Optical switch and optical chip for realizing optical switching function

Abstract

The invention discloses an optical switch and an optical chip for realizing an optical switching function, and relates to the technical field of laser. The optical switch comprises: M input ports, N output ports, and an optical switch wherein at least one of the M input ports is configured to receive an input optical signal; the optical switch is configured to couple each input optical signal to one of the N output ports in a phase-controlled array beamforming manner, wherein M and N are both positive integers greater than 1. The large-scale cost of the optical switch is low, and the optical switch can be produced on a silicon-based chip in a large scale. In addition, the optical switch can be realized on an optical chip, and has the advantage of miniaturization.

Description

Technical Field

[0001] This disclosure relates to the field of laser technology, specifically to an optical switch and an optical chip that implements optical switching functionality. Background Technology

[0002] Related multiple-input and multiple-output optical switching systems require complex fiber arrays or optical switching devices and cannot flexibly switch between multiple inputs and multiple outputs.

[0003] The disadvantages of related optical switches are poor scalability (expanding the number of switching ports often leads to more switching layers and greater insertion loss) and long switching time (such as with MEMS array solutions). Summary of the Invention

[0004] This disclosure provides an optical switch and an optical chip for implementing optical switching functions.

[0005] In a first aspect, this disclosure provides an optical switch comprising: M input ports, N output ports, and an optical switch, wherein at least one of the M input ports is configured to receive an input optical signal; and the optical switch is configured to couple each input optical signal to one of the N output ports via a phase-controlled array beamforming method, wherein M and N are both positive integers greater than 1.

[0006] Optionally, the optical switch further includes: M input channels, each corresponding one-to-one with the M input ports, each of the M input channels being configured to receive the input optical signal from a corresponding input port among the M input ports, convert the input optical signal into an intermediate optical signal, wherein the intermediate optical signal is transmitted to one of the N output ports; and N output channels, each corresponding one-to-one with the N output ports, wherein the N output channels are configured to convert the intermediate optical signal into an output optical signal, and output the output optical signal through a corresponding output port among the N output ports.

[0007] Optionally, each of the M input channels includes: a 1×K beam splitter configured to split the input optical signal corresponding to the input channel into K input sub-signals; and K first phase shifters configured to generate the intermediate optical signal from the K input sub-signals in a beamforming manner by the phase control array under the control of one or more first control signals, wherein K is a positive integer greater than 1.

[0008] Optionally, the K first phase shifters are specifically configured to generate the same or different phase delays for the K input sub-signals under the control of one or more first control signals, and the K input sub-signals with the same or different phase delays are coherently superimposed to form the intermediate optical signal propagating toward one of the N output ports.

[0009] Optionally, each of the N output channels includes an optical mode field converter, which is configured to receive the intermediate optical signal, match the mode field of the received intermediate optical signal with the mode field of the output waveguide, and convert the intermediate optical signal into an output optical signal, which is output from the corresponding output port among the N output ports.

[0010] Optionally, each of the N output channels includes: H second phase shifters configured to receive the intermediate optical signal from one of the M input channels and to perform phase adjustment on the intermediate optical signal under the control of one or more second control signals to generate H output sub-signals; and a combiner configured to combine the H output sub-signals in a coherent superposition manner to generate the output optical signal, where H is a positive integer greater than 1.

[0011] Optionally, each of the N output channels includes a lens configured to receive the intermediate optical signal from one of the M input channels and focus the intermediate optical signal onto the corresponding output channel.

[0012] Optionally, the one or more first control signals and the one or more second control signals are provided by a first phase controller driver chip (generally a digital-to-analog converter chip and a control logic chip) and a second phase controller driver chip (generally a digital-to-analog converter chip and a control logic chip), respectively.

[0013] Optionally, each of the N output channels includes an optical amplifier configured to optically amplify the intermediate optical signal from one of the M input channels.

[0014] In a second aspect, this disclosure provides a chip for implementing optical switching functions, the chip including one or more optical switches according to the first aspect. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the optical switch disclosed herein. Figure 1 ; Figure 2 This is a schematic diagram of the transmission of intermediate optical signals in the optical switch of this disclosure; Figure 3This is a schematic diagram of the optical switch disclosed herein. Figure 2 ; Figure 4 This is a schematic diagram of the optical switch disclosed herein. Figure 3 ;as well as Figure 5 is a schematic diagram of the expansion method of the optical switch disclosed herein. Detailed Implementation

[0016] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.

