Enhancement of optical nonlinearity by XPM time trapping

Abstract

Systems and methods are disclosed for trapping an optical signal in a nonlinear optical quantum computing system. The nonlinear optical quantum computing system is provided with an optical signal and a trapping field. The trapping field propagates with the optical signal and confines the optical signal in time and / or space. The nonlinear optical quantum computing system may be configured as a ring, a single-path waveguide, or a segmented single-path waveguide. In some cases, multiple optical signals may be input to the system and evaluated in a multiplexed manner.

Description

[Technical Field]

[0001] Priority This application claims priority to U.S. Provisional Patent Application No. 63 / 319,680, filed March 14, 2022, entitled "Enhancing Optical Nonlinearities via XPM Time Trapping," which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to systems and methods for enhancing optical nonlinearities, and in particular, to systems and methods for enhancing optical nonlinearities by using one or more of cross-phase modulation temporal trapping. [Background technology]

[0003] Optical quantum computing (OQC) involves the use of optical (photonic) systems to perform computing operations. For example, FIG. 1A depicts a model of dual-rail qubit encoding, according to some embodiments. As depicted, qubits are typically encoded in a dual-rail basis based on states occupied by photons. These states can be based on space, time, frequency, etc. This dual-rail basis has inherent advantages, such as making the states immune to errors due to timing or frequency shifts. Additionally, single-photon gates can be easily implemented using linear optics. For example, FIG. 1B depicts an exemplary single-photon gate implemented in an OQC system, according to some embodiments. As depicted, the X-gate and Z-gate are implemented using linear optics.

[0004] However, other gates in an OQC system are more difficult to realize. For example, an entangling gate is much more difficult to realize than a single-photon gate. For example, FIG. 1C shows a diagram of a controlled-Z (CZ) gate implemented in an OQC system using Hong-Ou-Mandel (HOM) interference and a Kerr phase gate, according to some embodiments. In this illustrated example, the CZ gate can be realized using HOM interference and a Kerr phase gate that performs the following operation:

[0005]

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[0006] OQC systems can be divided into two camps, linear OQC and nonlinear OQC, depending on how the Kerr gate is implemented. For example, FIG. 1D depicts an exemplary implementation of a Kerr gate in a linear OQC system according to some embodiments and an alternative system that can be used for nonlinear optical quantum computing. As shown, in linear OQC (LOQC), the Kerr gate is implemented using a single-photon source, a detector, and linear optics. Currently, such gates are producible, but are probabilistic gates with an upper bound of p<3 / 4, with the best-known systems having p=2 / 27. Two approaches have been developed to handle probabilistic gates: (1) the KLM approach, which improves gate probability with the conditional preparation of entangled ancilla states, and (2) the cluster state approach, which focuses on constructing large cluster states with CZ operations. However, these approaches incur a significant amount of overhead in encoding the necessary ancilla states / clusters.

[0007] In contrast, nonlinear optical QC (NLOQC) systems implement the gate deterministically using nonlinear optics. Nonlinear optical QC (NLOQC) systems involve the use of photon-photon interactions, but this interaction typically produces a particularly weak response, so increasing the strength by optimizing various parameters of the interaction is a particularly desirable goal. NLOQC systems avoid the overhead of extracting auxiliary / cluster states, but require the single-photon Kerr gate.

[0008]

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[0009] While the above discussion focuses on quantum gates based on dual-rail encoding, the difference between LOQC and NLOQC is more general. Specifically, quantum operations can be constructed using optical detection and heralding (LOQC) or deterministically through nonlinear interactions (NLOQC). As another example, in the continuous-variable framework of Gottesman-Kitaev-Preskill (GKP) states, the main challenge is to construct GKP states and cubic-phase states, which are resource states in computational protocols. These states can be constructed using heralded linear circuits (LOQC) or deterministically through coherent nonlinear interactions (NLOQC).

[0010] As a result, NLOQC systems have sought to increase the photon interaction time or spatially confine the photons to better detect the interaction. Over the past half century or so, systems using these techniques have increased the interaction strength by 10 6 However, further improvements are needed to reach the single-photon regime and enable nonlinear optical quantum computing.

