Beam Delivery System

Abstract

The present invention provides a novel beam delivery system for quantum computing applications, the beam delivery system comprising an on-chip beam delivery photonic integrated circuit and an optical repeater assembly. The on-chip beam delivery photonic integrated circuit may comprise one or more layers, and the layers may comprise one or more inputs connecting to one or more outputs. The optical repeater assembly receives one or more beams from one or more outputs of the layers of the on-chip beam delivery photonic integrated circuit. The optical repeater assembly focuses each received beam on a corresponding position of an atomic object confinement device.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit and priority of U.S. Provisional Patent Application 63 / 037,482, filed on June 10, 2020, the entire content of which is incorporated herein by reference. Technical Field

[0003] Various embodiments relate to beam delivery systems, and more particularly to beam delivery systems having beam delivery photonic integrated circuits for quantum computing applications. Background Art

[0004] In various atomic systems, it is important to be able to deliver laser beams to a dense one - dimensional or multi - dimensional array of atomic systems with precise spacing and pattern distribution. For example, trapped - ion quantum computing uses laser beams to perform various functions within a trapped - ion quantum computer. Such applications require precise and accurate delivery of the laser to the ion trap in terms of position, spacing, pattern distribution, polarization, frequency, and phase. Summary of the Invention

[0005] Exemplary embodiments provide beam delivery elements for quantum computing applications.

[0006] According to one aspect, a beam delivery photonic integrated circuit is provided. In an exemplary embodiment, the beam delivery system includes: a beam delivery photonic integrated circuit including: one or more optical inputs; a plurality of waveguide outputs, wherein each of the plurality of waveguide outputs is tapered; a plurality of beam paths, each beam path connecting one of the plurality of waveguide outputs to at least one of the one or more optical inputs, wherein the beam delivery photonic integrated circuit is located on a chip, and an optical repeater assembly configured to receive beams provided by at least two of the plurality of waveguide outputs and focus each received beam on a corresponding position among a plurality of positions of an atomic object confinement device.

[0007] In another exemplary embodiment, one or more of the plurality of beam paths include optical elements configured to tune the beam for at least one of frequency, phase, or intensity.

[0008] In another exemplary embodiment, at least one of the plurality of waveguide outputs is directed to a photodetector.

[0009] In another exemplary embodiment, the plurality of beam paths are defined lithographically.

[0010] In another exemplary embodiment, the plurality of waveguide outputs are located on a polished edge of the beam delivery photonic integrated circuit.

[0011] In another exemplary embodiment, each waveguide output is located on one side of the beam delivery photonic integrated circuit and is parallel to each other.

[0012] In another exemplary embodiment, each waveguide output of the plurality of waveguide outputs is at most 150 micrometers apart from the next nearest waveguide output of the plurality of waveguide outputs.

[0013] In another exemplary embodiment, an optical input end face is coupled to an optical fiber providing an input beam.

[0014] In another exemplary embodiment, a beam delivery system includes: a beam delivery photonic integrated circuit including a first waveguide layer and a second waveguide layer, the first waveguide layer including: a first optical input; a plurality of first waveguide outputs, wherein the plurality of first waveguide outputs are tapered; a plurality of first beam paths, each first beam path connecting one of the plurality of first waveguide outputs to the first optical input, the second waveguide layer including: a second optical input; a plurality of second waveguide outputs, wherein the plurality of second waveguide outputs are tapered; a plurality of second beam paths, each second beam path connecting one of the plurality of second waveguide outputs to the second optical input, wherein the beam delivery photonic integrated circuit is located on a chip, an optical repeater assembly configured to receive beams provided by at least one of the plurality of first waveguide outputs and at least one of the plurality of second waveguide outputs, and the optical repeater assembly further configured to focus each received beam on corresponding ones of a plurality of positions of an atomic object confinement device.

[0015] In another exemplary embodiment, one or more of the plurality of first waveguide outputs or the plurality of second waveguide outputs are directed to a photodetector.

[0016] In another exemplary embodiment, one or more of the plurality of first beam paths or the plurality of second beam paths include optical elements configured to tune a beam for at least one of frequency, phase, or intensity.

[0017] In another exemplary embodiment, the plurality of first waveguide outputs and the plurality of second waveguide outputs are located on a polished edge of the beam delivery photonic integrated circuit.

[0018] In another exemplary embodiment, each of the plurality of first waveguide outputs and the plurality of second waveguide outputs is located on one side of the beam delivery photonic integrated circuit and is parallel to each other.

[0019] In another exemplary embodiment, each of the plurality of first waveguide outputs is at most 150 micrometers apart from the next nearest waveguide output of the plurality of waveguide outputs.

[0020] In another exemplary embodiment, at least one of the first waveguide layer or the second waveguide layer comprises a dielectric material.

[0021] In another exemplary embodiment, the first waveguide layer and the second waveguide layer are made of different materials.

[0022] In another exemplary embodiment, a beam delivery system includes: a beam delivery photonic integrated circuit that includes: a plurality of optical inputs; a plurality of waveguide outputs, where the plurality of waveguide outputs are tapered; a plurality of beam paths, each beam path connecting one of the plurality of waveguide outputs to only one of the plurality of optical inputs, where the beam delivery photonic integrated circuit is located on a chip, an optical repeater assembly configured to receive beams provided by at least two of the plurality of waveguide outputs and focus each received beam on corresponding ones of a plurality of positions of an atomic object confinement device.

[0023] In another exemplary embodiment, one or more of the plurality of beam paths include optical elements configured to tune a beam for at least one of frequency, phase, or intensity.

[0024] In another exemplary embodiment, at least one of the plurality of waveguide outputs is directed to a photodetector.

[0025] In another exemplary embodiment, the plurality of beam paths are defined lithographically. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Accordingly, the present invention has been described generally, and now reference will be made to the drawings, which are not necessarily to scale, and in which:

[0027] Figure 1 A schematic diagram of an exemplary trapped atomic object quantum computer system according to an exemplary embodiment is provided.

[0028] Figure 2 A schematic diagram of an exemplary controller that can be used according to an exemplary embodiment is provided.

