Broadcast-capable optical multicast switch

Abstract

Embodiments of the present disclosure relate to optical multicast switches with broadcast capability. An apparatus includes a first input port, a first switch, and a second switch. The first switch and the second input port are in optical communication with the first input port. The apparatus also includes a second input port, a third switch, and a fourth switch. The third switch and the fourth switch are in optical communication with the second input port. Each switch is switchable between a first state for passing optical signals and a second state for blocking optical signals. The apparatus also includes a first combiner in optical communication with the first input port via the first switch and in optical communication with the second input port via the third switch. The apparatus also includes a second combiner in optical communication with the first input port via the second switch and in optical communication with the second input port via the fourth switch.

Description

[0001] Related Applications

[0002] This application is a divisional application of the application for patent with application number 201810996572.8, application date of April 9, 2019, and title of “Optical Multicast Switch with Broadcasting Capability”. TECHNICAL FIELD

[0003] One or more embodiments relate to methods and apparatuses for optical multicast switching with broadcasting capability. BACKGROUND

[0004] A multicast switch (MCS) is a device that combines optical switching and multiplexing, which is used to provide a colorless, directionless, and contentionless solution, often used with reconfigurable optical add-drop multiplexers (ROADMs). In a typical M x N MCS structure, where M is the number of input ports and N is the number of output ports, an optical signal can be received by any one of the M input ports and transmitted at any one of the N output ports. In other words, a MCS is a full interconnect.

[0005] Figure 1 A schematic diagram of a known multicast switch 100 is shown. The multicast switch 100 includes a first 1 x 2 switch 110 and a second 1 x 2 switch 120. The first switch 110 can direct an input optical signal to a first path 115a or a second path 115b, and the second 1 x 2 switch 120 can direct an input optical signal to a first path 125a or a second path 125b. The multicast switch 100 also includes a first combiner 130 connected to the paths 115a and 125a, and a second combiner 140 connected to the paths 115b and 125b. The first combiner 130 is connected to a first output port 135, and the second combiner 140 is connected to a second output port 145 to pass an output signal.

[0006] In operation, the multicast switch 100 directs an input signal at the first switch 110 to the first output port 135 by directing the input signal to the first path 115a, and directs the input signal at the first switch 110 to the second output port 145 by directing the input signal to the second path 115b. Similarly, the multicast switch 100 can direct an input signal at the second switch 120 to the first output port 135 by directing the input signal to the first path 125a, and direct the input signal at the second switch 120 to the second output port 145 by directing the input signal to the second path 125b.

[0007] As in Figure 1As can be seen, the switch 110 can direct the input signal to either the first path 115a or the second path 115b, but not both. This can create several problems in practice. For example, known MCS architectures are typically based on a head-end switch and a tail-end switch, and require coordination of both switches for path reconfiguration. Additionally, optical networks using known multicast switches at the head-end can only implement a 1 : 1 protection scheme, which generally has slower recovery compared to a 1+1 protection scheme. SUMMARY

[0008] Some embodiments described herein generally relate to optical multicast switching with broadcast capability, and in particular, to methods and apparatus for reconfigurable multicast switching between switching and splitting using N 1x1 switches (rather than a 1xN switch).

[0009] In some embodiments, an apparatus includes a first input port, a first switch, and a second switch. The first switch is in optical communication with the first input port and is switchable between a first state for passing optical signals and a second state for blocking optical signals. The second switch is in optical communication with the first input port and is switchable between the first state and the second state. The apparatus further includes a second input port, a third switch, and a fourth switch. The third switch is in optical communication with the second input port and is switchable between the first state and the second state. The fourth switch is in optical communication with the second input port and is switchable between the first state and the second state. The apparatus further includes a first combiner in optical communication with the first input port via the first switch and in optical communication with the second input port via the third switch. The apparatus further includes a second combiner in optical communication with the first input port via the second switch and in optical communication with the second input port via the fourth switch.

[0010] In some embodiments, a method includes receiving a first portion of a first optical signal at a first switch, the first switch being switchable between a first state for passing the first portion and a second state for blocking the first portion. The method further includes receiving a second portion of the first optical signal at a second switch, the second switch being switchable between the first state and the second state. The method further includes receiving a third portion of a second optical signal at a third switch, the third switch being switchable between the first state and the second state, and receiving a fourth portion of the second optical signal at a fourth switch, the fourth switch being switchable between the first state and the second state. The method further includes combining possible optical signals sent through the first switch and the third switch to generate a first output signal, and combining possible optical signals sent through the second switch and the fourth switch to generate a second output signal.

[0011] In some embodiments, an optical network includes a transmitter to transmit an optical signal and a splitter to split the optical signal into a first portion and a second portion. A first switch is configured to receive the first portion of the optical signal and is switchable between a first state to pass the first portion of the optical signal and a second state to block the first portion of the optical signal. A second switch is configured to receive the second portion of the optical signal and is switchable between a first state to pass the second portion of the optical signal and a second state to block the second portion of the optical signal. The optical network further includes a receiver in optical communication with the first switch and the second switch to receive possible optical signals transmitted from the first switch and the second switch. The optical network further includes a processor operably coupled to the first switch and the second switch. Upon execution of processor-executable instructions, the processor selects the first switch to enter the first state to transmit the first portion and selects the second switch to enter the second state to block the second portion to generate a 1 : 1 protection scheme in the optical network. The processor further selects the first switch to enter the first state to transmit the first portion and selects the second switch to enter the first state to transmit the first portion to generate a 1+1 protection scheme in the optical network. BRIEF DESCRIPTION OF DRAWINGS

[0012] Those skilled in the art will appreciate that the figures are mainly for illustrative purposes and are not intended to limit the scope of the subject matter described herein. The figures are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein can be shown exaggerated or enlarged in the figures for the sake of clarity. In the figures, like reference numerals typically refer to like features (e.g., functionally similar and / or structurally similar elements).

[0013] Figure 1 A schematic diagram of a known multicast switch is shown.

[0014] Figure 2 A schematic diagram of an apparatus that can be configured for multicast switching and broadcast in accordance with some embodiments is shown.

[0015] Figure 3 A schematic diagram of a reconfigurable multicast switch configured in a switching mode for multiplexing in accordance with some embodiments is shown.

[0016] Figure 4 A schematic diagram of a reconfigurable multicast switch configured in a broadcast mode for multiplexing in accordance with some embodiments is shown.

[0017] Figure 5 A schematic diagram of a reconfigurable multicast switch configured in a standard mode for demultiplexing in accordance with some embodiments is shown.

[0018] Figure 6A diagram illustrating a reconfigurable multicast switch configured for demultiplexing in a protection mode is shown in accordance with some embodiments.

[0019] Figure 7 A diagram illustrating an optical network reconfigurable between a 1+1 protection scheme and a 1:1 protection scheme is shown in accordance with some embodiments.

