EP4652749A1 - Fiber optic switch, system and method, including for use with multi-operator service providers - Google Patents

Abstract

A remote switch switches between multiple operators and customers, and includes 2 x 2 switching units operatable in three states: a bar state; a cross state; and a coupler state, based on different voltages applied to each switching unit. Each operator has a first input supplied by an OLT to a first splitter with 16 outputs connected to a different 2 x 2 switching unit for that operator. Each of the two outputs of each 2 x 2 switching unit is connected to an input of a selection switch to select the signal of one operator to a particular ONU. There are 32 selection switches. Each of the selection switches is connected to a dedicated customer ONU.

Description

FIBER OPTIC SWITCH, SYSTEM AND METHOD, INCLUDING FOR USE WITH MULTI-OPERATOR SERVICE PROVIDERS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is being filed on January 16, 2024, as a PCT International Application and claims the benefit of U.S. Provisional Application No. 63/439,253 filed on January 16, 2023, and U.S. Provisional Application No. 63/439,963 filed on January 19, 2023, the disclosures of which are hereby incorporated by reference in their entireties.

BACKGROUND

[0002] Multiple service providers may offer service to a multi-dwelling unit, whereby each dwelling (or customer) has the option to select one of the service providers. In some cases, a select dwelling may switch service providers at a later date.

[0003] Various issues arise in the field with multi-dwelling unit (MDU) equipment for the multi-operator case. Similarly, this also represents a problem for street cabinets. Expensive truck roll interventions are required by technicians to access equipment onsite for any new subscriptions or to change to another operator. If manual patch cords are used in the demarcation area of the equipment by different crews of installers, poor management of those patch cords over time can result in disorderly patch cord arrangements when cords become tangled with each other. Sometimes signal service can be impacted if the patch cords are bent too much or pulled too much.

[0004] Examples of known equipment for multi-operator service are shown in WO2012/152635A2 and W02013/092250A1.

[0005] Improvements are desired.

SUMMARY

[0006] Different fiber optic switch architecture solutions are presented to solve issues in the field with multi-dwelling unit equipment for the multi-operator case. Solutions presented here can also solve issues of street cabinets. A remote switching solution based on 2 x 2 switching units, allows for remote switching for new subscriptions or to change to another operator.

[0007] The switch of the present invention allows remote switching between operators and customers. [0008] The 2 x 2 switching units of the switch operate in three states: 1) a bar state; 2) a cross state; and 3) a coupler state.

[0009] In one example, three different voltages can be applied to each switching unit to result in the desired operation in one of the three states.

[0010] In one example, Mach-Zehnder based 2 x 2 switching units are provided. [0011] In another example, opto-mechanical 2 x 2 switching units are provided. [0012] The switching units can be operated remotely.

[0013] In one example switch system and method, each operator has a first input supplied to a first splitter arrangement with N outputs. Each splitter output N is connected to a different 2 x 2 switching unit (2 possible inputs and 2 possible outputs). There are N number of 2 x 2 switching units for each operator. There are M number of operators. Each of the 2 outputs of each 2 x 2 switching unit is connected to an input of an M x 1 selection switch to select the signal of one operator to a particular ONU in the back. There are 2N number of selection switches at the back of the switch architecture. Each of the selection switches is connected to a dedicated customer ONU. In this system, each 2 x 2 switching unit has only one input connected to a port of an OLT card in the central office of the operator. The N number of 2 x 2 switching units for each operator operate in three states: 1) a bar state; 2) a cross state; and 3) a coupler state to supply each of the 2N number of selection switches, as desired.

[0014] In one example system, there are 16 operator outputs per operator to the switch. There are 32 customer ONU’s.

[0015] In a further example system and method, at least one operator has a second input (connected to a different port of an Optical Line Termination (OLT)) supplied to a second splitter arrangement also with N outputs. Each splitter output N from the second splitter arrangement is connected to a different one of the 2 x 2 switching units at the second input. In this further system, each 2 x 2 switching unit for the at least one operator has one input connected to the first splitter arrangement and one input connected to the second splitter arrangement of the at least one operator. The N number of 2 x 2 switching units for the at least one operator operate in two states: 1) a bar state; and 2) a cross state; but not in 3) a coupler state, to supply each of the 2N number of selection switches, as desired.

[0016] A remote switching solution based on 1 x 2 switching units, also allows for remote switching for new subscriptions or to change to another operator. [0017] A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows:

[0019] Figure 1 shows a prior art multi-operator arrangement for a multi dwelling unit where the operators and the customers are connected with patch cords.

[0020] Figure 2 is a similar view to Figure 1 further showing the connections between operators and customers with patch cords of the prior art.

