Optomechanical transducer device and corresponding method

Abstract

Embodiments of the present disclosure relate to optomechanical transducer devices and corresponding methods. An exemplary device includes an optically transparent substrate having a first surface and a second surface; a piezoelectric film disposed on the first surface and oscillating in response to a light beam propagating through the substrate; at least one reflective facet facing the substrate and disposed at the piezoelectric film; and an optical element that receives the light beam at an input end and guides the light beam to an output end coupled to the second surface. The optical element includes an optical focusing path that focuses the light beam at a focal point of the piezoelectric film, and at least one optical collimation path that collimates the light beam onto at least one of the reflective facets. The optical element guides light reflected from at least one of the reflective facets to the input end, and the reflected light indicates the position of the optical element relative to the focal point.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of Italian Application No. 1020200000013462, filed on June 5, 2020, which is hereby incorporated herein by reference. Technical Field

[0003] This specification relates to opto-mechanical systems. One or more embodiments can be used for optical alignment. Background Art

[0004] Micro-opto-electro-mechanical systems (MOEMS), also known as optical micro-electro-mechanical systems or optical MEMS, are systems that involve sensing or manipulating optical signals in very small size ranges, which, for example, use integrated mechanical, optical, and electrical systems to couple mechanical modes to optical modes, or optical modes to mechanical modes.

[0005] Systems of this type are discussed, for example, in Midolo, L., Schliesser, A. & Fiore, A., "Nano-opto-electro-mechanical systems", Nature Nanotech 13, 11 - 18 (2018), doi:10.1038 / s41565-017-0039-1.

[0006] Opto-mechanical sensors can convert the mechanical motion of a membrane (on the micron scale) into an optical signal, or an optical signal into the mechanical motion of a membrane.

[0007] For example, an opto-mechanical sensor can include an oscillating nano- or micro-membrane and a light beam that is focused on the active area of the membrane, which is the area where opto-mechanical conversion can be maximized. For example, such an active area can be arranged at the center of the die or any other part thereof.

[0008] Sensors of this type are disclosed, for example, in A. Simonsen, S. Saarinen, J. Sanchez, J. A. Schliesser, and E. Polzik, "Sensitive optomechanical transduction of electric and magnetic signals to the optical domain," Opt. Express 27, 18561 - 18578 (2019).

[0009] In this type of membrane-based opto-mechanical sensor, the light beam used is focused to achieve a target spot size, e.g., in the micrometer range.

[0010] As a result, the optical alignment between the focused beam (the focus) and the membrane (the active) region is a relevant figure of merit.

[0011] For various reasons, optical alignment using a focused beam can be challenging, e.g., it is difficult to accurately determine the correct position of the beam's minimum waist, which can lead to poor performance and difficulties in optimizing the alignment; and it complicates the algorithm for searching for the best alignment.

[0012] Conventional optical alignment arrangements using a focused beam can involve complex read processes, including performing scans along the X and Y axes for each position along the light propagation direction (commonly referred to as the Z-axis); analyzing all the data to find the correct focus depth; setting the system to a certain focus depth; and performing further scans to determine an improved alignment.

[0013] The conventional solutions as described above thus suffer from the problems of the following drawbacks: complexity of the alignment system and method; and the costs in terms of time and consumption associated with direct readout and feedback of optoelectronic devices / components. Summary of the Invention

[0014] An object of one or more embodiments is to help overcome the drawbacks in the foregoing discussion.

[0015] According to one or more embodiments, such an object can be achieved by an electro-optical device having the features set forth in the following claims.

[0016] One or more embodiments can relate to a corresponding optical alignment method.

[0017] The claims are part of the technical teaching provided herein with reference to the embodiments.

[0018] One or more embodiments can include optical elements. An example of an optical lens can be a gradient refractive index, briefly GRIN, lens.

[0019] One or more embodiments can provide one or more of the following advantages: the use of a GRIN lens directly attached to the surface cancels possible focusing misalignment errors; direct readout of the chip performance can be redundant; optical alignment can be performed using standard equipment and processes; and using the reflected power of a collimated beam for optical alignment can render the readout of the chip's performance redundant, thus simplifying the alignment process.

[0020] One or more embodiments can relate to combining a GRIN lens with an optical buffer to make the total length of the focusing and collimating systems the same.