[0011] It would be desirable to provide an NLOQC system that offers enhanced photon interaction strength and reduced mode volume compared to conventional techniques, and the present disclosure is directed to this end. Summary of the Invention

[0012] The systems and methods may be used for nonlinear optical quantum computing using temporal confinement techniques configured to confine light using nonlinear interactions between target and trapping fields.

[0013] In an embodiment, a method for confining an optical signal in a nonlinear optical quantum computing system comprises generating an optical signal in the nonlinear optical quantum computing system and generating a trapping field configured to confine the optical signal by inducing a nonlinear interaction, wherein the trapping field propagates with the optical signal.

[0014] In another embodiment, a nonlinear optical quantum computing system is configured to generate an optical signal and induce a nonlinear interaction to generate a trapping field that confines the optical signal, wherein the trapping field propagates with the optical signal. [Brief explanation of the drawings]

[0015] [Figure 1A] FIG. 1 depicts a model of dual-rail qubit encoding, according to some embodiments. [Figure 1B] FIG. 1 depicts an exemplary single-photon gate implemented in an optical quantum computing system, according to some embodiments. [Figure 1C] FIG. 1 is a diagram of a CZ gate implemented using HOM and Kerr phase gates in an optical quantum computing system, according to some embodiments. [Figure 1D] 1A-1C depict exemplary implementations of Kerr gates in linear optical quantum computing systems and alternative systems that may be used for nonlinear optical quantum computing, according to some embodiments. [Figure 2A] FIG. 1 depicts a temporal trapping mechanism configured to confine an optical signal in a nonlinear optical quantum computing system, according to some embodiments. [Figure 2B] FIG. 2 is a diagram depicting an optical signal without a temporal trap, according to some embodiments. [Figure 2C]FIG. 1 is a diagram representing an optical signal subjected to a temporal trap where a bound state is separated from a continuous mode by an energy gap, according to some embodiments. [Figure 3A] FIG. 1 is a diagram of a target field confined in a temporal trap, according to some embodiments. [Figure 3B] FIG. 1 is a diagram of a target field confined in a spatial trap, according to some embodiments. [Figure 3C] FIG. 1 is a diagram of a target field confined in a temporal and spatial trap, according to some embodiments. [Figure 4A] FIG. 1 depicts a ring structure of a nonlinear optical quantum computing system configured to confine an optical signal, according to some embodiments. [Figure 4B] FIG. 1 depicts a single-pass waveguide structure of a nonlinear optical quantum computing system configured to confine an optical signal, according to some embodiments. [Figure 4C] FIG. 1 depicts a segmented single-pass waveguide structure of a nonlinear optical quantum computing system configured to confine an optical signal, according to some embodiments. [Figure 5A] FIG. 1 illustrates an instantaneous method for loading and unloading trapped pulses from an optical cavity using a fast switch, according to some embodiments. [Figure 5B] FIG. 10 depicts a step-by-step method for loading and unloading trapped pulses from an optical cavity using slow switches, according to some embodiments. [Figure 5C] FIG. 10 depicts loading and unloading trapped pulses in a manner to form a grid-state temporal dual-rail qubit, according to some embodiments. [Figure 6A] FIG. 1 depicts an exemplary demultiplexing solution for implementing a CZ gate, according to some embodiments. [Figure 6B]FIG. 1 depicts an exemplary multiplexing solution for implementing a CZ gate, according to some embodiments. [Figure 7A] FIG. 1 depicts an exemplary quantum computing gate that can be implemented with intracavity pulses using trapping potential engineering, according to some embodiments. [Figure 7B] 7B is a diagram depicting a linear optical transformation corresponding to the exemplary quantum computing gate of FIG. 7A in accordance with some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0016] Embodiments disclosed herein describe temporally confining optical signals (e.g., photons). For example, a trapping pulse can be generated to co-propagate with the optical signal, and the trapping pulse uses cross-phase modulation (XPM) to create a dynamic / flying photonic cavity that confines the optical signal. In other words, the trapping pulse propagates along with the optical signal. These embodiments, in turn, can increase the interaction strength between the trapping pulse and the optical signal by orders of magnitude compared to existing systems, resulting in significant improvements to photonic platforms such as thin-film lithium niobate for implementing nonlinear optical quantum dots (OQC). Furthermore, time multiplexing can be performed to generate multiple identical qubits from a single resonator to enable highly parallelized computation, cluster state generation, and quantum simulation.

