Cold atom sensor of gyroscope type with corrected deviation

Abstract

The invention relates to an interferometric inertial ultra-cold atomic sensor (10) of the gyroscope type, comprising:-an atomic chip (ACh) comprising at least one set of first and second elementary sensors (SENA, SENB)-a power supply device (PSD),-a magnetic field generator and the power supply device being configured to apply a magnetic field, a DC current and a microwave signal in a predetermined sequence, arrangement and sequence of said set of one or more electrically conductive elements of each sensor are further configured such that a path (TR1) associated with a first base sensor and a path (TR2) associated with a second base sensor The invention is characterised in that it is identical and tracked simultaneously in opposite directions by a cloud of ultra-cold atoms associated with a given internal state,-the sensor further comprising a detection system (SDET).

Description

Technical Field

[0001] The present invention relates to the field of inertial sensors and more specifically to interferometric inertial cold atom sensors integrated in an atom chip. More specifically, the present invention relates to a gyroscope type cold atom sensor on an atom chip used during the measurement of an inertial parameter (usually the rotational speed) which uses a microwave field and an appropriate DC current to spatially separate and move two atomic clouds in two internal states. Background Art

[0002] In general, an inertial sensor is a device that makes it possible to measure a physical parameter related to movement, such as acceleration or angular velocity, which, when associated with a clock, allows the determination of spatial position. Devices that measure acceleration and rotational speed are called Inertial Measurement Units (IMU).

[0003] On-chip cold atom interferometry techniques allow this type of inertial measurement to be performed and are often compact and performant enough to be used in embedded applications.

[0004] The operation of cold atom gyroscopes is based on interferometry, and measuring the phase difference of the interferometer allows obtaining a measurement of the rotation.

[0005] In cold atom interferometry, two electronic states of an atom (such as rubidium 87), namely a first internal state |a> and a second internal state |b>, are interfered in a Ramsey sequence. The Ramsey interferometer sequence measures the phase accumulated during the realization of the sequence via the measurement of at least one population of selected states |a> or |b> (preferably, for greater accuracy, the measurement of both populations).

[0006] In order for such an interferometer to be sensitive to rotation, both states must trace a closed path that bounds a non-zero region, and do so in opposite directions for |a> and |b>. Thus, a term that depends on the Sagnac effect and therefore on the rotation speed is added to the energy difference between the two states.

[0007] A brief summary of the operating principle of measuring rotation by interferometry based on a clock-type Ramsey sequence, in which the phase of the interferometer at the end of the sequence is proportional to the energy difference between two states of the interferometer, is provided below.

[0008] In the case of a clock, the phase of the interferometer is given by:

[0009]

[0010] in:

[0011] ωab =ω 0a -ω 0b

[0012] is the phase of the atom in state |a>, and is the phase of the atom in state |b>,

[0013] ω is the angular frequency of the local oscillator,

[0014] is the electron energy of level |a>, and is the electron energy of level |b>.

[0015] ω ab is the angular frequency corresponding to the energy difference between states |a> and |b>, and T R is the free evolution time (Ramsey time).

[0016] If during this sequence, an atom in state |a> and an atom in state |b> are each made to trace the same closed path containing a non-zero region in opposite directions, then a term describing a phase shift that is sensitive to the rotation around the normal to this region appears due to the Sagnac effect: the clock becomes a gyroscope.

[0017] If the path of state |a> describes, for example, a rectangle traced clockwise, and state |b> describes the same path but counterclockwise, then the phase shift is given by:

[0018]

[0019] Where Ω z is the angular velocity around the z-axis, r a and v a (r b and v b ) are the position and velocity of the atom in state |a> (respectively state |b>) in the reference frame associated with the sensor, and a is the acceleration experienced by the sensor, which is oriented along the axis separating the two states and is measurable. m is the mass of the atom, and is the reduced Planck constant.

[0020] For paths that form a cycle so that each state returns to its initial position at the end of the sequence, it can be shown that if a is a constant, then the term expressed in terms of a·r equals 0, and the term (Ω z ∧r a ) 2 and (Ω z ∧r b ) 2Then, it can be expressed as follows (in Ω z In T R When the period is constant), write the phase shift:

[0021]

[0022] where A is a vector perpendicular to the area described by the path of the two states and whose norm is equal to the area, and N is the number of complete turns traced by each state.

[0023] Therefore, the total phase output by the interferometer at the end of this sequence is:

[0024]

[0025] Knowing the phase As well as the other quantities and parameters of formula (1) make it possible to determine the rotation speed about the z-axis of the plane perpendicular to the path.

[0026] The following will outline the operating principles of an atom chip based ultracold atom gyroscope making it possible to generate an ultracold atom cloud and the path allows the measurement of rotational speed via a phase such as described above.

[0027] Ultracold atoms are defined as atoms whose temperature is below 400 nanoKelvin and preferably below 300 nanoKelvin. The temperature of hot ultracold atoms (eg for rubidium atoms) is between 50 and 400 nanoKelvin and preferably between 100 and 300 nanoKelvin.

[0028] The principle is to obtain a path to be traced by two counter-propagating clouds of magnetically trapped atoms. The creation of the magnetic trap and its movement along this path is achieved via wires / elements and microwave guides placed on and in the atom chip.

[0029] Various conductive elements and waveguide topologies are known to those skilled in the art.

[0030] The document US2018 / 0352642 describes Figure 1 The first example is shown in .

[0031] The surface of the chip defines the XY plane or measurement plane which is perpendicular to the Z axis.

[0032] The chip 1 comprises a unit suitable for generating a first ultracold atomic trap T1 and a second ultracold atomic trap T2, the traps allowing a cloud of ultracold atoms 12 to be fixed in a state different from the internal state of another trap at a predetermined distance h from the measurement plane 13. For example, the trap T1 comprises atoms in an electronic level or state |a> (cloud CL1), while the trap T2 comprises atoms in a state |b> (cloud CL2). The levels |a> and |b> are separated by a frequency ωab / 2π. For example, in the case of rubidium 87, two hyperfine levels are involved |F=1,m- F =-1> and |F=2,m- F =1>, which are separated by about 6.8GHz.

[0033] These units also allow the cloud to move along a path 16 (also denoted TZ) lying in a plane parallel to the measurement plane 13 and at a height h from this plane, such as Figure 1 These units consist of waveguides and wires.

[0034] The waveguides CPW1 and CPW2 are suitable for the angular frequency ω b and ω a The microwaves are propagated. The waveguides are arranged symmetrically, preferably in parallel, with respect to the Y axis of the measurement plane. The two waveguides CPW1 and CPW2 are connected to at least one generator for generating a voltage or a current at microwave frequencies. For example, each of these waveguides is produced by depositing three wires in parallel so that a coplanar waveguide is formed. In other embodiments, other types of waveguides can be used, in particular waveguides whose production is compatible with microfabrication processes using deposition or etching. For example, it is possible to produce a microstrip line.

