Method and apparatus associated with optical switch

Abstract

Aspects of the present disclosure relate to an optical switch, a method of operating an optical switch, and a system including an optical switch. The optical switch includes an input for receiving an optical data input and an optical address input. The optical switch further includes an output for outputting the optical data output. The optical switch additionally comprises a first non-linear optical medium, where the first non-linear optical medium is arranged to combine the optical data input and the optical address input to generate an optical data output. The frequency of the optical data output depends on the frequency of the optical data input and the frequency of the optical address input.

Description

[0001] The present invention relates to an optical switch. Aspects of the present invention relate to an optical switch, a method of operating an optical switch, and a system including an optical switch. Background Art

[0002] Data centers tend to use data networks to communicate between multiple interconnected server computers (also known as nodes). Each node has a unique address, which enables a network switch (such as a Layer 2 network switch) to transfer data from the first node to the intended receiving node.

[0003] Network switches are typically electronic switches. Commercial Layer 2 network switches typically have the ability to support approximately 50 nodes within a network. Therefore, a data center with a large number of nodes will use different types of architectures to connect more nodes than a single network switch can support. Since, on average, data centers transfer data from more than 40,000 nodes, a large number of network switches are required to route the data.

[0004] It is in this context that the present invention has been designed. Summary of the Invention

[0005] In one aspect, an optical switch includes an input end for receiving an optical data input and an optical address input. The optical switch further includes an output end for outputting an optical data output. The optical switch additionally includes a first non-linear optical medium, wherein the first non-linear optical medium is arranged to combine the optical data input and the optical address input to generate the optical data output. The frequency of the optical data output depends on the frequency of the optical data input and the frequency of the optical address input.

[0006] Advantageously, the use of a non-linear optical medium enables logical operations to be performed entirely within the optical domain.

[0007] Further advantageously, as a result of performing logical operations in the optical domain, the optical switch consumes less power and has a faster switching capability compared to current state-of-the-art electronic switches. The faster switching capability enables the data throughput of the optical switch to be maximized.

[0008] Each switching operation performed within an electronic network switch requires electronic logic operations to correctly route data to the intended nodes. Such logic operations introduce latency and power consumption within the network switch. On average, in a data center where data is pushed from 40,000 nodes at approximately 25 Gb / s per network connection, Layer 2 electronic switches are estimated to account for 20% of the power consumption drawn by the data center. Additionally, data centers themselves account for approximately 3.7% of global carbon emissions, and this figure is increasing year by year. Against the backdrop of global efforts to reduce carbon emissions, the expansion of data center scale is unsustainable given that the amount of data created is estimated to increase from 97 zettabytes in 2022 to 181 zettabytes between 2022 and 2025.

[0009] Optical transceivers can be used to optically transmit data at very high speeds, but current technologies still require the switching operation itself to be performed in the electronic domain because electronic logic operations are needed. Therefore, power is still consumed to perform the electronic switching operation, and further power is consumed when converting the transmitted data between the electronic transmission device and the optical transmission device.

[0010] With the all-optical switch according to the present invention, no electronic logic is used during data transmission between nodes. Instead, the logic operations are performed entirely in the optical domain. The all-optical switch requires less power than an electronic switch because there is no need to power the electronic logic operations and no need to convert data between the electronic transmission device and the optical transmission device.

[0011] Furthermore, current optical transceivers are capable of sending data at very high bandwidths (such as 400 Gb / s per serial channel). However, the switching capacity is still limited to the 25 Gb / s per port capacity of traditional prior art electronic switches. Therefore, the switching capacity per port of the switch is limited from 400 Gb / s of the transmission link to 25 Gb / s, so the network cannot operate at the speed it could otherwise achieve. Thus, electronic switches introduce latency due to the logic operations performed for data routing and switching. In contrast, the passive nature of the all-optical switch according to the present invention means there is no limit to the throughput of the all-optical switch. Therefore, the all-optical switch can keep up with all data transmission speeds, so no bottleneck is formed at the switch and no latency is introduced due to performing logic operations. Data can be transmitted through the all-optical switch at, for example, 400 Gb / s to match the data transmission speed. This data throughput is 15 times that achievable with current prior art electronic switches.