[0029] Figure 3 A schematic diagram of an exemplary computing entity that can be used according to an exemplary embodiment is provided.

[0030] Figure 4A block diagram of an exemplary beam delivery photonic integrated circuit in accordance with an exemplary embodiment is provided.

[0031] Figure 5 An exemplary optical repeater assembly in accordance with an exemplary embodiment is shown.

[0032] Figure 6 A flowchart showing various processes, procedures, and / or operations performed in fabricating a beam delivery photonic integrated circuit in accordance with an exemplary embodiment is provided.

[0033] Figures 7A through 7T Cross-sectional views of various stages of fabricating a beam delivery photonic integrated circuit in accordance with an exemplary embodiment are provided. DETAILED DESCRIPTION

[0034] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Unless otherwise specified, the term "or" (also denoted as " / ") is used herein in an alternative and conjunctive sense. The terms "exemplary" and "example" are used for examples without indication of a quality level. Unless otherwise specified, the terms "generally" and "about" refer to within engineering and / or manufacturing limits and / or within the user's measurement capabilities. Throughout the specification, like reference numerals refer to like elements.

[0035] As described above, in various atomic systems, it is important to be able to precisely and accurately deliver one or more laser beams in terms of position, spacing, mode distribution, polarization, frequency, and / or phase to the atomic system. For example, in atomic systems such as atomic clocks, Bose-Einstein condensate systems, trapped ion systems, and / or other atomic systems, precise and accurate laser beam delivery is important for various uses of the system, manipulating the system, etc. Various exemplary embodiments corresponding to a quantum computer system for trapping atomic objects (e.g., atoms, ions) will now be described in more detail.

[0036] Exemplary quantum computer system

[0037] Figure 1A schematic diagram of an exemplary captured atomic object quantum computer system 100 according to an exemplary embodiment is provided. In various embodiments, the quantum computer system 100 includes a computing entity 10 and a quantum computer 110. In various embodiments, the controller 30 of the quantum computer 110 can communicate with the computing entity 10 via one or more wired and / or wireless networks 20. In various embodiments, the quantum computer 110 includes a controller 30, a cryogenic and / or vacuum chamber 40 that encapsulates an atomic object confinement device 50 (e.g., an ion trap, etc.), one or more manipulation sources, one or more laser systems 70, etc. In various embodiments, the atomic object confinement device 50 is a confinement device configured to perform atomic object confinement on one or more atomic objects therein, and the manipulation source is configured to provide manipulation signals to one or more parts of the atomic object confinement device 50 via an optical path. In various embodiments, the manipulation signals can be used to initialize one or more atomic objects into the qubit space, perform cooling operations, perform measurement operations, provide one or more gate signals, etc. In various embodiments, the manipulation source including one or more laser systems 70 is configured to provide one or more manipulation signals (e.g., gate signals) to one or more parts of the atomic object confinement device 50 to implement one or more quantum gates (e.g., quantum logic gates). In various embodiments, the quantum gate can be a single qubit gate, a two qubit gate, etc. In various embodiments, the one or more gate signals can be provided to the one or more parts of the atomic object confinement device 50 via an optical path 68, which can include a beam delivery photon integrated circuit 400 and an optical repeater assembly 500. In various embodiments, the atomic objects confined or captured within the atomic object confinement device 50 are ions, atoms, etc. For example, in an exemplary embodiment, the atomic object is a ytterbium ion. In an exemplary embodiment, the atomic object includes qubit ions and corresponding cooling ions.

[0038] In various embodiments, the computing entity 10 is configured to allow a user to provide input to the quantum computer system 100 (e.g., provided via a user interface of the computing entity 10) and receive, view, etc. the output from the quantum computer system 100. The computing entity 10 can communicate with the controller 30 via one or more wired or wireless networks 20. For example, the computing entity 10 can be configured to provide a quantum circuit to the controller 30 for execution by the quantum computer 110, and the controller 30 can provide the results of executing one or more quantum circuits to the computing entity 10.

[0039] In various embodiments, the controller 30 is configured to control the atomic object confinement device 50, a cooling and / or vacuum system (not shown) that controls the temperature and pressure within the cryogenic and / or vacuum chamber 40, a manipulation source, the laser system 70, the servo system, and / or other components of the quantum computer 110 (e.g., an optical collection system configured to "read" the output of the quantum computer). In various embodiments, the controller 30 is configured to control various components of the quantum computer 110 according to executable instructions, command sets, etc. provided by the computing entity 10 and / or generated by the controller 30. In various embodiments, the controller 30 is configured to receive an output from the quantum computer 110 (e.g., from the optical collection system) and provide the output and / or the results of processing the output to the computing entity 10.

[0040] Exemplary controller

[0041] In various embodiments, the quantum computer 110 includes a controller 30 configured to control various elements of the quantum computer 110. In various embodiments, the controller 30 may be configured to cause the quantum computer 110 to perform various operations (e.g., computational operations such as gate operations, cooling operations, transfer operations, qubit interaction operations, qubit measurement operations, leakage suppression operations, etc.). For example, the controller 30 may be configured to cause the manipulation source to provide a manipulation signal to an atomic object confined / captured within the atomic object confinement device 50. For example, the controller 30 may be configured to cause the laser system 70 (possibly in coordination with the servo system) to provide one or more gate signals to one or more atomic objects confined and / or captured within the atomic object confinement device 50 in order to implement, for example, one or more quantum gates. In various embodiments, the controller 30 may be configured to control: a cryogenic system and / or a vacuum system that controls the temperature and pressure within the cryogenic chamber and / or the vacuum chamber 40, a manipulation source, and / or to control the environmental conditions (e.g., temperature, humidity, pressure, etc.) within the cryogenic chamber and / or the vacuum chamber 40 and / or other systems configured to manipulate and / or cause a controlled evolution of the quantum state of one or more atomic objects within the atomic object confinement device 50.

