Capacitive Coupling Compensation for Direct Current Electrodes in Ion Traps

An ion trap system and method of using an ion trap system, the system including a substrate, a radio frequency (RF) source configured to provide an RF signal, an RF electrode disposed in the substrate and connected to the RF source, a direct current (DC) source configured to provide a DC signal, a DC electrode disposed in the substrate and connected to the DC source, wherein the DC electrode is separate from the RF electrode, and a coupling compensation system configured to provide a compensating RF signal associated with the RF signal.

TECHNICAL FIELD

The present disclosure relates generally to a system and method for accurately controlling and moving ions in an ion trap, and, in particular embodiments, to a system and method for providing a compensation for capacitive coupling between control electrodes in ion movement trap systems.

BACKGROUND

Generally, ion traps may be used as ion shuttling systems in trapped ion quantum computing, with ions used as qubits for computation, and the excitation state of an electron indicating a logical value or logic state, or as atomic clock systems. Ions such as barium (Ba), magnesium (Mg), calcium (Ca), beryllium (Be), or the like, may be positively charged, and an electron of the ion may be used as the logic element. Two or more ions may be entangled, providing substantial speed and power savings over conventional computing. Additionally, ion traps may be used in atomic clocks, where the vibration of the ions' internal state is used as a frequency reference, for example for the definition of a second.

However, ion traps require a well-controlled environment, and precise handling of the ions. Ions in an ion trap are trapped or controlled using a radio frequency (RF) electrical field. Additionally, direct current (DC) electrical fields may be provided by DC electrodes separate from RF electrodes, with the DC fields used to control or move the trapped ions. The use of both RF and DC electrical fields through different electrodes may results in capacitive coupling between the DC electrodes and RF electrodes, effectively attenuating, or otherwise interfering with, the DC signals provided at the DC electrodes. In order to provide the desired DC and RF fields for precise control of ions, interference with the RF and DC fields should be eliminated to the greatest possible extent.

SUMMARY

An embodiment ion trap system includes a substrate, a radio frequency (RF) source configured to provide an RF signal, an RF electrode disposed in the substrate and connected to the RF source, a direct current (DC) source configured to provide a DC signal, a DC electrode disposed in the substrate and connected to the DC source, wherein the DC electrode is separate from the RF electrode, and a coupling compensation system configured to provide a compensating RF signal associated with the RF signal.

An embodiment system includes a radio frequency (RF) electrode configured to provide an RF field in response to a received RF signal, where the RF field is configured to confine an ion, a direct current (DC) source configured to provide a DC signal, where the DC signal is configured to perform at least one of controlling or moving the ion, a coupling compensation system configured to provide a compensating RF signal associated with the RF signal, and a DC electrode connected to the coupling compensation system and connected to the DC source, where the DC electrode is separate from the RF electrode, and where the DC electrode is configured to provide a DC field according to the compensating RF signal and further according to the DC signal, and where the DC field is compensated, according to the compensating RF signal, for a capacitive coupling between the RF electrode and the DC electrode induced by the RF field.

An embodiment method includes applying a radio frequency (RF) field to an RF electrode to contain an ion in an ion trap system, determining a target direct current (DC) electrode of the ion trap system, determining a compensating RF signal associated with the RF signal, generating the compensating RF signal, applying the compensating RF signal to the target DC electrode wherein the compensating RF signal results in a DC field that is compensated for capacitive coupling between the RF electrode and the target DC electrode, and performing, using the compensating RF signal, at least one of controlling or moving an ion.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Illustrative embodiments of the system and method of the present disclosure are described below. In the interest of clarity, all features of an actual implementation may not be described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions may be made to achieve the developer's specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time-consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

Ion trapping is a promising candidate for quantum computing, atomic clocks, and other technologies dependent on isolating single ions. In a trapped ion quantum computing system, electrostatic potentials are used to move ions between storage and processing locations in a process called ion shuttling. Similarly, electrostatic potentials are used in atomic clocks to trap and control an ion, with properties of the ion used to define the length of a second. In order to control these potentials, hundreds, or even thousands, of electrodes must be simultaneously controlled in order to provide the desired electrical field (E-field).

A system for ion shuttling may use a limited number of digital-to-analog converters (DACs) that are multiplexed to a large number of electrodes in a multidimensional array. A multidimensional ion shuttling system provides for shuttling of multiple ions in multiple different directions simultaneously using the same DACs to avoid the cost, power requirements, and necessary die space associated with a one-to-one DAC-to-electrode arrangement.

