connected via an adaptor 165 located on the stackable rotors 120, which will be described in further detail below. According to the present disclosure, the inner fiber connectors 180 and the outer fiber connectors 195 can be selected from low-cost, off-the-counter connectors, which is advantageous to some cross-connect systems in the art.
The robotic switch 100 is configured to cross-connect any inner patch cord to any outer patch cord. The outer patch cords 190 are fixedly located with regard to the base board 105. In other words, the outer ports are fixed with regard to the base board 105. To establish a connection, the robotic switch 100 will locate the rotor at the right layer and cause the rotor to move to where the outer port is. When an outer fiber connector 195 is not connected to any inner fiber connectors 170, it is inserted into parking stands 220 not connected any inner fiber connectors. When a connection is to be established, the robotic arm 150 will insert, or latch, the outer fiber connectors 195 to the target layer above to establish a connection after the rotor already stepped the inner fiber connector into the port and ready to connect.
The illustration in
On the bigger end of the stackable rotor 120, the curved edge conforms to the curve of the circular stacked stators. Therefore, when the stackable rotor 120 rotates on the bearing 320, the curved edge keeps a constant and close distance to the stator slots. At the end of the curved edge, there is a coil set including three coils 210 mounted thereon. The three coils are separated with an equal angle separation θ from each other. According to an embodiment of the present disclosure, the coils are formed by forming conductive wires into loops and have two ends. The three coils 210 in the coil set are identified as 210 (A, A′), 210 (B, B′) and 210 (C, C′) respectively as illustrated in
According to an embodiment of the present disclosure, a fiber connector adaptor 165 is mounted on the stackable rotor plate between coil 210 (A, A′) and 210 (B, B′). The adaptor 165 is configured to provide adaptation to the off-the-shelf optical fiber connector 180 of an inner patch cord 170. The inner connector 180 is pre-inserted into the adaptor 165. When the robotic switch 100 is in operation, the controller will identify the port of the connection. That is, the controller will identify the layer to which the inner patch cord 170 is connected to and the slot to which the outer patch cord 190 is parked. The stackable rotor of the identified layer will step towards the destination slot where the outer patch cord connector 195 is parked.
At the designation port, the adaptor 165 will stop at the midpoint of the slot between two neighboring stator posts, such that the connector 195 of the outer patch cord 190 can be robotically latched on the adaptor 165 and establish a connection. According to an embodiment, to facilitate the automatic connection, the adaptor 165 is located ⅜θ degrees away from coil 210 (A, A′), the selection of this angle will be explained in further details below. As illustrated in
As illustrated in
The coils in the coil set are magnetically activated in turn to drive the stackable rotor 120 to continuously step, or rotate, to the desired slot, where the outer fiber connector can be picked up and inserted to the connector adaptor 165 by the vertically moving pickup arm 150. To describe the process, we assume that the stackable rotor 120 of ith layer that need to be stepped to the jth slot is currently in the position where the first coil 210 (A, A′) is aligned with the magnet 130 at kth stator post 115.
This position may result from the situation that the coil 210 (A, A′) was magnetically activated and the magnetic attraction between the 210 (A, A′) and the magnet 130 at the kth stator post 115 aligned them. As illustrated in
In the above example, the ith stackable rotor 120 turns in the clockwise direction. By changing the magnetic activation sequence, i.e. from activating the coil sets in the order of (A, A′), (B, B′), (C, C′) and so on, to activating them in the order of (C, C′), (B, B′), (A,A′) and so on, the ith rotor 120 will turn in the counter clockwise direction. As such, the robotic fiber switching system 100 may decide which direction is shorter to reach in terms of a circle and turn the stackable rotor in that direction accordingly. According to an embodiment, by choosing the angles θ and a satisfying θ=4/3 a, the rotor 120 evenly turns ⅓ a as the coils sequentially activates. The even movement in every step enhances the smoothness and durability of the switch 100. In addition, by placing the adaptor 165 ⅜θ degrees away from coil 210 (A, A′), which equals to ½ a degrees, when the 210 (A, A′) finally reaches and aligns with a stator post 115, the adaptor 165 will be located at the midpoint between the two neighboring stator posts 115 of the destination slot, ready for connection.
People skilled in the art understand that the robotic switch 100 may be optimized in choosing coils 210 and the magnets 130 that provide strong attraction within a working distance, i.e. ⅓ a in the example, to effectively and quickly step the rotor but with quickly attenuated attraction for longer distance, such as near ⅓ a to reduce attractions of the coil to other magnets 130. People skilled in the art also understand that numerous changes may be made to the switch 100. For example, different numbers of coils, such as 2, 4, or other numbers may be used or different angle correlations between a and θ may be adopted. For another example, the adaptor 165 may be placed at other positions with regard to the coil set together with other modifications to the embodiment. Those alternatives will require corresponding but apparent changes to the design details to the present embodiment. It is understood that those alternatives, whether described herein or not, are within the scope of the present disclosure.
According to the embodiment described above, the stator base 340 is a ring-shaped structure upon which the stator posts 115 are disposed. The stackable stators 110 are stacked by putting the stator bases 340 on top of each other with the stator posts 115 of the same ports aligned across the layers. As such, the stator bases 340 are stackable regarding each other. In another embodiment, the stackable stator base 340 connecting the neighboring posts is eliminated, in which case the stator posts 115 with magnets 130 of multiple layers of the same slot are directly stacked on top of each other. In this case, it is preferred that the stator posts are designed in LEGO®-like structure in the sense that one stator post 115 can be securely inserted into another stator post. This alternative embodiment provides the same slot space for the inner patch cords 170 and outer patch cords 190 to connect at the port and can be easily adapted to the overall all design of the robotic fiber switching system 100 described above.
In order to make a connection, the outer cord connector 195 is latched to the adaptor 165 after the adaptor has been stepped into position. As described above in connection with
Although the present disclosure describes or illustrates the connecting the inner and outer patch cords of the robotic switch operations as occurring in a particular order, the present disclosure contemplates any suitable operations occurring in any suitable order. Moreover, the present disclosure contemplates any suitable operations being repeated one or more times in any suitable order.
The present disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the embodiments herein that people having ordinary skill in the art would comprehend. Similarly, where appropriate, the appended claims encompass all changes, substitutions, variations, alterations, and modifications to the embodiments herein that people having ordinary skill in the art would comprehend.
None of the description in this disclosure should be read as implying that any particular element, step of function shall be an essential element that must be included in the claims scope. The scope of the patented subject matter is defined only by the claims as follows.
The present disclosure claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 62/822,302, filed on Mar. 22, 2019, entitled Robotic Fiber Cross-Connect System.