Optical flow switch using photonic integrated circuit

Abstract

The invention provides an optical flow switch realized by adopting a photonic switch and an optical flow switch package. The optical flow switch includes a network of photonic switches disposed between an input port and an output port thereof, the network spanning two or more reticles, and the two or more reticles may include an arrangement of photonic switches corresponding to a repeating reticle or group of reticles. The optical flow switch may be mounted on a glass substrate to form an optical flow switch package.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 440,332, filed on January 20, 2023, docket number L0858.70066US01, entitled “OPTICAL FLOW SWITCHING USING PHOTONIC INTEGRATED CIRCUITS,” U.S. Provisional Application No. 63 / 503,452, filed on May 19, 2023, docket number L0858.70075US00, entitled “MULTI-RETICLE OPTICAL FLOW SWITCH,” and U.S. Provisional Application No. 63 / 503,452, filed on May 19, 2023, docket number L0858.70075US01, entitled “OPTICAL FLOW SWITCH WITH CROSSING

[0013] The present invention relates to a patent application filed on July 14, 2009, entitled "STAMPS (Optical Flow Switch with Cross-Stamps)", each of which is incorporated herein by reference in its entirety. Background Art Technical Field

[0003] Various aspects described herein relate to photonic optical flow switches.

[0004] Related technologies

[0005] Optical flow switches (or optical circuit switches, OCSs) are fundamental building blocks in high-performance data centers or computing systems, routing optical signals between various components of the data center or computing system. They can also route optical signals encoded with light's amplitude, phase, directionality, and / or polarization. They can be used to adjust network topology, for example, by granting additional direct optical connections to servers transmitting high-bandwidth data to increase bandwidth. Summary of the Invention

[0006] Some embodiments provide an optical flow switch, which includes a photonic switch network arranged between an input port and an output port of the optical flow switch, and the photonic switch network spans two or more reticles.

[0007] In some embodiments, two or more reticles include the same reticle pattern, and the photonic switch network is formed by a repeated arrangement of the same reticle pattern.

[0008] In some embodiments, the photonic switch network comprises a Cantor network or a Benes network.

[0009] In some embodiments, the photonic switch network includes a first plurality of switches arranged to form a Benes switch.

[0010] In some embodiments, the photonic switch network further comprises a second plurality of switches, the second plurality of switches comprising an input routing switch coupled between the input port and the Benes switch. In some embodiments, a switch in the second plurality of switches is coupled between an input port of the input port and each of the Benes switches. In some embodiments, a switch in the second plurality of switches is coupled between an input port of the input port and a Benes switch disposed across two or more reticles.

[0011] In some embodiments, the second plurality of switches includes: a first input routing switch arranged to receive an optical signal from the input port, a second input routing switch arranged to receive the optical signal from the first routing switch, and a third input routing switch arranged to receive the optical signal from the second routing switch and transmit the optical signal to the Benes switch.

[0012] In some embodiments, the Cantor network includes an N×NCantor network, the input port includes k input ports, the two or more reticles include r reticles, and the Benes switch includes a total of m Benes switch, which and

[0013] In some embodiments, the first input routing switch includes k 1:r photonic switches; the second input routing switch includes kr 1:r photonic switches; and the third input routing switch includes kr 2 An r:q photon switch.

[0014] In some embodiments, the photonic switch network further includes a third plurality of switches, the third plurality of switches including an output routing switch coupled between the Benes switch and the output port. In some embodiments, a switch in the third plurality of switches is coupled between each Benes switch and an output port in the output ports. In some embodiments, a switch in the third plurality of switches is coupled between a Benes switch arranged across two or more reticles and an output port in the output ports.

[0015] In some embodiments, the two or more reticles include multiple rows or columns of reticles, wherein each row or column of reticles is formed by using the same reticle pattern group.

[0016] In some embodiments, the plurality of rows or columns of reticles includes X rows or X columns of reticles, and the optical flow switch further includes a 1:X and / or X:1 switch router disposed between the photonic switches of the photonic switch network. In some embodiments, X=2. In some embodiments, X=4.

[0017] In some embodiments, the optical flow switch further includes a 1:2 and / or 2:1 switching router disposed between the photonic switches of the photonic switch network.

[0018] In some embodiments, the photonic switches of the photonic switch network disposed in the first reticle are coupled to the photonic switches of the photonic switch network disposed in the second reticle via waveguides.

[0019] In some embodiments, the photonic switches of the photonic switch network are arranged in an arrangement spanning two or more chips. In some embodiments, the two or more chips are coupled using optical fibers.

[0020] In some embodiments, the photonic switches of the photonic switch network include 2×2 Mach-Zehnder interferometer (MZI) switches. In some embodiments, the photonic switches of the photonic switch network include three MZI switches arranged in series. In some embodiments, the photonic switches of the photonic switch network include extended MZI switches. In some embodiments, the photonic switches of the photonic switch network include silicon-based photonic switches.

[0021] In some embodiments, the input port and the output port include grating couplers, edge couplers, and / or V-groove couplers.

[0022] Some embodiments relate to an optical switch package comprising a switching photonic integrated circuit (PIC) including an optical flow switch and a glass substrate supporting the switching PIC.

[0023] In some embodiments, the optical switch package further comprises a plurality of input ports and a plurality of output ports, each of the plurality of input ports and each of the plurality of output ports comprising an active pluggable fiber array unit. The active pluggable fiber array unit comprises a plurality of optical couplers configured to couple optical fiber light to the glass substrate, and a plurality of optical amplifiers configured to amplify optical signals at each of the plurality of optical couplers.

[0024] In some embodiments, the optical switch package further includes a glass waveguide that optically couples the active pluggable fiber array unit to the switch PIC. In some embodiments, the glass waveguide is a fan-out component between the switch PIC and the active pluggable fiber array. In some embodiments, the glass waveguide is coupled to the switch PIC via a plurality of evanescent couplers.

[0025] In some embodiments, the switch PIC further includes a control circuit coupled to the optical flow switch.

[0026] In some embodiments, the control circuit is monolithically integrated into the switch PIC.

[0027] In some embodiments, the optical switch package further comprises a first amplifier PIC and a second amplifier PIC. The first amplifier PIC optically couples the input port to the switch PIC, and the second amplifier PIC optically couples the switch PIC with the output port.

[0028] In some embodiments, the switch PIC includes a first switch PIC and a second switch PIC, the first switch PIC and the second switch PIC include substantially identical switching networks, and the second switch PIC includes an optical flow switch having a switching network rotated 180 degrees relative to the switching network of the first switch PIC.

[0029] In some embodiments, the optical switch package further comprises a third amplifier PIC optically coupled between the first switch PIC and the second switch PIC. In some embodiments, the optical switch package further comprises a first amplifier PIC and a second amplifier PIC, wherein: the first amplifier PIC optically couples the input port to the first switch PIC, and the second amplifier PIC optically couples the second switch PIC to the output port.

[0030] In some embodiments, the glass substrate includes a first glass substrate and a second glass substrate, the first switch PIC is disposed on the first glass substrate, and the second switch PIC is disposed on the second glass substrate.

[0031] Some embodiments relate to a method for manufacturing an optical switch package. The method includes: transferring two or more reticles including at least one reticle pattern onto a photoresist supported by a switch photonic integrated circuit (PIC) substrate; depositing optical material on the switch PIC substrate through portions of the photoresist corresponding to the transferred two or more reticles, wherein the deposited optical material forms at least a portion of an optical flow switch, the optical flow switch including a photonic switch network spanning the two or more reticles; coupling a chip including a control circuit to the switch PIC substrate; and bonding the switch PIC substrate to a glass substrate.

[0032] In some embodiments, transferring the two or more reticles includes transferring two or more reticles having the same reticle pattern onto the photoresist such that the photonic switch network is formed by a repeated arrangement of the same reticle pattern.

[0033] In some embodiments, the deposited optical material forms a photonic switch network comprising a Cantor network or a Benes network.

[0034] In some embodiments, depositing optical material to form a photonic switch network includes a first plurality of switches arranged to form Benes switches.

[0035] In some embodiments, depositing the optical material further forms a second plurality of switches including an input routing switch coupled between an input port disposed on the switch PIC substrate and the Benes switch.

[0036] In some embodiments, the deposited optical material further forms a waveguide that couples switches in the second plurality of switches to the Benes switches disposed across the two or more reticles.

[0037] In some embodiments, transferring the two or more reticles includes transferring multiple rows or columns of reticles, wherein each row or column of reticles is formed using the same reticle pattern group.

[0038] In some embodiments, transferring the two or more reticles including at least one reticle pattern to a photoresist includes transferring the two or more reticles to a photoresist supported by two switch PIC substrates.

[0039] In some embodiments, depositing the optical material includes depositing silicon.

[0040] In some embodiments, the method further includes bonding a first amplifier PIC and a second amplifier PIC to a glass substrate, wherein the first amplifier PIC optically couples an input port of the glass substrate with the switch PIC substrate, and the second amplifier PIC optically couples the switch PIC substrate with an output port of the glass substrate.

[0041] In some embodiments, bonding the switch PIC substrate to the glass substrate includes bonding two switch PIC substrates to the glass substrate, the two switch PIC substrates supporting substantially identical multiple photonic switch networks.

[0042] In some embodiments, bonding two switch PIC substrates to a glass substrate includes bonding a first one of the switch PIC substrates to the glass substrate, and bonding a second one of the switch PIC substrates to the glass substrate in a manner rotated 180 degrees relative to an orientation of the first switch PIC substrate in a plane parallel to the plane of the glass substrate.

[0043] In some embodiments, the amplifier PIC is bonded to the glass substrate such that the amplifier PIC is optically coupled between the first switch PIC substrate and the second switch PIC substrate.

[0044] In some embodiments, the glass substrate includes a first glass substrate and a second glass substrate, bonding the first switch PIC substrate to the glass substrate includes bonding the first switch PIC substrate to the first glass substrate, and bonding the second switch PIC substrate to the glass substrate includes bonding the second switch PIC substrate to the second glass substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The following description of various aspects and embodiments will be made with reference to the accompanying drawings. It should be understood that the drawings are not drawn to scale. In the various drawings, identical or substantially identical components are represented by the same reference numerals. For clarity, not all components are labeled in every drawing.

[0046] Figure 1A is a schematic diagram of an optical flow switch layout across four identical reticles, according to some embodiments of the techniques described herein.

[0047] Figure 1B is a schematic diagram of a Benes switch according to some embodiments of the technology described herein.

[0048] Figure 1C is a schematic diagram of a photonic switch according to some embodiments of the technology described herein.

[0049] Figure 2 is a schematic diagram of a Cantor switch according to some embodiments of the technology described herein.

[0050] Figure 3A is a schematic diagram of a Cantor switching network according to some embodiments of the technology described herein.