[0012] In an embodiment, the input end of the all-optical switch includes a data input end for receiving an optical data input and an address input end for receiving an optical address input.

[0013] In an embodiment, the frequency of the optical data output depends on the arithmetic operation of the frequency of the optical data input and the frequency of the optical address input. The arithmetic operation can be an operation of summing the frequency of the optical data input and the frequency of the optical address input.

[0014] Advantageously, this processing of the optical signals input to the nonlinear optical medium enables logical operations to be performed entirely within the optical domain. There is no need to convert the data input or the address input into an electrical signal in order to perform logical operations. Converting an optical signal into an electrical signal for logical operations and then back into an optical signal would cause significant power consumption losses, which are avoided by performing logical operations within the optical domain.

[0015] In an embodiment, the first nonlinear optical medium includes a sum frequency generator (SFG) crystal.

[0016] Advantageously, these types of crystals can efficiently generate an output beam with a frequency that is the sum of the frequencies of two input beams.

[0017] In an embodiment, the SFG crystal is a periodically poled lithium niobate (PPLN) crystal. The bandwidth of the SFG crystal can be between 19.8 nm and 50 nm.

[0018] Advantageously, these specifications result in a more efficient system for performing logical operations in the optical domain.

[0019] In an embodiment, there is a demultiplexer for receiving the optical data output. The demultiplexer can be arranged to selectively output optical data having a predetermined frequency. The optical data having the predetermined frequency can be output to a first optical receiver device. The optical data not having the predetermined frequency can be output to a second optical receiver device.

[0020] Advantageously, the demultiplexer enables the optical data output to be routed to the intended destination node. The optical data output provided by the nonlinear optical medium may also include unwanted optical signals having different frequencies. The demultiplexer can separate the desired frequency output from multiple output frequencies and transmit the desired frequency output to the intended address. The unwanted optical signals can remain in a separate channel (such as the main waveguide) and are not routed to the destination address. The demultiplexer ensures that data is transmitted to the destination node only when the transmitter node has used the correct specific frequencies for both the data input and the address input.

[0021] Further advantageously, the demultiplexer can receive an optical data output that has passed through two or more non-linear optical media. Thus, the optical data output can be associated with two or more intended addresses. The demultiplexer can be a demultiplexer prism that separates a first signal for a first address, a second signal for a second address, etc. The demultiplexer prism also separates unwanted optical signals. The demultiplexer prism enables the separated first signal to be transmitted to the first address, the second signal to be transmitted to the second address, and so on, while the unwanted signals can remain in the waveguide of the optical switch.

[0022] In an embodiment, the optical switch further includes a second non-linear optical medium. The second non-linear optical medium is arranged in series with the first non-linear optical medium such that the optical data output by the first non-linear optical medium is provided as an input to the second non-linear optical medium.

[0023] Advantageously, the cascaded series non-linear optical media enable the optical switch to support multiple nodes. Each non-linear optical medium can support a single node.

[0024] In an embodiment, there is a demultiplexer prism configured to receive the optical data output from the second non-linear optical medium and separate the received optical data output from the second non-linear optical medium 202b into multiple light beams.

[0025] Advantageously, the demultiplexer prism enables all of the optical data output from the second non-linear optical medium to be separated such that the relevant light beams from the output can be routed to their respective address nodes. That is, the optical data output from the second non-linear optical medium can include multiple light beams, and each of the multiple light beams includes data intended for different address nodes. The demultiplexer prism separates the multiple light beams into individual light beams, whereby these individual light beams can then be transmitted to the intended address nodes.

[0026] In an embodiment, the optical switch further includes a third non-linear optical medium. The third non-linear optical medium is arranged in parallel with the first non-linear optical medium.

[0027] Advantageously, this arrangement also enables the optical switch to support multiple nodes. In addition, more than one non-linear operation can be performed at a time.