[0042] As Figure 2As shown, in various embodiments, the controller 30 may include various controller elements, including a processing element 205, a memory 210, a drive controller element 215, a communication interface 220, an analog-to-digital converter 225, etc. For example, the processing element 205 may include a programmable logic device (CPLD), a microprocessor, a coprocessing entity, an application-specific instruction set processor (ASIP), an integrated circuit, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a programmable logic array (PLA), a hardware accelerator, other processing devices and / or circuits, etc. and / or a controller. The term circuit may refer to a fully hardware implementation or a combination of hardware and a computer program product. In an exemplary embodiment, the processing element 205 of the controller 30 includes a clock and / or communicates with a clock.

[0043] For example, the memory 210 may include non-transitory memory such as volatile and / or non-volatile memory, such as one or more of the following: hard disk, ROM, PROM, EPROM, EEPROM, flash memory, MMC, SD memory card, memory stick, CBRAM, PRAM, FeRAM, RRAM, SONOS, racetrack memory, RAM, DRAM, SRAM, FPM DRAM, EDO DRAM, SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, RDRAM, RIMM, DIMM, SIMM, VRAM, cache memory, register memory, etc. In various embodiments, the memory 210 may store qubit records corresponding to qubits of a quantum computer (e.g., stored in a qubit record data repository, a qubit record database, a qubit record table, etc.), a calibration table, an executable queue, computer program code (e.g., one or more computer languages, a dedicated controller language, etc.), etc. In an exemplary embodiment, the execution of at least a portion of the computer program code stored in the memory 210 (e.g., by the processing element 205) causes the controller 30 to perform one or more steps, operations, processes, procedures, etc. described herein for tracking the phase of atomic objects within an atomic system and causing phase adjustment of one or more manipulation sources and / or the resulting signals.

[0044] In various embodiments, the drive controller element 215 may include one or more drives and / or controller elements each configured to control one or more drives. In various embodiments, the drive controller element 215 may include a drive and / or a drive controller. For example, the drive controller may be configured to cause one or more corresponding drives to be operated in accordance with executable instructions, commands, etc. scheduled and executed by the controller 30 (e.g., by the processing element 205). In various embodiments, the drive controller element 215 may enable the controller 30 to operate a laser system 70, a servo system, a vacuum and / or cryogenic system, etc. In various embodiments, the drive may be a laser drive; a microwave drive; a vacuum component drive; a cryogenic and / or vacuum system component drive; a current drive, etc. For example, the drive and / or the drive controller may be configured to cause a magnetic field generating device (e.g., including a circuit coupled to a voltage source (e.g., a current drive or a voltage drive), a permanent magnet, and / or a combination thereof) to generate a magnetic field having a specific direction and magnitude at one or more locations of the atomic object confinement device 50. In various embodiments, a plurality of locations (e.g., atomic object confinement device zones) of the atomic object confinement device 50 may be defined. In various embodiments, the controller 30 includes means for transmitting and / or receiving signals from one or more optical receiver components (such as cameras, MEM cameras, CCD cameras, photodiodes, photomultiplier tubes, etc.). For example, the controller 30 may include one or more analog-to-digital converter elements 225 configured to receive signals from one or more optical receiver components, calibration sensors, etc.

[0045] In various embodiments, the controller 30 may include a communication interface 220 for interacting and / or communicating with the computing entity 10. For example, the controller 30 may include a communication interface 220 for receiving executable instructions, command sets, etc. from the computing entity 10 and providing outputs received from the quantum computer 110 (e.g., from the optical collection system) and / or results of processing the outputs to the computing entity 10. In various embodiments, the computing entity 10 and the controller 30 may communicate via a direct wired and / or wireless connection and / or one or more wired and / or wireless networks 20.

[0046] Exemplary computing entity

[0047] Figure 3An illustrative schematic diagram of an exemplary computing entity 10 that can be used in conjunction with embodiments of the present invention is provided. In various embodiments, the computing entity 10 is configured to allow a user to provide input to the quantum computer 110 (e.g., via a user interface of the computing entity 10) and receive, display, analyze, etc. output from the quantum computer 110. For example, a user can operate the computing entity 10 to generate and / or program a quantum algorithm and / or a quantum circuit (e.g., which includes a D-state AC-Stark shift gate), and the quantum algorithm and / or the quantum circuit can be provided such that the controller 30 can receive the quantum algorithm and / or the quantum circuit and cause the quantum computer 110 to execute the quantum algorithm and / or the quantum circuit.

[0048] As Figure 3As shown, computing entity 10 may include an antenna 312, a transmitter 304 (e.g., radio component), a receiver 306 (e.g., radio component), and a processing element 308 that provides signals to the transmitter 304 and receives signals from the receiver 306, respectively (which may be collectively referred to as a transceiver). The signals provided to the transmitter 304 and received from the receiver 306 may include signaling information / data according to the air interface standards of an applicable wireless system to communicate with various entities such as controller 30, other computing entities 10, etc. In this regard, computing entity 10 may be operable with one or more air interface standards, communication protocols, modulation types, and access types. For example, computing entity 10 may be configured to receive and / or provide communications using a wired data transmission protocol such as Fiber Distributed Data Interface (FDDI), Digital Subscriber Line (DSL), Ethernet, Asynchronous Transfer Mode (ATM), Frame Relay, Data Over Cable Service Interface Specification (DOCSIS), or any other wired transmission protocol. Similarly, computing entity 10 may be configured to communicate via a wireless external communication network using any of a variety of protocols such as General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA2000), CDMA2000 1X (1xRTT), Wideband Code Division Multiple Access (WCDMA), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), Time Division-Synchronous Code Division Multiple Access (TD-SCDMA), Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), Evolution-Data Optimized (EVDO), High Speed Packet Access (HSPA), High Speed Downlink Packet Access (HSDPA), IEEE 802.11 (Wi-Fi), Wi-Fi Direct, 802.16 (WiMAX), Ultra Wideband (UWB), Infrared (IR) protocol, Near Field Communication (NFC) protocol, Wibree, Bluetooth protocol, Wireless Universal Serial Bus (USB) protocol, and / or any other wireless protocol. Computing entity 10 may use such protocols and standards to communicate using the following: Border Gateway Protocol (BGP), Dynamic Host Configuration Protocol (DHCP), Domain Name System (DNS), File Transfer Protocol (FTP), Hypertext Transfer Protocol (HTTP), TLS / SSL / Secure HTTP, Internet Message Access Protocol (IMAP), Network Time Protocol (NTP), Simple Mail Transfer Protocol (SMTP), Telnet, Transport Layer Security (TLS), Secure Sockets Layer (SSL), Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Datagram Congestion Control Protocol (DCCP), Stream Control Transmission Protocol (SCTP), Hypertext Markup Language (HTML), etc.