[0021] Figure 3 shows an example switch system of the present invention that does not use movable patch cords, but uses a remote switch to control the connections between the operators and the customers.

[0022] Figure 4 shows an example of day one operation of the switch of Figure 3 where the remote switch includes an N plurality of 2 x 2 switching units and 2N times as many selection switches, and where an operator's signal is connected to a 2N number of selection switches.

[0023] Figure 4A show the switching unit in the bar mode or state, or the cross mode or state, as indicated in the schematic representation of the operation of the switch.

[0024] Figure 5 shows an example of day one operation of the switch of Figure 3 for a switch where the remote switch includes an N plurality of 2 x 2 switching units and 2N times as many selection switches, and where an operator's signal is connected to a 2N number of selection switches, and all of 2N selection switches are provided with signal.

[0025] Figure 5A shows the switching unit in the coupler mode, as indicated in the schematic representation of the operation of the switch.

[0026] Figure 6 shows the remote switch architecture when a first operator adds an additional splitter arrangement.

[0027] Figure 6A shows the switching unit in the bar mode, or the cross mode, or the coupler mode, as indicated in the schematic representation of the operation of the switch. [0028] Figure 7 shows a multi-operator arrangement with four operators.

[0029] Figure 8 shows a multi-operator arrangement with three operators.

[0030] Figure 9 shows an alternative switching unit including a 1 x 2 micro-optical coupler/ switch with a splitter cube and a reflecting prism.

[0031] Figure 10 shows a further alternative switching unit including a 2 x 2 micro- optical coupler/switch with a splitter cube and a plurality of reflecting prisms.

DETAILED DESCRIPTION

[0032] Reference will now be made in detail to exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0033] In order to prevent undisciplined handling of the patch cords, an any-to-any switch alleviates the problems of manually controlled patch cords.

[0034] Figures 1 and 2 show a prior art connection that is implemented in an MDU 10. The feeder cables 14, 16 from different operators enter a respective operator box 24, 26, where the feeder cables are spliced or connected to a splitter 30. Splitter output ports can be connected with patch cords or jumpers 64, 68 to the customer box 20 into which a connector is spliced to the riser cable 60 going to the apartments where the ONU’s are placed. This is better illustrated in Figure 2 for the case of 2 operators each installing a 1 x 8 splitter.

[0035] Customer box 20, and each operator box 24, 26 includes a front door 40 that is moveable to expose interiors 58, 38 for storage of equipment and fiber connections. Side doors 44, 54 expose cross-connect area 66. Jumpers 64, 68 in cross-connect area 66 connect patch fields 42 of each operator box 24, 26 to patch field 50 of customer box 20. Feeder cables 14, 16 enter operator boxes 24, 26 at ports 28. Riser cable 60 exits at port 28 of customer box 20.

[0036] Riser cable 60 extends to floor boxes 70, which are then connected with drop cables 72 to each outlet 80 of each customer of customer premises 90. Each outlet 80 is connected to an Optical Network Unit (ONU).

[0037] Figure 3 shows schematically that a switch 110 can be added to an existing set of boxes 20, 24, 26. Switch 110 can be used with other equipment also. The switch 110 interfaces the operator boxes 24, 26 and the customer box 20. Once the switch 110 has been introduced and connected to the operators and the customers, reentries to add or change patch cords are not necessary anymore because the switch 110 can be programmed to facilitate the desired connections without any onsite access.

[0038] Jumpers 120, 122, 124 connect patch fields 42 of each operator box 24, 26, and patch field 50 of customer box 20 to switch 110. In one example, jumpers 120, 122, 124 are in the form of hydra cables.

[0039] Prior art any-to-any matrix switches are however still quite lossy. For example, for 16 or 32 ONU’s, the available power budget in PON’s is not adequate to allow for their introduction, since a 32 x 32 any-to-any switch will introduce losses higher than 6 dB.

[0040] A remote any-to-any switch that is described herein includes a switch based on an architecture that involves 2 x 2 switching units 140, and N x 1 selection switches 170 as building blocks. The 2 x 2 switching units are controllable switches that can operate in a bar state, a cross state, and in a coupler state, depending on how many customers desire service and how many output signals each operator offers. The selection switches 170 are controllable switches that operate to direct only the desired operator’s signal of the group of available operators’ signals, to the specific customer who selected the desired operator. As will be described further, this switching solution facilitates to connect customer ONU’s in a MDU to the OLT in the central office, at day 1 when only 1 splitter arrangement is installed in the multi-operator box for one or more of the operators. In general, N ports from splitters installed in the operator box can provide service to 2N ONU’s at day 1. Installing an extra splitter over time, allows for a cross over scenario, and 2N ports can then be connected to 2N ONU’s through the desired switch configuration.