[0051] Figure 3B According to some embodiments of the technology described herein, Figure 3A Schematic diagram of the waveguide connection configuration between the input routing switches of the Cantor switching network.

[0052] Figure 4A and Figure 4B is a schematic diagram of a 4×4 Cantor network implemented using two instances of the same reticle pattern, according to some embodiments of the techniques described herein.

[0053] Figure 5A and Figure 5B is a schematic diagram of an 8×8 Benes network implemented using two instances of the same reticle pattern, according to some embodiments of the techniques described herein.

[0054] Figure 6 Schematic diagram of an optical flow switch implemented using two chips, according to some embodiments of the technology described herein, where each chip includes a switching network portion implemented using multiple instances of the same reticle pattern.

[0055] Figure 7 is a diagram showing an example of a reticle and off-chip coupling technique according to some embodiments of the technology described herein.

[0056] Figure 8A is a schematic diagram of a photonic switch including a 2×2 Mach-Zehnder interferometer (MZI) switch according to some embodiments of the technology described herein.

[0057] Figure 8B is a schematic diagram of a photonic switch including three MZI switches connected in series, according to some embodiments of the technology described herein.

[0058] Figure 8C is a schematic diagram of a photonic switch including an extended MZI switch according to some embodiments of the technology described herein.

[0059] Figure 9A is a graph showing examples of switch excitation signals varying over time with and without pre-emphasis, according to some embodiments of the techniques described herein.

[0060] Figure 9B is a graph showing examples of switch states changing over time with and without pre-emphasis, according to some embodiments of the techniques described herein.

[0061] Figure 10 is a schematic diagram of an example of a switch linking optical flows according to some embodiments of the technology described herein.

[0062] Figure 11 is a schematic diagram of an example of a computing system including an optical flow switch, according to some embodiments of the technology described herein.

[0063] 12A to 12C is a schematic diagram showing the connection relationship between optical flow switches associated with three racks in a computing system according to some embodiments of the technology described herein.

[0064] Figure 13 is a schematic diagram showing a 16×16 Benes switch, according to some embodiments of the technology described herein.

[0065] Figure 14A is a schematic diagram showing a 16×16 Benes switch implemented using a two-column, two-row mask, according to some embodiments of the technology described herein.

[0066] Figure 14B is a schematic diagram showing a 16×16 Benes switch implemented using two columns and two rows of reticles, a reduced number of reticle sets, and a switch router, according to some embodiments of the technology described herein.

[0067] Figure 15 is a schematic diagram showing routing using 1:2 and 2:1 switches according to some embodiments of the techniques described herein.

[0068] Figure 16A is a schematic diagram showing a 16×16 Benes switch implemented using a two-column, four-row reticle, according to some embodiments of the technology described herein.

[0069] Figure 16B Schematic diagram showing a 16×16 Benes switch implemented using two columns and four rows of reticles, a reduced number of reticle sets, and a switch router according to some embodiments of the technology described herein.

[0070] Figure 17A is a schematic diagram showing a 512×512 Benes switch implemented using four reticles, according to some embodiments of the technology described herein.

[0071] Figure 17B and Figure 17C is a diagram illustrating some embodiments of the technology described herein. Figure 17A Schematic diagram of the switch output and target of the first routing layer of the Benes switch.

[0072] Figure 17D and Figure 17E is a diagram illustrating some embodiments of the technology described herein. Figure 17A Schematic diagram of the switch output and target of the second routing layer of the Benes switch.

[0073] Figure 18A is a schematic diagram showing a 16×16 Benes switch implemented using two columns and four rows of reticles, where each column is formed using the same reticle set, according to some embodiments of the technology described herein.

[0074] Figure 18B According to some embodiments of the technology described herein, Figure 18A Detailed view of the first row of Benes switches in Figure 1.

[0075] Figure 19 is a schematic diagram showing a 16×16 Benes switch implemented using two columns and four rows of reticles and a switch router, wherein each column is formed using the same set of reticles, according to some embodiments of the technology described herein.

[0076] Figure 20A is a schematic diagram of an optical flow switch package including a switching photonic integrated circuit (PIC) bonded to a glass substrate according to some embodiments of the technology described herein.

[0077] Figure 20B According to some embodiments of the technology described herein, Figure 20A Cross-sectional view of the optical flow switch package in Figure 2.

[0078] Figure 20C is a diagram showing some embodiments of the technology described herein. Figure 20A Simulation graph of the bit error rate (BER) of the optical flow switch package as a function of input power.

[0079] Figure 21 is a schematic diagram of another optical flow switch package including a switch PIC and two additional amplifier PICs bonded to a glass substrate, according to some embodiments of the technology described herein.

[0080] Figure 22A is a schematic diagram of another optical flow switch package including two switch PICs and three additional amplifier PICs bonded to a glass substrate according to some embodiments of the technology described herein.

[0081] Figure 22B is a diagram showing some embodiments of the technology described herein. Figure 22A Simulation curve of the bit error rate (BER) of the transmission path of the optical flow switch in the figure as the input power changes.

[0082] Figure 22C is a schematic diagram of another optical flow switch package including two switch PICs, each of which is bonded to a separate glass substrate, according to some embodiments of the technology described herein.

[0083] Figure 22D is a schematic diagram of another optical flow switch package including two switch PICs bonded to a glass substrate and optically coupled through an amplifier PIC, according to some embodiments of the technology described herein.

[0084] Figure 23 is a schematic diagram of a bidirectional optical flow switch package according to some embodiments of the technology described herein.

[0085] Figure 24 is a flow chart of a method 2400 of manufacturing an optical flow switch package according to some embodiments of the technology described herein.

[0086] Figure 25A is a schematic diagram of a PIC for implementing bidirectional wavelength division multiplexing (WDM) communications according to some embodiments of the techniques described herein.

[0087] Figure 25B According to some embodiments of the technology described herein, Figure 25A Schematic diagram of the polarization management module of the PIC.

[0088] Figure 26A FIG. 1 is a schematic diagram of a system for implementing bidirectional WDM communication between two PICs mediated by an optical flow switch according to some embodiments of the technology described herein.

[0089] Figure 26B is a schematic diagram of an optical flow switch suitable for mediating bidirectional WDM communications according to some embodiments of the technology described herein.

[0090] Figure 27A is a schematic diagram of an 8×8 Benes switch according to some embodiments of the technology described herein.

[0091] Figure 27B is a schematic diagram of a waveguide crossing structure according to some embodiments of the technology described herein.

[0092] Figure 27C According to some embodiments of the technology described herein, Figure 27A Schematic diagram of the waveguide crossover structure of the first column of the Benes switch.

[0093] Figure 27D is an illustration of a waveguide crossing structure according to some embodiments of the technology described herein.

[0094] Figure 28 is an illustration of a layout of a 64x64 Benes switch network according to some embodiments of the techniques described herein. DETAILED DESCRIPTION

[0095] Optical flow switches are typically implemented using three-dimensional free-space microelectromechanical system (MEMS) mirror switches. These MEMS mirror switches can be scaled to approximately 1,000 input and output ports with switching times of 10-20 milliseconds. However, manufacturing optical flow switches using three-dimensional MEMS mirror switches is challenging and requires calibration and installation of discrete components such as two-dimensional fiber arrays, microlens arrays, and beam steering mirrors. In addition, optical flow switches typically require the simultaneous use of electronic packet switches, which can lead to packet loss during periods of traffic contention. High production costs, relatively slow switching speeds, and potential data loss issues have hindered the implementation of three-dimensional MEMS optical flow switches in large computing systems and data centers.

[0096] The inventors have recognized and noted that the use of integrated photonics technology (such as silicon photonics) in optical flow switches can provide a feasible path for implementing optical flow switches in computing systems and data centers by achieving device miniaturization and improving the phase stability of optical signals transmitted through the optical flow switches. In addition, the use of integrated photonics technology can also provide significantly faster switching speeds (e.g., about 1 microsecond or less). Faster switching speeds give optical flow switches better programmability and higher utilization. For example, these switches can be reconfigured at runtime, and the endpoints of the switches can be linked in a polling manner at runtime to improve utilization.

[0097] The inventors further recognized and noted that integrated photonics, when implemented on a chip, requires only a relatively small number of layers to route optical signals (e.g., silicon and silicon nitride layers in the case of silicon photonics). Therefore, optical signal routing in integrated photonic systems is inherently two-dimensional. Such two-dimensional photonic switch structures traditionally limit the number of input and output ports due to the size limitations of photolithographic manufacturing masks. Furthermore, the scalability of photonic switching structures is also limited due to the difficulty in simultaneously controlling and stabilizing the photonic switches.

[0098] To this end, the inventors developed a multi-reticle photonic optical flow switch and a photonic switch structure. These structures have low manufacturing costs (e.g., fabrication using 200mm and 300mm complementary metal oxide semiconductor (CMOS) processes), are scalable to a large number of input and output ports, and have a fast reconfiguration time of sub-microseconds. Furthermore, the multi-reticle photonic optical flow switch in this paper can achieve non-blocking optical flow switching with a larger mode size than a single-reticle optical flow switch.

[0099] I. Multi-reticle optical flow switch

[0100] In some embodiments, the multi-reticle optical flow switch herein includes a series of substantially identical adjacent reticles that together implement a switching network, such as Figure 1A As shown in the example, the multi-reticle optical flow switch 100 includes four reticles 102a-102d, each of which is manufactured using the same reticle pattern, which is repeated from top to bottom on the multi-reticle optical flow switch 100. Each reticle 102a-102d includes an input port 104a and an output port 104b, each of which can couple the multi-reticle optical flow switch 100 to one or more optical fibers (for example, each port can couple 32 optical fibers).

[0101] In some embodiments, the switch network forming the multi-reticle optical flow switch 100 includes photonic switches arranged in a Cantor network topology. In a general N×N Cantor network, N input optical fibers are coupled to the multi-reticle optical flow switch 100 through input ports 104a and routed to the intermediate switching layer via input routing switches 106a, which includes log(N) independent switching layers. Benes switch, which is the smallest integer power of 2 greater than N. The Cantor network also includes an output routing switch 106b arranged to couple the Benes switch 108 to output ports 104b, which couple the multi-reticle optical flow switch 100 to output optical fibers.

[0102] Spatial expansion across the log(N) Benes switches 108 introduces circuit layout complexity that, when N is large, makes fabrication using a single two-dimensional reticle impractical. In some embodiments, multi-reticle optical flow switch 100 distributes the log(N) Benes switches across multiple reticles (e.g., reticles 102a-102d), thereby reducing circuit complexity within each reticle. Each Benes switch 108 is independent and operates using waveguide connections within its reticle.

