Scanner with optical network unit with mobile phase control

Description

TECHNICAL FIELD

[0001] The invention relates to a scanner or micro-scanner, i.e. a device for emitting an optical wave, or light wave, scanning a surface or a volume, as well as a method for producing such a scanner or micro-scanner. The invention can be used for one of the following fields: 2D (two-dimensional) or 3D (three-dimensional) optical scanner; 3D imaging, for example to scan a scene which is then reconstructed in 3D with an imager; Image projection, for example within a pico-projector (miniaturized projector) or to carry out an intra-retinal projection; Endoscopy; LIDAR, for example used in an autonomous vehicle or other. STATE OF THE PRIOR ART

[0002] A 2D optical micro-scanner is a device for scanning a scene with an optical beam, or light beam, scanning the space in two dimensions, i.e. scanning a surface.

[0003] Such a 2D optical micro-scanner is for example made with one or more micro-mirrors.

[0004] A first 2D micro-scanner architecture with micro-mirrors consists of using two micro-mirrors. Each of the two micro-mirrors makes it possible to orient an incident optical beam parallel to a scanning direction, the two scanning directions of the two micro-mirrors being perpendicular to each other. A first of the two micro-mirrors receives the beam from an optical source and reflects it towards a second of the two micro-mirrors. The first micro-mirror is set in motion so that the optical beam reflected by the first micro-mirror optically scans the reflective surface of the second micro-mirror and so that the optical beam reflected by the second micro-mirror, also set in motion, can scan a scene according to the plane defined by the two scanning directions.However, such a micro-scanner is not compact and is difficult to manufacture due to the necessary alignment of the two micro-mirrors relative to each other to manage the reflection of the incident beam on the mirrors. In addition, the dimensions of the second micro-mirror must be large. Heating problems can also arise in such a micro-scanner.

[0005] A second architecture of a 2D micro-mirror micro-scanner consists of using a single mirror movable around two axes perpendicular to each other, which allows an incident optical beam to be reflected by making it scan in two perpendicular directions. However, such a micro-scanner poses problems of mechanical crosstalk caused by imperfections in the decoupling arms of the actuator used to move the micro-mirror. Actuation along one axis generally generates parasitic movement along the other axis because the two axes are never perfectly decoupled.

[0006] It is also possible to produce a 2D optical micro-scanner with an OPA (Optical Phased Array), also called an optical phased array or optical phased array. Such a micro-scanner comprises several sources of optical beams, often originating from the same initial source, emitting a main optical beam divided into several sub-beams, for example by means of waveguides. The sub-beams are then phase-shifted relative to each other so as to produce, upon their emission, an optical wave whose emission angle, relative to the surface from which the optical wave is emitted, can be adjusted by varying the value of the phase shift between each sub-beam. This operating principle can be extrapolated to a 2D matrix of optical sources allowing scanning of an optical beam in two directions perpendicular to each other.

[0007] An OPA can be produced from optical sources operating in transmission, such as optical guide outputs, or optical sources operating in reflection, with in this case a control of the phase of each source which is ensured by the position of a micro-mirror forming part of a matrix of micro-mirrors.

[0008] For many applications, 2D optical micro-scanners require scanning the space with a first axis called "slow" and a second axis called "fast", and this with scanning angles, or sweeping angle, which can exceed 100° in both directions. For example, the target frequency for a projection application is 60 Hz for the slow axis (which corresponds to the video refresh rate) and 40 kHz for the fast axis to obtain 1080 HD resolution. For a LIDAR application, the frequencies linked to the slow and fast axes are defined by the number of points per frame which is a function of the size of the object to be detected over a given distance (for example, the frequency linked to the slow axis is equal to 10 Hz and that linked to the fast axis is equal to 1 kHz).

[0009] MEMS actuators used for micromirror movement can achieve optical scan angles of around 100°, but to achieve this, they must generally operate at the mechanical resonance frequency in order to maximize the amplitude of micromirror movements. However, the mechanical resonance frequencies of MEMS actuators are rarely lower than 1 kHz and often at least 10 kHz due to the stiffness of the material (e.g. silicon) used and their small dimensions. Movements along the slow axis are therefore difficult to achieve.

[0010] Document WO 2018 / 222727 A1 describes an optical scanner comprising an optical source coupled to at least one optical fiber. STATEMENT OF THE INVENTION

[0011] An aim of the present invention is to propose a scanner or micro-scanner which does not have the drawbacks of the prior art devices set out above, and which is suitable for carrying out scanning in one, two or three dimensions, with an emission angle of significant value for each dimension.