[0028] In an embodiment, the optical switch further includes a second non-linear optical medium and a third non-linear optical medium. The first non-linear optical medium, the second non-linear optical medium, and the third non-linear optical medium are arranged in parallel and each includes a PPLN crystal with a bandwidth of 19.8 nm.

[0029] Advantageously, in terms of the efficiency of the switch, this is considered to be the optimal arrangement of the optical switch.

[0030] On the other hand, there is a system including an optical switch. The optical switch is the switch according to any one of the foregoing embodiments.

[0031] Advantageously, due to the presence of the optical switch, this system performs logical operations entirely in the optical domain. Therefore, compared with current systems using prior art electronic switches, this system consumes less power and provides greater data throughput.

[0032] On the other hand, there is a method for operating an optical switch. The method includes inputting an optical data input and an optical address input to a nonlinear optical medium. The method further includes combining the optical data input and the optical address input by the nonlinear optical medium to generate an optical data output. The method also includes outputting the optical data output by the nonlinear optical medium. The frequency of the optical data output depends on the frequency of the optical data input and the frequency of the optical address input.

[0033] Advantageously, due to the presence of the optical switch, this method enables logical operations to be performed entirely in the optical domain. Therefore, compared with current methods of performing data exchange using prior art electronic switches, this method consumes less power and provides greater data throughput. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] One or more embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0035] Figure 1A An example of an optical switch according to aspects of the present disclosure is illustrated.

[0036] Figure 1B Another example of an optical switch according to aspects of the present disclosure is illustrated.

[0037] Figure 2 Additional examples of an optical switch according to aspects of the present disclosure are illustrated.

[0038] Figure 3 Another example of an optical switch according to aspects of the present disclosure is illustrated.

[0039] Figure 4 is a flowchart showing an example of a method for operating an optical switch according to aspects of the present disclosure.

[0040] Figure 5 An example complete system diagram according to aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0041] In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the invention. Except for operations that must occur in a particular order, the order of operations is not limited to that set forth herein and may be changed as will be apparent to those skilled in the art.

[0042] It should also be understood that the embodiments and their technical features described in this disclosure may be combined with each other in every combination, unless there is a potential conflict between two embodiments or features. That is, every combination of two or more of the above-described embodiments is contemplated and included in this disclosure. One or more features from any embodiment may be combined in any other embodiment and provide the corresponding one or more advantages.

[0043] Figure 1A An example of an optical switch 100 is shown. The optical switch 100 may be disposed in a network composed of multiple systems (nodes), where each node needs to communicate and interconnect with all other nodes. The optical switch maintains inputs and outputs to all nodes in the network.

[0044] The optical switch 100 includes a nonlinear optical medium 102. The nonlinear optical medium 102 is used to implement functions typically performed by electronic logic. The nonlinear optical medium 102 may perform arithmetic operations on the frequencies of the inputs provided to the nonlinear optical medium 102. For example, the arithmetic operation may be addition or subtraction of the received frequencies.

[0045] The optical switch further includes an input end 104 and an output end 106. The input end 104 receives an optical data input 108 and an optical address input 110, and provides the optical data input 108 and the optical address input 110 to the nonlinear optical medium 102. The nonlinear optical medium 102 processes the received optical data input 108 and optical address input 110 to form an optical data output 112. The output end 106 outputs the optical data output 112.

[0046] The optical data input 108 and the optical address input 110 are received from nodes in the network. The optical data input 108 includes the data that the node wishes to transmit, and the optical address input 110 includes the address of the desired destination node. The optical switch 100 receives the optical data input 108 and uses the optical address input 110 to effect the transmission of the data of the optical data input 108 to the destination node.

[0047] For clarity, in the drawings, the optical data input 108 is represented by a solid arrow, the optical address input 110 is represented by a dashed arrow, and the optical data output 112 is represented by a dotted arrow. This representation is used throughout all the drawings whenever possible.