[0035] The wires integrated into the chip 1 are capable of transmitting DC current. The wires are classified into wires Wiz along a symmetry axis Y perpendicular to X and contained in the measurement plane 13 and a plurality (n) of wires Wldi parallel to each other and parallel to the X axis, the index i varying from 1 to n, n being at least equal to 2. Figure 1 In the example of , n=3, that is, there are three wires WId1, WId2 and WId3. The wires are arranged so as to define n intersections Ci (intersecting between Wz and Wldi) located on the Y axis, which are 3 intersections C1, C2, C3 here.

[0036] Each conductor is connected to one or more current and / or voltage generators, which are themselves connected to a processing unit comprising at least one microprocessor. The voltage and / or current generators allow both DC current and AC current to be driven through the conductor. In particular, DC current is driven through the conductor.

[0037] In the sensor, the atom chip 1 is placed in a vacuum chamber, the vacuum of which is maintained, for example, using an ion pump and preferably includes a magnetic shield. The sensor includes an apparatus for generating ultracold atoms, which includes:

[0038] - an atom distributor, which is for example a heated filament that delivers rubidium vapor;

[0039] - A primary (optical and / or magnetic) atom trap, which allows to pre-cool a cloud of ultracold atoms and is positioned near the chip (with the view of loading described below of magnetic traps T1 and T2 with atoms).

[0040] The sensor also comprises a magnetic field source external to the chip 1. It allows generating a uniform and static magnetic field Bc over a thickness of the order of at least a height h above the measurement plane 13. Advantageously, the direction of the uniform magnetic field is parallel to the measurement plane.

[0041] exist Figure 1 , the path 16 shown by the dashed line shows the path of the ultracold atomic cloud 12. This closed path defines an area denoted as A. A distance h separates the plane of the path 16 and the measurement plane 13 of the chip. Preferably, h is between 500 nm and 1 mm, and preferably between 5 μm and 500 μm.

[0042] Figure 2 The geometry of the waveguides and wires of the atom chip and the wells T1 and T2 are shown. The specific arrangement of the wires and waveguides associated with the uniform magnetic field of the source makes it possible to easily obtain Figure 2 The two wells T1 and T2 shown in part a) of FIG. Each well T1 and T2 has the same non-zero minimum value V0 and the same curvature, which is a necessary condition for the sensor to operate. Specifically, when a DC current is applied to at least two wires at the intersection, the minimum value of the electric potential is located perpendicular to the intersection. When microwave power is then sent through the waveguide, the central minimum value is converted into two minima located on either side of the initial minimum value in the direction of the waveguide. If the initial minimum value is not strictly located at an equal distance from the two waveguides, the two potential minima created will not have strictly the same minimum value V0 and the same curvature.

[0043] Figure 2 Part c) of ) shows the layout of wires and waveguides (seen from above) defining the initial crossing point C1. Figure 2 Part b) shows a cross-sectional view of the corresponding layout of the wires and waveguides printed on the chip, which view is a cross-sectional view through the wire WId1 (which intersects the wire WIz along the symmetry axis Y). The waveguides CPW1 and CPW2 are coplanar waveguides located in the first layer N1. The insulating layer 18 advantageously allows the measurement plane to be flattened. The material of the electrically insulating layer can be, for example, silicon dioxide, silicon nitride or benzocyclobutene. A conductive material (for example gold) is used to manufacture the wires and is deposited on the substrate 15, thereby forming the second layer N2. The substrate can be, for example, made of silicon, aluminum nitride or silicon carbide.

[0044] Part a) shows the symmetric separation of the ultracold atoms, which is specific to the internal state of the ultracold atoms, and more precisely the potential variation as a function of the position on the X-axis of the chip 1 .

[0045] Curve "a" shows the curve corresponding to a uniform magnetic field and two secant wires (carrying current I Z The wire WIz and the transmitted current I d1 The result is that the local potential well (initial potential Vini) forms a three-dimensional atomic well T. Ultracold atomic clouds can be trapped in it and cooled.

[0046] Curve "b" schematically shows the frequency ω of the b The electric potential created by sending microwaves. b The field emitted by the passage of allows to modify the energy of the ultracold atoms and to move the atoms of the internal state |b>. Curve "e" shows the potential observed by the internal state |b> as a result of the contribution of the potentials shown by curves "a" and "b". Curve "e" has a local potential minimum that allows the cloud of ultracold atoms of the internal state |b> to be locally trapped.

[0047] Similarly, curve "d" schematically shows the frequency ω of the a The electric potential created by sending microwaves. a The field emitted by the passage of allows to modify the energy of the ultracold atoms and to move the atoms of the internal state |a>. Curve "c" shows the potential observed by the atoms of the internal state |a> as a result of the contribution of the potentials shown by curves "a" and curve "d". Curve "c" has a local energy minimum that allows the cloud of ultracold atoms of the internal state |a> to be locally trapped.

[0048] The correlation of the DC magnetic trap (created by the DC current in the wire and the uniform field Bc) and the microwave field creates a so-called "dressed" trap. The term "dressed" is understood to mean a trap created at least in part by a microwave, radiofrequency or optical oscillating field. Variations of the microwave fields (power, frequency and the waveguides in which they propagate) make it possible to move the dressed trap and therefore the atoms. Figure 2 The DC magnetic trap is represented by curve a in FIG. Figure 2 The curve d represents the a The microwave field at Figure 2 The microwave field at ωb is represented by curve b in FIG. The trimmed well T1 for the state |a> is represented by curve c (correlation of curves a and d), and the trimmed well T2 for the state |b> is represented by curve e (correlation of curves a and b).

[0049] The ultracold atomic cloud with internal states |a> and |b> can be simultaneously a The wave propagates through CPW2 and makes the frequency ω b The waves propagating are separated and trapped symmetrically with respect to the symmetry axis Y by CPW1. In order to obtain two wells whose minima are the same value V0 and whose curvatures are the same value, it is important that the intersection point C1 is placed on the symmetry axis Y at an equal distance from CPW1 and CPW2.

[0050] Frequencyω a and ω b is the frequency ω of the states |a> and |b> 0a and ω 0b To choose.

[0051] Figure 3 The principle of generating a path 16 is shown. Figure 3 Part a) schematically shows the behavior of each cloud of ultracold atoms at a characteristic time t 1 to 9 Part b) shows in a complementary manner the sequence of various currents applied to the conductors, powers applied to the waveguides and frequencies applied to the waveguides at times corresponding to those of part a).

[0052] exist Figure 3 In the sequence presented in the figure, the current I flowing through WIz z (not shown) is static and at a constant value. In part b), the values ​​of current, power and frequency are arbitrary values. The y-axis labeled delta frequency corresponds to the frequency variation expressed in arbitrary units about the average frequency value. In the case of using rubidium atoms, the current transmitted through the wire can be between 100 μA and 10 A, and the angular frequency injected into the waveguide can be between 6.6 GHz and 7 GHz.