[0012] For this, the present invention provides a scanner according to claim 1.

[0013] This scanner cleverly combines a phased array optical network with a moving part moved by an actuator so that the optical beam emitted from the optical phase shifters can perform a scan in one, two or even three dimensions. Such a scanner therefore makes it possible to combine the scan obtained by moving the first moving part of the support and that obtained via the phase shift achieved by the phased array optical network.

[0014] Such a scanner is more compact and easier to manufacture than a scanner requiring the alignment of two micromirrors. The proposed scanner does not pose a crosstalk problem, unlike scanners using a single micromirror that must be moved along two axes. In addition, the production of this scanner does not require managing the flatness of the mirrors or the deposition of reflective material on the mirrors.

[0015] This scanner also does not pose any problems with respect to movements along a slow axis because these movements of the optical beam can be ensured by the phased optical network if the scanning has to be done along a fast axis and a slow axis.

[0016] The scanner advantageously corresponds to a micro-scanner, that is to say a scanner comprising elements of micrometric or nanometric dimensions. This micro-scanner can correspond to a MEMS or NEMS type component.

[0017] The actuator can be MEMS or NEMS type.

[0018] The actuator may be configured to move the first movable part of the support in rotation about at least a first axis of rotation. This movement contributes to the scanning of the optical beam emitted from the optical phase shifters along a first dimension, i.e. parallel to a first scanning direction.

[0019] Here and throughout the rest of the document, the expression "scanning direction" is used to designate a plurality of mutually parallel axes along which the optical wave can be emitted.

[0020] The scanner can be such as: the support comprises a fixed part and a beam, the beam comprising a first portion and a second portion, the first portion of the beam being integral with the fixed part of the support and the second portion of the beam forming the first movable part of the support, and the actuator is configured to flex the second portion of the beam around the first axis of rotation and / or to deform in torsion the second portion of the beam around the first axis of rotation (which is then parallel to the length of the beam).

[0021] The rotational movement of the first mobile part of the support in rotation around the first axis of rotation is therefore obtained by putting the beam in bending and / or torsion.

[0022] Alternatively, the scanner may be such that: the support further comprises at least two first arms, the first movable part of the support being suspended by the two first arms which are aligned parallel to the first axis of rotation, the two first arms comprising first ends which are coupled to two opposite sides of the first movable part of the support, and the actuator comprises two first parts each configured to deform in torsion and / or in bending one of the two first arms.

[0023] In this configuration, the rotational movement of the first mobile part of the support around the first axis of rotation is therefore obtained by twisting and / or bending the first two arms.

[0024] In this case, the scanner can be such as: the support further comprises second arms and a second movable part which is suspended by the second arms which are aligned parallel to a second axis of rotation perpendicular to the first axis of rotation, the first two arms comprising second ends opposite the first ends and which are coupled to the second movable part, the second arms comprising first ends coupled to two opposite sides that the second movable part of the support comprises and second ends coupled to a fixed part that the support comprises, and the actuator comprises two second parts each configured to deform in torsion and / or in bending one of the two second arms.

[0025] In this configuration, the movement of the second moving part contributes to the scanning of the optical beam emitted from the optical phase shifters in a second dimension, i.e. parallel to a second scanning direction, perpendicular to the first dimension.

[0026] The first movable part of the support may comprise a face on which the phased optical network is arranged, the first and second arms being able to be aligned in two directions parallel to said face of the first movable part of the support.

[0027] The plurality of optical phase shifters may be aligned parallel or perpendicular to the first axis of rotation.

[0028] When the optical phase shifters are aligned parallel to the first axis of rotation, they contribute to the scanning of the optical beam emitted from the optical phase shifters in a second dimension perpendicular to the first dimension.

[0029] When the optical phase shifters are aligned perpendicular to the first axis of rotation, they contribute to the scanning of the optical beam emitted from the optical phase shifters along the first dimension.

[0030] Alternatively, the plurality of optical phase shifters may be arranged to form a matrix of multiple rows and multiple columns of optical phase shifters. Such a matrix of optical phase shifters may contribute to scanning the beam in two dimensions that may or may not correspond to the dimension(s) for which the moving portion of the support is set in motion. Such a matrix may also be used to perform a more complex optical function (focusing, diffraction, etc.). The phased array may be used to produce functions other than 2D scanning of an optical beam, such as for example to form diffractive optical elements such as dynamic virtual lenses for focusing or beam splitting. It may also be used to produce real-time holograms.