[0017] In this disclosure, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0018] In this disclosure, the term "multiple" refers to two or more, and other quantifiers are similar.

[0019] This disclosure presents an optical switch that is scalable, capable of providing more switch channels, and expands from small-scale to large-scale without incurring additional insertion loss and power consumption. The optical switch offers the advantage of short switching times, reaching the nanosecond level (depending on the response time of a single phase controller). The optical switch has low scalability and can be mass-produced on silicon-based chips. Furthermore, the optical switch can be implemented on optical chips, offering the advantage of miniaturization.

[0020] The solution disclosed herein enables high-response, low-cost optical switches, facilitating the migration of optical switches from the Spine layer (high-level, high-volume data) in data centers to the Leaf layer (low-level, frequent switching), thereby enabling a more efficient data center network architecture.

[0021] The technical solution of this disclosure is described in detail below. (Reference) Figure 1 , Figure 1 This is a schematic diagram of the structure of the optical switch provided in this disclosure. Figure 1 The optical switch 1 provided in this disclosure can transmit input signals from one or more input ports to any one of one or more output ports under the control of control signals, thereby realizing the function of optical switching.

[0022] Specifically, the optical switch 1 includes M input ports, at least one of which is configured to receive at least one input optical signal, where M is a positive integer greater than or equal to 1. In practical applications, some of the M input ports may receive input optical signals carrying information from the outside, while other input ports may not receive input optical signals; or all of the M input ports may receive input optical signals. The optical signals received by some or all of the M input ports may be the same or different. The input optical signal may be an optical signal carrying information, such as data information, communication information, or computational information. In the embodiments of this disclosure, there are no specific limitations on the frequency and phase of each input optical signal.

[0023] The optical switch 1 also includes an optical switch 10 and N output ports. The optical switch 10 is configured to control the optical mode field and propagation direction of each input optical signal (phased array principle) under the control of a control signal, and couple it to any one of the N output ports in a beamforming manner.

[0024] Specifically, the optical switch 10 of this disclosure includes M input channels IN1 to INM. Each of the M input channels IN1 to INM corresponds one-to-one with one of the M input ports and is configured to receive an input optical signal from one of the corresponding input ports. Each of the M input channels includes a beam splitter 101 and a phase controller 102. The beam splitter 101 is configured to split the input optical signal input from that input channel into K sub-signals. The phase controller 102 includes K sub-phase controllers 1021 to 102K, where K is a positive integer greater than or equal to 1. The K input sub-signals are respectively input to the K sub-phase controllers. Each of the K sub-phase controllers 1021 to 102K can be controlled individually or jointly, and each sub-phase controller can adjust the phase of its corresponding sub-signal. The phases of the K input sub-signals, adjusted by K sub-phase controllers 1021~102K, can be superimposed through phased array beamforming to form an optical signal with a specific mode field and propagation direction, called an intermediate optical signal. This intermediate optical signal is then transmitted to one of N output ports, where N is a positive integer greater than or equal to 1.

[0025] At least one of the N output ports is configured to receive an intermediate optical signal from one of the M input channels and convert it into an output optical signal, where N is a positive integer greater than or equal to 1. The conversion of the intermediate optical signal into the output optical signal by the N output ports is an inverse beamforming operation, which combines and focuses the intermediate optical signal to generate the output optical signal. Inverse beamforming is the reverse application of beamforming technology; its core is to focus the energy of the received optical signal in a specific direction while suppressing interference signals from other directions.

[0026] The optical switch disclosed herein can transmit the input optical signal from each input port to any one of N output ports, thereby realizing the function of optical switching. In the embodiments of this disclosure, the number of input ports M and the number of output ports N can be the same or different. When both the number of input ports M and N are equal to 1, the optical switch 1 of this disclosure can be equivalent to a single-input single-output optical switch. When the number of input ports M and N are not equal to 1, the optical switch 1 of this disclosure can be equivalent to a multiple-input multiple-output system. The values ​​of M and N can be designed according to actual needs. For example, a typical value of M can be 1 to 2. P Between 1 and 2, P is a positive integer greater than or equal to 1; typical values ​​for N can be between 1 and 2. Q Q is a positive integer greater than or equal to 1.