[0103] In some embodiments, the Benes switch 108 is implemented using a recursive structure, such as Figure 1B In such embodiments, the i th The input fiber can be routed to the i-th of any log(N) Benes switches 108 through 1:log(N) active switches in the input routing switch 106a. th The output routing switch 106b performs the reverse operation: it routes the i-th input pattern from any Benes switch 108. th The output pattern is routed to the i-th output port 104b th Output optical fibers.

[0104] In some embodiments, the input and output routing switches 106a, 106b include optical signal routing across reticle boundaries. Independent 2×2 photonic switches in different reticles can be connected by waveguides extending across the reticle boundaries, and waveguide continuity at the reticle boundaries can be achieved using reticle stitching technology.

[0105] In some embodiments, the input routing switch 106a, the Benes switch 108, and / or the output routing switch 106b are formed by photonic switches, examples of which are shown in FIG. Figure 1CThe photonic switch 110 may be a Mach-Zehnder interferometer (MZI) switch, comprising: two input waveguides 110a for transmitting input optical signals to a first coupler; two electronically controlled phase modulators 110b disposed on opposite interferometer arms of the MZI switch; and two output waveguides 110c for transmitting output optical signals from a second coupler. The phase modulator 110b selects which output waveguide 110c to use. For alternative examples of photonic switches comprising MZI switches, see Figures 8A to 8C Description.

[0106] In some embodiments, the input and output ports 104a, 104b can be coupled to multiple optical fibers. The optical fibers can be connected to the switching network through coupling technologies such as grating couplers, edge couplers, or V-groove couplers. Waveguide array-to-fiber adapters (WAFTs) can be used to reduce the spacing between adjacent input terminals from 127 microns or 250 microns for standard optical fibers to a spacing of less than 10 microns. Therefore, WAFTs can be used to increase the number of spatial mode inputs and outputs at the edge of the switch reticle, which is currently limited to the 32 mm boundary of a standard 26 mm × 32 mm reticle. Multi-core optical fibers can be connected to the input and output ports 104a, 104b through grating couplers that match the core array, further increasing the number of spatial mode inputs and outputs of the switch.

[0107] It should be understood that while the multi-reticle optical flow switch example described herein is described as providing unidirectional communication, the photonic switching network can also be used for bidirectional communication, as the technology described herein is not limited in this respect. For example, the endpoint on the left side of the illustrated multi-reticle optical flow switch can be configured to send data to the endpoint on the right side, and vice versa.

[0108] In some embodiments, the total number of Benes switches in a multi-reticle optical flow switch is given by m=qr, where each reticle is arranged with q independent Benes switch. The number of switches per mask q can be selected to meet The number of optical fibers k at each mask input / output end is the minimum integer that satisfies The maximum integer.

[0109] According to some embodiments of the technology herein, Figure 2 A schematic diagram of a general Cantor switch 200 is shown. The Cantor switch 200 includes a total of 2 k 1:k input photonic switches 202-1 to 202-2 k These input photonic switches 202-1 to 202-2 k Optically coupled to k 2 k ×2 kBenes switches 204-1 to 204-k. Benes switches 204-1 to 204-k are then optically coupled to the symmetrically arranged two k k:1 output photonic switches 206 - 1 to 206 - 2 k .

[0110] In some embodiments, the input routing and / or output routing of the Benes switch of the multi-reticle optical flow switch can be implemented by three groups of photonic switches, such as Figure 3A The reticle 300 is shown as an example. The reticle 300 can be repeatedly arranged (e.g., to form a column of substantially identical reticles) to form a switching network of a multi-reticle optical flow switch. The reticle 300 may include k input ports 301-1 to 301-k, which are configured to couple k input optical fibers to k first input routing switches 302. The first input routing switch 302 may be a 1:r reticle selection (RS) active switch. The i th RS switch RS i Can be tuned to its jth th output patterns, where j represents the position of the mask in the network, and the selected data path is indicated by the solid line between the switches. Figure 3A As shown, all RS in the mask 300 i Can be configured to route input data to their corresponding top output modes.

[0111] In some embodiments, first input routing switch 302 can be configured to provide an optical output to second input routing switch 304. Reticle 300 can include kr second input routing switches 304, which can be 1:r Benes switch select type A (SSA) active switches. Second input routing switches 304 can control which reticle the input data is sent to during transmission through the multi-reticle optical flow switch.

[0112] In some embodiments, the second input routing switch 304 can be configured to provide an optical output to the third input routing switch 306. The reticle can include a total of kr 2 A third input routing switch 306 , which is an r:q type switch select B (SSB) active switch, is configured to control the routing of optical signals to specific Benes switches 308 - 1 to 308 - q within the reticle 300 .

[0113] In some embodiments, output routing can be implemented by three sets of output routing switches that are structurally symmetrical to the input routing switches 302, 304, and 306. For example, the output routing switches may include a first output routing switch 310, and the switches may include a total of kr 2The output routing switch may further include a second output routing switch 312, which may include a total of kr r:1 SSA active switches. The output routing may further include a third output routing switch 314, which may include a total of k r:1 RS active switches. The third output routing switch 314 may be optically coupled to a total of k output ports 315-1 to 315-k, each of which may be coupled to an output optical fiber.

[0114] In some embodiments, the only connection between routing switches formed by cross-reticle waveguides is the connection between the SSA and SSB switches. Since each reticle in a multi-reticle optical flow switch is manufactured using the same manufacturing reticle, the cross-reticle waveguides need to be configured to remain continuous at the reticle boundary. r In a switching network with}, the waveguide routing between the SSA switch and the SSB switch can be achieved by considering a waveguide with 2r-1 masks {R -(r-2) ,R -(r-3) ,…,R0,R1,…,R r} network is configured, where the mask pattern is located at the center position R1. Figure 3B As shown in the example (where Ω = (i-1) / r), the waveguide connection between the SSA switch 304 and the SSB switch 306 is routed using an extended mask network, and the input and output port naming convention is R a SSA b P c , where a is the mask label, b is the SSA switch number, and c is the switch port label.

[0115] Figure 4A and Figure 4BFigure 4 is a schematic diagram of a 4×4 Cantor network 400 implemented using two reticles 402a and 402b fabricated using the same reticle pattern, according to some embodiments of the techniques described herein. Network 400 receives four inputs 401-1 through 401-4, with each reticle 402a and 402b receiving two inputs. Each reticle 402a and 402b includes two first input routing switches 302 (comprising 1:2 RS switches), four second input routing switches 304 (comprising 1:4 SSA switches), four third input routing switches 306 (comprising 4:1 SSB switches), and one 4×4 Benes switch 408-1 or 408-2. The output routing of Benes switches 408-1 and 408-2 is implemented using a symmetrical output network comprising four first output routing switches 310 comprising 1:4 SSB switches, four second output routing switches 312 comprising 4:1 SSA switches, and two third output routing switches 314 comprising 2:1 RS switches. The third output routing switch 314 is optically coupled to outputs 415 - 1 through 415 - 4 , respectively.

[0116] The multi-reticle input and output routing strategy of this article is also applicable to other switching networks besides Cantor networks. In the most general case, the reticle selection (RS) stage (e.g., the first input routing switch 302) can configure the switching network to perform the function of a specific reticle position. For example, the RS switch can be configured to select the input mode represented by the specific input fiber in the schematic diagram. The switch selection A (SSA) stage (e.g., the second input routing switch 304) can route the optical signal to the reticle where the target switch is located (e.g., acting as a cross-reticle transmitter). The switch selection B (SSB) stage (e.g., the third input routing switch 306) can receive the signal routed by the SSA switch (e.g., acting as a cross-reticle receiver) and select the target Benes switch within the reticle to which the signal should be routed. For 2 k Cantor network, target switch is 2 k Benes switch; and for 2 k Benes network, the target switch is 2 k-1 Benes switch.

[0117] Figure 5A and Figure 5BFigure 5 is a schematic diagram of an 8×8 Benes network 500 formed using two reticles 502a and 502b fabricated using the same reticle pattern, according to some embodiments of the techniques described herein. Network 500 receives eight inputs 501-1 through 501-8, four of which are provided to each reticle 502a and 502b. Each reticle 502a and 502b includes four first input routing switches 302 with 1:2 RS switches, four second input routing switches 304 with 2:2 SSA switches, four third input routing switches 306 with 2:1 SSB switches, and one 4×4 Benes switch 408-1 or 408-2. The output routing of Benes switches 408-1 and 408-2 is achieved through a symmetrical output network comprising four first output routing switches 310 with 1:2 SSB switches, four second output routing switches 312 with 2×2 SSA switches, and four third output routing switches 314 with 2:1 RS switches. The third output routing switch 314 is optically coupled to outputs 515 - 1 through 515 - 8 , respectively.

[0118] More specifically, 2 k ×2 k The input and output layers of the Benes network are composed of 2 k-1 Taking the double mask as an example: the first input routing switch layer can be implemented as a 2×2 photonic switch. k-1 A 1:2 switch is used to specify the input corresponding to a given fiber mode. The second input routing switch can include 2 k-1 2×2 switches, each switch receives data from two switches of the first input switch layer at the same time. The third input switch layer may include 2 k-1 2:1 switches, each receiving input from the second input routing switch layer and outputting to the local (i.e., on the same mask) k-1 ×2 k-1 Benes switch.

[0119] In addition, the routing strategy in this article can also be applied recursively. For example, this strategy can be used to build 2 k Cantor network, whose target switch is 2 k Benes switch. 2 k Each of the Benes switches can be Figures 3A to 5B The same input and output routing strategy is constructed, where 2 k Each of the Benes switches has two 2 k-1 Benes switch as its target switch.

[0120] II. Inter-mask waveguide cross structure

[0121] In some embodiments, data routing between reticles can be achieved using a variety of physical mechanisms. However, reticle-stitched waveguide couplers can broaden optical modes near reticle boundaries. Therefore, by aligning two reticle-stitched couplers on either side of the reticle boundary, low-loss data transmission across the reticle boundary can be achieved in a continuous waveguide. Reticle stitching enables a monolithic switch fabric composed of multiple identical reticles without the need for dicing and waveguide coupling between separate chips.

[0122] The inventors further recognized that the compressive strain experienced by commercial photonic wafers imposes a limit on the aspect ratio of monolithic photonic integrated circuits. Where a high aspect ratio is required (e.g., when the number of reticles, r, becomes large), according to some embodiments, the complete switching network can be subdivided onto multiple chips, with each chip comprising smaller monolithic subcircuits constructed from fewer reticles. These subcircuits can then be connected between chips using off-chip waveguide coupling methods, such as fiber edge coupling, grating coupling, or photonic wire bonding.

[0123] Figure 6 FIG2 is a schematic diagram of a multi-reticle optical flow switch 600 implemented using two chips 602, each chip including two reticles in a four-reticle switching network, according to some embodiments of the technology described herein. The reticles can support, for example, a Cantor network including a Benes switch 604. The two halves of the switching network formed on the two chips 602 can be connected via an optical fiber bundle 606 or other suitable off-chip optical signal coupling technology.