[0031] The actuator may comprise actuating means of at least one of the following types: electrostatic, magnetic, piezoelectric, thermal. Other types of actuating means are also possible.

[0032] The actuator may comprise one or more separate parts, each comprising a portion of piezoelectric material disposed between two electrodes. Such a configuration is particularly advantageous because each part of the actuator may be integrated directly onto the or one of the moving parts.

[0033] The plurality of optical phase shifters may comprise diffraction gratings coupled to thermal or piezoelectric phase shifting means. The optical beam is emitted from the diffraction gratings.

[0034] Optical phase shifters can generate an optical wave by constructive interference or by destructive interference.

[0035] The invention also relates to a method of producing a scanner according to claim 12.

[0036] The implementation of the phased optical network may include: depositing a first cladding layer on the support; depositing a core layer on the first cladding layer; etching the core layer, forming diffraction gratings; depositing a second cladding layer on the diffraction gratings and on the first cladding layer.

[0037] A cladding layer refers to a layer of material suitable for forming a cladding of waveguides and diffraction gratings. A core layer refers to a layer of material suitable for forming the core of waveguides and diffraction gratings.

[0038] The production of the actuator may include: depositing a first electrically conductive layer on the second layer of SiO 2; depositing or transferring a layer of piezoelectric material on the first electrically conductive layer; depositing a second electrically conductive layer on the layer of piezoelectric material; successive etchings of the second electrically conductive layer, of the layer of piezoelectric material and of the first electrically conductive layer, forming at least one portion of piezoelectric material arranged between two electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be better understood by reading the description of exemplary embodiments given purely for informational purposes and in no way limiting, with reference to the appended drawings in which: THE figures 1 to 3 represent scanners, objects of the present invention, according to several embodiments; the figures 4 to 15represent the steps of a method for producing a scanner, the subject of the present invention, according to one embodiment.

[0040] Identical, similar or equivalent parts of the different figures described below bear the same numerical references so as to facilitate the transition from one figure to another.

[0041] The different parts represented in the figures are not necessarily on a uniform scale, to make the figures more readable.

[0042] The different possibilities (variants and embodiments) must be understood as not being mutually exclusive and can be combined with each other. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0043] A scanner 100 according to a first embodiment is described below in connection with the figure 1 .

[0044] The scanner 100 comprises a support 102. The support 102 is made from a substrate comprising for example a semiconductor such as silicon.

[0045] The support 102 forms a fixed part 104, that is to say non-movable.

[0046] In this first embodiment, the support 102 comprises a beam 106 of which a first portion 108 is secured to the fixed part 104 of the support 102. A second portion 110 of the beam 106 is not arranged on the fixed part 104 and forms a movable part of the support 102 which can be set in motion relative to the fixed part 104. On the figure 1 , the two portions 108, 110 of the beam 106 are symbolically separated by a dotted line.

[0047] The scanner 100 also comprises an actuator 112 configured to move the movable part of the support 102. This actuator 112 is for example of the electrostatic, magnetic, piezoelectric or thermal type. In the example shown in the figure 1 , the actuator 112 is of the piezoelectric type, and comprises a portion of piezoelectric material arranged between two electrodes.

[0048] The actuator 112 is arranged on the beam 106, and here at least partially covers the first portion 108 and a portion of the second portion 110 of the beam 106. The actuator 112 is thus configured to move the movable part, formed by the second portion 110 of the beam 106, relative to the fixed part of the support 102. In this first embodiment, this movement corresponds to a bending of the second portion 110 of the beam 106 around an axis of rotation 114. Thus, by applying a non-zero electrical voltage to the electrodes of the actuator 112, the latter can move the second portion 110 of the beam 106 in rotation around the axis of rotation 114, by bimetallic effect.

[0049] In the example shown on the figure 1 , a larger dimension of the beam 106, i.e. its length (dimension parallel to the X axis visible on the figure 1), is perpendicular to the axis of rotation 114 (which is parallel to the Y axis visible on the figure 1 ). The length of the beam 106 is for example between 1 µm and several millimeters, or between 1 µm and 9 mm. The thickness of the beam 106 (dimension parallel to the Z axis visible on the figure 1 ) is for example between 100 nm and several tens of microns, or between 100 nm and 99 µm.