[0017] Optical nonlinearities can be enhanced by various factors that provide a combination of phase matching and confinement. Birefringence phase matching, quasi-phase matching, waveguiding, loss reduction, resonance, and dispersion engineering are exemplary techniques used to enhance optical nonlinearities and approach the strong coupling limit. Strong coupling occurs when the nonlinear Hamiltonian is large enough to shift the energy levels by more than the linewidth, creating a strong anharmonic oscillator that behaves like a qubit. Alternatively, strong coupling is said to occur when a system simultaneously achieves a strong optical quality factor Q and a small mode volume V in a medium with high material nonlinearity. While the above advances have enabled strong coupling in cQED systems, NLOQC has not been achieved in cQED due to difficulties in fabrication and scaling. In contrast, χ (3) and (2) Bulk nonlinearities such as θ and θ are more robust and scalable, but are weaker than cQED and require larger geometrical enhancements. NL )

[0018]

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[0019] [Table 1]

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[0020] As mentioned above, competing approaches for NLOQC systems may include short optical pulses in photonic crystal cavities, microring resonators, or dispersion-engineered waveguides. An analysis of each with respect to temporal trapping using cross-phase modulation is presented below.

[0021] In the case of photonic crystal cavities, two-dimensional photonic crystals are used to direct light into

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[0022] Dielectric bowtie "tip" structures have been shown to achieve deep subwavelength confinement without compromising optical quality. The tip structure design can be understood in terms of competing Maxwell boundary conditions in slot / bridge structures or field divergence at dielectric corners. Because the tip is dielectric, losses in plasmonic bowtie cavities do not occur. In addition, because the tip is a subwavelength feature, it does not scatter light into the far field. Rather, the optical energy remains distributed over a volume much larger than the tip itself, but due to field divergence,

[0023]

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[0024] Ring resonators can achieve high Q-factors when volume is not an important consideration. Unlike photonic crystals, rings are guided by total internal reflection and are not wavelength sensitive. Therefore, ring resonators tend to have high Q-factors, limited primarily by waveguide losses. Furthermore, such resonances can easily span an octave. For example, using Smart Cut LiNbO3, a Q of 3 dB / m (Q=10 7 ) has been achieved. Better manufacturing processes and materials can further reduce losses. For example, chemical mechanical polishing (CMP)-based processes achieve a loss of 0.3 dB / m (Q=10), which is close to the limit of bulk materials. 8 ) have been achieved. In addition, the ring is a convenient system to work with because of its simple design, ability to tolerate shallower etch angles, and support for both quasi-phase matching and dispersion-engineered designs.

[0025] The drawback of using a ring resonator is the large mode volume (

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[0026] Strong photon-photon coupling can be achieved by temporally confining photons using short optical pulses in a waveguide. Although such pulses broaden rapidly, the waveguide can be successfully engineered to eliminate leading-order dispersion terms such as group velocity mismatch (GVM) and group velocity dispersion (GVD). Such "dispersion-engineered" waveguides allow short pulses to propagate much longer distances than would otherwise be possible. This can lead to novel "quasi-static" (dispersion-free) nonlinear interactions. Therefore, short optical pulses in the waveguide can have pulse widths much shorter than the repetition rate of the ring, enabling high optical quality factors for ring cavities with significantly smaller mode volumes.

[0027] However, optical pulses are subject to residual dispersion. For example, to take advantage of a high Q factor, the pulses

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[0028] Table 2 summarizes the figures of merit for each platform, and the LiNbO3(χ (2) ) and Si(χ (3)) cooperativity calculations are given. Based on the values ​​in Table 2, using Si as a material is not suitable for strong coupling. Similarly, for LiNbO3, strong coupling may not be achievable using either a photonic crystal cavity or a ring resonator, although improvements to ring resonators may make it more feasible in the future. On the other hand, strong coupling is already achievable with short optical pulses if dispersion and distortion can be controlled. As disclosed herein, temporal trapping using cross-phase modulation controls the dispersion and distortion of short optical pulses, enabling strong coupling in NLOQC systems.