[0049] Via these communication standards and protocols, computing entity 10 can communicate with various other entities using concepts such as Unstructured Supplementary Service Information / Data (USSD), Short Message Service (SMS), Multimedia Messaging Service (MMS), Dual Tone Multi-Frequency signaling (DTMF), and / or Subscriber Identity Module dial pad (SIM dial pad). Computing entity 10 can also download changes, add-ons, and updates, e.g., download to its firmware, software (e.g., including executable instructions, applications, program modules), and operating system.

[0050] Computing entity 10 may also include a user interface device that includes one or more user input / output interfaces (e.g., a display 316 and / or speaker / speaker driver coupled to processing element 308 and a touch screen, keyboard, mouse, and / or microphone coupled to processing element 308). For example, the user output interface may be configured to provide interchangeably applications, browsers, user interfaces, interfaces, dashboards, screens, web pages, pages, and / or similar terms used herein that are executed on and / or accessible via computing entity 10, to cause the display or auditory presentation of information / data, and to interact therewith via one or more user input interfaces. The user input interface may include any of a plurality of devices that allow computing entity 10 to receive data, such as a keypad 318 (hard or soft), touch display, sound / voice or motion interface, scanner, reader, or other input device. In an embodiment that includes keypad 318, keypad 318 may include (or cause the display of) conventional numeric keys (0-9) and associated keys (#, *), as well as other keys for operating computing entity 10, and may include a full set of alphabetic keys or a set of keys that can be enabled to provide a full set of alphanumeric keys. In addition to providing input, the user input interface may also be used to, e.g., activate or deactivate certain functions, such as a screen saver and / or sleep mode. Through such input, computing entity 10 can collect information / data, user interactions / inputs, etc.

[0051] The computing entity 10 may further include an embeddable and / or removable volatile memory or storage device 322 and / or non-volatile memory or storage device 324. For example, the non-volatile memory may be ROM, PROM, EPROM, EEPROM, flash memory, MMC, SD memory card, memory stick, CBRAM, PRAM, FeRAM, RRAM, SONOS, racetrack memory, etc. The volatile memory may be RAM, DRAM, SRAM, FPM DRAM, EDO DRAM, SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, RDRAM, RIMM, DIMM, SIMM, VRAM, cache memory, register memory, etc. The volatile and non-volatile storage devices or memories may store databases, database instances, database management system entities, data, applications, programs, program modules, scripts, source code, object code, bytecode, compiled code, interpreted code, machine code, executable instructions, etc. to implement the functions of the computing entity 10.

[0052] Exemplary laser system and beam delivery photonic integrated circuit

[0053] The beam delivery photonic integrated circuit 400 may have one or more inputs and have multiple outputs. The inputs and outputs may be connected by waveguides fabricated on the chip, and the waveguides may be fabricated lithographically on the chip. The beam path connecting the inputs and outputs and the spacing between the inputs and outputs may be defined lithographically. The outputs may be a dense output group for parallel laser beam output. The dense output group may be located on a single chip and may allow the positions of the outputs to be fixed relative to each other, which may provide higher system stability. The fixed spacing may eliminate the need for individual optical path adjustment for each beam. The size of the chip (including the inputs and outputs) may be several centimeters on each side. The number of outputs may be increased or decreased by adjusting the number of cascaded splitters in the beam delivery photonic integrated circuit. However, the device does not become more complex with more beams, partly due to the fixed spacing of the outputs. For example, a chip with an edge length of 4 mm may provide 100 parallel beams from 100 outputs. In the case of small size, the chip may be packaged with the shared imaging system of the optical repeater assembly 500. Additionally, one or more beam delivery photonic integrated circuits may be used with the shared imaging system to create an array. For example, two beam delivery photonic integrated circuits (each having 100 beam outputs) may be used orthogonally together to produce a 100×100 array. Additionally, the beam delivery photonic integrated circuit 400 may have one or more input layers and output layers.

[0054] As Figure 1As shown, the beam delivery photonic integrated circuit 400 can be located outside the vacuum chamber 40, or alternatively, the beam delivery photonic integrated circuit can be located inside the vacuum chamber 40.

[0055] In various embodiments, the laser system 70 provides one or more gate signals to one or more portions of the atomic object confinement device 50 that confines / captures a set of atomic objects to be used as qubits of the quantum computer 110. For example, if the qubit space is defined based on the hyperfine splitting of the energy levels of the atomic objects, the frequency of the laser beam can be approximately 100 MHz to 100 GHz.

[0056] The beam delivery photonic integrated circuit 400 can include one or more inputs and two or more outputs. As Figure 4 shown, the inputs and outputs are connected to a plurality of beam paths. Each beam path can include one or more beam splitters, and at least one of the beam paths in the beam path includes a modulator. The beam splitters can be configured in a cascaded arrangement. For example, the output of a first beam splitter can be connected to the input of another beam splitter. In various embodiments, the input can be connected to the output through the beam path without any beam splitters. In addition or alternatively, the beam delivery photonic integrated circuit 400 can include one input leading to only one output. In addition or alternatively, there can be a plurality of inputs and outputs, each input and output being connected by a beam path in the beam delivery photonic integrated circuit 400.