[0050] The scanner 100 also comprises a phased optical grating 116. This grating 116 is arranged on the movable part of the support 102, that is to say on the second portion 110 of the beam 106. The grating 116 comprises an optical source 118 coupled to several waveguides 120 separating the main optical beam from the optical source 118 into several secondary optical beams. The optical source 118 is for example of the LASER type and the wavelength of the light emitted by the source 118 depends in particular on the intended application for the scanner 100. For example, for a LIDAR application, the wavelength of the light emitted by the optical source 118 may be between 905 nm and 1550 nm for reasons of eye safety. Each waveguide 120 is coupled to at least one optical phase shifter 122 applying a phase shift to the received secondary optical beam.Each optical phase shifter 122 comprises, for example, a diffraction grating coupled to phase shifting means making it possible to apply a phase shift to the secondary optical beam received by the optical phase shifter 122. In the first embodiment described here, the optical phase shifters 122 are aligned next to each other on the second portion 110 of the beam 106 and parallel to the axis of rotation 114. The phase shifting means (not visible in the . figure 1 ) optical phase shifters 122 correspond for example to piezoelectric actuators or to heating means.

[0051] Details of the production of such an array 116 are for example described in the document “Silicon optical phased array with high efficiency beam formation over 180 degree field of view” by CT Phare et al., Applied Physics Optics 2018.

[0052] Thanks to the bending of the beam 106 around the rotation axis 114 carried out by the actuator 112, the optical wave emitted by the grating 116 can be directed along a first scanning direction perpendicular to the surface of the beam 106 on which the grating 116 is located, forming, with respect to the axis parallel to the length of the beam 106 at rest, i.e. not bent by the actuator 112, an angle ϕ which can vary for example between approximately -20° and +20°, or even larger values ​​such as for example between approximately -90° and +90°.

[0053] In addition, the phase-controlled optical grating 116 makes it possible to emit an optical beam forming an optical wave along a second scanning direction parallel to the rotation axis 114, and therefore perpendicular to the first scanning direction. The optical wave emitted by the grating 116 can therefore be directed along this second scanning direction by forming, with respect to an axis parallel to the length of the beam 106, an angle θ which can vary for example between approximately -80° and +80°. For example, when the grating 116 comprises 64 optical phase shifters incorporating thermal phase shifting means, the angle θ obtained can reach 160° (-80° to +80° with respect to the axis parallel to the length of the beam 106).

[0054] For example, when the beam 106 has a thickness equal to 2 µm, the amplitude of the oscillation obtained at the end of the beam 106 where the network 116 is located can be between 10 nm and a few hundred microns, or between 10 nm and 900 µm, depending on the length of the beam 106.

[0055] In the first embodiment described above, the first scanning direction obtained by the phase shift of the optical wave emitted by the phase-controlled optical network 116 is perpendicular to the second scanning direction obtained by setting in motion the mobile part of the support 102. The optical wave emitted by the scanner 100 can therefore scan a surface whose limits are defined by the maximum values ​​of the angles θ and ϕ.

[0056] A scanner 100 according to a second embodiment is described below in connection with the figure 2 .

[0057] The scanner 100 according to this second embodiment comprises a support 102 and an actuator 112 similar to those previously described for the first embodiment.

[0058] The scanner 100 according to this second embodiment comprises the phase-controlled optical grating 116 arranged on the second portion 110 of the beam 106. The grating 116 comprises the optical source 118 which is coupled to the optical phase shifters 122 which are aligned next to each other on the second portion 110 of the beam 106. The optical phase shifters 122 comprise, for example, as in the first embodiment, diffraction gratings coupled to piezoelectric or thermal phase shifting means.

[0059] Unlike the first embodiment, the optical phase shifters 122 are here aligned perpendicular to the axis of rotation 114. Thus, the phase-controlled optical grating 116 makes it possible to emit an optical wave along the first scanning direction. The optical wave emitted by the grating 116 can therefore be directed along this first scanning direction by forming, with respect to the axis parallel to the length of the beam 106 not bent by the actuator 112, an angle θ which can vary for example between approximately -20° and +20°, or even larger values ​​such as for example between approximately -90° and +90°. This deviation of angle θ of the optical wave is added to that of angle ϕ provided by the bending of the beam 106 around the axis of rotation 114 carried out by the actuator 112.Thus, relative to the axis parallel to the length of the beam 106 not bent by the actuator 112, the optical wave can be emitted along the first scanning direction forming the angles -(θ+ϕ)° and +(θ+ϕ)°.