[0029] [Table 2]

[0030] In some embodiments, a temporal trapping method based on cross-phase modulation (XPM) can be used to project the dynamics of a dispersion-engineered waveguide onto a single-pulse basis. In addition to the data pulse, the cavity hosts a trap pulse driven by a powerful classical pulse train. XPM between the trap field and the data pulse results in a time-dependent detuning, which acts as a potential well that confines the signal in time. The interplay between temporal trapping and dispersion leads to the emergence of stable pulse modes, whose solutions are derived from the bound-state eigenmodes of the Schrödinger equation. Spurious modes are detuned from resonance as a result of the energy gap between the bound and continuum states, thereby loosely projecting the pulse dynamics onto a single-mode target. In other words, XPM time gating allows NLOQC systems to obtain a coherency boost of pulse operation with the relative simplicity of single-mode dynamics.

[0031] 2A depicts a temporal trapping mechanism configured to confine an optical signal in a nonlinear optical quantum computing system, according to some embodiments. As shown in FIG. 2A, the trapping field 205 is an optical pulse that imparts a time-dependent phase shift to the target fields (pump field 210 and signal field 215). The dynamics of the target field are

[0032]

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[0033]

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[0034] Figure 2B illustrates an optical signal without a temporal trap, according to some embodiments. As shown, in a dispersion-engineered cavity without a temporal trap, all modes are degenerate in the comoving reference frame. As a result, the pulse shape is susceptible to residual cavity dispersion and modal distortion that inevitably arise from the nonlinearity itself. Figure 2C illustrates an optical signal subject to a temporal trap, according to some embodiments, in which bound states are separated from continuous modes by an energy gap. In contrast to the above, as shown in Figure 2C, in a temporal trap, bound states are separated from all continuous modes (and higher-order bound states) by an energy gap ΔE. This energy gap detunes all spurious modes, resulting in a pulse that is free from residual dispersion or nonlinear distortion. The dynamics is projected into single-mode subspace, thereby enabling the realization of high-fidelity gates. In this way, temporal trapping overcomes the trade-off between interaction strength and gate fidelity that occurs in waveguide NLO. In other words, the temporal trap provides high fidelity and strong interaction.

[0035] 3A depicts a diagram of a target field confined in a temporal trap, according to some embodiments, in which the confinement may be performed within the temporal trap as illustrated in FIG.

[0036] 3B depicts a diagram of a target field confined in a spatial trap, according to some embodiments. In these embodiments, the confinement may be performed in a spatial-soliton analog of the trap. In these embodiments, a bulk crystal or slab may be used, and the trapping field may create a waveguide that blocks diffraction of the target field.

[0037] 3C depicts a diagram of a target field confined in a temporal and spatial trap, according to some embodiments, in which confinement can be performed in a trap that comprises both a temporal trap and a spatial soliton analog.

[0038] In some embodiments, confinement may be facilitated by cross-phase modulation from optical pulses, as illustrated in FIG. 2A above.

[0039] In some embodiments, confinement can be facilitated by Pockels modulation from radio frequency (RF) / terahertz (THz) pulses. In such embodiments, trapping is mediated by the Pockels effect, which can be more powerful than cross-phase modulation and can allow control of the sign of the trapping phase. Using THz trapping fields, it may be possible to confine light to sub-picosecond pulses.

[0040] In some embodiments, the cascade χ from the light pulse (2) The interactions may facilitate confinement. In such embodiments, χ (2) Cascading interactions can produce effective cross-phase modulation interactions. Furthermore, the cascaded χ (2) The interaction can provide control over the sign of the cross-phase modulation interaction, thus enabling bright phase trapping in the normal dispersion regime. (2) The interaction may allow independent tuning of the magnitude (and sign) of the cross-phase modulation of both the pump and signal fields, which provides additional functionality for tuning the trap when the pump and signal GVD fields are opposite in sign or differ by a large factor.

[0041] 4A-4C depict alternative structures for a nonlinear optical quantum computing system configured to confine an optical signal, according to some embodiments. As illustrated in FIG. 4A, the structure may include a ring, racetrack, or other ring-shaped cavity 400. In such embodiments, dedicated couplers 405a, 405b for trapping wavelengths that are typically longer than the target wavelength are included to prevent the trapping field from resonating. Additionally, dedicated couplers may be used to divide the resonator into a trapping region 410 and an NLO region 415.