[0020] Figure 8 A method of optical communication is shown in accordance with some embodiments. DETAILED DESCRIPTION

[0021] In some embodiments, an apparatus includes a first input port, a first switch, and a second switch. The first switch is in optical communication with the first input port and is switchable between a first state for passing optical signals and a second state for blocking optical signals. The second switch is in optical communication with the first input port and is switchable between the first state and the second state. The apparatus further includes a second input port, a third switch, and a fourth switch. The third switch is in optical communication with the second input port and is switchable between the first state and the second state. The fourth switch is in optical communication with the second input port and is switchable between the first state and the second state. The apparatus further includes a first combiner in optical communication with the first input port via the first switch and in optical communication with the second input port via the third switch. The apparatus further includes a second combiner in optical communication with the first input port via the second switch and in optical communication with the second input port via the fourth switch.

[0022] In some embodiments, the first switch and the second switch include a variable optical attenuator (VOA) configured to balance power. In some embodiments, each switch can be combined with an additional VOA to achieve independent switching and power balancing functions.

[0023] In some embodiments, the apparatus is configured to a switching mode in which the first input port is configured to pass a first optical signal of a first wavelength. The first switch is selected to the first state to pass the first optical signal to the first combiner, and the second switch is selected to the second state to block the first optical signal from the second combiner. The second input port is configured to pass a second optical signal of the first wavelength. The third switch is selected to the second state to block the second optical signal from the first combiner, and the fourth switch is selected to the first state to pass the second optical signal to the second combiner.

[0024] In some embodiments, the apparatus is configured into a broadcast mode in which the first input port is configured to pass a first optical signal of a first wavelength. The first switch and the second switch are selected into the first state to pass the first optical signal to the first combiner and the second combiner. The second input port is configured to pass a second optical signal of a second wavelength different from the first wavelength. The third switch and the fourth switch are selected into the first state to pass the second optical signal to the first combiner and the second combiner.

[0025] In some embodiments, the apparatus further comprises a controller operably connected to the first switch, the second switch, the third switch, and the fourth switch to control the apparatus between a first operational mode, a second operational mode, and a third operational mode. In the first operational mode, the first switch is configured in the first state, the second switch is configured in the second state, the third switch is configured in the second state, and the fourth switch is configured in the first state. In the second operational mode, the first switch, the second switch, the third switch, and the fourth switch are configured in the first state. In the third operational mode, the first switch, the second switch, the third switch, and the fourth switch are configured in the second state.

[0026] In some embodiments, the first combiner is operably coupled to a first multiplexer and the second combiner is connected to a second multiplexer.

[0027] In some embodiments, the apparatus further comprises a first splitter and a second splitter. The first splitter is configured to receive a first optical signal having a first spectral component of a first wavelength and a second spectral component of a second wavelength and split the first optical signal into a first portion and a second portion. The second splitter is configured to receive a second optical signal having a third spectral component of the first wavelength and a fourth spectral component of a fourth wavelength and split the second optical signal into a third portion and a fourth portion. A fifth switch is in optical communication with the first splitter and is configured in a first state to pass the first portion of the first optical signal. A sixth switch is in optical communication with the second splitter and is configured in a second state to block the first portion of the second optical signal. A first output port is in optical communication with the fifth switch and the sixth switch to pass the first portion of the first optical signal passed by the fifth switch. A seventh switch is in optical communication with the first splitter and is configured in the second state to block the second portion of the first optical signal. An eighth switch is in optical communication with the second splitter and is configured in the first state to pass the second portion of the second optical signal. The apparatus further comprises a second output port in optical communication with the seventh switch and the eighth switch to pass the second portion of the second optical signal passed by the eighth switch.

[0028] In some embodiments, the apparatus further includes a first splitter and a second splitter. The first splitter is configured to receive a first optical signal having a first spectral component of a first wavelength and a second spectral component of a second wavelength, and to split the first optical signal into a first portion and a second portion. The second splitter is configured to receive a second optical signal having a third spectral component of the first wavelength and a fourth spectral component of the second wavelength, and to split the second optical signal into a third portion and a fourth portion. A fifth switch is in optical communication with the first splitter and is configured in a first state to transmit the first portion of the first optical signal. A sixth switch is in optical communication with the second splitter and is configured in a second state to block the first portion of the second optical signal. A first output port is in optical communication with the fifth switch and the sixth switch to transmit the first portion of the first optical signal transmitted by the fifth switch. A seventh switch is in optical communication with the first splitter and is configured in a first state to transmit the second portion of the first optical signal. An eighth switch is in optical communication with the second splitter and is configured in a second state to block the second portion of the second optical signal. The apparatus further includes a second output port in optical communication with the seventh switch and the eighth switch to transmit the second portion of the first optical signal transmitted by the seventh switch.

[0029] In some embodiments, the apparatus further includes a controller operably coupled to the first switch, the second switch, the third switch, and the fourth switch to select the apparatus between a first operational mode and a second operational mode. In the first operational mode, the first input port is in optical communication with the first combiner and is optically blocked from the second combiner, and the second input port is in optical communication with the second combiner and is optically blocked from the first combiner. In the second operational mode, the first input port is in optical communication with the first combiner and is optically blocked from the second combiner, and the second input port is in optical communication with the first combiner and is optically blocked from the second combiner.

[0030] Figure 2 A schematic diagram of an apparatus 200 that can be configured for multicast switching and broadcast is shown in accordance with some embodiments. The apparatus 200 includes a first input port 212 connected to two switches 210a (referred to as a first switch) and 210b (referred to as a second switch), each of which can be switched between a first state (also referred to as a pass state) for transmitting an optical signal and a second state (also referred to as a block state) for blocking an optical signal. The first switch 210a is connected to a first path 215a, and the second switch 210b is connected to a second path 215b.

[0031] The apparatus 200 also includes a second input port 222 connected to two switches 220a (referred to as a third switch) and 220b (referred to as a fourth switch), each of which is also switchable between a first state for passing optical signals and a second state for blocking optical signals. The third switch 220a is connected to a third path 225a, and the fourth switch 220b is connected to a fourth path 225b.

[0032] The apparatus 200 also includes a first combiner 230 connected to the first path 215a and the third path 225a to combine possible signals passing from the first path 215a and the third path 225a. A first output port 235 is connected to the first combiner 230 to pass the combined signal. A second combiner 240 is connected to the second path 215b and the fourth path 225b to combine possible signals passing from the third path 215b and the fourth path 225b. A second output port 245 is connected to the second combiner 240 to pass the combined signal.

[0033] In some embodiments, one or more of the switches 210a, 210b, 220a, and 220b can be manually controlled. In some embodiments, one or more of the switches 210a, 210b, 220a, and 220b can be controlled by a controller 250. For example, the controller can select the first state or the second state of the switches based on a desired mode of operation of the apparatus 200.

[0034] In operation, the four switches 210a, 210b, 220a, and 220b can have various combinations to configure the apparatus 200 into different modes of operation. In some instances, the first switch 210a and the second switch 210b can be configured in the first state (i.e., the pass state), while the third switch 220a and the fourth switch 220b can be configured in the second state (i.e., the block state). In this case, the apparatus 200 can broadcast an input signal received by the first input 212 to both output ports 235 and 245.

[0035] In some instances, the first switch 210a and the second switch 210b can be configured in the second state (i.e., the block state), while the third switch 220a and the fourth switch 220b can be configured in the first state (i.e., the pass state). In this case, the apparatus 200 can broadcast an input signal received by the second input 222 to the output ports 235 and 245.