[0053] In step A0, there is a stage of preparing atoms. An ultracold atomic cloud 12 is generated, which comprises the stages of distributing the atoms, cooling the atoms, initializing the atoms to at least one internal state |a>, and trapping the ultracold atomic cloud at a distance h from the measurement plane (trap T, Figure 2 Curve "a", part a)). The height h is different from 0 because the uniform magnetic field Bc is non-zero.

[0054] The trapping is achieved by passing a DC current through the wire WIz and through one of the wires WIdi, the intersection of these two wires defining the starting point (here C1 and WId1). At the same time, a bias magnetic field Bc is applied parallel to the plane of the atomic chip, which is superimposed on the magnetic field created by the first two wires. The atomic cloud is then trapped by the potential Vini perpendicular to C1 (the intersection of wires Wlz and Wld1).

[0055] In step B0, the internal state is initialized by coherently superimposing the ultracold atoms in states |a> and |b> via a first pulse π / 2. This pulse can be generated by a laser, a microwave transmitter or more generally using a method in which a wave is emitted at a suitable transition frequency. The current I Z and I d1 are applied to the wire WIz and the wire WId1, respectively. The two internal states |a> and |b> are coherently and spatially superimposed perpendicularly to the intersection C1.

[0056] In step C0, the cloud of atoms of the internal state |a> in one trap T1 is spatially separated from the cloud of atoms of the internal state |b> in the other trap T2, and the traps are moved in opposite directions along a closed path 16 contained in a plane perpendicular to the measurement axis Z. The cloud of atoms of the internal state |a> has been symbolized by a disk of light texture, while the cloud of atoms of the internal state |b> has been symbolized by a disk of darker texture. This step is in Figure 3 In the example, the 1 to 9 Executed.

[0057] In t 1 and t 2 The microwave power injected into the waveguides CPW1 and CPW2 gradually changes from 0 to its maximum value. b , and sends an angular frequency ω to the waveguide CPW2 a , which allows two clouds of different internal states to move a distance d on either side of the symmetry axis Y to 2 Therefore, the above at time t 1 The ultracold atomic trap T described in is transformed into two ultracold atomic traps T1 and T2, each trap allowing an ultracold atomic cloud to be fixed in an internal state different from that of the other trap (in the present case, in one of these traps (e.g. T1) in the internal state |a> and in the other trap T2 in the internal state |b>, as in Figure 2 as described in part a) of the present invention).

[0058] The intersection point Ci corresponds to the intersection of the wire WIz and the wire WIdi.

[0059] In t 2 and t 3 Between, the current I d1 Gradually shrinking, and I d2 gradually reaches its maximum value (separation t 2 and t 3 The time interval is usually of the order of 10 ms and can be between 0.1 ms and 100 ms): the two wells T1 and T2 are moved to the right to the direction of t 3 The location is shown schematically.

[0060] In t 3 and t 4 Between, the current I d2 Gradually shrinking, and I d3 Gradually reaching its maximum value: move the two wells to the right to the maximum value for t 4 The location is shown schematically.

[0061] In t 4 and t 5 The microwave power is gradually reduced to return the two wells to the same position on the chip, as shown in Figure 2. 5 Shown schematically.

[0062] In t 5 At , modify the angular frequencies of the two microwave guides: change the angular frequency ω a is applied to CPW1, and the angular frequency ω b applied to CPW2.

[0063] In t 5 and t 6 The power in the two waveguides gradually changes from 0 to its maximum value: the wells are separated in the vertical direction, as shown in the figure for t 6 Shown schematically.

[0064] In t 6 and t 7 Between, the current I d3 Gradually shrinking, and I d2 Gradually reaches its maximum value: the two wells T1 and T2 are moved to the left to the 7 The location is shown schematically.

[0065] In t 7 and t 8 Between, the current I d2 Gradually shrinking, and I d1 Gradually reaching its maximum value: move the two wells to the left for t 8 This operation can be repeated multiple times with other first conductive lines to increase the area enclosed by the path 16 .

[0066] In t 8 and t 9 The microwave power in the waveguide is gradually reduced. The two wells T1 and T2 move until they merge into a well located for t 1 A single well at the starting point is schematically shown.

[0067] Thus, DC currents are applied to the two conductors corresponding to the initial intersection C1, and as time passes, these currents are successively applied to the various intersections Ci located on the axis of symmetry while microwave power is applied to the waveguide.

[0068] During step C0, the DC current applied to each conductor WIdi varies between 0 and a maximum value Idimax (at Figure 3 is normalized to 1) and changes continuously (increases and decreases), while the magnetic field Bc and the current I z remains constant during the sequence. Throughout the sequence A0, B0 and C0, the two wells T1 and T2 remain at height h.

[0069] The two traps T1 and T2 move in the "on" direction of the intersections: from intersection C1 to intersection Cn. The return trip is made by reversing the microwave frequency and successively switching on a DC current in the wires corresponding to the various intersections, passing it from Cn to C1. Thus, the traps travel a closed path 16.

[0070] In step D0, the internal states |a> and |b> are recombined by applying a second pulse π / 2 to the ultracold atoms, which transfers the phase difference to the two atomic-level populations. Next, the atomic density in the internal states selected from at least |a> and |b> is measured.

[0071] Finally, in step E0, the Sagnac phase shift (interferometer phase shift) of the ultracold atoms is determined and the rotation speed of the sensor around the Z axis is calculated.

[0072] In order to measure the rotational speed about an axis, it is necessary to generate a path in a plane perpendicular to that axis.

[0073] The document US2023 / 0178262 describes Figure 4 A second example of a chip topology is shown in FIG.

[0074] The atomic chip comprises a first pair of waveguides (CPWX1, CPWX2) parallel to each other and placed symmetrically with respect to the X axis, and a second pair of waveguides (CPWY'1, CPWY'2) parallel to each other and placed symmetrically with respect to the Y' axis, which in this non-limiting example is perpendicular to the X and equal to the Y axis. The Y' axis is different from the X axis, and the two pairs of waveguides are secant and define a parallelogram. The chip also comprises two wires W1 and W2 crossing at point O. When the two wires pass a DC current, they generate a potential Vini, which has a minimum value at point O. Therefore, the starting cloud CL is trapped above point O. For reasons of symmetry, point O preferably coincides with the center of the parallelogram.

[0075] In this document, the paths generated are perpendicular to X (path TX) and Y (path TY). To measure the rotational velocity Ωx around the X axis, path TX is generated via waveguides, wires and field B0. Similarly, to measure the rotational velocity Ωy' around the Y' axis, path TY' is generated via waveguides, wires and field B0.

[0076] exist Figure 5 The movement of atoms along the path TX is shown in FIG. 0 Starting at t (DC current is applied to the two wires W1 and W2 to generate Vini). 1 At t, the clouds are separated, the two clouds being separated in the same way as described in document US2018 / 0352642 (applying a microwave signal to the waveguide). 2 At t , clouds CL1 and CL2 are "raised" from height h1 to height h2 by modifying the value of the current flowing through the wire and / or by modifying the value of field B0. A substantially vertical segment of the path is then traced over a distance w = h2 - h1 (for an example of a timing diagram describing the order of application of the various signals, see the cited document). Next, at t 3 At t, the two clouds are brought back to the X-axis, still at height h2, by gradually reducing the power applied to the waveguide to zero. The other part of the second path segment at h2 on the other side of the X-axis (t 4 ,t 5 ) is obtained by reversing the value of the frequency of the microwaves applied to the waveguides CPWX1 and CPWX2. 5 At t, the height h1 is returned by returning the current through the wire to its initial value and / or by returning the magnetic field to its initial value. Finally, at t 6 At , the microwave power applied to the waveguide is reduced to zero and the two clouds meet.