[0124] In some embodiments, a hybrid coupling architecture can still be implemented using a single fabrication reticle. Flexibility can be achieved in the coupling mechanism implemented by designing the reticle splice coupler to mode match the edge-coupled fiber, or by using active switches to select the coupling mechanism. Figure 7 FIG2 is a schematic diagram of a chip edge 700 illustrating examples of reticle and off-chip coupling techniques according to some embodiments of the technology described herein. A waveguide 704 can be coupled to an off-chip optical device via a single reticle tile coupler 702, or the coupling method can be selected using a switch 706. For example, switch 706 can provide a selection between a reticle tile coupler 702 and a grating coupler 708. Alternatively or additionally, switch 706 can provide a selection between a reticle tile coupler 702 and an edge coupler 710.

[0125] III. Photonic switch with minimized crosstalk

[0126] The crosstalk between optical signals in an optical flow switch will reduce the signal-to-noise ratio (SNR) of the transmitted optical signal. s (expressed in percentage) of the 2 × 2 optical switch and the crosstalk is ∈ sIf the optical cross structure is realized, the SNR degradation degree is about , where N S and N X They represent the number of 2×2 optical switches and the number of optical cross-connect structures in a specific optical path, respectively.

[0127] The inventors have realized that the crosstalk of an optical flow switch is mainly determined by the crosstalk of a switch with a finite extinction ratio. Figure 8A As shown in the example in , in a 2×2 MZI switch, the extinction ratio of switch 800a with phase modulator 802 may be limited by the deviation of the input and output directional couplers from the ideal 50:50 splitting ratio. Deviation from the ideal 50:50 splitting ratio results in the entire 2×2 switch not being able to achieve a perfect (or as close to ideal as possible) crossover state or a perfect through state. This deviation is usually caused by manufacturing defects that cause slight deviations in the coupling lengths of the directional couplers within the 2×2 MZI switch. In addition, the deviation from the 50:50 splitting ratio may also be different for different wavelengths, which may significantly affect the performance of the optical flow switch if the waveguide carries wavelength-multiplexed signals.

[0128] In some embodiments, crosstalk can be reduced by using multimode interferometers (MMIs) as input and output 50:50 beam splitters. MMIs are generally more robust to variations caused by manufacturing defects. Furthermore, these MMIs can be designed using photonic reverse engineering, which often results in better performance through finer lithographic definition.

[0129] In some embodiments, as Figure 8B As shown in the example in [ 1 ], switching crosstalk can also be reduced by replacing a single MZI with three series-coupled MZIs 804a, 804b, and 804c. The first MZI 804a and the last MZI 804c can be tuned to operate as 50:50 input and output beam splitters. Slight deviations from the ideal 50:50 splitting ratio of the input and output beam splitters formed by MZIs 804a and 804c do not prevent MZI switch 800b from achieving a near-ideal 50:50 state. Once the first and last MZIs (804a and 804c) are tuned to operate as 50:50 input and output beam splitters, the middle MZI (804b) can operate as if it had an ideal 50:50 input and output directional coupler.

[0130] In some embodiments, as Figure 8C As shown in the example in FIG, the switch crosstalk can be reduced by spatially extending the 2×2 switch. By spatially extending the MZI switch 800c, it is ensured that no two signals in the optical flow switching are processed by the same 2×2 switch.

[0131] Reducing crosstalk can also be achieved by reducing crosstalk in optical crosstalk. For example, improved crosstalk structures with lower crosstalk can be created through photonic reverse engineering and manufactured through more precise lithography techniques, enabling finer patterning. Another way to reduce crosstalk in crosstalk structures is to use multiple optical routing layers. For a crossover between a silicon layer and a silicon nitride layer with a vertical spacing of approximately 2 microns, each crossover will result in less than 1 millidecibels of loss and less than -80 decibels of crosstalk. At this vertical distance, an intermediate layer (such as a silicon nitride layer) can be used to transmit the signal from the bottom silicon layer to the top silicon nitride layer. In this configuration, the optical signal is first transferred to the intermediate layer through a tapered structure and then transferred to the top layer through another tapered structure. Signal transmission from the bottom to the top layer can also be achieved through the intermediate layer. By increasing the distance between the silicon layer and the silicon nitride layer, lower crosstalk loss and crosstalk can be achieved. At a larger vertical distance, multiple intermediate layers can be used.

[0132] IV. Exchange speed

[0133] A variety of modulation physics schemes are applicable to photonic switching elements. For example, carrier injection or depletion in silicon photonic devices can be used to modulate the switching of a switch between the crossover state and the through state. Although carrier injection and depletion can achieve sub-picosecond modulation, the mechanism exhibits phase-dependent losses. As another example, the switching of a switch between the crossover state and the through state can also be modulated using microelectromechanical systems (MEMS) to physically drive the interferometer arms of a 2×2 MZI switch. MEMS actuation can provide sub-microsecond modulation. However, the release process of MEMS switches may not always be compatible with the processes used to manufacture integrated photonic devices (e.g., CMOS-compatible silicon photonic processes). As another example, in systems implemented using nonlinear photonic materials (such as χ(2) in InP), the switch can be modulated by nonlinear optics. This nonlinear process can be used to provide a low-loss phase shift to modulate the switching of the switch between the crossover state and the through state. If the nonlinear process is strong enough (e.g., through large gain amplification), one optical signal can be modulated to act on the switch of another optical signal. Finally, thermo-optical modulation is another modulation technique compatible with photonic switching elements. Heating or cooling the switching element waveguide effectively creates a phase shift that can be used to modulate the switching of the switch between the through and crossover states.

[0134] In all of the above examples, equalization techniques can be used to shorten the switching time between the through state and the crossover state, and vice versa. The optimal excitation signal can be derived by compensating for the slower response limited by the physical mechanism of the modulation. For example, in thermo-optical modulation, a pre-emphasis filter that accounts for the relatively slow heat propagation and diffusion processes can produce a faster switching response than a simple step response. This pre-emphasis filter can be designed to increase the amplitude of certain frequency responses, such as the high-frequency response. Similarly, for carrier-depletion switching, a different pre-emphasis filter can be designed to compensate for carrier recombination time; for MEMS switching technology, another pre-emphasis filter can be used to compensate for the slower drive bandwidth of the MEMS device.

[0135] Figure 9A is a graph showing the change of a switch excitation signal with and without pre-emphasis over time according to some embodiments of the technology described herein, where curve 902 represents the excitation signal with pre-emphasis and curve 904 represents the excitation signal without pre-emphasis. Figure 9B The graph shows the time evolution of the switch state with and without pre-emphasis. Curve 906 represents the switch state with pre-emphasis, and curve 908 represents the switch state without pre-emphasis. The horizontal dashed lines represent the crossover and pass states of the switch. The pre-emphasis filter avoids state switching responses that require multiple exponential time constants.

[0136] In some embodiments, the equalization filter can be applied using either a single-ended or double-ended approach. Other equalization approaches include de-emphasis filters, which attenuate the amplitude of certain frequency responses. For example, a de-emphasis filter can be used to offset the high-frequency losses of certain modulation schemes (such as carrier injection or depletion) to achieve a flat modulation response.

[0137] In some embodiments, the analog front end that drives the switch and maintains its stability (for example, against temperature fluctuations during operation) can be integrated in the following ways: monolithic integration on the same chip (applicable to silicon photonic switches), 3D stacking integration (for example, an application-specific integrated circuit (ASIC) with an analog output DAC and a readout ADC is attached to the top of the switch via direct bump connections or interposer bonding), or 2D / 2.5D integration (for example, the ASIC sends and receives signals via an interposer substrate or PCB).

[0138] V. Switch Control

[0139] The inventors further recognized that reconfiguring an optical flow switching network on a nanosecond or picosecond timescale may be inefficient or impossible. Instead, the switching network can be configured on an application-by-application basis. The optical flow switch can be configured to create a network topology between the terminal processor and the storage unit before operation, thereby achieving optimal runtime performance of the computing system for a specific application. When another application is required to run in the system, the optical flow switch can be reconfigured to another network topology to achieve optimal runtime performance for the second application. In this scenario, the optical flow switch can exhibit quasi-static characteristics.

[0140] In some embodiments, the optical flow switch can remain dynamic even at slower time scales than the clock frequency (e.g., on the order of GHz). In one example, one or more terminals of the switching system may issue a request to the control circuit that controls the optical flow switch to establish one or more optical connections from the transmitter to one or more receivers. The number of optical connections may depend on the requested bandwidth. For example, if the optical communication transceiver uses eight optical wavelengths per connection and each wavelength is modulated at 56Gbps, a single optical connection can provide 448Gbps of bandwidth between the transmitter and the receiver. Two optical connections can provide double the bandwidth (e.g., 896Gbps) between the transmitter and the receiver. The request to increase the optical connection can be made on the packet switching network - when a request to transmit a large amount of data is received, the optical switching network will establish the corresponding optical connection. Otherwise, the data is transmitted only in the form of electrical signals through the packet switching network.

[0141] In some embodiments, connections between senders and receivers can be established according to a predefined schedule. For example, senders and receivers can be paired in a round-robin fashion, ensuring that each sender has the opportunity to transmit data to each receiver within a predefined schedule. This predefined schedule is stored in memory on the sender, receiver, and optical switching network, ensuring that all participating components know the identities of the current sender and receiver at all times. In some embodiments, the predefined schedule can be stored within the optical switching network. The sender and receiver can authenticate each other before data transmission.

[0142] In some embodiments, connection establishment can also depend on the wavelength of the transmitter's transmission. In wavelength division multiplexing (WDM), input data can be demultiplexed using a set of resonant devices (such as ring resonators or racetrack resonators) or an unbalanced MZI series. Each wavelength can traverse the same or different paths. Data can also be re-wavelength-multiplexed onto a single output waveguide or fiber using the same resonant device. In another scenario, one or more wavelengths can be used to transmit the switching network configuration to a control processor.

[0143] In some embodiments, the optical flow switch can be configured in broadcast mode. A 2×2 photonic switch can be configured to split the input signal in any ratio between a through state (100:0) and a cross state (0:100). Leveraging this feature, the optical flow switch can be configured to broadcast a single input signal (or multiple wavelength signals multiplexed into a single input waveguide) to multiple receiving ends.

[0144] VI. Overcoming optical loss

[0145] Figure 10 1 is a schematic diagram of an example of linked optical flow switches according to some embodiments of the technology described herein. System 1000 includes a transmitting device, which includes a substrate 1002, a transmitting photonic integrated circuit (PIC) 1004, an application-specific integrated circuit (ASIC) 1006, and a laser 1008. System 1000 also includes a receiving device, which includes a substrate 1016, a receiving PIC 1018, and an ASIC 1020. The transmitting device is coupled to the receiving device via a plurality of optical flow switches 1010, which can include any of the optical flow switches described herein.