[0057] Figure 4 A block diagram of an exemplary beam delivery photonic integrated circuit 400 according to an exemplary embodiment is provided, and Figure 4 an example of a waveguide layer that can be located in a single plane is provided. The beam delivery photonic integrated circuit 400 can be a photonic integrated circuit fabricated on a chip. As described herein, the waveguides in one waveguide layer of the beam delivery photonic integrated circuit 400 can be made of one or more deposited films of waveguide material. The fabrication can use lithography, which can allow for the defined geometries of the inputs, beam paths, and outputs. The beam splitters can be made of a single material and configured based on the properties of the material and the wavelength of the light used. In various embodiments, there can be multiple waveguide layers such that Figure 4 more than one waveguide layer as shown is located in the beam delivery photonic integrated circuit 400. In an alternative embodiment, there can be a first waveguide layer and a second waveguide layer. In yet another alternative embodiment, there are more than two waveguide layers.

[0058] Links for input and output may exist between layers. For example, the input of the first layer can be an input into the second layer to create a link between the two layers. The link between the two layers can be at any position in the layer, such as but not limited to at a splitter stage or the input of an optical element, or at the output of a splitter or an optical element. In an alternative embodiment, the input of the first layer can be linked to the input of the second layer such that the output of the second layer is based on the inputs to the first and second layers and so on. In an alternative embodiment, the output of a splitter or an optical element of the first layer can be linked to the input of a splitter or an optical element of the second layer.

[0059] In Figure 4 In the embodiment shown, the output of the laser 70 is input into the beam delivery photonic integrated circuit 400 via the optical input device 410. In various embodiments, the output of the laser 70 can be output on an optical fiber, and the optical input device 410 can be a single end-face coupled optical fiber. In an alternative embodiment, the output of the laser 70 can be in free space and input into the optical input device 410.

[0060] After the optical input device 410, the beam delivery photonic integrated circuit 400 can split the signal into multiple waveguides using a series of cascaded waveguide-based splitters. Figure 4 The first splitter is shown as a splitter 420 having two outputs. Each of the two outputs of the splitter 420 reaches another splitter, namely the splitter 430A and the splitter 430B respectively. Each of the two outputs of the splitter 430A reaches another splitter, namely the splitter 440A and the splitter 440B respectively. Each of the two outputs of the splitter 430B reaches another splitter, namely the splitter 440C and the splitter 440D respectively. Thus, as Figure 4 shown, there are three stages of cascaded splitters: the first-stage splitter 420, the second-stage splitters 430A, 430B, and the third-stage splitters 440A, 440B, 440C, and 440D. Although Figure 4 a three-stage splitter is shown, other embodiments can have additional cascaded splitter stages, such as having dozens or hundreds of splitter stages. Additionally, although Figure 4 the splitters are shown in a single plane, the splitters can be configured in three-dimensional directions such that there can be multiple cascaded stages occurring in multiple dimensions (e.g., the X, Y, or Z dimensions). In addition to or alternatively, multiple beam delivery photonic integrated circuits 400 can be provided on one chip, which can be accomplished by isolating the inputs and outputs of each beam delivery photonic integrated circuit 400 from each other.

[0061] Similarly as Figure 4 shown, at the last stage of the splitter (at Figure 4After being split into splitters 440A, 440B, 440C, and 440D (shown in ), the beam paths can have optical elements. The optical elements can allow the beams in the beam paths to be tuned independently of the beams in other beam paths, such as being tuned for one or more parameters. In one embodiment, the tunable parameters include frequency, phase, and / or intensity. Other parameters are discussed herein. In Figure 4 Figure 4 all but one of the beam paths have optical elements 450 (shown in Figure 4 Figure 4 as 450A, 450B, 450C, 450D, 450E, 450F, and 450G), and the beam path that does not have the integrated circuit element 450 can have a modulator 455, or may not have a modulator 455. In an exemplary embodiment, N beams from the output of the beam delivery photonic integrated circuit 400 can each be delivered to a specific part of the atomic object confinement device 50. For example, a first beam from a first output (e.g., 460A) and a second beam from a second output (e.g., 460B) are delivered to a first part of the atomic object confinement device 50, and the Nth beam from the Nth output can be delivered to the Nth part of the atomic object confinement device 50.

[0062] In various embodiments, the optical element 450 can be an interferometer, a phase modulator, a photodetector, an amplitude modulator, a combiner, a taperer, a polarization controller, a lens, and / or a combination of the foregoing devices. For example, the optical element 450 can be configured to implement control of the output power of a light beam. For example, in an exemplary embodiment, the optical element 450 is a Mach-Zehnder interferometer that implements control of the output power of a corresponding light beam, and the output power of the corresponding light beam can be controlled by resistively heating one arm of the Mach-Zehnder interferometer. For example, the Mach-Zehnder interferometer can act as a phase shifter to balance the power of the light beam. This can be referred to as thermally tuning the phase of the light beam along the path to achieve a desired output power. The output of each Mach-Zehnder interferometer can leave the beam delivery photonic integrated circuit 400 through a corresponding output 460. In an alternative embodiment, the optical element can be a ring modulator. In various embodiments, each of the plurality of outputs 460 of the beam delivery photonic integrated circuit 400 is positioned and / or disposed along a single polished edge of the beam delivery photonic integrated circuit 400. In addition or alternatively, tapering the waveguide size near the output 460 can allow and produce a desired output beam profile, such as a desired mode field or mode distribution at the output 460. The taper of each waveguide output 460 can be the same, or the tapers can be different. The beam delivery photonic integrated circuit 400 can be configured such that the stability of the position and pointing of the light beam can maintain a constant intensity at an ion fluctuation level <0.1%. Additionally, in various embodiments, the power balance between the focused light beams can have equal intensity at all ion regions of the atomic object confinement device 50, and each light beam can have a polarization purity of 20 dB or better. The beam delivery photonic integrated circuit 400 can be mechanically polished and trimmed and can have metal traces to define the Mach-Zehnder interferometer heater element and its leads. Also as Figure 4 shown, each light beam path can terminate at an output 460 (depicted as 460A, 460B, 460C, 460D, 460E, 460F, 460G, and 460H in Figure 4 ). The output 460 can be along a single polished edge of the beam delivery photonic integrated circuit 400. Additionally, in some embodiments, the output 460 can be located on more than one edge.