[0036] In some examples, the first switch 210a is configured in a first state, the second switch 210b is configured in a second state, in which case the input signal from the first input port 212 is passed to the first output port 235. The third switch 220a can be configured in the second state, and the fourth switch 220b can be configured in the first state, to pass the input signal from the second input port 222 to the second output port 245.

[0037] In some examples, the input signal from the first input port 212 can be passed to the second output port 245, and the input signal from the second input port 222 can be passed to the first output port 235. In this mode, the first switch 210a can be configured in the second state, and the second switch 210b is configured in the first state. The third switch 220a can be configured in the first state, and the fourth switch 220b can be configured in the second state.

[0038] In some examples, all switches 210a, 210b, 220a, and 220b are configured in a first state for broadcasting. In this mode, the input signal from the first input port 212 is broadcast to both output ports 235 and 245, and the input signal from the second input port 222 is also broadcast to both output ports 235 and 245.

[0039] In some examples, all switches 210a, 210b, 220a, and 220b are configured in a second state (also referred to as a full blocking mode) for channel regulation (also referred to as path regulation). In this mode, the properties of the optical signal from each path (e.g., from the first input port 212 to the first output port 235 or any other channel) can be measured by a detector before the channel is actually used. For example, this regulation step can ensure that there are no wavelength “collisions” in the couplers connected to the device 200, thereby reducing the likelihood of service interruption. In some embodiments, the properties of the optical signal can be the wavelength and / or power of the optical signal. In some embodiments, the properties of the optical signal can be the polarization of the optical signal. In some embodiments, the properties of the optical signal can be the optical spectrum of the optical signal.

[0040] In Figure 2In the example shown, the apparatus 200 includes two input ports 212 and 222 and two output ports 235 and 245 for illustrative purposes. In practice, any other number of input ports and output ports can also be used. In general, the apparatus 200 can include M input ports and N output ports, where M and N are positive integers. In this case, each input port splits an input signal into N parts, each part directed to a corresponding switch (i.e., N switches for each input port). The number of combiners is also N, and each combiner is connected to all M input ports. In some embodiments, an input port directs an input signal to all output ports simultaneously (e.g., in a broadcast mode). In some embodiments, an input port directs an input signal to only one of the output ports (e.g., in a switching mode). In some embodiments, an input port directs an input signal to a subset of the N output ports.

[0041] In some embodiments, the number of input ports M can be 2 to 2048 (e.g., 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, or 2048, including any values and sub-ranges therebetween). In some embodiments, the number of output ports N can be 2 to 2048 (e.g., 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, or 2048, including any values and sub-ranges therebetween).

[0042] In some embodiments, the number of input ports and the number of output ports can be the same. In some embodiments, the number of input ports and the number of output ports can be different.

[0043] In some embodiments, the first combiner 230 and the first output port 235 can be different parts of a single piece element, such as a 2x1 fiber coupler. In some embodiments, the first combiner 230 and the first output port 235 can be physically separate components and removably coupled to each other.

[0044] The switches 210a, 210b, 220a, and 220b can include various types of switches (collectively referred to as switches 210 and 220) for passing / blocking optical signals. In some embodiments, the switches 210 and 220 include a variable optical attenuator (VOA). The VOA can pass an optical signal in a low-loss state and block the optical signal in a high-loss state. In some embodiments, the attenuation ratio of the VOA can be greater than 15 dB (e.g., greater than 15 dB, greater than 20 dB, greater than 25 dB, or greater than 30 dB, including any values and sub-ranges therebetween).

[0045] In some embodiments, switches 210 and 220 can comprise electro-optical switches, which generally employ one or more electro-optical crystals that have a variable refractive index under an electric field. In some embodiments, the electro-optical crystals can comprise at least one of lithium niobate (LiNb03), lithium tantalate (LiTa03), lead zirconium titanate (Pb(Zr,Ti)03), and lanthanum zirconium titanate ((Pb,La)(Zr,Ti)03), among others. In some embodiments, the electro-optical switches can be based on Mach-Zehnder interferometers, in which an optical signal is split into two arms of the interferometer, and changing the refractive index in one arm can change the interference between the optical signals from the two arms. For example, constructive interference can be configured for a first state that generates an output signal that is substantially identical to the input optical signal, while destructive interference can be configured for a second state that generates an output signal with negligible power.

[0046] In some embodiments, switches 210 and 220 can comprise acousto-optical switches, which use sound waves to change the transmission of the switch. In some embodiments, switches 210 and 220 can comprise opto-mechanical switches, which generally redirect optical signals by moving optical fiber cable elements with mechanical devices. For example, an opto-mechanical switch can use a stepper motor to move a mirror that directs the optical signal light from an input to a desired output.

[0047] In some embodiments, switches 210a, 210b, 220a, and 220b can also be used for power balancing. For example, the input levels at first input port 212 and second input port 222 can be different. Thus, if no compensation or balancing is performed, the signals reaching first combiner 230 from first input port 212 and second input port 222 can also be different. However, first switch 210a can include a VOA for attenuating the input signal from the first input port and / or third switch 220a can also include a VOA for attenuating the input signal from the second input port. The attenuation allows the two signals reaching first combiner 230 to have substantially equal power, regardless of their respective input powers. Similar balancing can also be performed for second combiner 240 in second path 215b and fourth channel 225b.

[0048] In some embodiments, input ports 212 and 222 are connected to wavelength sources, such as transceivers (not shown). In some embodiments, input ports 212 and 222 are directly connected to the transceivers. In some embodiments, input ports 212 and 222 are connected to the transceivers via optical switches (not shown) for direction selection. In some embodiments, input ports 212 and 222 are connected to the transceivers via wavelength multiplexers (not shown).

[0049] In some embodiments, the input ports 212 and 222 are configured to receive a single-color input signal, i.e., an optical signal having a single wavelength or a single spectral component. In some embodiments, the input ports 212 and 222 are configured to receive an input signal having multiple spectral components, each at a different wavelength.

[0050] The controller 250 in the apparatus 200 can comprise any suitable processor capable of executing computer instructions. Each module in the processor can be any combination of a hardware-based module (e.g., a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a digital signal processor (DSP)) configured to perform a particular function, and / or a software-based module (e.g., a module of computer code stored in memory and / or executed at the processor). The processor can be a microcontroller, FPGA, ASIC, or any other suitable processor configured to run and / or execute the modules. The processor and modules of the processor can be configured to collectively perform the methods described herein, and / or implement the apparatuses described herein.

[0051] Figure 3 A schematic diagram of a reconfigurable multicast switch 300 configured for multiplexing in a switched mode is shown, in accordance with some embodiments. The multicast switch 300 comprises a first input port 312 for receiving a first optical signal 301 of a first wavelength λ1, and splitting the first optical signal 301 into a first portion 301a and a second portion 301b. The first portion 301a is sent to a first switch 310a connected to a first path 315a, and the second portion 301b is sent to a second switch 310b connected to a second path 315b.