[0060] In the two embodiments previously described, the second portion 110 of the beam 106 is set in motion by bending. Alternatively, it is possible for the actuator 112 to deform the second portion 110 of the beam 106 in torsion around the axis of the beam 106 which is parallel to the length of the beam 106. This torsional movement makes it possible to obtain a rotational movement of the second portion 110 around the axis of the beam 106 and therefore to obtain a sweep different from those previously described. This torsional deformation of the second portion 110 of the beam 106 may or may not be combined with the bending movement of the second portion 110 of the beam 106.

[0061] A scanner 100 according to a third embodiment is described below in connection with the figure 3 (which corresponds to a top view of the scanner 100).

[0062] The scanner 100 comprises a support 102 different from that previously described for the first and second embodiments. The support 102 here comprises a first mobile part 124 suspended by two first arms 126 aligned parallel to a first axis of rotation 128 of the first mobile part 124. On the figure 3, the first axis of rotation 128 is parallel to the Y axis. First ends of the arms 126 are coupled to two opposite sides of the first movable part 124. Second ends of the arms 126 are coupled to a second movable part 130 of the support 102. This second movable part 130 is suspended from a fixed part 132 of the support 102 by second arms 134 aligned parallel to a second axis of rotation 136 perpendicular to the first axis of rotation 128. On the figure 3 , the second axis of rotation 136 is parallel to the X axis. First ends of the second arms 134 are coupled to two opposite sides of the second movable part 130 and second ends of the second arms 134 are coupled to the fixed part 132.

[0063] The first arms 126 and the second arms 134 are aligned in two directions (axes X and Y) parallel to a face 138 of the first movable part 124 on which a phased optical grating 140 is arranged. The grating 140 comprises the optical source 118 coupled to the waveguides 120 separating the main optical beam from the optical source 118 into several secondary optical beams. Each waveguide 120 is coupled to several optical phase shifters 122, for example similar to those previously described for the first and second embodiments. In the third embodiment described here, the optical phase shifters 122 are arranged by forming a matrix of several rows and several columns of optical phase shifters 122.

[0064] In this third embodiment, the actuator 112 comprises several distinct parts, referenced 112.1, 112.2, 112.3 and 112.4 on the figure 3, each arranged on one of the first and second arms 126, 134. Each of these parts 112.1 - 112.4 comprises for example a portion of piezoelectric material arranged between two electrodes and makes it possible to deform in torsion the arm on which this part of the actuator 112 is arranged. Thus, the parts 112.1 and 112.2 of the actuator 112 make it possible to move in rotation around the first axis of rotation 128 the first movable part 124 thanks to the torsion of the first arms 126, and the parts 112.3 and 112.4 of the actuator 112 make it possible to move in rotation around the second axis of rotation 136 the second movable part 130, and therefore also the first movable part 124, thanks to the torsion of the second arms 134.

[0065] Rotating the movable part 124 around the first axis of rotation 128 makes it possible to orient the optical beam emitted by the grating 140 along a first scanning direction parallel to the second axis of rotation 136. Rotating the movable parts 124 and 130 around the second axis of rotation 136 makes it possible to orient the optical beam emitted by the grating 140 along a second scanning direction parallel to the first axis of rotation 128.

[0066] For example, when the first movable part 124 has a substantially circular shape, the radius of the first movable part 124 is for example between approximately 250 µm and 1 mm, and its resonant frequency may be between approximately 1 kHz and 15 kHz depending on the shape and dimensions of the first arms 126. For example, a first movable part 124 with a radius equal to 500 µm actuated at a resonant frequency of 8.707 kHz by applying a voltage equal to 1 V RMS to each part of the actuator 112 makes it possible to obtain, at the edges of the first movable part 124, a displacement of amplitude equal to 4.7 µm relative to the position of the first movable part 124 at rest.

[0067] According to a first example of this third embodiment, the phase-controlled optical grating 140 can be used to increase the surface area scanned by the optical beam emitted by the grating 140. In fact, the angle deviations of the optical beam obtained by the movements of the first mobile part 124 around the axes of rotation 128 and 136 are combined in this case with the angle deviations of the optical beam obtained by the phase shifts generated by the grating 140.

[0068] According to a second example of this third embodiment, the network 140 can be used to fulfill a different function such as focusing along a dimension perpendicular to the surface 138 on which the network 140 is arranged (dimension parallel to the Z axis on the figure 3). Thus, it is possible to focus the optical beam emitted by the grating 140 at a variable distance from the surface 138. The grating 140 can be used to form diffractive optical elements such as dynamic virtual lenses for beam focusing or splitting. It can also be used to produce holograms.