[0146] One or more optical flow switches 1010 may include an amplifier 1012 coupled adjacent to an inter-switch optical coupler 1014. The amplifier 1012 may be configured to overcome losses introduced by the optical flow switches 1010. The amplifier 1012 may be integrated with the optical flow switches 1010 on a single monolithic circuit, or it may be fabricated separately from the optical flow switches 1010 and placed before or after the one or more optical flow switches. Multiple amplifiers may also be provided in the system. The placement of the amplifier depends on the minimum signal power required by the amplifier, the maximum saturated output power of the amplifier, and the signal power required at the receiving end. The amplifier 1012 may be a semiconductor optical amplifier (SOA), an erbium-doped fiber amplifier (EDFA), a bismuth-doped fiber amplifier (BDFA), or a praseodymium-doped fiber amplifier (PDFA).

[0147] VII. Computing system including optical flow switch

[0148] Figure 11 FIG1 is a schematic diagram of an example computing system 1100 including four racks 1102a-1102d according to some embodiments of the technology described herein. Racks 1102a-1102d include optical flow switches 1104 and photonic interconnects 1106. The photonic interconnects 1106 can be coupled to the inputs and outputs of the optical flow switches 1104 within the same rack via optical fibers 1108. One or more photonic interconnects 1106 can be directly connected via optical fibers (not shown). The optical flow switches 1104 are optically coupled to each other via optical fibers 1110. It should be understood that the optical flow switches 1104 can be any of the optical flow switches described herein.

[0149] In some embodiments, the photonic interconnect structure 1106 includes built-in circuit switching functionality, enabling reconfiguration of the communication topology between ASIC chips, memory chips, and / or network chips utilizing the photonic interconnect structure. For example, one or more such chips may be coupled and mounted at various locations within the photonic interconnect structure 1106, and the electrical communication signals output by these chips may be converted into photonic signals within the photonic interconnect structure 1106.

[0150] In some embodiments, the photonic interconnect structure 1106 can be configured to provide full interconnectivity between the electronic chips mounted on top of it. Furthermore, each location on the photonic interconnect structure 1106 is provided with an input fiber and an output fiber for connecting to the optical flow switches 1104 within the same rack 1102a-1102d. Some of the outputs of a single optical flow switch 1104 can be connected to the inputs of other optical flow switches 1104.

[0151] 12A to 12C For display and computing systems (such as Figure 11 Schematic diagram of the connection relationship between the optical flow switches associated with the three racks and the photonic interconnect structure in the computing system 1100 shown in FIG. 12A to 12C In the example, each rack includes an 8×8 optical flow switch and four nodes and chips, represented by circles. Connections between the four nodes and chips within a single rack can be implemented using a photonic interconnect fabric, or alternatively, fiber optic connections can be used. Each chip can be configured with a dedicated unidirectional fiber link to the input of the optical flow switch in the same rack as the chip, and another unidirectional fiber link to the output of the optical flow switch in the same rack.

[0152] VIII. Multi-mask optical flow switch using multi-mask mask patterns

[0153] The inventors have further recognized and demonstrated that using multiple sets of mask patterns to create a specific photonic switch architecture can achieve performance advantages. Figure 13 As an example, the 16×16 Benes switch 1300 shown in FIG. 1 includes 56 photon switches 1302. Figure 14A As shown, Benes switch 1300 can be manufactured using an arrangement consisting of two columns and two rows of reticles 1402a-1402d. However, this arrangement requires four independent reticle sets, one for each reticle 1402a-1402d. Due to the large number of independent reticle sets required to manufacture Benes switch 1300, the manufacturing cost of this type of optical flow switch may be high. Furthermore, not all manufacturing foundries can support four independent reticle sets on a single wafer.

[0154] In contrast, according to some embodiments of the technology described herein, Figure 14B An example of a 16×16 Benes switch 1400 that can be manufactured using fewer reticle sets is shown. For example, Benes switch 1400 can be manufactured using two reticle sets. One reticle set can be used to manufacture reticles 1402a and 1402c that form the left column of Benes switch 1400, while the other reticle set can be used to manufacture reticles 1402b and 1402d that form the right column.

[0155] exist Figure 14B In the example, the number of reticle sets is reduced because: (i) Benes switch 1400 can be recursively described as comprising two 8×8 Benes switches 1404; and (ii) the waveguide layer that originally spanned the horizontal boundary between two rows of reticles is replaced by waveguide and switch router 1412. Because Benes switch 1400 can be implemented with only two rows, switches in switch router 1412 use 1:2 and 2:1 configurations. In an optical flow switch, if a layer is implemented using an N-row architecture, the switches used in the switch router should be 1:N and N:1 optical switches.

[0156] Figure 15 is a schematic diagram of routing in the first layer of an 8x8 Benes switch 1500 according to some embodiments of the techniques described herein. In some embodiments, a switch router 1502 may include actively configurable 1:2 and 2:1 switches to implement routing functionality within a Benes switch architecture.

[0157] Figure 16A FIG. 1 is another example of a 16×16 Benes switch 1600 implemented using eight reticles 1602a-1602h in two columns and four rows according to some embodiments of the technology described herein. Figure 16A As shown, manufacturing the Benes switch 1600 requires the use of two sets of mask groups (four mask groups in each set), and many manufacturing plants may not be able to support this process requirement.

[0158] In contrast, Figure 16B As shown in the example of FIG1 , a 16×16 Benes switch 1610 can reduce the number of reticles used by replacing the interconnections across four reticles with a switch router 1612 comprising 1:4 and 4:1 routing switches. Furthermore, a switch router 1614 comprising 1:2 and 2:1 routing switches can replace the interconnections across two reticles. In this way, the 16×16 Benes switch 1610 can be recursively simplified into a set of 4×4 Benes switches 1604.

[0159] The above routing strategy can be scaled up to support larger-scale N×N Benes switch architectures. Figure 17A Figure 1 is a schematic diagram of a 512×512 Benes switch 1700 implemented using four reticles, according to some embodiments of the technology described herein. An input fiber is coupled to a first photonic switch 1702, which is optically coupled to a second photonic switch 1706 via a first switching router 1704. First switching router 1704 includes 1:4 and 4:1 switches, interconnecting the first and second photonic switches 1702 and 1706 across six reticles. Second photonic switch 1706 is then optically coupled to a Benes switch 1710 via a second switching router 1702, which includes 1:2 and 2:1 switches. A symmetrical output routing structure couples Benes switch 1710 to the output fiber.

[0160] Figure 17B and Figure 17C 1704 shows the output address and destination address of the switch in the first switching router 1704 in some embodiments according to the techniques described herein. Figure 17B In the example, the output address of the RS switch in the first switching router 1704 is represented by a string of three numerical values, which respectively indicate the mask number, the target switch number, and the output port number. Figure 17C In the SS switch, the target address is represented by a string consisting of three values, which indicate the mask number, the sending RS switch number, and the output port number respectively.

[0161] Figure 17D and Figure 17E 1708 shows the output address and destination address of the switch in the second switching router 1708 in some embodiments according to the technology described herein. Figure 17D In the example, the output address of the RS switch in the second switching router 1708 is represented by a string of three numerical values, which respectively indicate the mask number, the target switch number, and the output port number. Figure 17E In the SS switch, the target address is represented by a string consisting of three values, which indicate the mask number, the sending RS switch number, and the output port number respectively.

[0162] In some cases, due to preferences or manufacturing plant requirements, it may be necessary to distribute the switching network between multiple columns of masks, where each column uses the same set of masks. In Benes or Cantor network switches, there is symmetry in the center of the switch. This symmetry can be described as mirror symmetry or 180-degree rotation around the z-axis. If the manufacturing process allows for either symmetry, then a symmetry such as Figure 14B and Figure 16BThe optical flow switch manufacturing scheme shown in Figure 1 is a simplification of the optical flow switch manufacturing process. However, most manufacturing facilities require that each reticle must use the same reticle set. The inventors have recognized and confirmed that a solution to this problem is to add additional input and output switches to each reticle. These additional switches can achieve the routing function of the Benes switch while meeting the manufacturing requirement that each reticle column must use the same reticle set.

[0163] Figure 18A A schematic diagram shows an example of a 16×16 Benes switch 1800 implemented using two columns 1802 and 1804 and four rows of reticles, where each column is formed using the same set of reticles (i.e., the two reticles in each row are identical), according to some embodiments of the technology described herein. Figure 18B is a detailed view of the first row of Benes switch 1800. Each reticle of Benes switch 1800 includes additional switch pairs at its input and output.

[0164] In some embodiments, to pass an optical signal from left to right through the rows of reticles 1811a and 1811b, the signal can enter the switching network through edge coupler 1812a. The optical signal then encounters a first pair of switches 1814. First pair of switches 1814 can be configured to select whether the input optical signal is passed through first pair of switches 1814 to the remaining switches within reticle 1811a or output from reticle 1811b through edge coupler 1812b.

[0165] If the first pair of switches 1816 is configured to pass the optical signal from the first pair of switches 1814 to the rest of the optical flow switches, the optical signal will be transmitted to the second pair of switches 1816. In some embodiments, the second pair of switches 1816 can be configured to select whether to output the received optical signal to the next reticle 1811b or to instead receive an input signal from a reticle (not shown) located to the left of reticle 1811a.

[0166] The inventors also realized that Figures 14B to 17E The switch routing technique described can be used with 18A to 18B According to some embodiments of the present technology, Figure 19 A schematic diagram of a 16×16 Benes switch 1900 is shown, where each column is fabricated using the same mask set. Figure 19 In the example of FIG. 1 , each column of the Benes switch 1900 includes a first switching router 1902 having a 1:4 switch and a second switching router 1904 having a 1:2 switch.

[0167] It should be noted that although the Figures 14B to 19The switching network design techniques described are for various types of Benes switches, but the Cantor switching network also has the same mirror symmetry characteristics as the Benes switch. Figures 14B to 19 The switch design techniques described herein are also applicable to Cantor switching networks or other switching networks with mirror symmetry, as the techniques described herein are not limited in this respect.

[0168] IX. Optical flow switch package

[0169] In some embodiments, an optical flow switch (e.g., manufactured using a single reticle or multiple reticles, as described herein) can be packaged using a glass substrate. Figure 20A and Figure 20B In an example, an optical flow switch package 2000 includes a glass substrate 2002 bonded to an electronic substrate 2001 (e.g., a printed circuit board or other substrate suitable for transmitting electrical signals). Glass substrate 2002 includes glass waveguides 2009, which are configured to optically extend the waveguide spacing (e.g., approximately 30 μm) on a switch photonic integrated circuit (PIC) 2020 to the optical fiber connection spacing (e.g., approximately 127 μm or 250 μm) at the edge of glass substrate 2002. In some embodiments, glass waveguides 2009 are optically coupled to switch PIC 2010 via evanescent couplers 2011 (e.g., 512 evanescent couplers) disposed on the switch PIC 2010.