[0077] By integrating additional wires defined at the intersections inside the parallelogram defined by the waveguides, the geometry of the chip of document US2018 / 0352642 can be combined with the geometry of document US2023 / 0178262. Thus, an interferometric inertial sensor is produced that allows the measurement of three rotational speeds Ωy, Ωy and Ωz.

[0078] Document US2023 / 0178262 describes the creation of a matrix array chip AchM0 that allows the creation of multiple elementary sensors. Figure 6 An example of a 6x6 matrix array is shown. Waveguides extending along 6 axes Xn and along 6 axes Ym form the columns and rows of the matrix array (in another geometry described in the referenced document, the waveguides form diagonals). Each pixel (n, m) of the matrix array corresponds to a potential elementary sensor. For example, the chip of column C1 measures ax, the chip of column C2 measures Ωy, the chip of row L1 measures ay, and the chip of row L2 measures Ωx. Since the measurements require a specific order of coplanar waveguides, the coplanar waveguides cannot be shared in two simultaneous measurements of two different inertial parameters. Therefore, the pixel 4 surrounded by the circle is not used. Therefore, the matrix array chip is reconfigured as required: the desired measurement type (ax, ay, Ωx, Ωy, t), the desired accuracy (which depends on the number of chips performing measurements simultaneously), etc. Therefore, parallel, redundant and / or complementary measurements are performed on the same matrix array chip.

[0079] According to another atomic chip geometry described in document US2022 / 0397396, additional pairs of waveguides and flared wires defining the DC plane are used to create paths along three axes. A specific sequence of microwave signals is applied to each pair, including at a frequency ω a , frequency ω b The signal at and the signal including two frequencies (the signal is represented by ω a +ω b and is called the "sum" signal). Applying a "sum" signal (from the frequency ω a The signal and frequency ω b One effect of the signal generated by summing the signals of the cloud is to repel the two clouds to the side opposite to the side where the waveguide through which the signal is flowing is located, so as to produce a path for measuring the rotation speed around the Z axis (see, for example, Figures 16 to 18 of the referenced document). The referenced document also describes a passage from height h1 to height h2 when two waveguides placed on either side of the cloud are simultaneously traversed by the "sum" signal, so as to produce a path for measuring the rotation speed around the X and Y axes (see, for example, Figures 20 and 22 of the referenced document).

[0080] Another chip geometry is described in document US2022 / 0397397, which includes two secant conductive strips whose intersection is at least partially contained in a parallelogram defined by two pairs of waveguides. The paths are generated by applying a specific sequence of microwave signals to the waveguides, also using the "repulsion" effect of the "sum" signal.

[0081] The two aforementioned chip geometries are also compatible with the matrix array architecture.

[0082] In order to obtain a more accurate measurement of the rotation around a certain axis, it is possible to exploit measurement redundancy (using multiple sensors, for example sensors in a matrix array architecture such as described above).

[0083] Therefore, a sensor based on a matrix array chip comprising a plurality of elementary sensors having the various geometries described above allows:

[0084] Performing clock functions, measurement of acceleration along two orthogonal axes, and measurement of rotation about three paired orthogonal axes on a single chip;

[0085] The basic geometry is replicated on the same atom chip in order to perform all the aforementioned measurements in parallel and to achieve redundancy between the various measurements.

[0086] However, this solution does not allow to eliminate measurement biases or correction errors.

[0087] Each measurement has an associated uncertainty, which is represented by an error in the measurement. This error may be due to random factors that are unavoidable and cannot be corrected (although their magnitude can be estimated), and to systematic factors that are due to sensor defects or imperfect measurement conditions. The latter type of error is also called bias.

[0088] An object of the present invention is to overcome the above mentioned drawbacks by providing an inertial sensor and a measurement method which allow to correct certain biases in order to obtain a better sensor performance. Summary of the invention

[0089] An object of the present invention is an interferometric inertial ultracold atomic sensor of the gyroscope type, comprising:

[0090] - an atomic chip placed in a vacuum chamber, comprising an XY plane, called measurement plane, perpendicular to the Z axis, and comprising at least one set of first elementary sensors and second elementary sensors, each elementary sensor comprising:

[0091] o at least one first pair of waveguides parallel to each other and at least one second pair of waveguides parallel to each other and secant to the first pair,

[0092] ○ A group of one or more conductive elements;

[0093] - an atom generation device configured to generate an initial cloud of ultracold atoms associated with the first elementary sensor and an initial cloud of ultracold atoms associated with the second elementary sensor, the initial clouds being positioned close to the XY plane of the chip,

[0094] - a generator for generating a uniform magnetic field;

[0095] a power supply device comprising at least one microwave generator and at least one generator of DC current, said power supply device being configured to apply a microwave signal to said waveguide and a DC current to said conductive element,

[0096] - the magnetic field generator and the power supply device are configured to apply the magnetic field, the DC current and the microwave signal in a predetermined sequence,

[0097] - during the implementation of each sensor, the arrangement of the set of one or more conductive elements and the order are configured as:

[0098] o an initial potential for generating said initial cloud for trapping ultracold atoms,

[0099] o spatially separating the initial cloud into a first ultracold atomic cloud in a first internal state and a second ultracold atomic cloud in a second internal state by forming a first ultracold atomic trap and a second ultracold atomic trap, respectively,

[0100] o and moving the trap along a closed path parallel or perpendicular to XY, the closed path being traced by the first cloud of ultracold atoms in one direction and by the second cloud of ultracold atoms in the opposite direction,

[0101] - said arrangement and said order of said set of one or more conductive elements of each sensor are further configured so that a path associated with said first elementary sensor and a path associated with said second elementary sensor are identical and are simultaneously tracked in opposite directions by the cloud of ultracold atoms associated with a given internal state,

[0102] The sensor further comprises a detection system configured to measure at least a first phase of the first elementary sensor and a second phase of the second elementary sensor, wherein the rotation speed is determined from a difference between the first phase and the second phase.

[0103] According to one embodiment, the power supply device is further configured to apply a DC current to the waveguide.

[0104] According to one embodiment, the sensor according to the invention comprises at least three sets configured to respectively perform measurements of rotations around three orthogonal axes.

[0105] According to one embodiment, the atomic chip has a matrix array structure, pixels of which define potential elementary sensors, and a set comprises two pixels of the matrix array.

[0106] According to one embodiment, the set of first elementary sensors and second elementary sensors have a common pair of waveguides or a common at least one conductive element.