[0048] The optical data input 108 is a data light beam that can be modulated at one of D frequencies (i.e., f d0-d(D-1) ). To transmit data, the transmitting node modulates the light beam to encode the serialized form of the transmitted data. The optical address input 110 is an address light beam that can be modulated at one of A frequencies (i.e., f a0-a(A-1) ). To transmit data, the transmitting node also modulates the light beam, where the frequency of this light beam represents the destination node. The destination node can also be referred to as the address node, the intended node, or the receiving node. Each destination node is sensitive only to a combination of f a and f d . In this way, the transmitter can select which one of multiple destination nodes to send the data optically to directly, without intermediate conversion to an electrical signal.

[0049] Figure 1B Another example of the arrangement of the optical switch 100 is shown. The input end 104 includes a data input end 104a and a separate address input end 104b. The data input end 104a receives the optical data input 108, while the address input end 104b receives the optical address input 110.

[0050] The nonlinear optical medium 102 can be a sum frequency generator (SFG). These crystals receive two light beams with frequencies of f a and f d , and generate an output light beam with a frequency of f a + f d . The efficiency of this conversion depends on many factors (such as the intensity of the light beam) and can range from less than 1% to 50%. Therefore, the output of the nonlinear optical medium 102 may also include unwanted frequencies. The unwanted frequencies may include f a + f a , f d + f d , as well as the un-converted light beams f a and f d .

[0051] The optical data output 112 is provided to a separating device, such as a demultiplexer 114. The demultiplexer 114 can be configured to separate the desired frequency f a + f d from the light beam of the optical data output 112. The light beam including the desired frequency f a + f dThe light beam can be transmitted to the destination address 116. Unwanted frequencies can remain in the main waveguide of the optical switch 100. That is, the unwanted frequencies can not be transmitted to a specific receiver.

[0052] When multiple switches are required for the network, a single SFG crystal with a large bandwidth can be used as the nonlinear optical medium 102. The large bandwidth increases the number of different wavelengths of light that the nonlinear optical medium 102 can accept, and thus increases the number of nodes that the optical switch can support.

[0053] Using an optical switch according to Figure 1A or Figure 1B a mesh topology of interconnected nodes can be constructed.

[0054] Figure 2 Another example of an optical switch 200 is shown. In this optical switch 200, there are a first nonlinear optical medium 202a and a second nonlinear optical medium 202b arranged in series. As the bandwidth of the nonlinear optical medium (such as an SFG crystal) increases, the conversion efficiency of the nonlinear optical medium decreases. Therefore, using multiple nonlinear optical media can support a larger number of nodes more efficiently.

[0055] Setting two nonlinear optical media in this figure is merely exemplary, and those skilled in the art will recognize that three or more nonlinear optical media can be arranged in series. For clarity, this figure shows only two nonlinear optical media.

[0056] The first nonlinear optical medium 202a and the second nonlinear optical medium 202b can be optimized respectively for different addresses f a1 + f d and f a2 + f d respectively.

[0057] The nonlinear optical medium (such as an SFG) can be designed to perform f a + f d most efficiently. That is, the nonlinear optical medium can be phase - matched such that it performs a nonlinear operation only when a specific input is present. If the address beam frequency is different from f a or the data beam frequency is different from f d , the efficiency of performing addition by the SFG will be reduced by several orders of magnitude. When the SFG is mismatched with the address frequency and the data frequency, they will pass the input beams f a and f d with only a small loss. Therefore, in a series of SFGs, if any one of the SFGs in the chain matches f a and f d , the result (f a+ f d ). Then, all possible results generated by the operations performed by the serial SFG crystals can be separated by a separating device. If none of the SFGs are tuned to match f a and f d , no output will be generated.