[0069] As a variant of this third embodiment, it is possible for the support 102 to comprise, as in the example previously described, the first mobile part 124 suspended by the first two arms 126, but for the second ends of the arms 126 to be coupled directly to the fixed part 132. In this case, the support 102 does not comprise the second mobile part 130 or the second arms 134. The grating 140 can make it possible to carry out angle deviations around the axis 136, i.e. to move the optical beam along the second scanning direction, even in the absence of the second mobile part 130 and the second arms 134, thanks to the phase shifts of the grating 140.The amplitude of displacement of the optical beam along the second scanning direction will however be less than in the example previously described since in this variant, the displacement of the movable part of the support 102 does not contribute to the displacement of the optical beam along the second scanning direction.

[0070] Generally, for all embodiments, the actuator 112 may be of the electrostatic (or capacitive), magnetic, piezoelectric or thermal type.

[0071] Many variants of the scanner 100 can be envisaged.

[0072] According to a variant, it is for example possible that the scanner 100 previously described according to the first or second embodiment comprises a phase-controlled optical network similar to the network 140 previously described for the third embodiment, that is to say comprising a matrix of several rows and several columns of optical phase shifters 122. In this case, the network 140 can contribute to increasing the angle of the deviation brought about by the movement of the beam 108 along the first scanning direction, and to deflecting the emitted optical beam in another scanning direction perpendicular to the first scanning direction.Alternatively, the grating 140 may be used to deflect the emitted optical beam in two directions perpendicular to that in which the beam 108 provides a deflection, one of these two directions being used, for example, to focus the emitted optical beam along an axis perpendicular to the surface on which the grating 140 is located.

[0073] According to another variant, it is for example possible that the scanner 100 previously described according to the third embodiment comprises a phased optical network similar to the network 116 previously described for one of the first and second embodiments.

[0074] For all embodiments, the support 102 (fixed part + mobile part) can also be moved in order to increase the possibilities of direction towards which the optical beam is sent.

[0075] In the various embodiments and examples previously described, the movable part of the support is set in rotational motion around one or more axes of rotation. Generally, it is possible for the movable part of the support to be set in motion by a rotational and / or bending and / or translational movement.

[0076] An example of a method for producing the scanner 100, according to one of the embodiments previously described, is detailed below in connection with the figures 4 to 15 .

[0077] The scanner 100 is made from a substrate 105, comprising for example silicon. On the figure 4 , the substrate 105 comprises alignment marks 107. The substrate 105 here forms the support 102.

[0078] The phased optical grating 116 or 140 is first produced on the substrate 105. In the example described here, the grating produced corresponds to the grating 116 previously described in connection with the first and second embodiments.

[0079] For this, a first layer of sheath 109 is produced, or deposited, on the substrate 105. The layer 109 comprises for example SiO 2 , obtained for example by oxidation of the silicon of the substrate 105 (see Figure 5 ). The dielectric material of layer 109 is suitable for forming a cladding material of a waveguide, and corresponds for example to SiO 2 or a polymer material. Layer 109 has for example a thickness of between approximately 500 nm and 3 µm.

[0080] A waveguide core layer 111 is then deposited on layer 109. The optical index, or refractive index, of the material of layer 111 is different from that of layer 109. In the embodiment described here, the material of layer 111 is SiN. Other materials may be used to make layer 111, such as polycrystalline silicon. The thickness of layer 111 is, for example, between approximately 100 nm and 1 µm.

[0081] The layer 111 is then etched, or structured, in order to form in particular the diffraction gratings of the optical phase shifters 122 as well as the waveguide(s) 120 used to route the optical beam(s) from the light source 118 to the optical phase shifters 122 (see figure 6 ).

[0082] A second layer of sheath 113 is then produced to cover the etched layer 111 (see figure 7). The material of layer 113 is chosen such that the optical index of the material of layer 113 is different from that of layer 111 and is for example similar to that of layer 109. The dielectric material of layer 113 is suitable for forming a cladding material of a waveguide, and corresponds for example to SiO 2 . The thickness of layer 113 is for example between approximately 500 nm and 3 µm.

[0083] The actuator 112 is then produced. In the production method described here, the actuator 112 is of the piezoelectric type.

[0084] A first electrically conductive layer 115 is deposited on layer 113 (see figure 8). This first electrically conductive layer 115 is intended to form one of the electrodes of the actuator 112, or one of the electrodes of each of the different parts of the actuator 112 (as is the case for the third embodiment previously described). The layer 115 comprises, for example, platinum or molybdenum, the nature of this material being chosen according to the piezoelectric material which will be used. The thickness of the layer 115 is, for example, between approximately 100 nm and 200 nm.