[0041] For the switch chip in one example preferably all 2 x 2 switching units 140 and N x 1 selection switches 170 can be Mach-Zehnder building blocks and can be integrated on the same PLC integrated glass optics chip. However, to address different applications, modular chips can be designed where the N x 1 selection switches can be integrated onto a separate chip.

[0042] Figures 4, 5 and 6 show an MDU involving 2 operators where at day 1 a 1 x 16 splitter arrangement 130 of a 1 x 16 splitter 132 of each operator is installed in each operator box 24, 26 and connected to an OLT. A switching solution involving a row of two times 16 2 x 2 switching units 140 that are connected to the splitter ports on one side and on the chip connected to a row of 322 x 1 selection switches 170 solves the problems outlined before. Each operator has a set of 16 2 x 2 switching units 140 that optically connect along connections 134 to the respective splitters 132. The 2 x 2 switching units 140 each optically connect along connections 160 to two 2 x 1 selection switches 170. The output ports from the selection switches 170 of the chip are connected to the riser cable 60 that connects the ONU’s.

[0043] Figure 4A shows the switching unit 140 in bar mode or cross mode, as indicated in the schematic representation of the operation of the switch. Switching unit 140 has two input ports 142, 148, and two output ports 144, 146. In Figures 4 and 5 only port 142 is connected to a splitter output. When applying a voltage VI the switching unit is put in a bar mode. Signal 150 is provided to port 144. When voltage V0, such as no voltage or other voltage, is applied to the electrode of the switching unit, the switching unit operates in a cross state. Signal 150 is provided to port 146.

[0044] Figure 5A shows the switching unit 140 in the coupler mode, as indicated in the schematic representation of the operation of the switch. When applying a voltage V2, such as less than V 1 , and greater than V0, the switching unit is put in a coupler mode, causing a 50 % power split of the splitter port connected to an input port of the 2 x 2 switching units 140. Split signal 150a is provided to port 144, and split signal 150b is provided to port 146. Also, split second signal 152a is provided to port 144, and second split signal 152b is provided to port 146.

[0045] Figure 6 shows the remote switch architecture when a first operator adds an additional splitter arrangement. At day 1 (Figures 5, 5A) to alleviate blocking, the 2 x 2 switching units will need to be put in a coupler mode to provide service to two ONU’s. As illustrated in the Figures 5A and 6A this is accomplished by a lower voltage V2 that needs to be applied to the electrode of the switching/splitting unit. After adding the second splitter there is the possibility to reach all ONU’s and the splitting units of the switch can be put in cross or bar mode (Figures 4A and 6A) without the power loss incurred when the switching/splitting units are in the coupler modes.

[0046] Figure 6 may also illustrate a day 1 situation if operator 1 has 32 splitter outputs from box 24, and operator 2 has only 16 splitter outputs from box 26. Operator 1 operates splitting units of the switch in cross or bar mode (Figures 4A and 6A). Operator 2 operates in coupler mode to serve all the ONU’s until additional splitters and signals are added on day 2.

[0047] As illustrated in Figures 4A, 5A, and 6A, the switching units 140 can operate in bar, cross or coupling functionality, depending on the voltage that is applied. In one example, these switching units 140 are Mach-Zehnder type switching units. Note that when the 3dB coupling functionality is not introduced, blocking will occur when e.g. ONU 1 and ONU 17 are requiring service at day 1. When in that case the corresponding Mach-Zehnder switch building block is put in a 3 dB coupler mode, the problem is alleviated at the cost of introducing an extra 3 dB power budget requirement, which is usually available in an optical distribution network of a PON. This extra power budget is needed for the system of Figure 5 to function. At a later stage, when the second splitter is installed by the operator upon rise of the take rates, the switching units 140 can be put into a switching mode (bar or cross) yielding an extra 3 dB of optical power budget.

[0048] Each switching unit 140 is low loss and broadband (1250 nm to 1650 nm) when operating in the cross and bar states. For example, the loss in switching unit 140 may be in the range of 0.2 - 1 dB per unit, and preferably lower than 0.5 dB. When operating in the coupler state, the loss is about 3 dB uniform over the wavelength range. The extra loss induced in the coupler state can be alleviated by providing a second splitter allowing to put all switching units 140 in bar or cross states. Compare Figure 5 for operator box 24 having a single splitter 132, to Figure 6 where operator box 24 has a second splitter 132.

[0049] Other technology besides the 2 x 2 Mach-Zehnder type switching units on a chip may be used, with low insertion loss, including MEMS, beam steering or mechatronic solutions.