[0027] In some embodiments, the beam splitter 101 of each of the M input channels is a 1×K beam splitter, configured to split the input optical signal input from the input port corresponding to the input channel IN into K input sub-signals. The K sub-phase controllers in each input channel can be K first phase shifters, configured to change the phase of the K input sub-signals under the control of multiple first control signals, and generate a corresponding intermediate optical signal in a beamforming manner, transmitting the intermediate optical signal to one of the N output ports, where a typical value of K is 2. R R is a positive integer greater than 1. In some implementations, R is less than or equal to P. For example, P=8, Q=7 or 8, R=4. In other embodiments, R may be greater than P. In embodiments of this disclosure, the values ​​of R, P, and Q can be any other values ​​when expanding the number of input and output ports, which will not be further described herein.

[0028] A 1×K optical splitter includes one input port and K output ports. The corresponding input optical signal enters the 1×K optical splitter through the input port, and the K input sub-signals are output from the K output ports, respectively, to K first phase shifters 1021~102K. Each of the K first phase shifters 1021~102K can be an electro-optical phase shifter. The electro-optical phase shifter can change the phase of the optical signal output from each first phase shifter under the control of one or more first control signals. The one or more first control signals can come from one or more electrical drivers (e.g., digital-to-analog converters DAC) inside the optical switch 1, or from one or more electrical drivers outside the optical switch 1. The number of electrical drivers can be equal to K, or greater than or less than K. In some embodiments of this disclosure, the number of electrical drivers is equal to the number K of the first phase shifters in each input channel. Accordingly, in Figure 1 In the present disclosure, embodiments show M input channels IN1, IN2, IN3...INM, each input channel may include K electrical drivers.

[0029] Under the control of the first control signal output by the electric driver corresponding to the input channel, K first phase shifters generate the same or different phases for K input sub-signals. The phase combination of the K input sub-signals generated by the K first phase shifters generates an intermediate optical signal pointing to one of the N output ports. The intermediate optical signal can be transmitted in free space or in a sheet waveguide (e.g., a silicon slab).

[0030] refer to Figure 2 , Figure 2 This is a schematic diagram of the transmission of the intermediate optical signal generated by the input channel of this disclosure. Figure 2 In this diagram, each input channel and each output port are positioned in the XY plane. The K first phase shifters in each input channel have coordinates (xi, y1), (xi, y2), (xi, y3), ..., (xi, yK). The coordinates of the position where the j-th output port receives the beam (i.e., the position where the beam reaches the j-th output port) are (xo, yj). To ensure that the beam output from each first phase shifter reaches the j-th (1≤j≤N) output port, a control signal needs to be applied to each first phase shifter in that input channel to delay the phase of the input sub-signal. For the s-th (1≤s≤K) first phase shifter among the K first phase shifters 1021~102K, its phase delay for the s-th input sub-signal is... The following formula must be satisfied:

[0031] in, It is the wavelength of the optical signal, and C is a constant that can be selected between 0 and 2 μm depending on the specific design.

[0032] Specifically, the input optical signal is uniformly split from the 1×K beam splitter 101 of each input channel, and beams of the same frequency and polarization direction are independently output from K output ports. For example, reference Figure 2 Each input channel has K first phase shifters (1021~102K) arranged in a plane, such as the XY plane. The spacing between the K first phase shifters is d (the value of d is usually 0.5~2 times the optical wavelength λ to avoid excessive sidelobes). Multiple control signals can be applied to this input channel, each applied to one of the K first phase shifters. Each of the K first phase shifters (1021~102K) can independently control the phase of its corresponding input sub-signal (ranging from 0 to 2π). Phase compensation allows different first phase shifters to output optical signals with the same or different phases. These multiple optical signals with the same or different phases, after being phase-shifted by the K first phase shifters, are superimposed in phase in the target direction and cancel each other out in the non-target direction, forming an intermediate optical signal directed towards one of the N output ports. The phase of the intermediate optical signal is parabolic or quasi-parabolic and focused on the corresponding output port among the N output ports. Its phase relationship design should ensure that the intermediate optical signal is coupled to the receiver at the output end with maximum coupling efficiency. When the input optical signals from two input channels are output through the same output port, the switching time of the optical switch of this disclosure (i.e., the switching time from transmission from one input channel to one output port to transmission from another input channel to the same output port) is determined by the beamforming time and the phase adjustment time of each electrical driver. The response time of the phase shifter employing the photoelectric effect is on the order of nanoseconds.

[0033] The intermediate optical signal can propagate in free space or in a slab waveguide. It should be understood that, although in... Figure 2 The original design places M input ports, M input channels, and N output ports in the same XY (two-dimensional) plane. However, in practical applications, these ports can be arranged in three-dimensional space (3D). In this case, the M input ports and M input channels can be located on different planes from the N output ports. Therefore, the positional relationship between the input channels and output ports needs to be designed according to the formula above to ensure that the intermediate optical signal output from the input channels can reach any of the output ports. This will not be described in detail here.