[0170] In some embodiments, the optical fan-out allows for the use of direct-plug fiber array connectors 2004, such as multi-fiber connectors (e.g., 16-fiber or 32-fiber multi-fiber push-on (MPO) connectors) that can be directly plugged into the glass substrate to optically couple optical fibers 2003a and 2003b to the glass waveguide 2009. Direct-plug fiber array connectors 2004 can be active pluggable fiber array units. For example, direct-plug fiber array connectors 2004 can include semiconductor optical amplifiers (SOAs) to amplify optical signals entering and exiting the optical flow switch package 2000, thereby minimizing overall losses incurred by the optical flow switch package 2000.

[0171] In some embodiments, glass substrate 2002 also provides electrical connections between switch PIC 2010 and substrate 2001. The glass substrate may include a bottom redistribution layer (RDL) 2006 and a top RDL 2008. Glass substrate 2002 may be bonded to substrate 2001 via electrical connections 2005 formed between substrate 2001 and bottom RDL 2006 (e.g., via solder bonding or other suitable electrical bonding techniques). Bottom RDL 2006 may be electrically coupled to top RDL 2008 via through-glass vias 2007.

[0172] In some embodiments, the switch PIC 2010 is bonded to the glass substrate 2002 via a top RDL 2008 (e.g., using solder bonding or other suitable electrical bonding techniques). The switch PIC 2010 includes a photonic switch element 2016 (e.g., forming a photonic switching network of an optical flow switch, as described herein). Furthermore, a control chip 2020 including control circuitry 2022 is bonded to the top of the switch PIC 2010. The control circuitry 2022 can be configured to provide control signals to the photonic switch element 2016 (e.g., to reconfigure the photonic switch element 2016 during operation of the optical flow switch package 2000). Electrical signals from the substrate 2001 are routed to the control chip 2020 via through-silicon vias (TSVs) 2018.

[0173] Figure 20C Figure 2 is a graph showing simulated bit error rate (BER) versus input power for an optical flow switch package 2000, according to some embodiments of the technology described herein. The graph shows simulation results for a 64 Gbps non-return-to-zero (NRZ) optical signal transmitted through a 512×512 photonic switch network. The graph includes four curves: simulated BER for a single pass through the network (2032), two passes (2034), three passes (2036), and four passes (2038).

[0174] In some embodiments, the amplification function may be provided by one or more PICs disposed on the glass substrate 2002 rather than by an active fiber array unit. Figure 21 An example of an optical flow switch package 2100 is shown, which includes amplifier PICs 2130a and 2130b coupled between a switch PIC 2010 and respective passive fiber array elements 2104. The amplifier PICs 2130a and 2130b are coupled to the switch PIC 2010 via a glass waveguide 2132. These amplifier PICs 2130a and 2130b may be PICs including SOAs.

[0175] In some embodiments, the mirror symmetry of a Benes or Cantor switching network can be exploited to simplify the fabrication of the switching PIC. Figure 22AAn example of an optical flow switch package 2200a is shown. The package includes two switch PICs 2210a and 2210b, with a third amplifier PIC 2030 positioned between them. Each of the two switch PICs 2210a and 2210b includes only half of the entire switching network used in the optical flow switch package 2200a (i.e., the switching network of the switch PIC 2010 is divided between the two switch PICs 2210a and 2210b). The first switching network of the switch PIC 2010a is arranged on the glass substrate 2002 in a first orientation, while the second switching network of the switch PIC 2010b is arranged on the glass substrate 2002 in a second orientation that is rotated 180 degrees relative to the first orientation of the switch PIC 2010a. In other words, the switch PICs 2010a and 2010b include switching networks that are mirror images of each other.

[0176] Figure 22B is a diagram showing some embodiments of the technology described herein. Figure 22A Simulation graph showing the bit error rate (BER) of the transmission path of the optical flow switch as a function of input power. This graph shows the simulation results of a 64Gbps non-return-to-zero (NRZ) optical signal passing through a 512×512 photonic switch network and a central amplifier. The graph includes four curves: the simulated BER of a single pass through the network (2232), two passes (2234), three passes (2236), and four passes through the network (2238). Figure 20C Compared with the curve in Figure 22B The BER curve shows that the additional amplifier PIC2230 reduces the overall noise figure of the optical flow switch package 2200a. Figure 20A and Figure 20B The single-switch configuration shown in the figure significantly reduces the optical power required to achieve the same BER with the same number of optical flow switch passes. This difference in required optical power can be understood as the additional power penalty incurred due to the higher optical noise figure of the single-switch configuration.

[0177] In some embodiments, additional amplification functionality between the two switch PICs 2210a and 2210b can be provided by a direct pluggable fiber array connector 2004. According to some embodiments of the technology described herein, Figure 22CAn example of an optical flow switch package 2200c is shown. The package includes two switch PICs 2210a and 2210b, each bonded to a separate glass substrate. Amplification between the two switch PICs 2210a and 2210b is provided by a central pair of direct-plug fiber array connectors 2004. The central pair of direct-plug fiber array connectors 2004 can be coupled using optical fibers or other suitable off-chip optical coupling technologies.

[0178] In some embodiments, the amplification function of the optical flow switch input and output can be provided by the direct plug-in fiber array connector 2004. According to some embodiments of the technology described herein, Figure 22D An example of an optical flow switch package 2200d is shown. The package includes two switch PICs 2210a and 2210b bonded to a glass substrate and optically coupled via an amplifier PIC. The input and output amplification functions of the optical flow switch package 2200d are provided by the direct pluggable fiber array connector 2004 described herein.

[0179] Figure 24 2 is a flow chart of a method 2400 for manufacturing an optical flow switch package, according to some embodiments of the technology described herein. Process 2400 may begin at step 2402, where two or more reticles including at least one reticle pattern are transferred to a photoresist supported by a switch PIC substrate. For example, the two or more reticles may be transferred to the photoresist by exposing portions of the photoresist to ultraviolet (UV) light through a transparent portion of at least one reticle pattern. The photoresist may be a positive-tone photoresist, such that the exposed regions of the photoresist are soluble in a photoresist developer. Alternatively, the photoresist may be a negative-tone photoresist, such that the regions of the photoresist not exposed to UV light are soluble in a photoresist developer.

[0180] In some embodiments, two or more reticles have the same reticle pattern. When these reticles are transferred to photoresist, the same pattern can be repeatedly imprinted on the photoresist. Through iterative exposure, a repeating reticle pattern is formed on the photoresist, which is used to construct a photonic switch network. Alternatively, two or more reticles can be associated with multiple sets of reticle patterns. These pattern sets can be repeatedly imprinted on the photoresist. Through iterative exposure, column by column or row by row, a repeating reticle pattern is formed on the photoresist, which is used to construct a photonic switch network.

[0181] In some embodiments, the photonic switch network can be formed across two switch PIC substrates. In this case, transferring two or more reticles to photoresist includes transferring these reticles to photoresist regions corresponding to the regions where the separate switch PIC substrates are formed. For example, the two or more reticles can be transferred to photoresist regions of the substrates to be cut, where these regions will subsequently be separated from each other. Alternatively, the two or more reticles can be transferred to photoresist regions of different substrates.

[0182] After step 2402, process 2400 may proceed to step 2404. In step 2404, an optical material may be deposited on the switch PIC substrate using the photoresist regions corresponding to the transferred two or more reticles. The optical material may be deposited using any suitable deposition technique (e.g., chemical vapor deposition, atomic layer deposition, etc.). The optical material may include a semiconductor material (e.g., silicon).

[0183] In some embodiments, the deposited optical material can form at least a portion of a photonic switch network, comprising a Cantor network or a Benes network. In some embodiments, the deposited optical material can form at least a portion of a photonic switch network, comprising a first plurality of switches arranged to form a Benes switch. The deposited optical material can also form a second plurality of switches, including input routing switches coupled between input ports on a switch PIC substrate and the Benes switches. Finally, the deposited optical material can form waveguides and / or waveguide cross-coupling switches, with these second plurality of switches connected to the Benes switches distributed across two or more reticles.

[0184] After step 2404, process 2400 may proceed to step 2406. At step 2406, a chip including a control circuit may be coupled to the switch PIC substrate. For example, the chip may be electrically coupled to the top surface of the switch PIC substrate (e.g., Figure 20B The chip can be electrically coupled to the top surface of the switch PIC substrate by any suitable method, such as solder bonding.

[0185] After step 2406 is completed, process 2400 may proceed to step 2408. At step 2408, the switch PIC substrate may be bonded to the glass substrate. For example, the switch PIC substrate may be electrically and optically coupled to the top surface of the glass substrate (e.g., as described herein). Figure 20B (See the example of FIG. 1 ). Optical coupling between the waveguide on the glass substrate and the waveguide on the switch PIC substrate can be achieved using an evanescent coupler. Electrical coupling can be achieved by bonding the switch PIC substrate to the top redistribution layer of the glass substrate using any suitable method, such as solder bonding.

[0186] In some embodiments, bonding the switch PIC substrate to the glass substrate further comprises bonding a second switch PIC substrate. The two switch PIC substrates may support substantially identical photonic switch networks, with each switch PIC substrate supporting half of a complete switching network for forming an optical flow switch (e.g., Figure 22A The two switch PIC substrates may also be arranged so that their respective photonic switch networks have mirror symmetry (eg, rotated 180 degrees relative to each other in a plane parallel to the plane of the glass substrates).

[0187] In some embodiments, process 2400 also includes bonding one or more amplifier PICs to a glass substrate. For example, two amplifier PICs may be bonded to a glass substrate, with a first amplifier PIC coupling an input port of the glass substrate to a switch PIC substrate, and a second amplifier PIC coupling the switch PIC substrate to an output port of the glass substrate. In some embodiments including two switch PICs, alternatively or additionally, an amplifier PIC may be bonded between the two switch PICs such that the two switch PICs are optically coupled through the amplifier PIC.

[0188] In some embodiments, the glass substrate includes two glass substrates, and the switch PIC includes two switch PICs. Bonding the switch PICs to the glass substrates includes bonding a first switch PIC to the first glass substrate and bonding a second switch PIC to the second glass substrate. In some embodiments, the method may further include optically coupling the two switch PIC substrates using an optical element (e.g., an optical fiber coupled between the two glass substrates).