[0063] In an exemplary embodiment, a light beam path without the optical element 450 can be used to provide intensity feedback to the system. For example, Figure 4The output 460H can be input into a photodetector (e.g., a photodiode) or an optical intensity measurement device that can measure the intensity of the output of the light beam via the output 460H. The rapid power fluctuations caused by the input beam coupling variation are common mode for all beams and can be removed using external feedback based on only one output beam (such as using Figure 4 the output 460H). In an exemplary embodiment, the modulator 455 can also be a Mach-Zehnder interferometer.

[0064] Each output 460 can be fixed (relative to the other outputs 460 and / or the beam delivery photonic integrated circuit 400) and can provide six degrees of freedom (e.g., degrees of freedom in the space of X, Y, and Z coordinates and pitch, yaw, and roll). The output can be configured for aligning the output beam with the ion array and / or with the optical repeater assembly and the ion array. The pitch of the outputs 460 can be configured to match the required parameters corresponding to the atomic object confinement device 50, including but not limited to providing a desired mode field and / or mode distribution, position, polarization, frequency, phase, focused beam waist, and / or pitch. For example, the pitch of the outputs 460 can be configured to provide a desired relationship between the mode field diameter of the light beam emitted through the outputs 460 and the pitch between the output 460 and the adjacent output. Additionally, the degrees of freedom can be provided regardless of how many parallel outputs 460 may be present on the beam delivery photonic integrated circuit 400. For example, the output of the first beam delivery photonic integrated circuit 400 can be aligned with a specific position within the atomic object confinement device 50 based on six degrees of freedom, and a second beam delivery photonic integrated circuit having twice the number of outputs of the first beam delivery photonic integrated circuit can be aligned with a specific position within the atomic object confinement device 50 based on six degrees of freedom. Thus, in various embodiments, the alignment of the beam delivery photonic integrated circuit 400 with a specific position within the atomic object confinement device 50 does not increase in complexity as the number of outputs 460 of the beam delivery photonic integrated circuit 400 increases. In one example, the diameter of the output can be approximately 1 micron, and the pitch of the outputs can be approximately 150 microns.

[0065] Although Figure 4 each splitter is shown as a 1:2 splitter, in various embodiments, the splitter can be a 1:N splitter, i.e., the splitter has one input and N outputs. In addition or alternatively, the cascading can use or not use splitters with the same ratio (e.g., 1:2, 1:3, 1:4, etc.).

[0066] Optical repeater assembly

[0067] The output of the beam delivery photonic integrated circuit 400 is provided to the optical repeater assembly 500. The optical repeater assembly 500 can be configured to provide a desired magnification, such as by configuring the pitch and / or the mode field diameter. As the number of beams from the beam delivery photonic integrated circuit 400 grows, the complexity of the optical repeater assembly 500 may or may not increase. For example, the optical repeater assembly 500 can be modified to address or correct field-related aberrations.

[0068] In some embodiments, the laser 70 can be a monochromatic laser, which can allow for the use of a single material (e.g., a single glass material) for the optical repeater assembly 500. In other embodiments, more than one material can be used to form or fabricate the optical repeater assembly 500. For example, in an exemplary embodiment where the laser 70 is not a monochromatic laser, the optical repeater assembly 500 can be formed or fabricated from multiple materials.

[0069] Figure 5 The optical repeater assembly 500 is shown. Figure 5 An exemplary optical repeater assembly 500 is shown. The output of the beam delivery photonic integrated circuit 400 is input into the optical repeater assembly 500. Figure 5 Three different colors (e.g., 505A, 505B, and 505C) are used, where each color represents the beam output of one output from the beam delivery photonic integrated circuit. A first set of optical elements before the aperture stop can collect light from the photonic chip in a telecentric or non-telecentric manner, which can depend on the design output of the chip, and can route the light to a second set of optical elements, which can produce a telecentric or non-telecentric output, where each beam is focused to the desired location at an appropriate magnification. Figure 5 Multiple optical elements located at 510A - 510K in the optical repeater assembly 500 are shown. In the illustrated embodiment, the optical elements 510A - 510K can be 11 lenses of various shapes, such as concave lenses, convex lenses, bi-concave lenses, bi-convex lenses, plano-convex lenses, plano-concave lenses, plano-convex lenses, positive meniscus lenses, or negative meniscus lenses. In alternative embodiments, there can be more or fewer optical elements. The optical elements in the optical repeater assembly 500 can be spherical, aspherical, annular, or diffractive in nature, depending on the design output of the photonic chip and the desired characteristics of the light at the image plane. The optical elements can be coated or not coated with an anti-reflection coating and can be made of one or more materials to meet the design requirements. The total number of optical elements can vary to meet the design requirements. The system can be composed of all reflective elements, all refractive elements, or a combination of refractive and reflective elements.

[0070] The shape of the lens in the optical repeater assembly 500 can be configured to have various numbers of lenses with various shapes to precisely and accurately deliver a light beam to the atomic object confinement device in terms of position, spacing, mode distribution, polarization, frequency, and phase.

[0071] As Figure 5 shown, there can be only one optical repeater assembly 500 for the light beam delivery photonic integrated circuit 400. For example, the optical repeater assembly 500 can act as a repeater assembly for each output 460 of the light beam delivery photonic integrated circuit 400 that provides a light beam to the atomic object confinement device 50. The light beam delivery photonic integrated circuit 400 has outputs located at specific positions, which allows the light beam outputs of the light beam delivery photonic integrated circuit 400 to be known and allows the optical repeater assembly 500 to be configured based on the positions of the outputs. In other embodiments, more than one optical repeater assembly 500 can be used with the light beam delivery photonic integrated circuit 400. In other embodiments, one optical repeater assembly 500 can be used with more than one light beam delivery photonic integrated circuit 400. In other embodiments, the vacuum chamber 40 can also include multiple optical elements (such as 45A, 45B).