[0034] In some embodiments of this disclosure, the optical switch 1 further includes N output channels, each of which includes an edge coupler 20 or a grating coupler 20. The N output channels correspond one-to-one with the N output ports, each output channel is connected to a corresponding output port, and each edge coupler 20 or grating coupler 20 is located in front of the corresponding N output ports along the optical path. The edge coupler 20 is typically a tapered coupler used to couple the received intermediate optical signal into the waveguide of the corresponding output port. The tapered design is to better adapt the mode field of the switched intermediate optical signal to the mode field of the output waveguide. The grating coupler 20 uses the action of a grating to couple the intermediate signal light from the xy plane to the vertical direction, facilitating fiber reception.

[0035] Each of the N output channels also includes an optical mode field converter 40, which is configured to receive an intermediate optical signal from the edge coupler 20 or the grating coupler 20, focus the intermediate optical signal into an output optical signal using inverse beamforming, and output the output optical signal to the corresponding output port among the N output ports.

[0036] In other embodiments of this disclosure, reference is made to Figure 3 , Figure 3 This is another structural schematic diagram of the optical switch disclosed herein. The optical switch 1 of this disclosure includes N output channels OUT1~OUTN, with each of the N output channels corresponding one-to-one with an N output port. Each of the N output channels includes H second phase shifters 1051~105H. The second phase shifters 1051~105H are configured to receive an intermediate optical signal from one of the M input channels and, under the control of a second control signal, convert the intermediate optical signal into an output sub-signal. In embodiments of this disclosure, the number of second control signals can be H, greater than H, or less than H. A corresponding second control signal can be set for each second phase shifter; in this case, the number of second control signals is H.

[0037] Each of the N output channels also includes a combiner 104, configured to combine H output sub-signals to produce an output optical signal, where H is a positive integer greater than 1. The value of H ranges from 2^3 to 2^3. u U is a positive integer. In some embodiments, U is less than Q. For example, u = 8, Q = 7 or 8. In other embodiments, U may be greater than or equal to Q. In embodiments of this disclosure, the numbers of H and Q can be any other values ​​when expanding the number of output ports, which will not be further described herein.

[0038] In this embodiment, the H second phase shifters 1051~105H can be electro-optical phase shifters. The electro-optical phase shifters can change the phase of the optical signal input from each second phase shifter under the control of a second control signal. The second control signal can come from one or more electrical drivers (e.g., digital-to-analog converters DAC) inside the optical switch 1, or from one or more electrical drivers outside the optical switch 1. The number of electrical drivers can be equal to H, or greater than or less than H. In some embodiments of this disclosure, the number of electrical drivers is equal to H. Figure 3 The diagram shows N groups of electric drivers, each corresponding to one output channel, and each group of electric drivers can include H electric drivers.

[0039] In this embodiment of the present disclosure, by setting N output channels OUT1~OUTN, multiple second phase shifters can be used to obtain better mode matching with multiple first phase shifters, thereby better coupling the received intermediate optical signal into the waveguide of the output channel. Each second phase shifter is specifically designed to match the phase distribution of the input phase controller and to provide phase inverse compensation for the received signal at the receiving end, thereby better coupling to the waveguide of the output channel at the receiving end, providing better isolation for the received signal, and obtaining better coupling efficiency.

[0040] Optionally, an optical amplifier 50 may be provided in each output channel in this disclosure. The optical amplifier 50 is disposed at the optical waveguide end of the output channel in a heterogeneous integration manner. The optical amplifier 50 may be constructed of group III-V compounds. Heterogeneous integration provides optical gain by bonding the bonded group III-V active material to silicon-on-insulator (SOI), thereby realizing the optical amplification function. Group III-V semiconductor materials (such as indium phosphide (InP), gallium arsenide (GaAs), etc.) have excellent optical properties. By bonding the group III-V active material to the SOI substrate, key optical gain is provided for optical amplification. The optical amplifier 50 of this disclosure is configured to amplify the optical signal of the output channel, which reduces the limitation on the optical power of the input optical signal while ensuring the output optical power, thereby reducing the cost of using the optical switch.

[0041] The optical switch disclosed herein can be a standalone device or a standalone chip. It should be understood that the optical amplifier 50 of this disclosure is merely optional. When the optical switch is located on a standalone chip, considering manufacturing costs or complexity, the optical amplifier 50 may not be included on the standalone chip. In the accompanying drawings of this disclosure, the optical amplifier 50 is shown in dashed lines.