The use of numerous DC electrodes at the same times as multiple RF electrodes that provide RF containment fields results in capacitive coupling between the DC electrodes and the RF electrodes. However, while filter capacitors between a DC electrode and ground may filter some RF signals to reduce the induced capacitive coupling, the size of filter capacitors required for large scale applications makes filter capacitors impractical to scale. Using active capacitive coupling compensation instead of filter capacitors may provide for a more fine-tuned and adjustable coupling compensation with more complete coupling reduction and improved scalability.

FIG.1is a logical diagram illustrating an ion trap system100with a coupling compensation system112according to some embodiments. The system100has one or more ion trap areas104A-104D that include ion shuttling systems, and which are configured to shuttle ions between target areas such as an ion reservoir106, ion read-out area108, and other areas such as ion disposal areas (not shown), processing areas110, and between the ion trap areas104A-104D. The system100may also have one or more shuttling controllers102electrically connected to the ion shuttling systems of the ion trap areas104A-104D to control movement of ions. The shuttling controllers102switch voltages to elements of the ion trap areas104A-104D to provided DC voltages that create voltage profiles for moving the ions.

While the system100is illustrated with four ion trap areas104A-104D and one shuttling controller102with the ion trap areas104A-104D in a symmetrical arrangement, the system100is not limited to such an arrangement. The shuttling controller102provides addressable voltage control of electrodes, and is, therefore, configured to control any number of cascaded ion trap areas104A-104D, in any arrangement.

Additionally, the shuttling controller102may be provided as a unitary controller, with a single controller, or multiple shuttling controllers102, controlling any number or size of the ion trap areas104A-104D. The ion trap areas104A-104D may also be cascaded so that additional ion trap areas104A-104D and shuttling controllers102may be connected to existing ion trap areas104A-104D and shuttling controller102to expand the shuttling area, number of ions controlled, and capabilities of the system100. The shuttling controller102may address one or more DC electrodes for controlling positioning or movement of an ion in the ion trap areas104A . . .104C. Additionally, any of the ion reservoir106, ion read-out area108, ion disposal areas, processing areas110, or other ion system parts may also have ion shuttling systems or movement control systems with DC electrodes for controlling positioning or movement over an ion, and these additional DC electrodes may be controlled by the shuttling controllers,102, or by another control system.

The system100may have a RF system with an RF controller116that provides an RF containment field separately from the DC bias of the DC electrodes and other compensation electrodes. The RF field may be provided by electrodes that are separate from electrodes used to provide a shuttling or keeping voltage fields or compensation voltage fields. In some embodiments, the RF field may be operated at around 200 volts, and 20 megahertz (MHz), and the DC fields may be provided locally and separately to shuttle ions being contained by the RF field.

In order to prevent the RF field provided by the RF controller116such as, for example, a directly connected RF resonator, from interfering with DC fields provided by the shuttling controller102or other DC signal or voltage source, a coupling compensation system112may be provided to modify voltages on one or more DC electrodes to compensate for capacitive coupling between RF electrodes and DC electrodes. In some embodiments, a compensation RF signal that is out of phase with the containment RF signal provided by the RF controller116may be provided on one or more DC electrodes to provide a DC field at the respective DC electrode with a net DC field that omits, avoids, or at least reduces, RF components induced by the capacitive coupling between the RF and DC electrodes.

FIG.2is a diagram illustrating an ion shuttling system200according to some embodiments. The ion shuttling system200may include a shuttling controller102connected to DC electrode210such as a confinement, compensation or shuttling electrode. The DC electrodes210may be arranged in a two-dimensional pattern, or in another arrangement with one dimension, or in three dimensions for layered patterns.

The ion shuttling system200may also have additional electrodes such as RF electrodes218adjacent to, or between, the DC electrodes210and other electrodes such as lane elements202, ground electrodes, compensation electrodes, sensors electrodes, or the like. In some embodiments, the system200may have lane elements202along which an ion may be shuttled. The shuttling controller102provides a DC biasing voltage to the DC electrodes210to move and steer ions along shuttling lanes204,206. The shuttling controller102provides a voltage to each DC electrode210, and the provided voltage may be connected though a filtering switch so that the voltage is filtered as it is turned on. The voltage at each DC electrode210may be set or held by a latch, capacitor, or the like, associated with the respective DC electrode210, or may be continuously provided with a transient signal or other signal having an RF or AC component for compensation of capacitive coupling.

The shuttling controller102may address an individual electrode element, which includes the latch and DC electrode210itself, and may provide a DC voltage signal or other signal to set the voltage for a particular DC electrode210. In some embodiments, the DC voltage may be held by the DC electrode's210associated latch. Thus, each DC electrode210may be addressed individually, and have a specific voltage applied.