[0052] The multicast switch 300 further comprises a second input port 322 for receiving a second optical signal 302 also of the first wavelength λ1, and splitting the second optical signal 302 into a third portion 302a and a fourth portion 302b. The third portion 302a is sent to a third switch 320a connected to a third path 325a, and the fourth portion 302b is sent to a fourth switch 320b connected to a fourth path 325b.

[0053] A first combiner 330 is connected to the first path 315a and the third path 325a, and a second combiner 340 is connected to the second path 315b and the fourth path 325b. Each combiner 330 and 340 is further connected to a respective output port 335 and 345, respectively. The first output 335 is configured to pass a first output signal 303, and the second output port 345 is configured to pass a second output signal 304.

[0054] In Figure 3In particular, the first switch 310a is set in a first state to pass the first portion 301a, which then travels to the first combiner 330. The second switch 310b is set in a second state to block the second portion 301b. The third switch 320a is set in the second state to block the third portion 302a, and the fourth switch 320b is set in the first state to pass the fourth portion 302b, which then travels to the second combiner 340. Thus, the first output signal 303 includes the first portion 301a, and the second output signal 304 includes the fourth portion 302b. Figure 3 The configuration in allows the same wavelength (i.e., λ1) from different line data to be used on alternative ports on the same broadcast MCS.

[0055] Figure 4 A schematic diagram of a reconfigurable multicast switch 400 configured for multiplexing in a broadcast mode is shown in accordance with some embodiments. The multicast switch 400 includes a first input port 412 for receiving a first optical signal 401 of a first wavelength λ1, and splitting the first optical signal 401 into a first portion 401a and a second portion 401b. The first portion 401a is sent to a first switch 410a connected to a first path 415a, and the second portion 401b is sent to a second switch 410b connected to a second path 415b.

[0056] The multicast switch 400 also includes a second input port 422 for receiving a second optical signal 402 of a second wavelength λ2, and splitting the second optical signal 402 into a third portion 402a and a fourth portion 402b. The second wavelength λ2 is different from the first wavelength λ1. The third portion 402a is sent to a third switch 420a connected to a third path 425a, and the fourth portion 402b is sent to a fourth switch 420b connected to a fourth path 425b.

[0057] A first combiner 430 is connected to the first path 415a and the third path 425a, and a second combiner 440 is connected to the second path 415b and the fourth path 425b. Each combiner 430 and 440 is also connected to a corresponding output port 435 and 445, respectively. The first output 435 is configured to pass a first output signal 403, and the second output port 445 is configured to pass a second output signal 404. The first output signal 403 is directed to a first multiplexer 450 and the second output signal 404 is directed to a second multiplexer 460.

[0058] In Figure 4In particular, the four switches 410a, 410b, 410c and 410d are all configured in the first state to pass the optical signals. Thus, the first output signal 403 comprises the sum of the first portion 401a of the first optical signal 401 and the third portion 402a of the second optical signal 402. The second output signal 403 comprises the sum of the second portion 402a of the first optical signal 401 and the fourth portion 402b of the second optical signal 402. Thus, Figure 4 This mode shown allows the same wavelength (common line data) to be sent to both output ports at the same time.

[0059] The multicast switches 300 and 400 shown in Figure 3 and Figure 4 may have the exact same hardware structure and the switches can be set in different combinations to achieve different modes of operation.

[0060] Figure 5 A schematic diagram of a reconfigurable multicast switch 500 configured for demultiplexing in a standard mode is shown in accordance with some embodiments. In Figure 3 and 4 the communication is eastbound. In Figure 5 and 6 the communication is westbound. The multicast switch 500 comprises a first input port 535 for receiving a first optical signal 501 and a first splitter 530 for splitting the first optical signal 501 into a first portion 501a and a second portion 501b. The first portion 501a is sent to a first path 515a comprising a first switch 510a and the second portion 501b is sent to a second path 515b comprising a second switch 510b. A first output port 512 is connected to both switches 510a and 510b to pass signals sent through both switches 510a and 510b.

[0061] The multicast switch 500 further comprises a second input port 545 for receiving a second optical signal 502 and a second splitter 540 for splitting the second optical signal 502 into a third portion 502a and a fourth portion 502b. The third portion 502a is sent to a third path 525a comprising a third switch 520a and the fourth portion 502b is sent to a fourth path 525b comprising a fourth switch 520b. A second output port 522 is connected to both switches 520a and 520b to pass signals sent through both switches 520a and 520b.

[0062] In Figure 5In particular, the first optical signal 501 includes a first spectral component of a first wavelength λ1, a second spectral component of a second wavelength λ2, and a third spectral component of a third wavelength λ3. The second optical signal 502 includes a fourth spectral component of the first wavelength λ1, a fifth spectral component of a fourth wavelength λ4, and a sixth spectral component of a fifth wavelength λ5. The first switch 510a is set in a first state to pass the first portion 501a, the second switch 510b is set in a second state to block the third portion 502a, the third switch 520a is set in a second state to block the second portion 501b, and the fourth switch 520b is set in a first state to pass the fourth portion 502b. The end result is that the first output signal 503 includes spectral components at λ1, λ2, and λ3, and the second output signal 504 includes spectral components at λ1, λ4, and λ5.

[0063] The apparatus 500 can be combined with the apparatus 300 and 400 shown in Figure 3 and 4 to form a bidirectional device. For example, the output ports 512 in the multicast switch 500 and the input ports 412 in the multicast 400 can be arranged on one side of a chip. And the input ports 535 and 545 in the apparatus 500 and the output ports 435 and 445 in the apparatus 400 can be arranged on the other side of the same chip. In some embodiments, the chip can be an integrated circuit chip (also known as a module), and the input and output ports can be connected with optical fibers. In some embodiments, the chip can be a printed circuit. In some embodiments, the chip can be a semiconductor substrate, and the input and output ports can be connected via semiconductor waveguides fabricated in or on the substrate.

[0064] In some embodiments, the array of output ports for eastbound communication and the array of input ports for westbound communication can be arranged in a crosswise manner with respect to each other. For example, a first output port for eastbound communication can be adjacent to a first input port for eastbound communication, and a second output port for eastbound communication can be adjacent to a second input port for eastbound communication, and so on.

[0065] In some embodiments, the array of output ports for eastbound communication can be combined together and arranged on one portion of a chip, and the array of input ports for westbound can be combined together and arranged on another portion of the chip.

[0066] Figure 6A schematic diagram of a reconfigurable multicast switch 600 configured for demultiplexing in a protection mode is illustrated in accordance with some embodiments. Communications in the multicast switch 600 can be westbound as illustrated by the arrows. The multicast switch 600 includes a first input port 635 for receiving a first optical signal 601 and a first splitter 630 for splitting the first optical signal 601 into a first portion 601a and a second portion 601b. The first portion 601a is sent to a first path 615a including a first switch 610a and the second portion 601b is sent to a second path 615b including a second switch 610b. A first output port 612 is connected to both switches 610a and 610b to pass signals sent through both switches 610a and 610b.

[0067] The multicast switch 600 also includes a second input port 645 for receiving a second optical signal 602 and a second splitter 640 for splitting the second optical signal 602 into a third portion 602a and a fourth portion 602b. The third portion 602a is sent to a third path 625a including a third switch 620a and the fourth portion 602b is sent to a fourth path 625b including a fourth switch 620b. A second output port 622 is connected to both switches 620a and 620b to pass signals sent through both switches 620a and 620b.