[0189] X. Two-way communication

[0190] In some embodiments, the optical flow switch can be configured to enable bidirectional communication using light of two different polarizations within a single optical fiber. Figure 23 The illustrated embodiment of an optical flow switch package 2300 includes two switching branches: one for optical signals transmitted in one direction (e.g., from left to right) and the other for optical signals transmitted in the opposite direction (e.g., from right to left). The optical flow switch package 2300 includes amplifiers and polarization (de)multiplexing PICs 2340a and 2340b coupled to each set of passive fiber array units 2104. The two optical flow switching branches are connected between the amplifiers and polarization (de)multiplexing PICs 2340a and 2340b. Each branch includes two switch PICs 2210a and 2210b, and a central amplifier PIC 2230 coupled between the two switch PICs.

[0191] In some embodiments, the amplifier and polarization demultiplexing PICs 2340a and 2340b are each configured to demultiplex input optical signals using polarization states and multiplex output optical signals. When the optical fiber coupled to the passive fiber array unit 2104 is a polarization-maintaining (PM) fiber, the amplifier and polarization demultiplexing PICs 2340a and 2340b include a polarization splitter rotator module that receives two input signals of two polarization states (e.g., TE and TM polarizations) in a single glass / silicon waveguide and outputs only TE mode signals to two independent waveguides. If the optical fiber coupled to the passive fiber array unit 2104 is a single-mode (SM) fiber, the amplifier and polarization demultiplexing PICs 2340a and 2340b include the following: Figures 25A to 26B polarization device.

[0192] This arrangement of optical flow switch package 2300 allows for simplex communication links (e.g., from one transmitter to only one receiver). For example, the transmitter of a first PIC can communicate with the receiver of a second PIC, while the receiver of the first PIC can communicate with the transmitter of a third PIC. The first PIC does not need to receive signals from the second PIC.

[0193] In some embodiments, the amplifier and polarization demultiplexing PICs 2340a and 2340b may be configured as follows: Figure 25A , a polarization demultiplexing PIC system 2500 is shown in the example of FIG. This system is configured for bidirectional wavelength division multiplexing (WDM) communications. This polarization demultiplexing PIC system 2500 includes a laser 2502 that provides an optical signal to a PIC 2510 via a single-mode (SM) fiber 2504. The randomly polarized optical signal provided by laser 2502 is then transmitted to a polarization module 2520a, which splits, adjusts timing, and recombines the optical signal. Polarization module 2520a then outputs the optical signal to a transmitter 2512, which selects the desired communication wavelength.

[0194] In some embodiments, PIC 2510 receives an additional set of wavelengths from off-chip via single-mode (SM) fiber 2530. The received optical signal from SM fiber 2530 is similarly polarization-scrambled in polarization module 2520b. Optical wavelength filter 2514 separates the two sets of wavelengths and routes them appropriately to receiver 2516 on PIC 2510. Wavelength filter 2514 also functions as a circulator, tunable to transmit a first set of wavelengths to transmitter 2512 and a second set of wavelengths, different from the first, to receiver 2516. Alternatively, due to the polarization-independent nature of optical wavelength filter 2514, the positions of polarization module 2520b and optical wavelength filter 2514 can be interchanged, such that incident light from SM fiber 2530 passes through optical wavelength filter 2514 before passing through polarization module 2520b. However, the present technology is not limited in this respect.

[0195] Figure 25B FIG2 is a schematic diagram of an example of a polarization module 2520, which can be used as polarization module 2520a and / or 2520b on PIC 2510, according to some embodiments of the technology described herein. Polarization module 2520 includes a polarization beam splitter rotator (PSR) 2522, which is configured to convert received polarization-scrambled light into two independent outputs having TE polarization. PSR 2522 includes a beam splitter 2522a configured to split the light into two paths (one for TE light and the other for TM light); and a rotator 2522b included in the TM light path and configured to rotate the TM light to TE polarization.

[0196] In some embodiments, the two optical signals from PSR 2522 are output to respective adjustable delay lines 2524. These adjustable delay lines 2524 are configured to compensate for polarization mode dispersion (PMD) in single-mode fibers 2504 and 2530, since PMD is a linear phenomenon and the TE / TM signals travel along the same fiber path. The adjustable delay lines 2524 are also configured to perform timing adjustments on the two output TE signals so that they can be recombined in a phase-aligned manner at combiner 2526.

[0197] In some embodiments, the polarization demultiplexing PIC system 2500 can be combined with an optical flow switch to form a bidirectional communication system. Figure 26A An embodiment of a two-way communication system 2600 is shown. The system includes two Figure 25A and Figure 25B PICs 2510 are coupled to opposite inputs of an optical flow switch 2610. This configuration enables full-duplex communication between the two PICs. For any given switch configuration, a first PIC can send a signal to a second PIC and simultaneously receive a signal from the second PIC via the same flow switching path.

[0198] While the optical flow switch 2610 may be polarization independent, in some embodiments the switch may be polarization dependent and include a polarization management module. Figure 26B An example of an optical flow switch 2610 including a polarization management module 2613 is shown. Figure 26B As shown, optical flow switch 2610 receives an optical signal of a first wavelength 2611a on its left side and an optical signal of a second wavelength 2611b on its right side, where the first and second wavelengths are different. That is, the optical signal of the first wavelength 2611a is transmitted from left to right, while the optical signal of the second wavelength 2611b is transmitted through optical flow switch 2610 in the opposite direction, from right to left.

[0199] At each input / output end of the optical flow switch 2610, wavelength splitters 2612 and 2614 are coupled to both ends of the polarization management module 2613. These wavelength splitters 2612 and 2614 are configured to select optical signals of specific wavelengths to pass through the polarization management module 2613. Figure 26B In the configuration shown, the wavelength splitters 2612 and 2614 are polarization-independent. Alternatively, the polarization management module 2613 can also be configured to allow both wavelengths 2611a and 2611b to pass through, as the present invention is not limited in this respect.

[0200] In some embodiments, polarization management modules 2613 are configured to compensate for polarization scrambling in SM fibers, as described for polarization modules 2520. Furthermore, these polarization management modules 2613 are further configured to provide optical signals with desired polarization states to switching layers 2616 within optical flow switch 2610.

[0201] In some embodiments, two PICs communicating via optical flow switch 2610 may include two or more lasers, each configured to generate an optical signal having a first wavelength 2611a and a second wavelength 2611b. The two PICs may cooperatively determine a communication configuration: one PIC communicates using the first wavelength 2611a, while the other PIC communicates using the second wavelength 2611b.

[0202] In some embodiments, three or more PICs can communicate via an optical flow switch 2610. The system can determine that the first of the three or more PICs will transmit data to the second PIC using light having a first wavelength 2611a, while simultaneously transmitting data to the third PIC using light having a second wavelength 2611b. Subsequently, the second PIC can transmit data back to the first PIC using light having the second wavelength 2611b, while the third PIC can transmit data to the first PIC using light having the first wavelength 2611a. In such embodiments, the optical flow switch 2610 can include polarization management modules 2613 on both optical arms between the wavelength splitters 2612 and 2614, thereby removing the limitation that a single wavelength of light must propagate unidirectionally within the optical flow switch 2610. This configuration allows communication between two transceiver PICs via multiple flow switches.

[0203] XI. Cross mark for optical flow switch

[0204] The inventors recognized that the complexity of waveguide crossings poses a challenge when designing Benes switch layouts using silicon photonics technology. To this end, the inventors developed a technique for laying out optical flow switches by marking crossovers layer by layer or column by column.

[0205] According to some embodiments of the technology herein, Figure 27A A schematic diagram of an 8×8 Benes switch 2700 is shown. The Benes switch 2700 includes a photonic switch 2702 and a waveguide crossbar 2704. Figure 27B shows an example of a crossing mark that can be used to implement a waveguide crossing 2704, Figure 27D An example of the design of a cross mark used in the photolithography process is shown.

[0206] Figure 27C Depicted is the first layer 2706 of a Benes switch 2700 constructed using multiple columns of crossbars, according to some embodiments of the techniques described herein. Waveguide crossbars 2704 can be implemented using such crossbars, as the crossbars in a layer of a Benes switch can be understood as multiple layers or columns of crossbars. The first column includes M crossbars, the second column includes M-1 crossbars, the third column has M-2 crossbars, and so on. Here, M = S-1, where S represents the number of switches connected to that particular Benes layer. For example, the first layer of an 8×8 Benes switch has S = 4, while the second layer has S = 2. The columnar layout of the crossbars naturally forms a triangular structure. Figure 28 An example of a 64×64 Benes optical flow switch employing such a triangular layout is shown.

[0207] Several aspects and embodiments of the technology disclosed herein have been described so far, and it should be understood that those skilled in the art can easily make various changes, modifications and improvements. These changes, modifications and improvements are all within the spirit and scope of the technology herein. For example, a person of ordinary skill in the art can easily conceive of a variety of other alternative means and / or structures for achieving functions and / or obtaining results and / or one or more advantages of this invention, and such variations and / or modifications are considered to be within the scope of the embodiments described herein. Those skilled in the art can identify or determine many equivalents to the specific embodiments described herein simply through routine experimentation. Therefore, it should be understood that the foregoing embodiments are presented only as examples, and under the limitations of the appended claims and their equivalents, the implementation of the inventive embodiments may not be limited to the forms specifically described herein. In addition, any combination of two or more features, systems, articles, materials, kits and / or methods herein - as long as these features, systems, articles, materials, kits and / or methods do not conflict with each other - is within the scope of protection of the present disclosure.

[0208] As described, some technical solutions can be embodied as one or more methods. The steps included in the method can be performed in any suitable order, and thus, embodiments can be constructed in a different order than that shown in the exemplary embodiment, including performing some steps simultaneously even if these steps are shown as being performed sequentially in the exemplary embodiment.

[0209] For the use and understanding of all defined terms in this document, the definitions herein shall prevail over dictionary definitions, definitions in referenced documents and / or ordinary meanings of the terms.

[0210] Unless the context clearly indicates otherwise, the indefinite articles "a" and "an" used in this specification and claims should be understood to mean "at least one."

[0211] Likewise, the phrases "and / or" used in this specification and claims should be understood as an "optional or concurrent" relationship of connected elements, i.e., in some cases, the elements exist simultaneously, and in other cases, one or the other exists selectively. Multiple elements connected by "and / or" should be interpreted the same, i.e., "one or more" of the connected elements. In addition to the elements explicitly indicated by the "and / or" clause, other elements may optionally exist, whether or not related to these elements. Thus, as a non-limiting example, when used in conjunction with open language such as "including", a reference to "A and / or B" may mean: in one embodiment, only A (optionally including elements other than B); in another embodiment, only B (optionally including elements other than A); in yet another embodiment, both A and B (optionally including other elements); and so on.