In some embodiments, the shuttling controller102addresses the individual DC electrodes210using an electrode control or addressing system, which controls application of a voltage to the DC electrodes210. Thus, the DC electrode210in a particular column and row may have a DC voltage that is set by routing a voltage controlled by a DAC to a latch or storage element, such as a capacitor for the respective DC electrode210, so that the electrode latch or storage element sets the voltage at the DC electrode210.

However, in some embodiments, a coupling compensation system112may provide an AC or RF voltage that acts as a compensation RF signal for one or more of the DC electrodes210to compensate for capacitive coupling between the respective DC electrode210and one or more RF electrodes218. The coupling compensation system112may add the compensation RF signal to the DC signal to create an output signal at the DC electrodes210that has a DC component and an AC component. In other embodiments, the coupling compensation system112may have auxiliary electrodes (not shown) associated with respective DC electrodes210. The coupling compensation system112may provide an RF signal to the auxiliary electrodes to advantageously create a compensation capacitive coupling between the auxiliary electrode and respective DC electrode to compensate for the incidental capacitive coupling between the DC electrode210and RF electrode218. In some embodiments, the coupling compensation system112may set the phase and amplitude of the compensating RF signal based on location of the DC electrode210to which the compensating RF signal is being applied, so that the compensating RF signal may be varied or tailored to provide a specific compensating RF field for different DC electrodes210. For example, an amplitude of the compensating RF field may be based on a distance between the DC electrode210and the RF electrode218.

In other embodiments, an RF field generated by voltages applied to the RF electrodes218may hold an ion in a controlled position relative to the electrodes, or over a lane element202, where present. The DC shuttling field provided by DC electrodes210causes the ion to move along the electrodes or lane elements202. In some embodiments, movement or shuttling of the ion is performed by setting a DC voltage on an electrode to create DC bias in the E-field, with the DC bias allowing control of the position of an ion along, or parallel to, the lane204.

The voltages provided to the DC electrodes210may be provided by DC sources such as DACs that provide a voltage or voltage profile to one or more DC electrodes210. However, as the ion moves past DC electrodes210, different voltage profiles from different DACs may be needed on a particular electrode. This can be performed by using multiplexers or other switching or addressing to switch DACs supplying the voltage to a particular DC electrode210.

Changing the shuttling voltage on the DC electrodes210permits control of the movement of the ion, and ions may be moved along shuttling lanes204,206. Additionally, positioning of an electrode within a lane204,206relative to the DC electrodes210and RF electrodes218may be provided by differential DC voltages applied across a lane to laterally shift an ion.

The shuttling lanes206,204may be arranged so that shuttling lanes204,206cross to form intersections214to allow for switching an ion onto different shuttling lanes204,206for two dimensional movement. The DC electrodes210may be arranged so that free space is created between the DC electrodes210, and shield elements208may be provided to shield the DC electrodes210and ions located in shuttling lanes204,206from voltages provided for other ions in other locations along the shuttling lanes204,206. Such an arrangement may reduce cross-talk between ions in the ion shuttling system200and simplify production of the ion shuttling system200. Additionally, while the shuttling lanes204,206and DC electrodes210are arranged inFIG.2in a symmetrical pattern, the DC electrodes210and shuttling lanes204,206are not limited to such an arrangement, as any arrangement in two dimensions may be provided, including an arrangement where shuttling lanes204,20s6intersect or cross at non-right angles. Shuttling lanes204,206are not limited to crossing each other, as the shuttling lanes204,206may form a three way, or ‘T’ intersection, or may form a turn or angle, such as an ‘L’ shaped intersection.

FIG.3is a diagram illustrating a relationship between electrodes in an ion trap system300according to some embodiments. The ion trap system300may have elements formed on a substrate302. In some embodiments, elements of the ion trap system300may be formed using semiconductor packaging or fabrication techniques, for example, by depositing conductive material on the substrate302and forming electrodes, lane elements, shields, connectors, and the like, in, for example, glass or oxide layers. Additionally, connection layers (not shown), such as layers of conductive wiring, may be formed as a stack or on the backside of the system to provide connections to control elements such as electrodes, multiplexers, DACs, and the like. One or more other devices, such as transistors, or logic gates, or other circuits may also be formed or located on the surface of the substrate302, on the backside of the substrate302, on the wiring layers, or the like, to permit integration of the system elements into a package or system-on-chip (SoC). Additionally, any analog or digital circuit may be integrated with the passive part of the ion trap system consisting of electrodes and wiring, and integration may be done on the same substrate or using stacked dies.