[0072] Fabrication of beam delivery photonic integrated circuit

[0073] The light beam delivery photonic integrated circuit 400 can be fabricated using photonic circuit fabrication techniques, which can include lithography. Using geometries defined in a lithographic manner can allow for more stringent tolerances, which can lead to increased stability of the quantum computer. The waveguide layer in the light beam delivery photonic integrated circuit can be etched to form the desired waveguide geometries, including each splitter in the light beam delivery photonic integrated circuit 400. Using Figure 6 the process or a variant thereof, the light beam delivery photonic integrated circuit 400 can be fabricated on a single chip. Although the device fabrication described herein utilizes only one waveguide layer, the integrated circuit can be made into a multi-level integrated circuit, including splitters, couplers, and / or waveguides that allow for the delivery of multiple light beam arrays having different wavelengths.

[0074] In various embodiments, the waveguide layer can be achromatic and can be advantageous for light of multiple wavelengths, such as broadband infrared to ultraviolet light. In embodiments using ultraviolet and visible lasers (which may be required for addressing atomic objects confined and / or trapped in the atomic object confinement device), special materials optimized for ultraviolet or visible light wavelengths can be used to fabricate the device. In some embodiments, the waveguide layer can use single-mode waveguides. In other embodiments, multi-mode waveguide layers can be used. In some embodiments, the first layer can be made of a first material, and the second layer can be made of a second material.

[0075] Figure 6A flowchart is provided that illustrates various processes, procedures, and / or operations performed in fabricating a beam delivery photonic integrated circuit 400. Figures 7A through 7T Cross-sectional views of various stages of fabricating a beam delivery photonic integrated circuit 400 are provided.

[0076] At Figure 6 step 602, a first cladding layer 704 is deposited on a substrate 702 (e.g., Si), as shown in Figure 7A and Figure 7B . For example, the first cladding layer 704 including an oxide and / or dielectric (e.g., SiO2) can be deposited on the substrate 702. In various embodiments, the first cladding layer 704 can electrically isolate and / or thermally isolate the waveguide layer 706 from the substrate 702. Figure 7A shows a cross-section before completion of the step / operation 602, and Figure 7B shows a cross-section after completion of the step 602.

[0077] Continuing Figure 6 , at step 604, a waveguide layer 706 is deposited on the first cladding layer 704, as shown in Figure 7C . The waveguide layer 706 can be a deposited thin film. For example, the waveguide layer 706 including a material (e.g., a dielectric material such as Al2O3, Si3N4, HfO2, AlN, Ta2O5, etc.) of the passive waveguide layer 706 can be deposited on the first cladding layer 704. Figure 7C shows a cross-section after completion of the step 604.

[0078] Returning Figure 6 , at step 606, a hard mask layer 708 is deposited on the waveguide layer 706. The hard mask layer can have the same material as the first cladding layer 704 (e.g., SiOSiO2), or it can have a different material. For example, the hard mask layer 708 is deposited on the waveguide layer 706. For example, Figure 7D shows a cross-section after completion of the step / operation 606.

[0079] Continuing Figure 6 , at step 608, a resist layer 710, such as a photoresist, is added by spin coating. For example, one or more drops of the resist layer 710 material can be deposited on the surface of the hard mask layer 708, and the substrate 702 and the layers deposited and / or bonded thereon can be rotated at a high rate so that the one or more drops of the resist layer 710 material are evenly dispersed on the surface of the hard mask layer 708. Figure 7E shows a cross-section after completion of the step 608. For example, the resist layer 710 is deposited on the hard mask layer 708.

[0080] Returning Figure 6, at step 610, the bakeable resist layer 710 can be baked and then exposed to UV radiation to develop the resist layer 710A. Figure 7F Shows a cross-section after completion of step 610.

[0081] Continue Figure 6 , at step 612, the hard mask layer 708 is etched to form the hard mask layer 708A. In various embodiments, a photolithography and / or mask etching process can be used to etch the hard mask layer to form the hard mask layer 708A. Figure 7G Shows a cross-section after completion of step 612.

[0082] Return Figure 6 , at step 614, the resist layer 710 is removed. Figure 7H Shows a cross-section after completion of step / operation 614.

[0083] Continue Figure 6 , at step 616, the waveguide layer 706 is etched and / or patterned to form the waveguide layer 706A. Figure 7I Shows a cross-section after completion of step 616.

[0084] Continue Figure 6 , at step 618, a second cladding is deposited to form the cladding 708B. Figure 7J Shows a cross-section after completion of step 618. Step 618 may or may not result in cladding deposition such that the exposed surface of 708B requires smoothing or planarization. If the exposed surface is to be smoothed or planarized, an optional polishing step can be performed at step 620. For example, chemical mechanical polishing (CMP) can be used to polish the exposed surface of the cladding 708B such that the exposed surface is smooth and / or planar to form the cladding 7C. Figure 7K Shows a cross-section after completion of step 620. If the optional step 620 does not occur because the exposed surface does not require smoothing or planarization, the process continues Figure 6 to step 622 as shown.

[0085] At step 622, a metal layer can be deposited to form the metal layer 712. For example, the metal layer can be made of a material (Al, Ti, Au, etc.) and the metal layer can define a Mach Zehnder interferometer heater element and / or its leads. Figure 7L Shows a cross-section after completion of step 622.

[0086] Continue Figure 6 , at step 624, a resist layer 714, such as a photoresist, is added by spin coating. Figure 7M Shows a cross-section after completion of step 624.

[0087] Return Figure 6 At step 626, the resist layer 714 is baked and then exposed to UV radiation and developed to form the resist layer 714A. Figure 7N The cross-section after completion of step 626 is shown.

[0088] Continue Figure 6 At step 628, the metal layer 712 is etched to form the metal layer 712A. For example, the metal layer 712 can be etched to form the metal layer 712A, which defines one or more Mach Zehnder interferometer heater elements, corresponding leads, etc. Figure 7O The cross-section after completion of step 628 is shown.

[0089] Return Figure 6 At step 630, the resist layer 714A is removed. Figure 7P The cross-section after completion of step / operation 630 is shown.

[0090] Continue Figure 6 At step 632, a resist layer 716, such as a photoresist, is added by spin coating. Figure 7Q The cross-section after completion of step 632 is shown.