[0068] In Figure 6 the first optical signal 601 includes a first spectral component of a first wavelength λ1 and a second spectral component of a second wavelength λ2. The second optical signal 602 includes a third spectral component of the first wavelength λ1 and a fourth spectral component of the second wavelength λ2. In some embodiments, the first optical signal 601 and the second optical signal 602 can be substantially identical.

[0069] The first switch 610a is set in a first state to pass the first portion 601a, the second switch 610b is set in a second state to block the third portion 602a, the third switch 620a is set in the first state to pass the second portion 601b, and the fourth switch 620b is set in the second state to block the fourth portion 602b. The end result is that the first optical signal 601 received by the first input port 635 is broadcast to both output ports 612 and 622.

[0070] In some examples, in response to an unsatisfactory signal received at output ports 612 or 622, apparatus 600 can turn off switches 610a and 620a (i.e., set them to the second state) and turn on switches 610b and 620b (i.e., set them to the first state). This change in the switching configuration can broadcast the second optical signal 602 to both output ports 612 and 622. In some embodiments, the measurements are performed at input ports 635 and 645. In response to an unsatisfactory input signal, apparatus 600 can also turn off switches 610a and 620a (i.e., set them to the second state) and turn on switches 610b and 620b (i.e., set them to the first state).

[0071] Figure 7 A schematic diagram of an optical network 700 that is reconfigurable between a 1+1 protection scheme and a 1:1 protection scheme is shown, in accordance with some embodiments. Optical network 700 includes a first node 710 and a second node 720 that communicate with each other via two paths 730a and 730b. The following description uses eastbound communications to illustrate, and the communications in the reverse direction can be substantially symmetrical.

[0072] First node 710 includes a transceiver 712 to communicate optical signals that are received by a reconfigurable optical switch 714. Reconfigurable optical switch 714 includes a first switch 715a to receive a first portion of the optical signal and is connected to a first ROADM 716a. Reconfigurable optical switch 714 also includes a second switch 715b to receive a second portion of the optical signal and is connected to a second ROADM 716b. First ROADM 716a and second ROADM 716b are connected to first path 730a and second path 730b, respectively.

[0073] At the tail end, second node 720 includes a first ROADM 726a connected to first path 730a and a second ROADM 726b connected to second path 730b. A reconfigurable optical switch 724 is connected to both ROADMs 726a and 726b. In some embodiments, reconfigurable optical switch 724 includes a 2x1 switch 725, where each of its two input channels is connected to a corresponding ROADM 716a / b. Second node also includes a transceiver 722 to receive signals from reconfigurable optical switch 724.

[0074] Transceivers 712 and 722 can include one or more types of transmitters. In some embodiments, the transmitters can include coherent transmitters. In some embodiments, the transmitters can include C Form-factor Pluggable (CFP) transmitters. In some embodiments, the transmitters can include CFP4 transmitters, which can be coherent or non-coherent. In some embodiments, the transmitters can include 2nd Generation C Form-factor Pluggable-Analog Coherent Optics (CFP2-ACO) transmitters, which are coupled with a Digital Signal Processor (DSP) chip through a pluggable interface.

[0075] In some embodiments, the transmitters can include coherent in-phase / quadrature transmitters integrated with a DSP within a physical module. In some embodiments, the transmitters can include C Form-factor Pluggable-Digital Coherent Optics (CFP-DCO) transmitters integrated with a DSP and an optical front end. In some embodiments, the transmitters can include Quad Small Form-factor Pluggable (QSFP) transmitters. In some embodiments, the transmitters can include QSFP28 transmitters. These transmitters can be coherent or non-coherent.

[0076] ROADMs 716a, 716b, 726a, and 726b (collectively, ROADMs 716 and 726) can be based on various methods. In some embodiments, ROADMs 716 and 726 can be based on including wavelength blockers (WBs). In some embodiments, ROADMs 716 and 726 can be based on small switch arrays (SSAs). In some embodiments, ROADMs 716 and 726 can use wavelength selective switches (WSSs). In some embodiments, ROADMs 716 and 726 can be based on optical cross-connects (OXC).

[0077] Optical network 700 can be reconfigurable between a 1+1 protection scheme and a 1:1 protection scheme. In the 1+1 protection scheme, both first switch 715a and second switch 715b in first node 710 are set in a pass-through state to send a first portion of an optical signal to first path 730a and simultaneously send a second portion of the optical signal to second path 730b. This configuration of reconfigurable optical switch 714 is also referred to as a broadcast mode.

[0078] At the tail end, switch 725 can use 2x1 switch 725 to select the first portion of the optical signal from first path 730a. In the event of a failure detected in first path 730a, optical network 700 can close (e.g., via a controller, such as controller 250 shown in FIG. 2) the primary path and use second path 730b for communication by turning 2x1 switch 725 to the lower path (i.e., 730b). Figure 2 In some embodiments, the transmitters can include coherent in-phase / quadrature transmitters integrated with a DSP within a physical module. In some embodiments, the transmitters can include C Form-factor Pluggable-Digital Coherent Optics (CFP-DCO) transmitters integrated with a DSP and an optical front end. In some embodiments, the transmitters can include Quad Small Form-factor Pluggable (QSFP) transmitters. In some embodiments, the transmitters can include QSFP28 transmitters. These transmitters can be coherent or non-coherent.

[0076] ROADMs 716a, 716b, 726a, and 726b (collectively, ROADMs 716 and 726) can be based on various methods. In some embodiments, ROADMs 716 and 726 can be based on including wavelength blockers (WBs). In some embodiments, ROADMs 716 and 726 can be based on small switch arrays (SSAs). In some embodiments, ROADMs 716 and 726 can use wavelength selective switches (WSSs). In some embodiments, ROADMs 716 and 726 can be based on optical cross-connects (OXC).

[0077] Optical network 700 can be reconfigurable between a 1+1 protection scheme and a 1:1 protection scheme. In the 1+1 protection scheme, both first switch 715a and second switch 715b in first node 710 are set in a pass-through state to send a first portion of an optical signal to first path 730a and simultaneously send a second portion of the optical signal to second path 730b. This configuration of reconfigurable optical switch 714 is also referred to as a broadcast mode.

[0078] At the tail end, switch 725 can use 2x1 switch 725 to select the first portion of the optical signal from first path 730a. In the event of a failure detected in first path 730a, optical network 700 can close (e.g., via a controller, such as controller 250 shown in FIG. 2) the primary path and use second path 730b for communication by turning 2x1 switch 725 to the lower path (i.e., 730b). Figure 2 In some embodiments, the transmitters can include coherent in-phase / quadrature transmitters integrated with a DSP within a physical module. In some embodiments, the transmitters can include C Form-factor Pluggable-Digital Coherent Optics (CFP-DCO) transmitters integrated with a DSP and an optical front end. In some embodiments, the transmitters can include Quad Small Form-factor Pluggable (QSFP) transmitters. In some embodiments, the transmitters can include QSFP28 transmitters. These transmitters can be coherent or non-coherent.