In the ion trap system, one or more metal elements may be formed in a metallization layer, for example, using a damascene etch-and-fill process. The metallization layer may have one or more substrates such as insulator layers, that may be, for example, silicon dioxide, glass, or other insulating materials. In some embodiments, elements such as RF electrodes218, confinement, shuttling, or DC electrodes210, shield elements208, lane elements212, magnetic coils, or the like, may be formed in the metallization layers, and may be a conductive material such as copper, aluminum, gold, a metal alloy, ceramic or silicide, or another conductive material. Additionally, while not shown, connecting wiring may be provided in one or more additional metallization layers or insulator layers to connect the elements to each other or to other elements, such as switches, controllers, DACs, or the like.

In some embodiments, RF electrodes218may be disposed adjacent to a lane element202such as an RF ground, or the like, and adjacent to a DC electrode210. Thus, the RF electrode218may be disposed between the lane element202and an associated DC electrode210. Additionally, the ion trap system300may have multiple RF electrodes218. For example, the ion trap system may have two RF electrodes218, associated with a particular lane element202or portion of a lane element202, and with one or more RF electrodes218disposed one each side of the lane element202.

FIG.4Ais a logical diagram illustrating an electrode arrangement400with a coupling compensation system410according to some embodiments. In some embodiments, an RF source402generates an RF signal, and the RF signal is routed to an RF electrode218by an RF control system404. In some embodiments, the RF control system404may be one or more switches, DACs, multiplexers, or the like, that switch the RF signal to one or more selected RF electrodes218. In other embodiments, the RF control system404may control characteristics of the RF signal, such as the phase, or amplitude of the signal according to characteristics of the ion being contained. For example, the RF control system404may adjust the RF signal strength to create a stronger or weaker RF field in certain areas of an ion trap, or may adjust RF signal strength according to the position of the ion, heating or motion of the ion, or the like. In other embodiments, the RF source402may connect directly to the RF electrode218without an RF control system404.

The electrode arrangement400may further have a DC source408that provides a DC voltage to an associated DC electrode. The DC voltage may be routed to an identified DC electrode412, for example, by a switching system, routing system, or other system for connecting a particular DC source408to one or more selected DC electrodes412. The DC source408may be, for example, a DC voltage generator, a DAC, or the like, and may provide a constant, transient, or variable DC voltage to the DC electrode. However, the proximity of the RF electrode218to the DC electrode412may result in parasitic capacitive coupling406between the RF electrode and then DC electrode412.

A coupling compensation system410may be connected to the DC electrode412to provide a signal that compensates for the capacitive coupling406. In some embodiments, the coupling compensation system410is an active compensation system that provides or generates an RF or AC signal to the DC electrode that at least partially cancels, attenuates or compensates for the capacitive coupling406. Thus, the coupling compensation system410may provide an AC or RF signal that is associated with the RF signal provided by the RF source. For example, the coupling compensation system410may provide a compensating RF signal that mirrors, but is 180 degrees out of phase with, the RF signal provided by the RF source402. This provides destructive interference between the RF signal and the compensating RF signal so that the DC electrode412provides a DC field that is a result of the DC signal alone without the capacitive coupling406(or at least with attenuated capacitive coupling). In other embodiments, the coupling compensation system410may provide the compensating RFG signal and attenuate the compensating RF signal to adjust the destructive interference between the compensating RF signal and the RF signal from the RF source402. Thus, where the RF signal from the RF source402causes capacitive coupling406with a particular capacitance, the coupling compensation system410may provide a compensating RF signal that is different from, but associated with, the RF signal, and that compensates for the actual capacitive coupling406.

FIG.4Bis a logical diagram illustrating an electrode arrangement400with a coupling compensation system410connected to the RF source402according to some embodiments. In some embodiments, the coupling compensation system410may provide a compensation signal that is taken from, generated according to, or that is provided by, the RF source402. Therefore, the RF source402may avoid the need to an additional resonator or RF source. For example, the coupling compensation system410may have an electrical connection that connects one the RF source, or a portion of the RF source402to the DC electrode, or that combines the DC signal with the compensating signal to provide the compensated signal to the DC electrode412. In some embodiments, the coupling compensation system410may select an appropriate RF signal from a plurality of RF signals provided by the RF source402to selectively provide a compensating RF signal to the DC electrode412.