[0091] At Figure 6 At step 634 as shown, the resist layer 716 is baked and then exposed to UV radiation and developed to form the resist layer 716A. Figure 7R The cross-section after completion of step 626 is shown.

[0092] Return Figure 6 At step 636, the cladding 708B is etched to form the cladding 708C, and the cladding 704 is etched to form the cladding 704A. Figure 7S The cross-section after completion of step 636 is shown.

[0093] Continue Figure 6 At step 638, the resist layer 716A is cleaned and removed. Figure 7T The cross-section of the beam delivery photonic integrated circuit 400 after completion of step 638 is shown.

[0094] After cleaning, the edge of the output with the beam delivery photonic integrated circuit 400 can be polished.

[0095] Technical advantages

[0096] Various embodiments provide technical solutions to the technical problem of precisely and accurately delivering multiple laser beams (e.g., ultraviolet laser beams, visible laser beams, infrared laser beams, etc.) in a dense array (e.g., a dense array of atomic object confinement device regions) in terms of frequency, frequency offset, and / or phase. In one embodiment, the array of atomic object confinement device regions can be a one-dimensional or two-dimensional array of regions within an atomic object confinement device. The beam delivery photonic integrated circuit can be configured to deliver laser beams such that the laser beams can be parallel to each other and properly spaced to overlap with the atomic object confinement device regions with sub-micron precision. Additionally, the waveguide geometry defined lithographically provides higher stability. Additionally, the beam delivery photonic integrated circuit can be configured to provide more than one beam while being sized to fit within a sandwich test plate surrounding a vacuum chamber. Compared to other waveguides that include multiple components (e.g., optical fibers, grooves for holding optical fibers, couplers, splitters, interferometers, modulators, etc.), the beam delivery photonic integrated circuit 400 on a single chip can also be more easily used in a quantum computing system, especially when such components may occupy a large amount of space. Additionally, the beam delivery photonic integrated circuit 400 on a single chip allows the beam delivery photonic integrated circuit 400 to be placed close to the vacuum chamber 40. Furthermore, the alignment of the multiple beams provided by the beam delivery photonic integrated circuit 400 is simpler than that of conventional devices, and the complexity and / or the number of degrees of freedom do not increase as the number of outputs of the beam delivery photonic integrated circuit 400 increases. Specifically, multiple embodiments provide improvements over conventional devices, which can be a collection of individual optical fibers, collimators, and mirrors for each beam, but these systems require a large footprint on the sandwich test plate. Additionally, these systems are limited in terms of the degree to which they can be scaled by the amount of available space and their ability to package current laser beam delivery devices.

[0097] Various embodiments of the beam delivery photonic integrated circuit 400 provide systems that allow the delivery of multiple laser beams with balanced power and a constant intensity with a fluctuation level <0.1%. Thus, the embodiments provide an improvement in the operation of quantum computers.

[0098] Various embodiments also allow tuning in six degrees of freedom at once without the need to tune each individual beam, which allows an increase in the number of outputs without increasing the alignment complexity.

[0099] Conclusion

[0100] Many modifications and other embodiments of the invention set forth herein will come to mind to those skilled in the art to which the invention pertains after benefiting from the foregoing description and the teachings presented in the related drawings. Accordingly, it is to be understood that the invention is not limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A beam delivery system, comprising: A package including a beam delivery photonic integrated circuit and an optical repeater assembly, The beam delivery photonic integrated circuit includes: One or more optical inputs; A plurality of waveguide outputs, wherein each waveguide output of the plurality of waveguide outputs is tapered; A plurality of beam paths, each beam path connecting one of the plurality of waveguide outputs to at least one of the one or more optical inputs, Wherein at least one of the plurality of waveguide outputs connected to a first optical input of the one or more optical inputs is configured to be directed to a photodetector, and the photodetector is configured to measure the intensity of the waveguide output directed to the photodetector; and Wherein each beam path of the plurality of optical paths connected to the first optical input and not connected to at least one of the plurality of waveguide outputs configured to be directed to the photodetector includes a corresponding optical element, and the optical element is configured to remove power fluctuations of the beam provided by the corresponding waveguide output according to the intensity of the waveguide output directed to the photodetector; Wherein the beam delivery photonic integrated circuit is located on a chip; The optical repeater assembly includes a plurality of optical elements, and the optical repeater assembly is configured to receive the beams provided by at least two of the plurality of waveguide outputs, and focus each received beam on a corresponding position among a plurality of positions of an atomic object confinement device by passing the beams provided by each of the at least two waveguide outputs of the plurality of waveguide outputs through each of the plurality of optical elements.

2. The beam delivery system according to claim 1, wherein one or more optical elements in the plurality of beam paths are further configured to independently tune the corresponding beams for at least one of frequency, phase or intensity.

3. The beam delivery system according to claim 1, wherein the atomic object confinement device is located in a vacuum chamber, and the beam delivery system includes one or more optical elements located in the vacuum chamber.

4. The beam delivery system according to claim 1, wherein the plurality of beam paths are defined lithographically.

5. The beam delivery system according to claim 1, wherein the plurality of waveguide outputs are located on a polished edge of the beam delivery photonic integrated circuit.

6. The beam delivery system according to claim 1, wherein each of the waveguide outputs is located on one side of the beam delivery photonic integrated circuit and is parallel to each other.

7. The beam delivery system according to claim 1, wherein each of the plurality of waveguide outputs is spaced at most 150 micrometers from the next nearest waveguide output of the plurality of waveguide outputs.

8. The beam delivery system according to claim 1, wherein the optical input is end-face coupled to an optical fiber providing an input beam.

9. The beam delivery system according to claim 1, wherein the beam delivery photonic integrated circuit further includes a first waveguide layer and a second waveguide layer.

10. The beam delivery system according to claim 9, wherein the first waveguide layer and the second waveguide layer are made of different materials, and wherein the first waveguide layer includes a first optical input of the one or more optical inputs and a first output of the plurality of waveguide outputs, and the second waveguide layer includes a second optical input of the one or more optical inputs and a second output of the plurality of waveguide outputs.

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