[0076] ROADMs 716a, 716b, 726a, and 726b (collectively, ROADMs 716 and 726) can be based on various methods. In some embodiments, ROADMs 716 and 726 can be based on including wavelength blockers (WBs). In some embodiments, ROADMs 716 and 726 can be based on small switch arrays (SSAs). In some embodiments, ROADMs 716 and 726 can use wavelength selective switches (WSSs). In some embodiments, ROADMs 716 and 726 can be based on optical cross-connects (OXC).

[0077] Optical network 700 can be reconfigurable between a 1+1 protection scheme and a 1:1 protection scheme. In the 1+1 protection scheme, both first switch 715a and second switch 715b in first node 710 are set in a pass-through state to send a first portion of an optical signal to first path 730a and simultaneously send a second portion of the optical signal to second path 730b. This configuration of reconfigurable optical switch 714 is also referred to as a broadcast mode.

[0078] At the tail end, switch 725 can use 2x1 switch 725 to select the first portion of the optical signal from first path 730a. In the event of a failure detected in first path 730a, optical network 700 can close (e.g., via a controller, such as controller 250 shown in FIG. 2) the primary path and use second path 730b for communication by turning 2x1 switch 725 to the lower path (i.e., 730b). Figure 2

[0079] In some embodiments, a path failure can be determined based on the total optical power measured after the switch 725. For example, a detector (not shown) can be used to measure the amplitude, power, and / or intensity of the received signal. The measured signal is then sent to a controller. When the measured signal is below a threshold, the controller can determine that a failure in the primary path has occurred and switch the transmission path from the first path 730a to the second path 730b.

[0080] In some embodiments, a path failure can be determined based on the optical power of one spectral component in the received signal. In some embodiments, a path failure can be determined based on the optical power in a subset of spectral components in the received signal. In these embodiments, a spectral analyzer (not shown) can be used to measure the spectral power of the received signal.

[0081] In some embodiments, a path failure can be determined based on the signal-to-noise ratio (SNR) of the received signal. In some embodiments, a path failure can be determined based on the bit error rate (BER) in the received data. In some embodiments, a path failure can be determined based on measurements of properties of the optical signal at the two inputs of the switch 725 (e.g., total power, spectral power, signal-to-noise ratio, and / or BER, etc.).

[0082] In a 1:1 protection scheme, the first switch 715a in the first node 710 can be set in a first state to pass the first portion of the optical signal to the first path 730a, while the second switch 715b is set in a second state to block the second portion of the optical signal. The 2x1 switch 725 then connects the transceiver 722 to the first path 730a in order to receive the first portion of the optical signal.

[0083] In the event that a path failure is detected, the first switch 715a is switched to the second state to block the first portion of the optical signal, and the second switch 715b is switched to the first state to transmit the second portion of the optical signal. At the far end, the 2x1 switch 725 is also switched to connect the transceiver 722 to the second path 730b in order to receive the second portion of the optical signal.

[0084] In some embodiments, the switching between the 1+1 protection scheme and the 1:1 protection scheme can be performed manually (e.g., by an operator). In some embodiments, a controller (e.g., similar to the controller 735) can be used to automatically switch between the 1+1 protection scheme and the 1:1 protection scheme. Figure 2The controller 250 (shown in FIG. 1) can be used to automatically switch the optical network 700 between the two protection schemes. For example, upon execution of the processor-executable instructions, the controller sends a first control signal to select both switches 715a and 715b to enter the first state in order to configure the network 700 as a 1+1 protection scheme. In the event that a switch in protection scheme is desired, the controller sends a second control signal to select the first switch 715a to enter the second state. The controller can also send a third control signal to select the first switch 715a to return to the first state and select the second switch 715b to enter the second state to change the path within the 1:1 protection scheme.

[0085] In the optical network 700, the 1:1 protection scheme can reserve bandwidth on the secondary path (e.g., 730b) and allow for fast switching. The 1+1 protection scheme, when used with appropriate multiplexing, allows lower grade traffic to be configured on the secondary path (e.g., 730b) and then discarded when the primary path fails (i.e., different service levels). This allows customers to configure the optical network 700 in either of these modes to allow for more robust and efficient use of network resources. In some embodiments, this switching between the 1+1 and 1:1 schemes can be performed during channel provisioning. In some embodiments, the switching can be performed via the controller as part of a more comprehensive network optimization and automation scheme.

[0086] Figure 7 FIG. 1 illustrates that by using the reconfigurable optical switch 714 in the front end and configuring the reconfigurable optical switch 714 to a broadcast mode, the optical network 700 can have 1+1 protection capability. In contrast, optical networks using known multicast switches typically do not have the capability to implement a 1+1 protection scheme.

[0087] Furthermore, the optical network 700 can also easily switch between the 1+1 protection scheme and the 1:1 protection scheme. The switching (or reconfiguration) can be performed remotely using software control without changing any of the hardware components in the optical network 700. Thus, the optical network 700 can have significant flexibility in practice without the complexity for coordination between the first node 710 and the second node 720.

[0088] Figure 8A method 800 of optical communication is illustrated in accordance with some embodiments. The method 800 includes receiving a first portion of a first optical signal at an 810 at a first switch, the first switch being switchable between a first state for passing the first portion and a second state for blocking the first portion. At 820, a second portion of the first optical signal is received at a second switch that is switchable between the first state and the second state. The method 800 also includes receiving a third portion of a second optical signal at an 830 at a third switch that is switchable between the first state and the second state, and receiving a fourth portion of the second optical signal at an 840 at a fourth switch that is switchable between the first state and the first state. At 850, the possible optical signals transmitted by the first switch and the third switch are combined to generate a first output signal. At 860, the possible optical signals transmitted by the second switch and the fourth switch are combined to generate a second output signal.

[0089] In some embodiments, the first switch includes a first variable optical attenuator (VOA) and the third switch includes a third VOA. These two VOA can be used for power balancing between the first portion and the third portion. For example, the input level of the first portion of the first optical signal can be different from the input level of the third portion of the second optical signal. By changing the transmission ratio of at least one of these two portions, the power level at the time of combination (e.g., at 850) can be substantially identical. Similarly, power balancing can also be used for the second switch and the fourth switch, or any other group of switches.

[0090] In some cases, the first optical signal and the second optical signal are at a first wavelength, and the method 800 further includes selecting the first switch to enter the first state to transmit the first portion and selecting the third switch to enter the second state to block the third portion. Thus, the first output signal includes the first portion of the first optical signal and does not include the third portion of the second optical signal. The method 800 can also include selecting the second switch to enter the second state to block the second portion and selecting the fourth switch to enter the first state to transmit the fourth portion. Thus, the second output signal includes the fourth portion of the second optical signal.

[0091] In some cases, the first optical signal is at a first wavelength and the second optical signal is at a second wavelength that is different from the first wavelength. In these cases, the method 800 further includes selecting the first switch, the second switch, the third switch, and the fourth switch to be in the first state. In this case, the first output signal includes the first portion and the third portion, and the second output signal includes the second portion and the fourth portion.