[0085] A layer of piezoelectric material 117 is then deposited on layer 115 (see figure 9 ). This layer 117 comprises, for example, PZT, AIN, ZnO or BST (Ba 1-x Sr x TiO 3 ). The thickness of the layer 117 is, for example, between approximately 500 nm and 2 µm.

[0086] A second electrically conductive layer 119 is then deposited on the layer 117. This second electrically conductive layer 119 is intended to form the other electrode of the actuator 112 or of each of the parts of the actuator 112. The layer 119 comprises, for example, platinum or Mo or Ru. The thickness of the layer 119 is, for example, between approximately 100 nm and 200 nm.

[0087] This layer 119 is then etched, by dry or wet etching, so that the remaining portion(s) of this layer 119 form(s) the upper electrode of the actuator 112 or of each of the parts of the actuator 112.

[0088] The layer 117 is also etched by dry etching (for example plasma etching) so that the remaining portion(s) of this layer 117 form(s) the portion of piezoelectric material of the actuator 112 or of each of the parts of the actuator 112 (see figure 10). The layer 117 is etched such that the portion(s) of the layer 115 intended to form the lower electrode(s) of the actuator 112 are not completely covered by the remaining portion(s) of the layer 117, in order to have portions of the layer 115 electrically accessible.

[0089] The layer 115 is then etched by dry etching (for example plasma etching) so that the remaining portion(s) of this layer 115 form(s) the lower electrode of the actuator 112 or of each of the parts of the actuator 112 (see figure 11 ). Layer 115 is etched such that one or more portions of layer 115 are not covered by the remaining portion(s) of layer 117, in order to have portions of layer 115 electrically accessible.

[0090] When the optical phase shifters 122 comprise piezoelectric phase shifting means, the steps previously described for producing the actuator 112 can also be used to produce these piezoelectric phase shifting means which can correspond to piezoelectric actuators, coupled to each other or independent of each other, and comprising, like the actuator 112, a portion of piezoelectric material arranged between two electrodes. The mechanical deformations generated by actuating these piezoelectric actuators make it possible in this case to phase shift the optical wave emitted by the optical phase shifters 122.

[0091] Alternatively, when the optical phase shifters 122 comprise thermal phase shifting means, heating elements can be integrated between the waveguides 120 and the actuator 122, these heating elements in this case ensuring the phase shifting of the optical wave emitted by the optical phase shifters 122 by heating the material of the layer 111 to the desired temperature, depending on the required phase shift.

[0092] A passivation layer 121 is then deposited by covering the layer 113 as well as the actuator 112. The layer 121 comprises for example an oxide such as SiO 2 , SiN or Si 3 N 4 .

[0093] First openings 123 are then etched through the layer 121 in order to form accesses to the upper and lower electrodes of the actuator 112 (see figure 12 ).

[0094] One or more second apertures 125 are then etched through the layer 121, opposite the optical phase shifters 122, to allow the extraction of light from the optical phase shifters 122 (see figure 13 ).

[0095] Electrically conductive pads 127 are then produced, for example by depositing an electrically conductive material and then by etching this material, in the first openings 123. These pads 127 are electrically connected to the electrodes of the actuator 112 and allow the sending of control signals to the actuator 112 (see figure 14 ).

[0096] The substrate 105 is then etched from its rear face in order to form the moving part(s) of the scanner 100 (see figure 15 ). In the example described here, this etching of the substrate 105 makes it possible to form the beam 106 which comprises the first portion 108 and the second portion 110.

[0097] Electrically conductive pads 127 are then produced, for example by depositing an electrically conductive material and then by etching this material, in the first openings 123. These pads 127 are electrically connected to the electrodes of the actuator 112 and allow the sending of control signals to the actuator 112 (see figure 14 ).

[0098] The substrate 105 is then etched from its rear face in order to form the moving part(s) of the scanner 100 (see figure 15 ). In the example described here, this etching of the substrate 105 makes it possible to form the beam 106 which comprises the first portion 108 and the second portion 110.

Claims

1. A scanner (100) including at least: - a support (102) including at least one first movable part (110, 124), - an actuator (112) configured to move the first movable part (110, 124) of the support (102), and - a phased optical grating (116, 140) disposed on the first movable part (110, 124) of the support (102) and including at least one plurality of optical phase shifters (122) and an optical source (118) coupled to the plurality of optical phase shifters (122) which is able to emit an optical beam (106) coming from the optical source (118), the optical phase shifters (122) being configured to emit an optical beam (106) by constructive interferences or destructive interferences.