[0058] As Figure 2 shown, the first nonlinear optical medium 202a receives the optical data input 108 and the optical address input 110. The first nonlinear optical medium 202a outputs one or more light beams 204. The frequency of the one or more light beams 202 depends on whether the first nonlinear optical medium 202a is phase-matched with the frequency of the optical data input 108 and the frequency of the optical address input 110. If the first nonlinear optical medium 202a is phase-matched with the optical data input 108 and the optical address input 110, the frequency of the light beam 204 will be the sum of the frequency of the optical data input 108 and the frequency of the optical address input 110. If the first nonlinear optical medium 202a is not phase-matched with the frequency of the optical data input 108 or the frequency of the optical address input 110, the first nonlinear optical medium 202a will output a light beam 204 with the same frequency as the optical data input 108 and the optical address input 110. That is, the first nonlinear optical medium 202a will effectively output the optical data input 108 and the optical address input 110.

[0059] Then, the second nonlinear optical medium 202b receives the light beam 204 output from the first nonlinear optical medium 202a and the second optical address input 206 received from a different node. The second nonlinear optical medium 202b outputs the optical data output 112, where the frequency of the data output 112 depends on the frequency of the light beam 204 and the frequency of the second optical address input 206. The data output 112 may include multiple light beams, each with a different frequency.

[0060] For example, the first nonlinear optical medium 202a may be phase-matched with the address frequency f a1 , the second nonlinear optical medium 202b may be phase-matched with the address frequency f a2 , and both nonlinear optical media may be phase-matched with the data input with a frequency of f d . If the optical data input 108 has a frequency f d and the optical address input 110 has a frequency f a1 , then the first nonlinear optical medium 202a will output a light beam 204 with a frequency of f d + f a1 . This output light beam is provided as a data input to the second nonlinear optical medium 202b. The second nonlinear optical medium 202b may also receive the second optical address input 206. The second nonlinear optical medium 202b is not phase-matched to receive a frequency of fd + f a1 The data with this frequency thus has its output passing through the second nonlinear optical medium 202b and output as the optical data output 112.

[0061] As another example, in the case of the same first nonlinear optical medium 202a and second nonlinear optical medium 202b, if the frequency of the optical data input 108 is f d and the frequency of the optical address input 110 is f a2 , the first nonlinear optical medium 202a will not perform an operation on the input because the first nonlinear optical medium 202a is not phase - matched to accept f a2 as the frequency. The input will pass through the first nonlinear optical medium 202a as the light beam 204 and be provided to the second nonlinear optical medium 202b as the input to the second nonlinear optical medium 202b. Since the second nonlinear optical medium 202b is phase - matched to accept inputs with these frequencies, the second nonlinear optical medium 202b will perform a nonlinear operation on the light beam, resulting in a light beam with a frequency of f d + f a2 . Thus, the optical data output 112 will include a light beam with a frequency of f d + f a2 .

[0062] As another example, in the case of the same first nonlinear optical medium 202a and second nonlinear optical medium 202b, if the optical data input 108 has a frequency of f d and the optical address input 110 has a frequency of f a3 , neither the first nonlinear optical medium 202a nor the second nonlinear optical medium 202b will perform a nonlinear operation on the input. The input will pass through both nonlinear optical media unchanged, so the optical data output 112 will include light beams with frequencies of f a3 and f d . Similarly, if the frequency of the optical data input 108 is different from f d , neither the first nonlinear optical medium 202a nor the second nonlinear optical medium 202b will perform a nonlinear operation on the input, and the input will be output unchanged in the data output 112.

[0063] The optical data output 112 is fed into a demultiplexer prism 208 or a wavelength demultiplexer, where multiple light beams forming the data output 112 are separated here. The optical data having a predetermined frequency is output to the first optical receiver 210 device. The optical data not having the predetermined frequency may be output to the second optical receiver 212 device. Thus, the demultiplexer prism 208 routes the data to the correct address node according to the frequency received as input by the demultiplexer prism 208. If none of the nonlinear optical media in the optical switch 200 are tuned to match the frequency of the data input and the frequency of the address input, no output will be generated.

[0064] Using a serial chain structure of nonlinear optical media according to Figure 2 a bus-type and a star-type network topology can be generated.