[0042] In other embodiments of this disclosure, reference is made to Figure 4 , Figure 4This is another schematic diagram of the optical switch disclosed herein. The optical switch 1 includes N output channels, each corresponding one-to-one with an N output port. Each of the N output channels includes a lens 30, positioned in front of the optical path of the corresponding output port in the Nth output port. The lens 30 is configured to receive an intermediate optical signal from one of the M input channels and focus the intermediate optical signal into the waveguide or optical fiber of the corresponding output channel. In some embodiments, the optical inlet of the output port corresponding to the lens 30 needs to be located on the focal plane of the lens 30 to better obtain the optical signal.

[0043] In some embodiments of this disclosure, the N output channels and M input channels are located on different chips, or the N output channels and M input channels are located on the same chip or device. (See reference) Figure 5 , Figure 5 A schematic diagram showing the optical switch of this disclosure located on the same chip is illustrated. As shown, the input and output channels of the optical switch of this disclosure can be units on the chip. Figure 5 In this design, multiple input channels can form a single unit on the chip, and multiple output channels can also form a single unit. These multiple units are arranged in multiple rows and columns. This design makes it easier to expand the number of input and output channels, and it can overcome the limitations of die size on the wafer. Figure 5 As shown, for example, multiple die units in each column can form an input channel, and multiple die units in adjacent columns can form an output channel. Thus, multiple adjacent die units can be combined to form an optical switch with more input channels and more output channels. Figure 5 The diagram shows the input and output channels of an optical switch formed by splicing four adjacent die units.

[0044] The above description is only an optional embodiment of this disclosure. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principles of this disclosure, and these improvements and modifications should also be considered within the scope of protection of this disclosure.

Claims

1. An optical switch, comprising: M input ports, N output ports, and an optical switch. At least one of the M input ports is configured to receive an input optical signal; The optical switch is configured to couple each input optical signal to one of the N output ports by beamforming a phase-controlled array, where M and N are both positive integers greater than 1.

2. The optical switch according to claim 1, further comprising: M input channels are one-to-one with the M input ports. Each of the M input channels is configured to receive the input optical signal from one of the corresponding input ports, convert the input optical signal into an intermediate optical signal, and transmit the intermediate optical signal to one of the N output ports. There are N output channels, each corresponding to one of the N output ports. The N output channels are configured to convert the intermediate optical signal into an output optical signal and output the output optical signal through the corresponding output port among the N output ports.

3. The optical switch according to claim 2, wherein, Each of the M input channels includes: A 1×K beam splitter is configured to split the input optical signal corresponding to the input channel into K input sub-signals; K first phase shifters are configured to generate the intermediate optical signal by beamforming the K input sub-signals in the manner of the phase control array under the control of one or more first control signals, where K is a positive integer greater than 1.

4. The optical switch according to claim 3, wherein, The K first phase shifters are specifically configured to generate the same or different phase delays for the K input sub-signals under the control of one or more first control signals, and the K input sub-signals with the same or different phase delays are coherently superimposed to form the intermediate optical signal that propagates toward one of the N output ports.

5. The optical switch according to claim 3, wherein, Each of the N output channels includes an optical mode field converter, which is configured to receive the intermediate optical signal, match the mode field of the received intermediate optical signal with the mode field of the output waveguide, and convert the intermediate optical signal into an output optical signal, which is output from the corresponding output port among the N output ports.

6. The optical switch according to claim 2, wherein, Each of the N output channels includes: H second phase shifters are configured to receive the intermediate optical signal from one of the M input channels and to perform phase adjustment on the intermediate optical signal under the control of one or more second control signals to generate H output sub-signals; The combiner is configured to combine the H output sub-signals in a coherent superposition manner and generate the output optical signal, where H is a positive integer greater than 1.

7. The optical switch according to claim 2, wherein, Each of the N output channels includes: The lens is configured to receive the intermediate optical signal from one of the M input channels and focus the intermediate optical signal onto the corresponding output channel.

8. The optical switch according to claim 3 or 6, wherein the one or more first control signals and the one or more second control signals are provided by a first phase controller driver chip and a second phase controller driver chip, respectively.

9. The optical switch according to claim 2, wherein, Each of the N output channels includes: An optical amplifier configured to optically amplify the intermediate optical signal from one of the M input channels.

10. A chip, comprising: One or more optical switches according to any one of claims 1-9.

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