[0092] In some cases, the method 800 further includes selecting the first switch, the second switch, the third switch, and the fourth switch to operate between a first operating mode and a second operating mode. In the first operating mode, the first switch is configured in the first state, the second switch is configured in the second state, the third switch is configured in the second state, and the fourth switch is configured in the first state. In the second operating mode, the first switch, the second switch, the third switch, and the fourth switch are all configured in the first state.

[0093] In some examples, the method 800 further includes sending the first output signal to a first multiplex port on a multiplexer and sending the second output signal to a second multiplexer.

[0094] In some examples, the first optical signal has a first spectral component of a first wavelength and a second spectral component of a second wavelength, and the second optical signal has a third spectral component of the first wavelength and a fourth spectral component of a fourth wavelength. The method 800 further includes selecting the first switch into the first state to transmit a first portion of the first optical signal and selecting the second switch into the second state to block a third portion of the second optical signal. The method 800 further includes selecting the third switch into the second state to block a second portion of the first optical signal and selecting the fourth switch into the first state to transmit a fourth portion of the second optical signal.

[0095] In some examples, the first optical signal has a first spectral component of a first wavelength and a second spectral component of a second wavelength, and the second optical signal has a third spectral component of the first wavelength and a fourth spectral component of the second wavelength. The method 800 further includes selecting the first switch into the first state to transmit a first portion of the first optical signal and selecting the second switch into the second state to block a third portion of the second optical signal. The method 800 further includes selecting the third switch into the first state to transmit a second portion of the first optical signal and selecting the fourth switch into the second state to block a fourth portion of the second optical signal.

[0096] In some examples, the method 800 further includes sending a third optical signal to the first switch and the third switch. The method 800 further includes selecting the first switch and the third switch into the first state to transmit the third optical signal to the first input port. The method 800 further includes sending a fourth optical signal that is substantially identical to the third optical signal to the second switch and the fourth switch, and selecting the second switch and the fourth switch into the second state to block the fourth optical signal. At least one property of the third optical signal at the first input port is then detected. In response to the property of the third optical signal being unsatisfactory (e.g., less than a threshold value), the first switch and the third switch are transitioned to the second state, and the second switch and the fourth switch are transitioned to the first state.

[0097] In some examples, the property of the third optical signal includes a total amplitude (or power) of the third optical signal. In some examples, the property of the third optical signal includes an amplitude (or power) of one spectral component in the third optical signal. In some examples, the property of the third optical signal includes a signal-to-noise ratio (SNR) of the third optical signal. In some examples, the property of the third optical signal includes a bit error rate (BER) of the third optical signal.

[0098] While various embodiments have been described and illustrated herein, various other components and / or structures, as well as each of the various combinations and / or permutations of the components and / or structures, are possible. More generally, all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend on the specific application or applications for which the present disclosure is used. It is to be understood that the above description is intended to be illustrative, and not restrictive. Numerous embodiments other than the examples described are possible. Embodiments of the present disclosure relate to each individual feature, system, article, material, kit, and / or method described herein. Additionally, any combinations of two or more such features, systems, articles, materials, kits, and / or methods, if such combinations of features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, are part of the present disclosure.

[0099] Further, various inventive concepts can be implemented as one or more methods, of which an example has been provided. The acts performed as part of the method can be ordered in any suitable way. Accordingly, embodiments in which elements are performed in different orders are contemplated. Additionally, embodiments in which additional acts are performed are also contemplated.

[0100] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0101] As used herein, a "module" can be, for example, any component and / or collection of operatively-coupled electronic components associated with performing a particular function, and can include, for example, a memory, a processor, an electrical trace, an optical connector, software (stored and executed in hardware), and / or the like.

[0102] The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[0103] The phrase “and / or,” as used herein in the specification and in claims, should be understood to mean “either or both of” i.e., “one or the other or both” when applying this phrase to a list of two or more items. The use of “and / or” in the application of a list of two or more items should be considered in the same manner as if this phrase was explicitly set forth with respect to each item in the list. For example, “A and / or B” should be understood as “A, or B, or both A and B.” As used herein in the specification and in claims, the phrase “comprising” can include the notions of “consisting essentially of,” “consisting of,” and “substantially comprising” as well as “including,” “containing,” or “comprising.” As used herein in the specification and in claims, the phrase “consisting essentially of,” as used herein, has the same meaning as “consisting of,” or “comprising,” as used in the specification and in claims.

[0104] As used in the specification and claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when used in the context of items listed with “or” or “and / or,” such as, for example, in a list of a number or list of items conjoined with “or” or “and / or” such as, for example, “one or more of A, B, or C,” or “one or more of A, B, and / or C,” the phrase should be understood to mean either one or more of the elements so conjoined, i.e., A alone, or B alone, or C alone, or any combination thereof, or optionally, in addition to the combination of any of the elements conjoined by “or” or “and / or,” any number or list of elements not conjoined with the combination. Only terms expressly recited as the opposite of “and / or” or “or” should be understood to mean exclusively one element of any such combination, i.e., “only one of A or B” or “exactly one of A or B,” or, when used in claims, “consisting of,” which shall have its ordinary meaning as used in the patent law field.

[0105] As used in the specification and claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one, or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that the

[0106] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

1. An apparatus comprising: a first input port; a first switch in optical communication with the first input port and switchable between a first state for passing optical signals and a second state for blocking optical signals; a second switch in optical communication with the first input port and switchable between the first state and the second state; a second input port; a third switch in optical communication with the second input port and switchable between the first state and the second state; a fourth switch in optical communication with the second input port and switchable between the first state and the second state; a first combiner in optical communication with the first input port via the first switch and in optical communication with the second input port via the third switch; a second combiner in optical communication with the first input port via the second switch and in optical communication with the second input port via the fourth switch; and a controller operatively coupled to the first switch, the second switch, the third switch, and the fourth switch to control the apparatus between a first operational mode, a second operational mode, and a third operational mode, in the first operational mode, the first switch is configured in the first state, the second switch is configured in the second state, the third switch is configured in the second state, and the fourth switch is configured in the first state, in the second operational mode, the first switch, the second switch, the third switch, and the fourth switch are configured in the first state, in the third operational mode, the first switch, the second switch, the third switch, and the fourth switch are configured in the second state.

2. The apparatus of claim 1, wherein at least one of the first switch or the second switch comprises a variable optical attenuator (VOA) configured to balance power.

3. The apparatus of claim 1, wherein: the first input port is configured to pass a first optical signal of a first wavelength, the first switch is selected to the first state to pass the first optical signal to the first combiner, and the second switch is selected to the second state to block the first optical signal from the second combiner.

4. The apparatus of claim 1, wherein: the first input port is configured to pass a first optical signal of a first wavelength, the first switch is selected to the first state to pass the first optical signal to the first combiner, the second switch is selected to the second state to block the first optical signal from the second combiner, the second input port is configured to pass a second optical signal of the first wavelength, the third switch is selected to the second state to block the second optical signal from the first combiner, and the fourth switch is selected to the first state to pass the second optical signal to the second combiner.

5. The apparatus of claim 1, wherein: ​ the first input port is configured to pass a first optical signal of a first wavelength, and the first switch and the second switch are selected to the first state to pass the first optical signal to the first combiner and the second combiner.