[0107] According to another aspect, the present invention relates to an inertial measurement unit, which includes at least three gyroscope-type sensors according to the present invention, and the sensors are configured to measure the rotation speed around three orthogonal axes respectively, and the matrix array atomic chip also includes pixels configured to perform at least one clock measurement and pixels configured to perform acceleration measurements along at least two orthogonal axes.

[0108] According to another aspect, the invention relates to a method for measuring a rotational speed using an interferometric inertial ultracold atom sensor, the interferometric inertial ultracold atom sensor comprising an atom chip placed in a vacuum chamber, the atom chip comprising an XY plane, referred to as the measurement plane, perpendicular to the Z axis, and comprising at least one set of first and second elementary sensors, each elementary sensor comprising:

[0109] - at least one first pair of waveguides and at least one second pair of waveguides parallel to each other,

[0110] - a set of one or more conductive elements, the method comprising the steps of:

[0111] A. generating an initial cloud of ultracold atoms associated with the first elementary sensor and an initial cloud of ultracold atoms associated with the second elementary sensor, the initial clouds being positioned close to the XY plane of the chip,

[0112] B. Generate a uniform magnetic field,

[0113] C. generating an initial potential for trapping said initial cloud of ultracold atoms,

[0114] D. for each sensor, initializing a first internal state and a second internal state via a first π / 2 pulse,

[0115] E. for each sensor, spatially separating the initial cloud into a first ultracold atomic cloud in the first internal state and a second ultracold atomic cloud in the second internal state by forming a first ultracold atomic trap and a second ultracold atomic trap, respectively,

[0116] F. for each sensor, moving the trap along a closed path parallel or perpendicular to XY, the closed path being traced by the first ultracold atomic cloud in one direction and by the second ultracold atomic cloud in the opposite direction,

[0117] - Steps B to F are performed by applying a uniform magnetic field, applying a DC current to the conductive element and applying a microwave signal (I MW ) is applied to the waveguide to perform,

[0118] - said arrangement of one or more conductive elements of said set of elements and said predetermined order are also configured so that a path associated with said first elementary sensor and a path associated with said second elementary sensor are identical and are tracked simultaneously in opposite directions by a cloud of ultracold atoms associated with a given internal state,

[0119] G. recombining the first internal state and the second internal state by applying a second π / 2 pulse to the ultracold atoms,

[0120] H. At least a first phase of the first elementary sensor and a second phase of the second elementary sensor are measured, the rotation speed being determined based on a difference between the first phase and the second phase.

[0121] According to one embodiment, step C comprises applying a DC current to at least one conducting element.

[0122] According to one embodiment, step E comprises applying a microwave signal to said first pair of waveguides.

[0123] According to one embodiment, step F comprises applying a microwave signal to at least one waveguide of said second pair.

[0124] According to one embodiment, step F comprises applying a DC current to certain conductive elements.

[0125] The following description presents several examples of embodiments of the device of the invention: these examples do not limit the scope of the invention. These examples of embodiment contain not only the features essential to the invention but also additional features associated with the embodiment in question. BRIEF DESCRIPTION OF THE DRAWINGS

[0126] The invention will be better understood and other features, objects and advantages thereof will become apparent from the following detailed description, which is given by way of non-limiting examples with reference to the accompanying drawings, in which:

[0127] Figure 1(already described) shows a first example of the topology of an atom chip according to the prior art.

[0128] Figure 2 (already described) shows the geometry of the waveguides and wires of an atom chip according to the prior art as well as the ultracold atom traps and associated potentials.

[0129] Figure 3 (already described) shows the principle of path generation. Part a) schematically shows each cloud of ultracold atoms at a characteristic time t 1 to 9 Part b) shows in a complementary manner the sequence of various currents applied to the conductors, powers applied to the waveguides and frequencies applied to the waveguides at times corresponding to those of part a).

[0130] Figure 4 (already described) shows a second example of the topology of an atom chip according to the prior art.

[0131] Figure 5 (already described) shows that the atom adopts Figure 4 Move along the path shown in .

[0132] Figure 6 (already described) shows an example of a matrix array atom chip according to the prior art.

[0133] Figure 7 Two paths traced in opposite directions through an atom cloud in accordance with the present invention are shown.

[0134] Figure 8 An interferometric inertial ultracold atomic sensor according to the present invention is shown.

[0135] Fig. 9 A first way is shown of generating two paths TZ1 and TZ2 (measurements of Ωz) contained in the XY plane, which are traced in opposite directions by each cloud in the internal state |a> or |b>, where the clouds are moved using wires.

[0136] Fig.10 A second way of producing two paths TZ1 and TZ2 (measurements of Wz) contained in the XY plane, which are traced in opposite directions by each cloud in the internal state |a> or |b>, where the clouds are moved by applying a DC current to the wire.

[0137] Fig.11A third way is shown of producing two paths TZ1 and TZ2 (measurements of Wz) contained in the XY plane, which are traced in opposite directions by each cloud in the internal state |a> or |b>, where the cloud is moved by applying a DC current to the wire.

[0138] Fig.12 A fourth way is shown of producing two paths TZ1 and TZ2 (measurements of Wz) contained in the XY plane, which are traced in opposite directions by each cloud in the internal state |a> or |b>, where the cloud is moved by applying a microwave signal to the waveguide.

[0139] Fig.13 A fifth way is shown of producing two paths TZ1 and TZ2 (measurements of Wz) contained in the XY plane, which are traced in opposite directions by each cloud in the internal state |a> or |b>, where the cloud is moved by applying a microwave signal to the waveguide.

[0140] Fig.14 A sixth way of producing two paths TZ1 and TZ2 (measurements of Wz) contained in the XY plane, which are traced in opposite directions by each cloud in the internal state |a> or |b>, where the cloud is moved by applying a microwave signal to the waveguide. DETAILED DESCRIPTION

[0141] The idea of ​​the invention is to use two elementary sensors which are specifically configured to eliminate measurement deviations.

[0142] Formula (1) given above corresponds to a direction of travel of the atomic cloud CL1 (and CL2 in the opposite direction) on a path such as that described above. By way of illustration, the path is considered to be a rectangle R traced by CL1 (state |a>) in the clockwise direction and by CL2 (state |b>) in the counterclockwise direction, such as in Figure 7 as shown in Part A of the FIG.

[0143] For a gyroscope, the sign of the phase shift induced by the presence of rotation during the interferometry phase depends on the way the two atomic clouds trace a given geometric path. The sign of the phase shift depends on the direction of travel of each of these states relative to the direction of rotation.

[0144] Everything happens in the same direction (e.g. Fig. 9 The right side of Fig.10 ), then the direction of separation must be reversed. Or one leaves to the right and the other leaves to the left, and the directions are the same ( Fig.11 ).

[0145] Consider two cold atom gyroscopes placed on the same chip, where the traps are separated / moved using movable trapping potentials, each oriented so that it is sensitive to rotations around the same axis (e.g., the z-axis). This means that the two paths followed by the clouds are placed in the same plane. If the directions of travel of the atomic states used in these sensors are opposite, each gyroscope will accumulate the same phase shift, but the sign of the phase shift will be different. By making these two measurements simultaneously, it is possible to eliminate the presence of measurement bias, as explained below.