For example, an RF source may provide2signals that are 180 degrees out of phase with each other, with a first signal provided to a first RF electrode, and a second signal provided to a second RF electrode. The second signal may be 180 degrees out of phase with the first signal, with the two RF electrodes on opposite sides of an ion containment area. The out-of-phase RF signals are applied on opposite side of the ion to contain the ion. Since the RF source provides two different out of phase signals, a signal be selected to compensate for a disturbing signal. Thus, for compensation for coupling caused by, for example, the first RF electrode, a compensating signal may be the first RF signal that is phase shifted to generate the compensating signal, or may be the out-of-phase second RF applied to the second electrode, avoiding the need to phase shift any signal to generate the compensating signal.FIG.5Ais a logical diagram illustrating an electrode arrangement500with an auxiliary resonator502coupling compensation system410according to some embodiments. The coupling compensation system410may include an auxiliary resonator502in series with a DC source408so that the signal provided to the DC electrode412has both a DC component and an AC component. A phase control element504may keep the signal at the DC electrode412phase locked with the RF signal provided by the RF source to the RF electrode218. Thus, the auxiliary resonator may provide an AC or RF signal that is associated with the RF signal provided by the RF source402. In some embodiments, the phase control element504monitors the RF signal from the RF source402, and sets the phase of the compensating RF signal provided by the auxiliary resonator502. For example, the phase control element504may be a phase locked loop, or a phase detector that drives a voltage controlled oscillator auxiliary resonator502.

The coupling compensation system410may further control the compensating RF signal according to the RF signal provided by the RF source402, according to the capacitive coupling406, or according to other circuit parameters. For example, the amplitude of the compensating RF signal may be determined during, manufacturing or testing of the electrode arrangement500or ion trap system. This may permit use of a fixed compensating RF signal, and the circuit can be tuned to provide a predetermined compensating RF signal at the auxiliary resonator502.

FIG.5Bis a logical diagram illustrating an electrode arrangement520with a coupling compensation system410according to some embodiments. In some embodiments, the coupling compensation system410may use an RF signal from the RF source402and avoid using an auxiliary resonator. The coupling compensation system410may include a compensation control element522having connections, switching circuits, or the like, that selectively connect at least one RF signal from the RF source402to the DC electrode. The RF signal from the RF source402may act as the compensating RF signal, and the compensation control element522may select or connect a selected RF signal from the RF source to compensate for an identified interfering RF signal. In other embodiments, the compensation control could adapt the RF signal from the RF source402by modifying a phase of the RF signal from the RF signal and/or an amplitude of the RF signal to generate the compensating RF signal.

FIG.6Ais a logical diagram illustrating an electrode arrangement600with a bias tee604coupling compensation system410according to some embodiments. A bias tee604may have components, such as capacitive elements, or a combination of capacitive and inductive elements, that permit combination of DC and AC signals so that a DC voltage signal may be provided to the DC electrode412with an AC or RF component for compensation for the capacitive coupling406. As discussed above, the auxiliary resonator502provides the compensating RF signal, with the phase of the compensating RF signal controlled or set by the phase control element504, and the amplitude set to a predetermined value. Using the bias tee604permits use of an amplifier602that amplifies the DC signal from the DC source408without the amplifier602having to drive the capacitive load or the compensating RF signal. Additionally, a bias tee604after the amplifier602avoids phase shifting of the compensating RF signal by the amplifier602. While not shown, each DC electrode412may have a variable capacitor that filters the signal provided to the DC electrode412.

FIG.6Bis a logical diagram illustrating an electrode arrangement620with a coupling compensation system410according to some embodiments. In some embodiments, the coupling compensation system410may use an RF signal from the RF source402and avoid using an auxiliary resonator. The coupling compensation system410may include a compensation control element522having connections, switching circuits, or the like, that selectively connect at least one RF signal from the RF source402through the bias tee to the DC electrode. Thus, the RF signal from the RF source402may act as the compensating RF signal, and the compensation control element522may select or connect a selected RF signal from the RF source to compensate for an identified interfering RF signal. In other embodiments, the compensation control could adapt the RF signal from the RF source402by modifying a phase of the RF signal from the RF signal and/or an amplitude of the RF signal to generate the compensating RF signal.

FIG.7is a logical diagram illustrating an electrode arrangement700with a switched coupling compensation system410according to some embodiments. In some embodiments, the coupling compensation system410has a switching matrix706that connects the auxiliary resonator502to the DC electrode412through one or more capacitors of a capacitor bank704. The capacitor bank704may have capacitors with different capacitance values to attenuate the RF signal generated by the auxiliary resonator502before the compensating RF signal is added to the DC signal and is provided to the DC electrode412. In some embodiments, the capacitors of the capacitor bank704may have binary weightings, but in other embodiments, the capacitors may have different weights determined according to circuit or system requirements. Thus, in an embodiment, a constant base compensating RF signal may be generated for multiple DC electrodes, and each DC electrode412may have a switching matrix706and capacitor bank704to tune the constant base compensating RF signal for the individual DC electrode412.