6. The apparatus of claim 1, wherein: the first input port is configured to pass a first optical signal of a first wavelength, the first switch and the second switch are selected to the first state to pass the first optical signal to the first combiner and the second combiner, the second input port is configured to pass a second optical signal of a second wavelength, the second wavelength being different from the first wavelength, the third switch and the fourth switch are selected to the first state to pass the second optical signal to the first combiner and the second combiner.

7. The apparatus of claim 1, further comprising: a first multiplexer, the first combiner being operatively coupled to the first multiplexer; and a second multiplexer, the second combiner being connected to the second multiplexer.

8. The apparatus of claim 1, further comprising: a first splitter configured to receive a first optical signal, the first optical signal having a first spectral component of a first wavelength and a second spectral component of a second wavelength, the first splitter splitting the first optical signal into a first portion and a second portion; a second splitter configured to receive a second optical signal, the second optical signal having a third spectral component of the first wavelength and a fourth spectral component of a fourth wavelength, the second splitter splitting the second optical signal into a third portion and a fourth portion; a fifth switch in optical communication with the first splitter and configured in the first state to pass the first portion of the first optical signal; a sixth switch in optical communication with the second splitter and configured in the second state to block the first portion of the second optical signal; a first output port in optical communication with the fifth switch and the sixth switch to pass the first portion of the first optical signal passed by the fifth switch; a seventh switch in optical communication with the first splitter and configured in the second state to block the second portion of the first optical signal; an eighth switch in optical communication with the second splitter and configured in the first state to pass the second portion of the second optical signal; and a second output port in optical communication with the seventh switch and the eighth switch to pass the second portion of the second optical signal passed by the eighth switch.

9. The apparatus of claim 1, further comprising: a first splitter configured to receive a first optical signal, the first optical signal having a first spectral component of a first wavelength and a second spectral component of a second wavelength, the first splitter splitting the first optical signal into a first portion and a second portion; ​ a second splitter configured to receive a second optical signal having a third spectral component of the first wavelength and a fourth spectral component of the second wavelength, the second splitter splitting the second optical signal into a third portion and a fourth portion, a fifth switch in optical communication with the first splitter and configured in the first state to transmit the first portion of the first optical signal; a sixth switch in optical communication with the second splitter and configured in the second state to block the first portion of the second optical signal; a first output port in optical communication with the fifth switch and the sixth switch to transmit the first portion of the first optical signal transmitted through the fifth switch; a seventh switch in optical communication with the first splitter and configured in the first state to transmit the second portion of the first optical signal; an eighth switch in optical communication with the second splitter and configured in the second state to block the second portion of the second optical signal; and a second output port in optical communication with the seventh switch and the eighth switch to transmit the second portion of the first optical signal transmitted through the seventh switch.

10. The apparatus of claim 1, wherein: the controller additionally selects the apparatus to enter a fourth operational mode, wherein: in the first operational mode, the first input port is in optical communication with the first combiner and is optically blocked from the second combiner, and the second input port is in optical communication with the second combiner and is optically blocked from the first combiner, and in the fourth operational mode, the first input port is in communication with the first combiner and is optically blocked from the second combiner, and the second input port is in optical communication with the first combiner and is optically blocked from the second combiner.

11. The apparatus of claim 1, further comprising: a third input port; a fifth switch in optical communication with the third input port and switchable between the first state and the second state; and a sixth switch in optical communication with the third input port and switchable between the first state and the second state, the first combiner is in optical communication with the third input port via the fifth switch, and the second combiner is in optical communication with the third input port via the sixth switch.

12. An optical network, comprising: a transmitter to transmit an optical signal; a splitter to split the optical signal into a first portion and a second portion; a first switch configured to receive the first portion of the optical signal, the first switch switchable between a first state to pass the first portion of the optical signal and a second state to block the first portion of the optical signal; ​ ​ a second switch configured to receive the second portion of the optical signal, the second switch being switchable between a first state for passing the second portion of the optical signal and a second state for blocking the second portion of the optical signal; a receiver in optical communication with the first switch and the second switch to receive possible optical signals transmitted from the first switch and the second switch; and a controller operatively coupled to the first switch and the second switch, the controller when executing processor-executable instructions is to control the first switch and the second switch between a first operating mode, a second operating mode, and a third operating mode, wherein: in the first operating mode, the controller is adapted to select the first switch to enter the first state to transmit the first portion and to select the second switch to enter the second state to block the second portion, from thereby generating a 1:1 protection scheme in the optical network; in the second operating mode, the controller is adapted to select the first switch to enter the first state to transmit the first portion and to select the second switch to enter the first state to transmit the second portion, from thereby generating a 1+1 protection scheme in the optical network; and in the third operating mode, the controller is adapted to select the first switch to enter the second state to block the first portion and to select the second switch to enter the second state to block the second portion.

13. The optical network of claim 12, wherein at least one of the first switch or the second switch comprises a variable optical attenuator (VOA) configured to balance power.

14. The optical network of claim 12, wherein the first switch is a first 1x1 switch and the second switch is a second 1x1 switch.

15. The optical network of claim 12, wherein the transmitter is at least one of: a coherent transmitter, a C Form Factor Pluggable (CFP) transmitter, a CFP4 transmitter, or a 2nd Generation C Form Factor Pluggable-Analog Coherent Optical (CFP2-ACO) transmitter.

16. The optical network of claim 12, wherein the first switch is a first reconfigurable switch and the second switch is a second reconfigurable switch.

17. A method of receiving an optical signal, comprising: receiving a first portion of the optical signal via a first switch, the first switch being switchable between a first state for passing the first portion of the optical signal and a second state for blocking the first portion of the optical signal; receiving a second portion of the optical signal via a second switch, the second switch being switchable between the first state for passing the second portion of the optical signal and the second state for blocking the second portion of the optical signal; receiving possible optical signals transmitted from the first switch and the second switch via a receiver in optical communication with the first switch and the second switch; and controlling the first switch and the second switch between a first operating mode, a second operating mode, and a third operating mode via a controller operatively coupled to the first switch and the second switch, wherein: in the first operating mode, the controller is adapted to select the first switch to enter the first state to transmit the first portion and to select the second switch to enter the second state to block the second portion, so as to generate a 1:1 protection scheme in an optical network; in the second operating mode, the controller is adapted to select the first switch to enter the first state to transmit the first portion and to select the second switch to enter the first state to transmit the second portion, so as to generate a 1+1 protection scheme in the optical network; and in the third operating mode, the controller is adapted to select the first switch to enter the second state to block the first portion and to select the second switch to enter the second state to block the second portion.

18. The method of claim 17, wherein at least one of the first switch or the second switch comprises a variable optical attenuator (VOA) configured to balance power.

19. The method of claim 17, further comprising: transmitting the optical signal via a transmitter; and splitting the optical signal into the first portion and the second portion via a splitter.

20. The method of claim 19, wherein the transmitter is at least one of: a coherent transmitter, a C form-factor pluggable (CFP) transmitter, a CFP4 transmitter, or a 2ndgeneration C form-factor pluggable-analog coherent optical (CFP2-ACO) transmitter.

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