[0065] Figure 3 Another example of an optical switch 300 is shown. In this optical switch 300, there are a first nonlinear optical medium 302a, a second nonlinear optical medium 302b, and a nonlinear optical medium 302c arranged in parallel. The optical switch 300 further includes a beam splitter 304 and a wavelength division multiplexer 306.

[0066] The setting of three nonlinear optical media in this figure is merely exemplary, and those skilled in the art will recognize that any number of two or more nonlinear optical media can be arranged in parallel. For example, there may be two nonlinear optical media arranged in parallel, or four nonlinear optical media arranged in parallel. For clarity, this figure shows only three nonlinear optical media.

[0067] The beam splitter 304 receives the optical data input 308 and the optical address input 310, and distributes the received inputs to each nonlinear optical medium. In this case, the beam splitter 304 divides each of the optical data input 308 and the optical address input 310 into three light beams, and provides one light beam of the optical data input 308 and one light beam of the optical address input 310 to each nonlinear optical medium. That is, the beam splitter 304 enables each of the first nonlinear optical medium 302a, the second nonlinear optical medium 302b, and the nonlinear optical medium 302c to receive the optical data input 308 and the optical address input 310.

[0068] Each non - linear optical medium provides an output (312a, 312b, 312c) based on the frequency of the received light beam and whether the non - linear medium is phase - matched to the received frequency. If any one of the first non - linear optical medium 302a, the second non - linear optical medium 302b, or the non - linear optical medium 302c is phase - matched to use data having the frequency of the optical data input 308 and the frequency of the optical address input 310, then that non - linear optical medium will perform a non - linear operation on the input light beam. Then, the output from that non - linear optical medium can be routed via the wavelength division multiplexer 306 to the intended destination node. The wavelength division multiplexer 306 combines the received outputs (312a, 312b, 312c) into a combined output 314. The output 314 can be provided to a separating device (such as a demultiplexer) in order to route only the desired data to the intended destination node.

[0069] For example, the first non - linear optical medium 302a can be phase - matched with the address frequency f a1 , the second non - linear optical medium 302b can be phase - matched with the address frequency f a2 , the third non - linear optical medium 302c can be phase - matched with the address frequency f a3 and all non - linear optical media can be phase - matched with the data input having the frequency f d . If the optical data input 108 has the frequency f d and the optical address input 110 has the frequency f a1 , then the first non - linear optical medium 302a will output a light beam 312a having the frequency f d + f a1 . The second and third non - linear optical media are not phase - matched to the address frequency, so the input light beam will pass directly through these media to form outputs 312b and 312c respectively. The output light beams (312a, 312b, 312c) will enter the wavelength division multiplexer 306, where these output light beams are combined to form the output 314. Since the output light beam 314 includes a light beam having the frequency f d + f a1 , the output light beam 314 can be routed to the intended destination.

[0070] One of ordinary skill in the art will understand that an optical switch can include multiple non - linear optical media, where the non - linear optical media are arranged in serial and parallel arrangements.

[0071] Figure 4Shows an example method 400 for operating an optical switch. The switch can be the optical switch 100. At step 402, an optical data input 108 and an optical address input 110 are input into the nonlinear optical medium 102. At step 404, the nonlinear optical medium 102 combines the optical data input 108 and the optical address input 110 to generate an optical data output 112. At step 406, the nonlinear optical medium 102 outputs the optical data output 112. The frequency of the optical data output 112 depends on the frequency of the optical data input 108 and the frequency of the optical address input 110.

[0072] The method can further include providing the optical data output 112 to a demultiplexer 114. The method can further include separating the optical data output 112 by the demultiplexer 114 into multiple light beams and selectively outputting the optical data having a desired frequency. The selected optical data can be transmitted or output to a first optical receiver. The optical data not having the desired frequency can be output to a second optical receiver.

[0073] Method 400 can further include performing any of the actions described for the optical switch in Figure 1A , Figure 1B , Figure 2 or Figure 3 . For the sake of brevity, these actions are not repeated here.