In some embodiments, the coupling compensations system410includes a compensation connection controller702that controls the switching matrix706to connect the auxiliary resonator502through the capacitor bank704. In some embodiments, the compensation connection controller702may be one or more latches that are set or programmed at a startup of the overall system, and that turn transistors in the switching matrix706on or off to provide connections through selected capacitors in the capacitor bank704.

The DC source408may be connected to the DC electrode412to provide a desired DC voltage to a selected DC electrode412. In some embodiments, the DC source408may connect directly to the DC electrode412. In other embodiments, one or more optional elements, such as an amplifier602, or a switching system (not shown), or the like may be disposed between the DC source408and the DC electrode412to modify the signal from the DC source, route the signal to an appropriate DC electrode412, or otherwise manage or process the signal from the DC source408.

In some embodiments, the switching matrix706and capacitor bank704may connect the auxiliary resonator502directly to the DC electrode412. However, in other embodiments, the amplifier602may be between the DC electrode412and the capacitor bank704, however the amplifier may cause a phase shift in the compensating RF signal provided by the auxiliary resonator502, and the phase control may be configured to cause the auxiliary resonator502to provide the base compensating RF signal with a phase that is 180 degrees out of phase with the RF signal provided by the RF source402, and further with a phase adjustment to correct for the phase shift introduced by the amplifier602.

In another embodiment, the coupling compensation system410may omit the auxiliary resonator502and phase control504, and may couple the DC electrode412to the RF source402to provide, to the DC electrode412, an RF signal selected as a compensating RF signal to compensate for the capacitive coupling406. Thus, the coupling compensation system410may connect the RF source to the switching matrix706so that the capacitor bank704attenuates the RF signal to generate the desired compensating RF signal before the compensating RF signal is added to the DC signal and is provided to the DC electrode412.

FIG.8is a logical diagram illustrating an electrode arrangement800with an auxiliary electrode802coupling compensation system410according to some embodiments. In some embodiments, a coupling compensation system410may include an auxiliary resonator502that provides a compensating RF signal to an auxiliary electrode802that is separate from the DC electrode412and from the RF electrode218. The compensating RF signal provided to the auxiliary electrode802may be provided with an amplitude and phase that provide compensation coupling804between the auxiliary electrode802and the DC electrode412. The compensation coupling804may be capacitive coupling that effectively compensates for the capacitive coupling406between the RF electrode218and the DC electrode412.

In another embodiment, the coupling compensation system410may omit the auxiliary resonator502and phase control504, and may couple the DC electrode412to the RF source402to provide, to the auxiliary electrode802, an RF signal selected as a compensating RF signal to compensate for the capacitive coupling406. Thus, the coupling compensation system410may connect the RF source402to the auxiliary electrode802to generate the compensation coupling804.

FIG.9is a logical diagram illustrating an electrode arrangement with an amplifier-based coupling compensation system410according to some embodiments. In some embodiments, a coupling compensation system410may include an auxiliary resonator502and phase control element504that are coupled to a DC electrode412through an amplifier902. The amplifier902may be an inverting amplifier uses the compensating RF signal as an input, and modulates and amplifies the DC signal from the DC source408by the compensating RF signal. In such an arrangement, a feedback resistor904may be a variable resistor to provide an adjustable gain, where input resistors906are substantially constant.

The coupling compensation system410may connect to the DC electrode412through one or more switches908. In some embodiments, the one or more switches908may be a switching matrix that routes or connects the combination of the DC signal and compensating RF signal to selected DC electrodes412to provides a shuttling or keeping voltage that has a compensation RF component provided by the auxiliary resonator502.

In another embodiment, the coupling compensation system410may omit the auxiliary resonator502and phase control504, and may couple the RF source402to an input resistor906or directly to the amplifier902. Thus, the coupling compensation system410may connect the RF source402to the auxiliary electrode802to provide the compensating RF signal from the RF source402.