[0146] Therefore, from Figure 7 Starting with part A of , if the propagation direction of the atoms in each state is reversed (i.e., the path of state |a> describes the rectangle in the counterclockwise direction, and state |b> describes the same path, but in the clockwise direction), as Figure 7 As shown in part B of , the phase shift changes sign.

[0147] set up For the corresponding Figure 7 The phase accumulated during the interferometric measurement sequence of part A, and For the corresponding Figure 7 The phase accumulated during the interferometric measurement sequence of part B. Rewriting equation (1) gives:

[0148]

[0149] Assuming that the measurement is subject to bias, it can be stated that:

[0150]

[0151] in, is an additional phase due to the bias present in any measurement (the so-called additive bias).

[0152] If there is a (non-negligible) deviation, then determine Allows elimination of:

[0153]

[0154] In order to carry out a measurement which allows the aberration to be removed, it is necessary to perform two interferometric measurement sequences in parallel using two sensors on the same chip.

[0155] The interferometric inertial ultracold atom sensor 10 according to the present invention uses this property and Figure 8It comprises an atomic chip ACh placed in a vacuum chamber, comprising an XY plane perpendicular to the Z axis, the XY plane being referred to as the measurement plane. The chip comprises at least one set of first elementary sensors SENA and second elementary sensors SENB. Each elementary sensor comprises at least one first pair of waveguides (CPWX1, CPWX2) parallel to each other and at least one second pair of waveguides (CPWY'1, CPWY'2) parallel to each other and secant to the first pair. The intersection of the two pairs defines a parallelogram, such as Figure 4 As shown, the atomic chip also includes a group of one or more conductive elements CE1.

[0156] The sensor further comprises an atom generation device ACG configured to generate an initial cloud of ultracold atoms associated with the first elementary sensor SENA and an initial cloud of ultracold atoms associated with the second elementary sensor SENB. The initial cloud is positioned close to said XY plane of the chip. The sensor further comprises a generator GB for generating a uniform magnetic field Bc and a power supply device PSD. The power supply device comprises: at least one microwave generator GMW configured to apply a microwave signal to the waveguide; and at least one generator of a DC current configured to apply a DC current to the conductive element. The magnetic field generator GB and the power supply device PSD are configured to apply a magnetic field Bc, a DC current and a microwave signal in a predetermined order.

[0157] When each sensor is implemented, the arrangement and predetermined order of the set of one or more conductive elements is configured to perform the various steps described above on the cloud.

[0158] First, it involves: generating an initial electric potential Vini for trapping the initial cloud of ultracold atoms, and then spatially separating the initial cloud into a first ultracold atomic cloud in a first internal state (CL1A for SENA and CL1B for SENB) and a second ultracold atomic cloud in a second internal state (CL2A for SENA and CL2B for SENB) by forming a first ultracold atomic trap (T1A for SENA and T1B for SENB) and a second ultracold atomic trap (T2A for SENA and T2B for SENB), respectively.

[0159] Next, the trap is moved along a closed path parallel or perpendicular to XY traced by the first ultracold atomic cloud in one direction and by the second ultracold atomic cloud in the opposite direction.

[0160] The arrangement of the set of one or more conductive elements and the predetermined order are also configured such that a path TR1 associated with the first elementary sensor and a path TR2 associated with the second elementary sensor are identical and are simultaneously tracked in opposite directions by the ultracold atomic cloud associated with a given internal state. Figure 7 The principle of two paths being tracked in opposite directions is shown in FIG.

[0161] The sensor further comprises a detection system SDET configured to measure at least a first phase of a first elementary sensor and the second phase of the second elementary sensor The rotation speed is determined from the difference between the first phase and the second phase (characteristic expressed by formula (2)). Thus, during the implementation of the sensor according to the invention, a double simultaneous measurement of the same parameter (phase accumulated during the interferometric measurement sequence) is performed.

[0162] Using the interferometer characteristics expressed by equations (2A), (2B) and (3), the rotation speed thus determined is corrected for "additive" biases that affect each measurement equally. This reduction in measurement bias results in a reduced measurement uncertainty (i.e. improved sensitivity) for the gyroscope according to the invention, which allows longer inertial navigation times to be obtained.

[0163] The sensor according to the invention is compatible with any atomic chip geometry comprising two pairs of microwave guides which make it possible to generate wells called "trimmed" wells (see prior art), i.e. to generate trapping potentials, and to selectively move these wells along closed paths depending on the internal state.

[0164] Therefore, the conductive elements CE1 of the chip can be arranged in various ways. What is important is to generate a trapping potential generated from the combination of the DC field generated by the conductive elements passing the DC current and the microwave field generated by the waveguide passing the microwave signal, which can be moved to create a closed path.

[0165] For example, the sensor according to the invention is compatible with all chip geometries described in the prior art associated with various solution modes, ie with a specific sequence of applied magnetic field, DC current and microwave field.

[0166] Generally, according to the prior art:

[0167] An initial trapping potential is generated by applying a DC current to a conductive element (usually two wires crossing at point O, or two strips crossing, or a flared wire, etc.).

[0168] The two wells T1 and T2 are separated by applying a microwave signal to each waveguide.

[0169] The movement of the well by moving the minimum of the trapping potential results from:

[0170] applying a DC current to other wires (US2018 / 0352642), to the same wires, and / or applying a different magnetic field (US2023 / 0178262),

[0171] Or microwave signals are applied to the waveguide in a specific sequence, switching the waveguide on and off with signals of various frequencies associated with specific conductive element geometries: a flared wire (US2022 / 0397396); two secant strips (US2022 / 0397397).

[0172] Specifically, the minimum of the DC magnetic field is moved (which results from the DC current and uniform magnetic field in the wire), which moves the minimum of the trap produced from the combination of the DC magnetic field and the MW field (which results from the transmission of the microwave signal through the waveguide), or the DC magnetic field is fixed and the MW magnetic field changes, which moves the trap produced from the combination of the DC magnetic field and the MW field.

[0173] According to another embodiment, once the cloud has been separated, the microwave signal applied to the waveguide is replaced by a DC current. This embodiment is described in the context of a gyroscope applied in document FR2306475 (not yet published at the filing date). In this case, the power supply device PSD is also configured to apply a DC current to the waveguide. This replacement allows to reduce the measurement noise.

[0174] The sensor according to the invention is therefore independent of the geometry of the atomic chip and of the method for selectively separating / moving the traps. The chip may employ another geometry of conductive elements associated with waveguides not described in the aforementioned document as well as additional waveguides. The implementation of the sensor may use a separation / movement method (sequence) making it possible to generate movable trapping potentials (i.e., whose minimum can be moved) other than those described in the aforementioned document.

[0175] Non-limiting examples of embodiments of sensors according to the invention will now be described.