[0074] The power consumption of current state-of-the-art electronic switches is 850 watts (W), while the passive nature of the network switch of the present invention means that the switching logic does not require electrical power, so the power required for the switching logic is reduced by 100% in principle. However, a power budget of up to 80 W is reserved for any potential amplification of the input signals required by the optical switch. Even with this power budget, the power is still reduced by 90%. Simulations in MatLab show that integrated switching may require 20 W of electrical power for amplification, while bench switching may require up to 40 W of electrical power. This is a significant improvement over standard electronic switching circuits.

[0075] Further simulations were conducted in Matlab to model the performance of each of a single broadband SFG crystal, three serial SFG crystals, and three parallel - arranged SFG crystals. The simulations included 1 km of optical fiber on either side of a 5 × 5 mm integrated lithium niobate chip. The simulations assumed a constant input power of 100 mW. The single broadband SFG crystal was a 12.5 - nm PPLN, while the serial and parallel arrangements used 4.3 - nm PPLN. The results concluded that in an integrated setup, using a single broadband SFG crystal is more efficient than using multiple smaller - bandwidth PPLNs, and the serial arrangement is the least efficient. In particular, the single broadband crystal is optimal for low - port - number integrated setups. For bench - top setups, it was found that the single broadband SFG is the least efficient, and the arrangement with three parallel SFG crystals is optimal. In particular, the arrangement with 3 parallel SFG crystals is estimated to be optimal for port numbers above 20.

[0076] There can be provided a system including an optical switch according to any one of Figure 1A , Figure 1B , Figure 2 or Figure 3 . The system can further include conversion means for converting a signal output from the optical switch to a lower frequency. The conversion means can include a down - converter. Converting the optical data output using the conversion means enables the output signal to be detected by a standard transceiver.

[0077] The optical switch described herein with respect to network switches can be used in any switching embodiment. For example, the optical switch can be used for long - distance switching via satellite. The optical switch can be used for XPU interconnection. XPU interconnection is a switch at a lower level and is connected to the memory of each processor on a multi - processor motherboard. Traditionally, a motherboard with multiple processors would have a shared memory, where each processor can access the shared memory. However, if multiple processors need to access the memory simultaneously, this can lead to race conditions and processing time gaps. XPU interconnection exchanges data directly into the private memory of each processor.

[0078] Figure 5 An example system 500 is shown. In this complete system diagram, the system 500 includes three parallel optical switches and down - conversion. The example system 500 includes multiple servers 502a, 502b, 502c. These servers can also be referred to as nodes. Each node can be connected to a corresponding transceiver 504a, 504b, 504c for sending and receiving data on optical signals transmitted between the multiple nodes.

[0079] System 500 further includes an optical fiber combiner 506 for receiving optical signals transmitted from each of a plurality of transceivers 504a, 504b, 504c. Each transceiver may use a separate optical fiber to transmit the optical signal, so the optical fiber combiner receives the optical signals via three input optical fibers. The optical fiber combiner 506 combines the optical signals received from each input optical fiber such that the optical signals can be further transmitted through the system 500 using fewer optical fibers. For example, the optical fiber combiner 506 may combine the signals received from the three input optical fibers into a single output optical fiber. Then, the single output optical fiber carries each signal received from the three input optical fibers. Providing the optical signals into a single optical fiber allows the optical signals to be efficiently transmitted over long distances.

[0080] In the example system 500, the signal output from the optical fiber combiner 506 is provided to an optical amplifier 508. The optical amplifier 508 may be an erbium-doped fiber amplifier. The optical amplifier 508 amplifies the optical signal to compensate for any optical losses in the optical fiber without converting the optical signal into an electrical signal.

[0081] The amplified optical signal output from the optical amplifier 508 is input to a wavelength division multiplexing (WDM) demultiplexer 510 to separate the signals so that the signals can be provided to each optical switch. Signals of different wavelengths are provided via separate optical fibers. The optical data (having a wavelength of 1554.5 nm in this case) output from the WDM demultiplexer is input to another optical fiber splitter 512 such that the optical data can be separated and simultaneously transmitted to each optical switch.