[0050] Figure 7 shows that the switch solution can also address a multi-operator case of 4 operators that install two 1 x 8 splitters (or one 1 :16 splitter). Switch 210 includes 16 2 x 2 switching units 140 per operator connected by optical connections 134 to each operator box 24, 26, 224, 226. For this application, 32 4 x 1 selection switches 270 are connected to the switching units 140 by optical connections 160. Selection switches 270 are controlled to select which operator’s signal is to be connected to the customer.

[0051] Figure 8 shows that the switch solution can also address a multi-operator case of 3 operators that install two 1 x 8 splitters (or one 1 :16 splitter). Switch 310 includes 16 2 x 2 switching units 140 per operator connected by optical connections 134 to each operator box 24, 26, 224. For this application, 32 3 x 1 selection switches 370 are connected to the switching units 140 by optical connections 160. Selection switches 370 are controlled to select which operator’s signal is to be connected to the customer.

[0052] One impact for the noted switches 110, 210, 310 is that the number of switch components is reduced compared to prior art any-to-any matrix switches. In some cases a 32 port any-to-any matrix switch (serving 32 ONU’s) might require at least 32 squared number of switch components, equaling 1024 switch components. In switch 110, there are 322 x 2 switching units 140, and 322 x 1 selection switches 170. In switch 210, there are 642 x 2 switching units 140, and 324 x 1 selection switches 270. In switch 310, there are 48 2 x 2 switching units 140, and 32 3 x 1 selection switches 370.

[0053] Other switching technology may be used, including opto-mechanical solutions. Figure 9 shows an alternative switching unit 540 including a 1 x 2 micro- optical coupler/s witch with a splitter cube 570 and a reflecting prism 580. In Figure 9(1), switch 540 is in the bar state. Input signal 542 includes a pigtailed fiber with a collimating lens 550. In the bar state, the full signal is passed to fiber 544 through free space and a corresponding collimating lens 550. Fiber 546 receives no signal. In Figure 9(11), the switch 540 is in the split mode wherein a splitter element 570 (e.g. a splitter cube) is inserted into the free space area, which splits the signal by 50% to pathway 562 and pathway 564, for each supplying respective fibers 544, 546 with a split signal. In Figure 9(111), the switch 540 is in the cross state wherein a reflecting element 580 (e.g. a reflecting prism) is inserted into the free space for directing pathway 560 to pathway 564 for supplying fiber 546 with the full signal. Fiber 544 receives no signal in this example. [0054] Splitter cube 570 and reflecting prism 580 can be mounted separately or together on movable structure(s) within switching unit 540. Switching unit 540 can include latching structure(s) to hold or locate the light reflecting and/or the light modifying structures 570, 580 in the desired locations, and without power if desired.

[0055] Figure 10 shows a further alternative switching unit 640 including a 2 x 2 micro-optical coupler/switch with a splitter cube 570, and a plurality of reflecting prisms 580, 582. In Figure 10(1), switch 640 is in the bar state. First input signal path 642 includes a pigtailed fiber with a collimating lens 550. In the bar state, input signal path 642 is passed by prism 580 to fiber 668 through free space and a corresponding collimating lens 550, along pathways 644, 650. Second input signal path 654 includes a pigtailed fiber with a collimating lens 550. In the bar state, input signal path 654 is passed by reflecting prism 582 to fiber 660 through free space and a corresponding collimating lens 550, and pathways 656, 658. In Figure 10(11), the switch 640 is in the split mode wherein a splitter cube 570 is inserted into the free space area, which splits the first input signal from pathway 642 by 50% to pathway 646 (and prism 582 and pathway 648), and 50% to pathway 652, for each supplying respective fibers 660, 668 with a split signal. In Figure 10(111), the switch 640 is in the cross state wherein two reflecting prisms 580, 582 (the same two prisms as in Figure 10(1) rearranged, or two other prisms) are inserted into the free space. Prism 582 directs first input signal path 642 to fiber 660. Input signal path 654 is passed by prism 580 to fiber 668. Additional prisms, splitters, couplers can be added to add a splitter function for pathway 654.

[0056] As noted above regarding switching unit 540, for switching unit 640, splitter cube 570 and reflecting prisms 580, 582 (and any additional prisms) can be mounted separately or together, on movable structures within switching unit 540. Switching unit 640 can include latching structure to hold or locate the light reflecting and light modifying structures 570, 580, 582 in the desired locations.

[0057] Suitable light reflecting and light modifying structures 570 (a Right Angle Prism Mirror), and splitters 580, 582 (a Non-Polarizing Beamsplitter Cube) are commercially available from Thorlabs Inc.