[0042] As shown in Figure 4B, the structure may include a single-pass waveguide 430. In such an embodiment, the trapping pulse may be a waveguide soliton that maintains its shape while simultaneously trapping the pump and signal fields. In contrast to the ring structure 400, the waveguide structure 430 may require more area but may improve throughput.

[0043] As illustrated in FIG. 4C, the structure may include a segmented single-pass waveguide 450. In such an embodiment, the trap pulse may be periodically refreshed. The segmented single-pass waveguide 450 may be used for waveguides that do not support trapped solitons. In such cases, the trap pulse, which may be dispersed or out of phase with respect to the pump and signal fields as it propagates along the waveguide, may be periodically replicated.

[0044] 5A-5C depict alternative methods for loading and unloading trapped pulses from an optical cavity, according to some embodiments. As illustrated in FIG. 5A, an optically trapped pulse 505 can be loaded 510 and unloaded 515 instantaneously using a fast switch. In such embodiments, the fast switch couples cavity modes into a single optical pulse. The switching hardware of the fast switch can operate at high speeds compared to the time between pulses.

[0045] As shown in Figure 5B, an optical trap pulse 530 is gradually loaded 535 and unloaded 540 with a slow switch. In such an embodiment, the slow switch couples the cavity modes to the optical pulse train. The switching hardware of the slow switch may be able to operate slower than the fast switch described above. This may be especially true in the time-multiplexed regime, where the time between pulses is very short.

[0046] As shown in Figure 5C, optical trap pulses can be loaded and unloaded using either fast or slow switches in a manner that forms a temporal dual-rail qubit of grid states. In such an embodiment, two-fold time multiplexing can be used to store two pulses 550, 555 in the cavity. The two pulses 550, 555 can be used for dual-rail encoding. For fast loading / unloading, this can map to a standard time-bin dual-rail base. For stepwise loading / unloading, this can map to the time base of the grid states. In this case, a single-qubit gate can be approximated using a phase modulator and a delay loop, and the gate fidelity can increase exponentially with the number of lobes in the grid states.

[0047] In some embodiments, trapping modes can be multiplexed in a single ring cavity. In such embodiments, multiplexing can allow a single cavity to support multiple identical qubits. Multiplexing can therefore simplify the hardware of an NLOQC system, as only a single cavity needs to be stabilized. In contrast, a non-multiplexed system may require each qubit to be stored in a separate cavity.

[0048] In some embodiments, time multiplexing can be used to generate and store multiple time-offset pulses. In such embodiments, if the trap signal and cavity are in N:1 resonance, the cavity can store N independent pulses that are offset in time. This technique can also be implemented in a synchronously pumped optical parametric oscillator (OPO) coherent Ising machine.

[0049] In some embodiments, directional multiplexing can be used to support different propagation directions. In such embodiments, the ring cavity can support propagation modes. Thus, data can be stored in both propagation directions within the ring. In this manner, directional multiplexing can be used to halve the number of rings required to implement a quantum gate, such as a CZ gate, as illustrated in FIG. 6B, compared to a non-multiplexed solution, as illustrated in FIG. 6B.

[0050] In some embodiments, backscattering can be suppressed in ring structures. Ring resonators with high optical quality factor Q can cause mode splitting resulting from resonantly enhanced backscattering. Mode splitting reduces gate fidelity because some light is lost due to reflection from the wrong port. Backscattering can be particularly significant because counterpropagating modes are degenerate due to reciprocity. However, the use of trapping fields can eliminate the occurrence of reciprocity, resulting in significant backscattering suppression.

[0051] 7A-7B show quantum computing gates implemented with intracavity pulses and corresponding linear optical transformations, according to some embodiments. As illustrated in FIGS. 7A-7B, the systems and methods described herein can be used to implement gates on intracavity pulses using trapping potential engineering. As discussed further herein, in a dual-rail base, single-qubit gates are reduced to linear optics, while entangled gates require a Kerr phase step, as illustrated in FIG. 7B. An intracavity dual-rail base can also be realized using time multiplexing as described above.