[0082] The signals from the WDM demultiplexer 510 and the optical fiber splitter 512 are combined by optical fiber combiners 514a, 514b, 514c. Each optical fiber combiner is associated with a corresponding optical switch 516a, 516b, 516c. In this case, there are three optical switches arranged in parallel. The optical fiber combiner combines the data optical signal and the address optical signal received from two separate optical fibers into a single optical fiber. Each optical switch receives the optical signal corresponding to the optical data input and the optical address input from its corresponding optical fiber combiner.

[0083] The optical switches 516a, 516b, 516c perform a logic operation on the data input and the address input and output an optical data output. The optical data output from each optical switch is provided to another optical fiber combiner 518 to combine the optical data outputs received on separate optical fibers into a single optical fiber. The optical fiber combiner 518 may include a wavelength division multiplexer.

[0084] The output from another optical fiber combiner 518 is provided as an input to a bandpass filter 520. The bandpass filter enables light of a desired wavelength to pass through the filter and absorbs or reflects light of other wavelengths. The bandpass filter may include a demultiplexing prism.

[0085] The signal output from the bandpass filter 520 is transmitted to an optical detector 522. The optical detector may convert the received optical signal into an electrical signal. The output from the optical detector may be transmitted to another wavelength division multiplexer 524. The wavelength division multiplexer 524 may process the received signal, extract data from the received signal, and transmit the extracted data to the intended destination node.

Claims

1. An optical switch, comprising: an input end for receiving an optical data input and an optical address input; an output end for outputting an optical data output; and a first nonlinear optical medium; wherein the first nonlinear optical medium is arranged to combine the optical data input and the optical address input to generate the optical data output; and wherein the frequency of the optical data output depends on the frequency of the optical data input and the frequency of the optical address input.

2. The optical switch according to claim 1, wherein the input end includes a data input end for receiving the optical data input and an address input end for receiving the optical address input.

3. The optical switch according to claim 1 or 2, wherein the frequency of the optical data output depends on the arithmetic operation of the frequency of the optical data input and the frequency of the optical address input.

4. The optical switch according to any one of claims 1 to 3, further comprising a demultiplexer for receiving the optical data output.

5. The optical switch according to claim 4, wherein the demultiplexer is arranged to selectively output optical data having a predetermined frequency.

6. The optical switch according to claim 5, wherein the optical data having the predetermined frequency is output to a first optical receiver device.

7. The optical switch according to claim 5 or 6, wherein the optical data not having the predetermined frequency is output to a second optical receiver device.

8. The optical switch according to any one of claims 1 to 7, further comprising a second nonlinear optical medium, wherein the second nonlinear optical medium is arranged in series with the first nonlinear optical medium such that the optical data output by the first nonlinear optical medium is provided as an input to the second nonlinear optical medium.

9. The optical switch according to claim 8, further comprising a demultiplexer prism configured to receive the optical data output from the second nonlinear optical medium and separate the received optical data output into multiple light beams.

10. The optical switch according to any one of claims 1 to 9, further comprising a third nonlinear optical medium, wherein the third nonlinear optical medium is arranged in parallel with the first nonlinear optical medium.

11. The optical switch according to any one of claims 1 to 10, wherein the nonlinear optical medium is a sum frequency generator (SFG) crystal.

12. The optical switch according to claim 11, wherein the SFG crystal is a periodically poled lithium niobate (PPLN) crystal.

13. The optical switch according to claim 11 or 12, wherein the bandwidth of the SFG crystal is between 19.8 nm and 50 nm.

14. A system comprising the optical switch according to any one of claims 1 to 13.

15. A method of operating an optical switch, the method comprising: inputting an optical data input and an optical address input to a nonlinear optical medium; combining, by the nonlinear optical medium, the optical data input and the optical address input to generate an optical data output; and outputting, by the nonlinear optical medium, the optical data output; wherein the frequency of the optical data output depends on the frequency of the optical data input and the frequency of the optical address input.

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