FIG.10Ais a logical diagram illustrating an electrode arrangement1000with a shim electrode1004according to some embodiments. In some embodiments, an ion1002may be confined or contained over a substrate1010by an RF field provided by RF electrodes (not shown). DC electrodes1006may provide a DC field1014such as a keeping field or shuttling field, which is grounded by a ground electrode1008. Shim electrodes1004may be provided, and a shim voltage may be applied to the shim electrodes1004to generate a shim RF field1012that causes an RF field at the position of the ion1002to compensate for the RF field caused by DC electrodes due to capacitive coupling with adjacent RF electrodes. The shim voltage may, in some embodiments, be an RF field that compensates the variations in the DC field that are created by the RF field. Using a shim electrodes1004avoids using a capacitance between the shim electrode1004and the DC electrode1006, because there is no substantial direct interaction between the DC electrodes1006and shim electrodes1004. Instead, the shim electrodes1004would rather compensate for the capacitive coupling between the RF electrode and the DC electrode1006by providing an E-field at the position of the ion1002by providing an additional E-field that compensates for the disturbing signal on the DC electrode at the position of the ion. The coupling compensation system410may be formed in accordance with any of the above-referencedFIG.4A-9.

FIG.10Bis a logical diagram illustrating an electrode arrangement1020with a shim electrode1004according to some embodiments. In some embodiments, an RF source402generates an RF signal, and the RF signal is routed to an RF electrode218by an RF control system404. The electrode arrangement1020may further have a DC source408that provides a DC voltage to an associated DC electrode1006that may be subject to capacitive coupling with the RF electrode218.

A shim electrode1004separate from the DC electrode1006may be provided in the electrode arrangement1020, and the shim electrode1004may be used to provide an E-field that modifies or adjusts the E-field in the region of an ion to compensate for inaccuracies in the E-field induced by the capacitive coupling between the RF electrode210and the DC electrode1006. A coupling compensation system410may be connected to the DC electrode412to provide a signal that compensates for the capacitive coupling406. Thus, the coupling compensation system410may provide an AC or RF signal that is associated with the RF signal provided by the RF source402. The coupling compensation system410may have an auxiliary resonator (not shown), may use an RF signal provided by the RF source402as a compensating RF signal, or may generate another RF signal that is tuned for adjustment of the DC field.

FIG.11is a flow diagram illustrating a method1100for providing capacitive coupling compensation according to some embodiments. In block1102, a target DC electrode is determined. The target DC electrode may be determined by a control system such as a compensation control system or the like, or may be determined by a shuttling or other DC electrode control system. The target DC electrode may, in some embodiments, may be a DC electrode to which a DC signal may be applied.

In block1106, an RF field may be applied. In some embodiments, the RF field may be applied to an RF electrode by an RF source. In block1108, an ion may be contained by an ion trap system, and in particular, the ion may be contained at least partially by the applied RF field. Containing the ion may include maintaining an ion over a desired location or element. Application of the RF field and containment of the ion may result in a capacitance being induced between the RF electrode and the target DC electrode.

In block1104, a compensating RF field may be determined. In some embodiments, the compensating RF field may be predetermined according to the location and a predetermined value of the RF field. In other embodiments, the compensating RF field may be determined dynamically, for example, by a monitoring system that monitors a capacitance of the target DC electrode, movement, heating, vibration, positioning, or other characteristics of the ion, according to environmental factors, or other parameters. Determining the compensating RF field may include determining a magnitude of the RF field, which may be similar to, proportional to, related to, or otherwise associated with, the magnitude of the RF field, or according to other parameters of the RF field. For example, the magnitude of the compensating RF field may be less than the magnitude of the RF field, as the geometry of the RF electrodes and DC electrodes may be such that the RF field does not create a perfect capacitive coupling.

In block1110, the phase of the compensating RF signal is determined. In some embodiments, the phase of the compensating RF signal may be phase locked with the phase of the RF signal, and may be phase locked to be 180 degrees out of phase with the phase of the RF signal. In some embodiments, the phase of the compensating RF signal may be adjusted from being 180 degrees out of phase with the phase of the RF signal to account for phase shifting by amplifiers, or other elements in the compensation or DC circuits, or to provide an RF field that compensates for the capacitive coupling between the RF electrode and the target DC electrode.

In block1112, the compensating RF signal is determined or generated. In some embodiments, the compensating RF signal may be generated by an auxiliary resonator such as an RF source, or the like. In some embodiments, the compensating RF signal may be generated by using the RF signal provided by the RF source and adjusting the phase and amplitude according to the determined phase and amplitude needed for the compensating RF signal. In other embodiments, a compensating signal from an RF source may be identified. For example, a compensating RF signal may be identified as being provided by an RF source that provides an RF signal having a desired phase that cancels the signal causing the capacitive coupling.