[0052] Figure 7B depicts linear optical transformations (phase shifters, beam splitters, waveguide crossings) implemented by adiabatically varying the potentials to bring the pulses together, thus allowing the time bins to interact, while the Keff phase gate occurs automatically by holding the pulse in place and waiting Δt ∼ 1 / ε, where ε is the nonlinear coupling. One advantage of using this approach is that the optical pulse does not need to enter or exit the cavity. Rather, each computation can be performed entirely using the intracavity state, eliminating the losses and complexity that arise from loading and unloading.

[0053] In some embodiments, various aspects described above may be applied to quantum simulations. For example, to emulate the Bose-Hubbard model, a temporal trapping cavity with multiple closely spaced modes may be used to realize a one-dimensional bosonic lattice that suffers from mode hopping and photon blockade.

[0054] In some embodiments, temporal trapping can be used to realize a collection of identical OPOs with thresholds on the order of one photon by pumping at the second harmonic. In such embodiments, the optical nonlinearities required to realize coherent Ising machines at the quantum (single-photon) limit can be exploited.

[0055] In some embodiments, the combination of nearest-neighbor coupling between closely spaced trapped modes and strong optical nonlinearities can facilitate the creation of large one-dimensional discrete-variable cluster states. In such embodiments, two- or three-dimensional discrete-variable cluster states can also be created.

[0056] In some embodiments, quantum non-demolition (QND) detection may be used for quantum sensing and computing. Kerr-based QND detection may be possible even with weak nonlinearities, but the required optical power is P∝χ -2 Since modern solid-state Kerr nonlinearities are weak, the required optical power is too large for practical use. Furthermore, cross-phase modulation signals are usually masked by self-phase modulation from a strong probe field. However, cascaded χ with temporal traps (2) Cross-phase modulation can be used to solve both of these problems in modern systems, so that strong (single-photon) and highly resonant cross-phase modulation effects can be achieved without undesirable self-phase modulation.

[0057] In some embodiments, the purity of spontaneous parametric down-conversion (SPDC) single-photon sources can be improved by using temporal traps to suppress correlations in the joint spectral density. These correlations can be suppressed by favoring down-conversion to bound states over other cavity states.

[0058] In some embodiments, the methods and systems described herein can be applied to pulse shaping in SHG, OPO, and other nonlinear processes. Pulse shaping can be performed on any of several nonlinear optical sources. Cross-phase modulation trapping can be used, for example, in place of synchronous pumping in pulsed OPOs. Alternatively, cross-phase modulation trapping can be used to provide an additional pulse-shaping degree of freedom.

[0059] The above description has been made with reference to specific embodiments for purposes of explanation. However, the above exemplary discussion is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments have been chosen and described to best explain the principles of the disclosure and its practical application, and thereby enable others skilled in the art to utilize the disclosure and various embodiments to the fullest extent, with various modifications as suited to the particular use contemplated.

[0060] The systems and methods disclosed herein may be implemented via one or more components, systems, servers, devices, or other subcomponents, or may be distributed among such elements. When implemented as a system, such a system may include and / or contain components such as software modules, a general-purpose CPU, RAM, etc., found in a general-purpose computer, among others. In implementations in which the innovations reside on a server, such a server may include or contain components such as a CPU, RAM, etc., found in a general-purpose computer.

[0061] Additionally, the systems and methods herein may be achieved through implementation using disparate or entirely different software, hardware, and / or firmware components beyond those described above. With respect to such other components (e.g., software, processing components, etc.) and / or computer-readable media associated with or embodying the invention, for example, aspects of the innovations herein may be implemented in conjunction with numerous general-purpose or special-purpose computing systems or configurations. Various exemplary computing systems, environments, and / or configurations that may be suitable for use with the innovations herein may include, but are not limited to, software and / or other components embodied within or in personal computers, servers or server computing devices such as routing / connection components, handheld or laptop devices, multiprocessor systems, microprocessor-based systems, set-top boxes, consumer electronic devices, network PCs, other existing computer platforms, distributed computing environments that include one or more of the above systems or devices, and the like.