[0058] Having described the preferred aspects and implementations of the present disclosure, modifications and equivalents of the disclosed concepts may readily occur to one skilled in the art. However, it is intended that such modifications and equivalents be included within the scope of the claims which are appended hereto.

Claims

What is claimed is:

1. A 2 x 2 switching unit operating in three states comprising:

1) a bar state;

2) a cross state; and

3) a coupler state.

2. The 2 x 2 switching unit of claim 1, including Mach-Zehnder based 2 x 2 switching units.

3. The 2 x 2 switching unit of claims 1 and 2, wherein different voltages are applied to each switching unit to result in operation in one of the three states.

4. A remote switching system for multi-operators service providers, comprising a remote control for remote switching for new subscriptions or to change to another operator; a plurality of 2 x 2 switching units; each operator having a first input from an Optical Line Termination supplied to a first splitter arrangement with N outputs; each splitter output N connected to a different 2 x 2 switching unit (2 possible inputs and 2 possible outputs); wherein there are N number of 2 x 2 switching units for each operator; wherein there are M number of operators; wherein each of the 2 outputs of each 2 x 2 switching unit is connected to an input of an M x 1 selection switch; wherein there are 2N number of selection switches; wherein the outputs of the M x 1 selection switches are provided to the customers; wherein each 2 x 2 switching unit has only one input connected to an operator on day one for at least one operator; wherein the N number of 2 x 2 switching units for each operator operate in three states:

1) a bar state;

2) a cross state; and 3) a coupler state to supply each of the 2N number of selection switches, as desired; wherein the remote control controls the 2 x 2 switching units and the M x 1 selection switches.

5. The remote switching system of claim 4, wherein at least one operator has a second input, connected to a different port of an Optical Line Termination, supplied to a second splitter arrangement also with N outputs; wherein each splitter output N from the second splitter arrangement is connected to a different one of the 2 x 2 switching units at the second input; wherein each 2 x 2 switching unit for the at least one operator has one input connected to the first splitter arrangement and one input connected to the second splitter arrangement of the at least one operator; wherein the N number of 2 x 2 switching units for the at least on operator operate in two states:

1) a bar state; and

2) a cross state; but not in a coupler state, to supply each of the 2N number of selection switches, as desired.

6. A method for remote switching for new subscriptions or to change to another operator in the systems of claims 4 and 5, wherein: there are N splitter outputs for at least one operator; controlling the 2 x 2 switching units and the M x 1 selection switches to serve any of the 2N number of customers, by operating the 2 x 2 switches in one of the three states:

1) a bar state;

2) a cross state; and

3) a coupler state to supply each of the 2N number of selection switches, as desired.

7. The method of claim 6, wherein: there are 2N splitter outputs for at least one operator; controlling the 2 x 2 switching units and the M x 1 selection switches to serve any of the 2N number of customers, by operating the 2 x 2 switches in one of the two states:

1) a bar state;

2) a cross state, but not a coupler state to supply each of the 2N number of selection switches, as desired.

8. A 1 x 2 switching unit operating in three states comprising:

1) a bar state;

2) a cross state; and

3) a coupler state.

9. The 1 x 2 switching unit of claim 8, at least on reflecting prism, and at least on beamsplitter cube.

10. A remote switching system for multi-operators service providers, comprising a remote control for remote switching for new subscriptions or to change to another operator; a plurality of 1 x 2 switching units; each operator having a first input from an Optical Line Termination supplied to a first splitter arrangement with N outputs; each splitter output N connected to a different 1 x 2 switching unit (1 input and 2 possible outputs); wherein there are N number of 1 x 2 switching units for each operator; wherein there are M number of operators; wherein each of the 2 outputs of each 1 x 2 switching unit is connected to an input of an M x 1 selection switch; wherein there are 2N number of selection switches; wherein the outputs of the M x 1 selection switches are provided to the customers; wherein each 1 x 2 switching unit is connected to an operator on day one for at least one operator; wherein the N number of 1 x 2 switching units for each operator operate in three states: 1) a bar state;

2) a cross state; and

3) a coupler state to supply each of the 2N number of selection switches, as desired; wherein the remote control controls the 1 x 2 switching units and the M x 1 selection switches.

11. A method for remote switching for new subscriptions or to change to another operator in the systems of claim 10, wherein: there are N splitter outputs for at least one operator; controlling the 1 x 2 switching units and the M x 1 selection switches to serve any of the 2N number of customers, by operating the 1 x 2 switches in one of the three states:

1) a bar state;

2) a cross state; and

3) a coupler state to supply each of the 2N number of selection switches, as desired.