2. The scanner (100) according to claim 1, wherein the actuator (112) is configured to move the first movable part (110, 124) of the support (102) in rotation about at least one first axis of rotation (114, 128).

3. The scanner (100) according to claim 2, wherein: - the support (102) includes a fixed part (104) and a beam (106), the beam (106) comprising a first portion (108) and a second portion (110), the first portion (108) of the beam (106) being integral with the fixed part (104) of the support (102) and the second portion (110) of the beam (106) forms the first movable part of the support (102), and - the actuator (112) is configured to bend the second portion (110) of the beam (106) around the first axis of rotation (114, 128) and / or to deform in twisting the second portion (110) of the beam (106) around the first axis of rotation.

4. The scanner (100) according to claim 2, wherein: - the support (102) further includes at least two first arms (126), the first movable part (124) of the support (102) being suspended by the two first arms which are aligned parallel to said the first axis of rotation (128), the two first arms (126) comprising first ends that are coupled to two opposite sides of the first movable part (124) of the support (102), and - the actuator (112) includes two first part (110, 124)s (112.1, 112.2) each one configured to deform in twisting and / or in bending one of the two first arms (126).

5. The scanner (100) according to claim 4, wherein: - the support (102) further includes second arms (134) and a second movable part (130) (130) which is suspended by the second arms (134) which are aligned parallel to a second axis of rotation (136) perpendicular to the first axis of rotation (128), the two first arms (126) comprising second ends opposite the first ends and which are coupled to the second movable part (130), the second arms(134) comprising first ends coupled to two opposite sides that the second movable part (130) of the support (102) includes and second ends coupled to a fixed part (132) that includes the support (102), and - the actuator (112) includes two second parts (112.3, 112.4) each one configured to deform in twisting and / or in bending of one of the two second arms (134).

6. The scanner (100) according to claim 5, wherein the first movable part (24) of the support (102) includes a face (138) whereon the phased optical grating (140) is disposed, the first and second arms (126, 134) being aligned in two directions parallel to said face (138) of the first movable part (124) of the support (102).

7. The scanner (100) according to one of the claims 2 to 6, wherein said at least one plurality of optical phase shifters (122) is aligned in parallel or perpendicularly to the first axis of rotation (114).

8. The scanner (100) according to one of the claims 2 to 6, wherein said at least one plurality of optical phase shifters (122) is arranged by forming an array of several lines and columns of optical phase shifters (122).

9. The scanner (100) according to any of the previous claims, wherein the actuator (112) includes means for actuating at least one of the following types: electrostatic, magnetic, piezoelectric, thermal.

10. The scanner (100) according to any of the previous claims, wherein the actuator (112) includes one or more separate parts (112.1 - 112.4), each one including a portion of piezoelectric material (117) disposed between two electrodes (115, 119).

11. The scanner (100) according to any of the previous claims, wherein the plurality of optical phase shifters (122) includes diffraction gratings coupled to thermal or piezoelectric means of phase shifting.

12. A method for producing a scanner (100), including at least the steps of: - producing, on a first part (110, 124) of a support (102), a phased optical grating (116, 140) including at least one plurality of optical phase shifters (122) and an optical source (118) coupled to the plurality of optical phase shifters (122) which is able to emit an optical beam coming from the optical source (118), the optical phase shifters (122) being configured to emit an optical beam by constructive interferences or destructive interferences; - producing an actuator (112) configured to move the first part (110, 124) of the support (102); - etching the support (102) such that the first part (110, 124) of the support (102) is movable.

13. The method according to claim 12, wherein producing the phased optical grating (116, 140) includes: - depositing a first cladding layer (109) on the support (102); - depositing a core layer (111) on the first cladding layer (109); - etching the core layer (111), forming diffraction gratings; - depositing a second cladding layer (113) on the diffraction gratings and on the first cladding layer (109).

14. The method according to claim 13, wherein producing the actuator (112) includes: - depositing a first electrically conductive layer (115) on the second cladding layer (113); - depositing or transferring a layer of piezoelectric material (117) on the first electrically conductive layer (115); - depositing a second electrically conductive layer (119) on the layer of piezoelectric material (117); - etching successively the second electrically conductive layer (119), the layer of piezoelectric material (117) and the first electrically conductive layer (115), forming at least one portion of piezoelectric material disposed between two electrodes.