In block1114, the DC signal is generated. The DC signal may be a DC compensation signal, and shuttling signal, a keeping signal or another DC signal. The DC signal may be generated according to the target DC electrode, and, in some embodiments, according to the positioning, or desired movement of the ion. The DC signal may in some embodiments, be a transient or varying signal generated as part of a voltage profile used for shutting an ion, or may be substantially constant DC signal. In block1116, the compensated DC signal is generated and applied to the target DC electrode. In some embodiments, the compensated DC signal has a DC component from the DC signal, and an AC or RF component from the compensating RF signal. Thus, the compensated DC signal may have an AC or RF component that is associated with the RF signal. The compensated DVC signal may be generated by injecting the compensating RF signal into the DC signal by, for example, a bias tee or a switching matrix, by adding the compensating RF signal to the DC signal, by modulating the DC signal by the compensating RF signal using an amplifier, or the like. In block1118an ion is controlled or moved using the compensated DC signal.

An embodiment ion trap system includes a substrate, a radio frequency (RF) source configured to provide an RF signal, an RF electrode disposed in the substrate and connected to the RF source, a direct current (DC) source configured to provide a DC signal, a DC electrode disposed in the substrate and connected to the DC source, wherein the DC electrode is separate from the RF electrode, and a coupling compensation system configured to provide a compensating RF signal associated with the RF signal.

In some embodiments, the coupling compensation system includes an auxiliary resonator configured to generate the compensating RF signal. In some embodiments, the compensating RF signal is at least one of generated based on the RF signal or provided from at least a portion of the RF source. In some embodiments, the coupling compensation system comprises an auxiliary electrode separate from the DC electrode and the RF electrode, wherein the coupling compensation system is configured to provide the compensating RF signal to the auxiliary electrode. In some embodiments, the coupling compensation system is configured to provide the compensating RF signal to the DC electrode. In some embodiments, the ion trap system further comprises a shim electrode separate from the DC electrode, where the coupling compensation system is configured to provide the compensating RF signal to the shim electrode. In some embodiments, the coupling compensation system includes a phase control element configured to set a phase of the compensating RF signal according to a phase of the RF signal. In some embodiments, the phase control element is configured to set a phase of the compensating RF signal to be about 180 degrees out of phase with the phase of the RF signal. In some embodiments, the coupling compensation system includes a bias tee configured to provide the compensating RF signal associated to the DC electrode. In some embodiments, the coupling compensation system includes an amplifier configured to provide the compensating RF signal associated to the DC electrode. In some embodiments, the coupling compensation system comprises an amplifier, and a phase control element configured to set a phase of the compensating RF signal according to a phase of the RF signal, where DC source is connected to the DC electrode through the amplifier, and the RF source is connected to the DC electrode through the amplifier. In some embodiments, the coupling compensation system comprises a capacitor bank configured to modify the compensating RF signal and to provide a modified compensating RF signal to the DC electrode.

An embodiment system includes a radio frequency (RF) electrode configured to provide an RF field in response to a received RF signal, where the RF field is configured to confine an ion, a direct current (DC) source configured to provide a DC signal, where the DC signal is configured to perform at least one of controlling or moving the ion, a coupling compensation system configured to provide a compensating RF signal associated with the RF signal, and a DC electrode connected to the coupling compensation system and connected to the DC source, where the DC electrode is separate from the RF electrode, and where the DC electrode is configured to provide a DC field according to the compensating RF signal and further according to the DC signal, and where the DC field is compensated, according to the compensating RF signal, for a capacitive coupling between the RF electrode and the DC electrode induced by the RF field.

In some embodiments, the coupling compensation system includes an auxiliary resonator connected to the DC electrode. In some embodiments, the coupling compensation system further includes a phase control element configured to set a phase of the compensating RF signal according to a phase of the RF signal. In some embodiments, the phase control element configured to set a phase of the compensating RF signal to be about 180 degrees out of phase with the phase of the RF signal. In some embodiments, the coupling compensation system further includes a capacitor bank configured to modify the compensating RF signal and to provide a modified compensating RF signal to the DC electrode.

An embodiment method includes applying a radio frequency (RF) field to an RF electrode to contain an ion in an ion trap system, determining a target direct current (DC) electrode of the ion trap system, determining a compensating RF signal associated with the RF signal, generating the compensating RF signal, applying the compensating RF signal to the target DC electrode wherein the compensating RF signal results in a DC field that is compensated for capacitive coupling between the RF electrode and the target DC electrode, and performing, using the compensating RF signal, at least one of controlling or moving an ion.

In some embodiments, the compensating RF signal is applied to the target DC electrode. In some embodiments, the phase of the compensating RF signal is about 180 degrees out of phase with a phase of the RF signal. In some embodiments, the method further includes generating a DC signal, and generating a compensated DC signal according to the DC signal and the compensating RF signal, and the performing at least one of controlling or moving the ion includes performing, using the compensated DC signal, the at least one of controlling or moving the ion.