[0062] In some cases, aspects of the systems and methods may be achieved or performed by logic and / or logic instructions, including, for example, program modules, executed in conjunction with such components or circuitry. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular instructions herein. The present invention may also be realized in the context of a distributed software, computer, or circuit configuration where circuitry is connected via communication buses, circuitry, or links. In a distributed configuration, control / instruction may originate from both local and remote computer storage media, including memory storage devices.

[0063] The software, circuitry, and components herein may include and / or utilize one or more types of computer-readable media. Computer-readable media can be any available medium that resides on, is associated with, or is accessible by such circuits and / or computing components. By way of example and not limitation, computer-readable media may comprise computer storage media and communication media. Computer storage media include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVDs) or other optical media, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by a computing component. Communication media may comprise computer-readable instructions, data structures, program modules, and / or other components. Additionally, communication media may include wired media such as a wired network or direct-wired connection, although as used herein such type of media does not include transitory media. Combinations of any of the above are also included within the scope of computer-readable media.

[0064] In this description, terms such as component, module, device, and the like may refer to any type of logical or functional software element, circuit, block, and / or process that may be implemented in various manners. For example, the functionality of various circuits and / or blocks may be combined into any number of other modules. Each module may be implemented as a software program stored in tangible memory (e.g., random access memory, read-only memory, CD-ROM memory, hard disk drive, etc.) that is read by a central processing unit to perform the functions of the innovations herein. Alternatively, a module may comprise programming instructions transmitted via a transmission carrier wave to a general-purpose computer or processing / graphics hardware. A module may also be implemented as hardware logic circuitry that performs the functions encompassed by the innovations herein. Finally, a module may be implemented using special purpose instructions (SIMD instructions), field programmable logic arrays, or a combination thereof that provides a desired level of performance and cost.

[0065] As disclosed herein, features consistent with the present disclosure may be implemented via computer hardware, software, and / or firmware. For example, the systems and methods disclosed herein may be embodied in various forms, including, for example, a data processor such as a computer, including a database, digital electronic circuitry, firmware, software, or combinations thereof. Moreover, while some of the disclosed implementations describe specific hardware components, systems and methods consistent with the innovations herein may be implemented in any combination of hardware, software, and / or firmware. Furthermore, the features and other aspects and principles described herein may be implemented in a variety of environments. Such environments and related applications may include general-purpose computers or computing platforms that may be specially constructed to execute various routines, processes, and / or operations in accordance with the invention, or may be selectively activated or reconfigured by code to provide the required functionality. The processes disclosed herein are not inherently related to any particular computer, network, architecture, environment, or other apparatus, but may be implemented by any suitable combination of hardware, software, and / or firmware. For example, various general-purpose machines may be used with programs written in accordance with the teachings of the invention, or it may be more convenient to construct a specialized apparatus or system to perform the required methods and techniques.

[0066] Aspects of the methods and systems described herein, such as logic, may be implemented as programmed functions in any of a variety of circuit configurations, including field programmable gate arrays ("FPGAs"), programmable array logic ("PAL") devices, electrically programmable logic and memory devices, and programmable logic devices ("PLDs") such as application-specific integrated circuits, as well as standard cell-based devices. Some other possibilities for implementing aspects include memory devices, microcontrollers with memory (such as EEPROMs), embedded microprocessors, firmware, software, etc. Additionally, aspects may be embodied in microprocessors with software-based circuit emulation, discrete logic (sequential and combinatorial), custom devices, fuzzy (neural) logic, quantum devices, and hybrids of any of the above device types. The underlying device technology may be provided in a variety of component types, including, for example, metal-oxide-semiconductor field-effect transistor ("MOSFET") technologies such as complementary metal-oxide-semiconductor ("CMOS"), bipolar technologies such as emitter-coupled logic ("ECL"), polymer technologies (e.g., silicon-conjugated polymer and metal-conjugated polymer-metal structures), and combinations of analog and digital.