[0176] Figures 9 to 14 The two paths TR1 and TR2 (for Ω) generated are shown to be contained in the XY plane. z The two paths are traced in opposite directions by each cloud in the internal state |a> or |b>. 1 to 7 The positions of the individual clouds are shown: 1 Starting situation; t 2 Separation 3 Move; 4 Recombination 5 Separation (in opposite direction); t 6 Move;7 The hue or texture of the waveguide shows its state, i.e. whether it is "off" (no signal applied; black) or "on" (signal applied; various shades of grey). 7 The direction of the arrow on the path shows the direction the path is traced by the cloud in the internal state |a> (dark grey). Other paths in the XY plane and other (XZ and YZ) planes can be obtained without limitation using the geometries and sequences described in the prior art.

[0177] Figures 9 to 11 A case is shown where the trap is moved by applying a DC current to the two intersection points. Figure 12 to Figure 14 The case where the trap is moved via a "repulsion" effect by applying a "sum" signal to one of a pair of waveguides not used for separation is shown. In all figures, the trap is moved horizontally along the X axis and separated vertically along Y by applying a microwave field to the waveguides along X (i.e., to CPWX1 and CPWX2). In these examples, Y'=Y, and the first pair of waveguides and the second pair of waveguides are perpendicular to each other in each sensor in the set.

[0178] exist Fig. 9 , the separation directions of the two states are opposite for the two paths (cloud CL1A in state |a> of SENA is upward, cloud CL1B in state |a> of SENB is downward), and each pair of clouds associated with one basic sensor moves in the same direction (here to the right).

[0179] exist Fig.10 , the separation directions of the two states are opposite for the two paths (cloud CL1A in state |a> of SENA is upward, cloud CL1B in state |a> of SENB is downward), and each pair of clouds associated with one basic sensor moves in the same direction (here, to the left).

[0180] exist Fig.11 In the figure, the separation direction of the two states is the same for both paths (cloud CL1A in state |a> for SENA and cloud CL1B in state |a> for SENB upward), and the two pairs of clouds associated with the two basic sensors move in opposite directions, to the left in SENA (clouds CL1A and CL2A) and to the right in SENB (clouds CL1B and CL2B).

[0181] exist Fig.12In , the separation direction of the two states is opposite for the two paths (cloud CL1A in state |a> of SENA is upward, cloud CL1B in state |a> of SENB is downward), and each pair of clouds associated with one elementary sensor moves in the same direction (here to the right). For this purpose, a "sum" signal is applied to the waveguide along Y on the side opposite to the movement (i.e. on the left-hand side).

[0182] exist Fig.13 In , the separation direction of the two states is opposite for the two paths (cloud CL1A in state |a> of SENA is upward, cloud CL1B in state |a> of SENB is downward), and each pair of clouds associated with one elementary sensor moves in the same direction (here to the left). For this purpose, a "sum" signal is applied to the waveguide along Y on the side opposite to the movement (i.e., on the right-hand side).

[0183] exist Fig.14 In , the separation direction of the two states is the same for both paths (cloud CL1A in state |a> for SENA and cloud CL1B in state |a> for SENB upwards), and the pairs of clouds associated with the two elementary sensors move in opposite directions, to the left in SENA and to the right in SENB. For this purpose, a "sum" signal is applied to the waveguide along Y on the right hand side in SENA and to the waveguide along Y on the left hand side in SENB.

[0184] According to one embodiment, the sensor according to the invention comprises at least three sets configured to respectively perform measurements of rotations around three orthogonal axes. For this purpose, in each set, a first pair of waveguides and a second pair of waveguides are perpendicular to each other. For example, the first set is configured to measure Ωz using the generation of a path perpendicular to Z, the second set is configured to measure Ωx using the generation of a path perpendicular to X, and the third set is configured to measure Ωy using the generation of a path perpendicular to Y (specifically, Y'=Y).

[0185] According to one embodiment, the individual sets are organized into a matrix array. According to one embodiment, the atomic chip of the sensor according to the invention has a matrix array structure, the pixels of which define potential elementary sensors. A set according to the invention comprising two sensors SENA and SENB corresponds to two pixels of the matrix array.

[0186] The structure of the matrix array is, for example, described in the prior art. According to one embodiment, Figure 6As shown, it is an arrangement of pairs of waveguides that define the columns and rows of the matrix array. According to another embodiment, it is an arrangement of conductive elements (wires / strips / flared wires) that define the rows and columns, with each pair of waveguides typically being along the diagonals of the matrix array (see example in document US2023 / 0178262).

[0187] To optimize the measurement, according to one embodiment, the set of first and second elementary sensors has a common pair of waveguides or a common at least one conductive element. Thus, it is possible to measure two phases according to the invention using the same sequence applied to a common waveguide or element.

[0188] Generally, in the figures showing various examples, it can be seen that in certain configurations, the waveguide along X can be used for two sensors ( Fig.11 and Fig.14 ) is common, or the waveguide along Y can be common ( Fig. 9 , Fig.10 , Fig.11 , Fig.12 and Fig.13 ), which optimizes the matrix array arrangement.

[0189] The present invention also relates to an inertial measurement unit on a matrix array atomic chip, which includes at least three gyroscope-type sensors according to the present invention, which are configured to measure the rotation speed around three orthogonal axes respectively. The matrix array atomic chip also includes pixels configured to perform at least one clock measurement and pixels configured to measure acceleration along at least two orthogonal axes.

[0190] According to another aspect, the invention relates to a method for measuring a rotational speed using an interferometric inertial ultracold atomic sensor 10 comprising an atom chip ACh placed in a vacuum chamber, the atom chip comprising an XY plane, called measurement plane, perpendicular to the Z axis, and comprising at least one set of first and second elementary sensors (SENA, SENB), each elementary sensor comprising:

[0191] - at least one first pair of waveguides (CPWX1, CPWX2) parallel to each other and at least one second pair of waveguides parallel to each other and secant to the first pair of waveguides

[0192] The second pair of waveguides (CPWY'1, CPWY'2),

[0193] - a group of one or more conductive elements

[0194] The method comprises a first step A, which comprises generating an initial cloud of ultracold atoms associated with a first elementary sensor SENA and an initial cloud of ultracold atoms associated with a second elementary sensor SENB, the initial cloud being positioned close to the XY plane of the chip. In step B, a uniform magnetic field is generated, and in step C, an initial potential Vini is generated for trapping the initial cloud of ultracold atoms.

[0195] Next, in each sensor, in step D, a first internal state |a> and a second internal state |b> are initialized via a first π / 2 pulse.

[0196] Next, in each sensor, in step E, the initial cloud is spatially separated into a first atomic cloud (CL1A, CL1B) in a first internal state and a second ultracold atomic cloud (CL2A, CL2B) in a second internal state by forming a first ultracold atomic trap (T1A, T1B) and a second ultracold atomic trap (T2A, T2B), respectively.

[0197] Next, in each sensor, in step F, the trap is moved along a closed path parallel or perpendicular to XY traced by the first ultracold atomic cloud in one direction and by the second ultracold atomic cloud in the opposite direction.