[0212] As used in this specification and claims, the phrase "at least one" when referring to a list of one or more elements should be understood to mean at least one element selected from that list of elements, but does not necessarily include at least one of every element explicitly listed in that list, nor does it exclude any combination of elements in that list. This definition also allows for the optional presence of additional elements in addition to the elements specifically identified in the list of elements to which the phrase "at least one" refers, regardless of whether those additional elements are related to the elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or the equivalent expression "at least one of A or B," or the equivalent expression "at least one of A and / or B") may mean: in one embodiment, at least one of A (optionally including multiple A's) and no B (optionally including elements other than B); in another embodiment, at least one of B (optionally including multiple B's) and no A (optionally including elements other than A); in yet another embodiment, at least one of A (optionally including multiple A's) and at least one of B (optionally including multiple B's) (optionally including other elements); and so on.

[0213] In the claims and the foregoing specification, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "having," and "consisting of" shall be understood as open-ended expressions, meaning including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be considered closed or semi-closed expressions, respectively.

[0214] The terms "about," "substantially," and "approximately" may refer to within ±20% of a target value in some embodiments, within ±10% in some embodiments, within ±5% in some embodiments, and within ±2% in some embodiments. These terms "about," "substantially," and "approximately" include the target value itself.

Claims

1. An optical flow switch, comprising: A photonic switch network is provided between the input port and the output port of the optical flow switch, wherein the photonic switch network spans two or more reticles.

2. The optical flow switch according to claim 1, wherein: The two or more reticles include the same reticle pattern, and The photonic switch network is composed of repeated arrangements of identical mask patterns. 3 . The optical flow switch according to claim 1 , wherein the photonic switch network comprises a Cantor network or a Benes network.

4. An optical flow switch according to claim 2 or 3, wherein the photonic switch network comprises a first plurality of switches arranged as Benes switches. 5 . The optical flow switch of claim 4 , wherein the photonic switch network further comprises a second plurality of switches, the second plurality of switches comprising an input routing switch coupled between the input port and the Benes switch. 6 . The optical flow switch of claim 5 , wherein a switch in the second plurality of switches is coupled between an input port in the input port and each Benes switch in the Benes switches. 7 . The optical flow switch of claim 5 , wherein a switch in the second plurality of switches is coupled between an input port in the input port and a Benes switch disposed on the two or more reticles.

8. The optical flow switch according to any one of claims 5 to 7, wherein the second plurality of switches comprises: a first input routing switch arranged to receive an optical signal from said input port; a second input routing switch arranged to receive an optical signal from said first routing switch; as well as A third input routing switch is arranged to receive the optical signal from the second routing switch and transmit the optical signal to the Benes switch.

9. The optical flow switch according to any one of claims 3 to 8, wherein: The Cantor network includes an N×NCantor network, The input port includes k input ports, The two or more masks include r masks, The Benes switch includes a total of m Benes switch, and 10. The optical flow switch according to claim 9, wherein: The first input routing switch includes a total of k 1:r photonic switches; The second input routing switch includes a total of kr 1:r photonic switches; and The third input routing switch includes a total of kr 2 An r:q photon switch.

11. The optical flow switch according to any one of claims 5 to 10, wherein the photonic switch network further comprises a third plurality of switches, the third plurality of switches comprising an output routing switch coupled between the Benes switch and the output port.

12. The optical flow switch of claim 11, wherein a switch in the third plurality of switches is coupled between each Benes switch and an output port in the output port.

13. The optical flow switch of claim 11 or 12, wherein switches in the third plurality of switches are coupled between Benes switches disposed on the two or more reticles and output ports in the output ports.

14. The optical flow switch according to any one of claims 1 to 13, wherein the two or more reticles comprise multiple rows or columns of reticles, each row or column of reticles being formed using the same reticle pattern group.

15. The optical flow switch according to claim 14, wherein: The plurality of rows or columns of masks include X rows or X columns of masks, and The optical flow switch further includes a 1:X and / or X:1 switching router arranged between the photonic switches of the photonic switch network. The optical flow switch according to claim 15 , wherein X=2. The optical flow switch according to claim 15 , wherein X=4. 18 . The optical flow switch according to claim 17 , further comprising a 1:2 and / or 2:1 switching router arranged between the photonic switches of the photonic switch network.

19. The optical flow switch according to any one of claims 1 to 18, wherein the photonic switch disposed in the first mask in the photonic switch network is coupled to the photonic switch disposed in the second mask in the photonic switch network through a waveguide.

20. The optical flow switch according to any one of claims 1 to 19, wherein the photonic switches in the photonic switch network are arranged across two or more chips.

21. The optical flow switch according to claim 20, wherein the two or more chips are coupled by using optical fibers.

22. The optical flow switch according to any one of claims 1 to 21, wherein the photonic switches in the photonic switch network comprise 2x2 Mach-Zehnder interferometer (MZI) switches.

23. The optical flow switch according to any one of claims 1 to 22, wherein the photonic switch in the photonic switch network comprises three MZI switches arranged in series.

24. The optical flow switch according to any one of claims 1 to 23, wherein the photonic switches in the photonic switch network comprise extended MZI switches.

25. The optical flow switch according to any one of claims 1 to 24, wherein the photonic switches in the photonic switch network comprise silicon photonic switches.

26. The optical flow switch according to any one of claims 1 to 25, wherein the input port and the output port comprise grating couplers, edge couplers and / or V-groove couplers.

27. An optical switch package, comprising: A switching photonic integrated circuit (PIC), comprising the optical flow switch according to any one of claims 1 to 26; as well as A glass substrate supports the switch PIC.

28. The optical switch package of claim 27, further comprising: A plurality of input ports and a plurality of output ports, each of the plurality of input ports and each of the plurality of output ports comprising an active pluggable fiber array unit, the active pluggable fiber array unit comprising: a plurality of optical couplers configured to couple optical fiber light to the glass substrate; and A plurality of optical amplifiers are configured to amplify an optical signal at each of the plurality of optical couplers.

29. The optical switch package of claim 28, further comprising a glass waveguide optically coupling the active pluggable fiber array unit to the switch PIC.

30. The optical switch package of claim 29, wherein the glass waveguide is a fan-out between the switch PIC and the active pluggable fiber array.

31. The optical switch package of claim 29 or 30, wherein the glass waveguide is coupled to the switch PIC via a plurality of evanescent couplers.

32. The optical switch package according to any one of claims 27 to 31, wherein the switch PIC further comprises a control circuit coupled to the optical flow switch.

33. The optical switch package of claim 32, wherein the control circuit is monolithically integrated in the switch PIC.

34. The optical switch package according to any one of claims 27 to 33, further comprising: First amplifier PIC; as well as Second amplifier PIC, where: The first amplifier PIC optically couples the input port to the switch PIC, and The second amplifier PIC optically couples the switch PIC and the output port.

35. The optical switch package according to any one of claims 27 to 34, wherein: The switch PIC includes a first switch PIC and a second switch PIC, The first switch PIC and the second switch PIC include substantially the same switch network, and The second switch PIC comprises an optical flow switch having a switch network rotated 180 degrees relative to the switch network of the first switch PIC. 36 . The optical switch package of claim 35 , further comprising a third amplifier PIC optically coupled between the first switch PIC and the second switch PIC.

37. The optical switch package of claim 36, further comprising: First amplifier PIC; as well as Second amplifier PIC, where: The first amplifier PIC optically couples the input port to the first switch PIC, and The second amplifier PIC optically couples the second switch PIC to the output port.

38. The optical switch package of claim 35, wherein: The glass substrate includes a first glass substrate and a second glass substrate. The first switch PIC is provided on the first glass substrate, and The second switch PIC is disposed on the second glass substrate.

39. A method for manufacturing an optical switch package, comprising: transferring two or more reticles including at least one reticle pattern onto a photoresist supported by a switching photonic integrated circuit (PIC) substrate; depositing an optical material on the switch PIC substrate through the photoresist portions corresponding to the transferred two or more reticles, wherein the deposited optical material forms at least a portion of an optical flow switch comprising a photonic switch network spanning the two or more reticles; coupling a chip including a control circuit to the switch PIC substrate; as well as The switch PIC substrate is bonded to a glass substrate.

40. The method of claim 39, wherein transferring the two or more reticles comprises transferring two or more reticles comprising an identical reticle pattern onto the photoresist such that the photonic switch network is formed by a repeated arrangement of the identical reticle pattern.

41. The method of claim 39 or 40, wherein depositing the optical material forms a photonic switch network comprising a Cantor network or a Benes network.

42. The method of any one of claims 39-41, wherein depositing the optical material forms a photonic switch network comprising a first plurality of switches arranged to form Benes switches.

43. The method of claim 42, wherein depositing the optical material further forms a second plurality of switches including input routing switches coupled between input ports disposed on the switch PIC substrate and the Benes switches.

44. The method of claim 42 or 43, wherein depositing the optical material further forms a waveguide that couples switches in the second plurality of switches to Benes switches disposed on the two or more reticles.

45. The method according to any one of claims 39 to 44, wherein transferring the two or more reticles comprises transferring a plurality of rows or columns of reticles, each row or column of reticles being formed by using the same reticle pattern group.

46. ​​The method of any one of claims 39-45, wherein transferring two or more reticles including at least one reticle pattern onto a photoresist comprises transferring the two or more reticles onto a photoresist supported by two switch PIC substrates.

47. The method of any one of claims 39-46, wherein depositing the optical material comprises depositing a silicon material.

48. The method according to any one of claims 39 to 47, further comprising bonding a first amplifier PIC and a second amplifier PIC to the glass substrate, wherein: The first amplifier PIC optically couples the input port of the glass substrate to the switch PIC substrate, and The second amplifier PIC optically couples the switch PIC substrate to an output port of the glass substrate.

49. The method of any one of claims 39-48, wherein bonding the switch PIC substrate to the glass substrate comprises bonding two switch PIC substrates to the glass substrate, the two switch PIC substrates supporting substantially identical photonic switch networks.

50. The method of any one of claims 39-49, wherein bonding the two switch PIC substrates to the glass substrate comprises: A first switch PIC substrate is bonded to the glass substrate, and a second switch PIC substrate is bonded to the glass substrate in a manner rotated 180 degrees relative to the orientation of the first switch PIC substrate in a plane parallel to the glass substrate.

51. The method of claim 49, further comprising bonding an amplifier PIC to the glass substrate such that the amplifier PIC is optically coupled between the first switch PIC substrate and the second switch PIC substrate.

52. The method of any one of claims 39-51, wherein: The glass substrate includes a first glass substrate and a second glass substrate. Bonding the first switch PIC substrate to the glass substrate includes bonding the first switch PIC substrate to the first glass substrate, and Bonding the second switch PIC substrate to the glass substrate includes bonding the second switch PIC substrate to the second glass substrate.

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