[0067] It should be noted that the various logic and / or functionality disclosed herein, in terms of their behavior, register transfers, logic components, and / or other characteristics, may be enabled using any number of combinations of hardware, firmware, and / or data and / or instructions embodied in various machine-readable or computer-readable media. Computer-readable media on which such formatted data and / or instructions may be embodied include, but are not limited to, various forms of non-volatile storage media (e.g., optical, magnetic, or semiconductor storage media), but again, do not include volatile media. Throughout the description, terms such as "comprises," "comprising," and the like, should be interpreted in an inclusive sense, i.e., "including, but not limited to," rather than an exclusive or exhaustive sense, unless the context clearly requires otherwise. Words using the singular or plural number also include the plural or singular number, respectively. In addition, the terms "herein," "herein," "upon," "under," and words of similar import refer to this application as a whole, and not to any particular portions of this application. When the word "or" is used in reference to a list of two or more items, the term covers all of the following interpretations of the term: any item in the list, every item in the list, and any combination of items in the list.

[0068] While certain presently preferred implementations of the invention have been specifically described herein, it will be apparent to those skilled in the art to which this invention pertains that variations and modifications of the various implementations shown and described herein can be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by applicable rules of law.

[0069] While the foregoing has been made with reference to particular embodiments of the present disclosure, it will be understood by those skilled in the art that changes can be made in the embodiments without departing from the principles and spirit of the disclosure, the scope of the invention as defined by the appended claims.

Claims

1. 1. A method for confining an optical signal in a nonlinear optical quantum computing system, comprising: generating an optical signal in the nonlinear optical quantum computing system; and generating a trapping field that confines the optical signal by inducing a nonlinear interaction, the trapping field propagating with the optical signal.

2. The method of claim 1 , wherein the trapping field comprises an optical pulse that imparts a time-dependent phase shift to a target field to create a temporal trap of the optical signal.

3. The method of claim 2 , wherein the trapping field comprises an electrical pulse.

4. The method of claim 1 , wherein the trapping field confines the optical signal in the time domain.

5. The method of claim 1 , wherein the trapping field confines the optical signal in space.

6. The method of claim 1 , wherein the trapping field confines the optical signal in the spatial and temporal domains.

7. 10. The method of claim 1, wherein the nonlinear optical quantum computing system comprises a resonator having a ring cavity with one or more couplers, the one or more couplers preventing the trapping field from resonating within the resonator.

8. generating a plurality of optical signals in the nonlinear optical quantum computing system; confine the plurality of optical signals with another trapping field having a period that is a multiple of the cavity period; 8. The method of claim 7, further comprising: performing time multiplexing among the trapped optical signals.

9. generating a second optical signal in the nonlinear optical quantum computing system, the second optical signal traveling in a direction opposite to the optical signal; confine the second optical signal within the trapping field; The method of claim 7 , further comprising performing directional multiplexing between the optical signal and the second optical signal.

10. 10. The method of claim 1, wherein the nonlinear optical quantum computing system comprises a single-path waveguide and the trapping field comprises a guided-wave soliton.

11. 10. The method of claim 1, wherein the nonlinear optical quantum computing system comprises a segmented single-path waveguide and the trapping field is periodically updated.

12. The method of claim 1 , wherein the optical signal comprises a single target optical pulse.

13. The method of claim 1 , wherein the optical signal comprises multiple optical pulses trapped in a single cavity.

14. 1. A nonlinear optical quantum computing system, comprising: generating an optical signal; A nonlinear optical quantum computing system configured to generate a trapping field that confines the optical signal by inducing a nonlinear interaction, the trapping field propagating along with the optical signal.

15. 15. The nonlinear quantum computing system of claim 14, wherein the trapping field comprises an optical pulse configured to impart a time-dependent phase shift to a target field to create a temporal trap of the optical signal.

16. 15. The nonlinear quantum computing system of claim 14, wherein the trapping field is configured to confine the optical signal in the time domain.

17. 15. The nonlinear quantum computing system of claim 14, wherein the trapping field is configured to confine the optical signal in space.

18. 15. The nonlinear quantum computing system of claim 14, comprising a resonator having a ring cavity, with one or more couplers within the resonator configured to block resonance of the trapping field.

19. generating a second optical signal; confine the second optical signal within the trapping field; 20. The nonlinear quantum computing system of claim 18, further configured to perform time multiplexing between the optical signal and the second optical signal.

20. generating a second optical signal traveling in the opposite direction to the optical signal; confine the second optical signal within the trapping field; 20. The nonlinear quantum computing system of claim 18, further configured to perform directional multiplexing between the optical signal and the second optical signal.

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