[0198] Steps B to F are performed by applying a uniform magnetic field near the chip, applying a direct current to the conductive element, and applying a microwave signal to the waveguide in a predetermined sequence.

[0199] The arrangement of the set of one or more conductive elements and the predetermined order is also configured so that the path TR1A associated with the first elementary sensor and the path TR2A associated with the second elementary sensor are identical and are tracked simultaneously in opposite directions by the ultracold atomic cloud associated with a given internal state.

[0200] In step G, the first internal state and the second internal state are recombined by applying a second π / 2 pulse to the ultracold atoms.

[0201] Finally, in step H, at least the first phase of the first elementary sensor is measured and the second phase of the second elementary sensor The rotation speed is determined based on the difference between the first phase and the second phase.

[0202] According to one embodiment, step C comprises applying a DC current to at least one conducting element.

[0203] According to one embodiment, step E comprises applying a microwave signal to the first pair of waveguides. According to one embodiment, step F comprises applying a microwave signal to at least one waveguide of the second pair.

[0204] According to one embodiment, step F comprises applying a DC current to certain conductive elements.

Claims

1. A gyroscope-type interferometric inertial ultracold atomic sensor (10), comprising: - an atom chip (ACh) placed in a vacuum chamber, which includes an XY plane perpendicular to the Z axis, called the measurement plane, And comprises at least one set of a first basic sensor and a second basic sensor (SENA, SENB), each basic sensor comprising: o at least one first pair of waveguides (CPWX1, CPWX2) parallel to each other and at least one second pair of waveguides (CPWY'1, CPWY'2) parallel to each other and secant to the first pair, ○ a group of one or more conductive elements, an atom generation device (ACG) configured to generate an initial cloud of ultracold atoms associated with said first elementary sensor (SENA) and an initial cloud of ultracold atoms associated with said second elementary sensor (SENB), said initial clouds being positioned close to said XY plane of said chip, - a generator (GB) for generating a uniform magnetic field (Bc), - a power supply device (PSD) comprising at least one microwave generator (GMW) and at least one generator of DC current (GDC), The power supply device is configured to apply a microwave signal to the waveguide and a DC current to the conductive element, - the magnetic field generator and the power supply device are configured to apply the magnetic field, the DC current and the microwave signal in a predetermined sequence, - during the implementation of each sensor, the arrangement of the set of one or more conductive elements and the order are configured as: i) generating an initial potential (Vini) for trapping said initial cloud of ultracold atoms, ii) spatially separating the initial cloud into a first ultracold atomic cloud (CL1A, CL1B) in a first internal state and a second ultracold atomic cloud (CL2A, CL2B) in a second internal state by forming a first ultracold atomic trap (T1A, T1B) and a second ultracold atomic trap (T2A, T2B), respectively, iii) and moving the trap along a closed path parallel or perpendicular to XY, the closed path being traced by the first cloud of ultracold atoms in one direction and by the second cloud of ultracold atoms in the opposite direction, - said arrangement and said order of said set of one or more conductive elements of each sensor are also configured so that a path (TR1) associated with said first elementary sensor and a path (TR2) associated with said second elementary sensor are identical and are simultaneously tracked in opposite directions by a cloud of ultracold atoms associated with a given internal state, The sensor further comprises a detection system (SDET) configured to measure at least a first phase of the first elementary sensor and the second phase of the second basic sensor The rotation speed is determined according to the difference between the first phase and the second phase.

2. A sensor according to the preceding claim, wherein: The power supply device (PSD) is also configured to apply a DC current to the waveguide.

3. The sensor according to any one of claims 1 and 2, comprising at least three sets configured to respectively make measurements of rotations about three orthogonal axes.

4. A sensor according to any one of the preceding claims, wherein: The atomic chip has a matrix array structure, the pixels of which define a potential elementary sensor, and a set includes two pixels of the matrix array.

5. The sensor according to the preceding claim, wherein The set of the first elementary sensor and the second elementary sensor has a common pair of waveguides or a common at least one conductive element.

6. An inertial measurement unit, comprising at least three gyroscope-type sensors according to any one of claims 4 and 5, wherein the sensors are configured to measure rotational speeds around three orthogonal axes respectively, and the matrix array atomic chip also includes pixels configured to perform at least one clock measurement and pixels configured to measure acceleration along at least two orthogonal axes.

7. A method for measuring a rotational speed using an interferometric inertial ultracold atom sensor (10), the interferometric inertial ultracold atom sensor (10) comprising an atom chip (ACh) placed in a vacuum chamber, the atom chip (ACh) comprising an XY plane perpendicular to the Z axis, referred to as the measurement plane, and comprising at least one set of first and second elementary sensors (SENA, SENB), each elementary sensor comprising: o at least one first pair of waveguides (CPWX1, CPWX2) parallel to each other and at least one second pair of waveguides (CPWY'1, CPWY'2) parallel to each other and secant to the first pair, ○ a group of one or more conductive elements, The method comprises the following steps: A. generating an initial cloud of ultracold atoms associated with the first elementary sensor (SENA) and an initial cloud of ultracold atoms associated with the second elementary sensor (SENB), the initial clouds being positioned close to the XY plane of the chip, B. Generate a uniform magnetic field, C. the initial potential (Vini) for generating said initial cloud for trapping ultracold atoms, D. for each sensor, initializing a first internal state and a second internal state via a first π / 2 pulse, E. for each sensor, spatially separating the initial cloud into a first ultracold atomic cloud (CL1A, CL1B) in the first internal state and a second ultracold atomic cloud (CL2A, CL2B) in the second internal state by forming a first ultracold atomic trap (T1A, T1B) and a second ultracold atomic trap (T2A, T2B), respectively, F. for each sensor, moving the trap along a closed path parallel or perpendicular to XY, the closed path being traced by the first ultracold atomic cloud in one direction and by the second ultracold atomic cloud in the opposite direction, Steps B to F are performed by applying a uniform magnetic field, applying a DC current to the conductive element, and applying a microwave signal (I MW ) is applied to the waveguide to perform, said arrangement of one or more conductive elements of said set of elements and said predetermined order are further configured such that a path (TR1A) associated with said first elementary sensor and a path (TR2A) associated with said second elementary sensor are identical and are simultaneously tracked in opposite directions by a cloud of ultracold atoms associated with a given internal state, G. recombining the first internal state and the second internal state by applying a second π / 2 pulse to the ultracold atoms, H. Measure at least the first phase of the first elementary sensor and the second phase of the second basic sensor The rotation speed is determined based on the difference between the first phase and the second phase.

8. A method according to the preceding claim, wherein: Step C includes applying a DC current to at least one conductive element.

9. The method according to any one of claims 7 and 8, wherein: Step E includes applying a microwave signal to the first pair of waveguides.

10. The method according to the preceding claim, wherein: Step F includes applying a microwave signal to at least one waveguide of the second pair.

11. The method according to claim 7, wherein: Step F includes applying a DC current to certain conductive elements.

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