[0021] One or more embodiments may relate to reading the reflected power of a collimated beam, which helps to "skip" a direct read of the chip.

[0022] In one or more embodiments, advantageously, the focusing system and the collimating system may be placed in the same fiber block so that the stability in a relative position arrangement is a function of the precision in the components of a single fiber block (about 1 micron).

[0023] In one or more embodiments, a reflective geometry may be formed on the chip, which helps to provide, for example, optical fiducial marks. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] One or more embodiments will now be described by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0025] Figure 1 is a cross-sectional view of an optomechanical transducer assembly;

[0026] Figure 2 、 Figure 2A and Figure 2B are diagrams of the fundamental principles of one or more embodiments;

[0027] Figure 3 is a diagram of the optical alignment method of the examples herein;

[0028] Figure 4 is a perspective view of an alignment system according to the present disclosure;

[0029] Figure 5 is along Figure 4 the cross-sectional view taken along the V-V line of;

[0030] Figure 6 is along Figure 4 the cross-sectional view taken along the VI-VI line of;

[0031] Figure 7 is Figure 4 the plan view of;

[0032] Figure 8 、 Figure 8A 、 Figure 9 and Figure 9A are diagrams of the fundamental optical principles of one or more embodiments;

[0033] Figure 10 and Figure 11 is a diagram of a power distribution power supply;

[0034] Figure 12 is a perspective view of a component as in the examples herein;

[0035] Figure 13 and Figure 14is a perspective view of a housing according to the present disclosure;

[0036] Figure 15 、 Figure 16 and Figure 17 are perspective views of an optical engine assembly according to the present disclosure;

[0037] Figure 18 is a perspective view of an optical element according to the present disclosure;

[0038] Figure 19 is a perspective view of a device according to the present disclosure; and

[0039] Figure 20 is an enlarged view substantially along Figure 19 arrow XX. DETAILED DESCRIPTION

[0040] In the following description, one or more specific details are illustrated with the aim of providing an in - depth understanding of examples of embodiments of this description. Embodiments may be obtained without one or more specific details, or by other methods, components, materials, etc. In other cases, well - known structures, materials, or operations are not illustrated or described in detail so as not to obscure certain aspects of the embodiments.

[0041] In the framework of this description, the reference to "an embodiment" or "one embodiment" is intended to indicate that the particular configuration, structure, or feature described with respect to that embodiment is included in at least one embodiment. Thus, phrases such as "in an embodiment" or "in one embodiment" that may appear at one or more points in this description do not necessarily refer to one or more identical embodiments.

[0042] Furthermore, particular conformations, structures, or features may be combined in any appropriate manner in one or more embodiments.

[0043] The headings / references used herein are for convenience only and thus do not delimit the scope or extent of the protection of the embodiments.

[0044] For ease of explanation, the drawings are in simplified form and the scale is not precise.

[0045] In the accompanying drawings herein, the same parts or elements are denoted by the same reference symbols, and for the sake of brevity, the corresponding descriptions will not be repeated for each drawing.

[0046] As Figure 1 exemplified in, the opto - mechanical transducer 10 may include:

[0047] - a housing 12, such as a ceramic housing, including having, for example, a diameter of approximately 4 mm (1 mm = 10 -3a base with a central hole 120 (m = 1 mm), and the central hole 120 is configured as an orifice for accommodating an optically transparent material (e.g., made of glass with a thickness of 0.2 mm) to form an optical window;

[0048] - a plurality of conductive leads 14, such as flat leads exposed at the surface of the housing 12;

[0049] - one or more optically transparent layers 16, 18, such as including a fused silica substrate 18 (about 0.5 mm thick), optionally stacked on top of a silicon wafer 16 with a hollow core 160 (aligned with the hole 120), where light can propagate in free space, and the core 160 extends, for example, about 0.35 mm thick;

[0050] - a film layer 20, such as a piezoelectric film, located on the top plane of the quartz wafer 18, and including at least a partially reflective "bottom" surface 200 facing the top plane surface of the quartz wafer 18;

[0051] - (micro) spacers 22, configured to keep the film layer 20 separated from the top plane surface of the quartz wafer 18 to allow the film to vibrate or oscillate;

[0052] - conductive contact pads 24, coupled to the top surface of the film layer 20, and configured to control and / or detect changes in the opto-mechanical characteristics of the film 20 via electrical signals emitted or received from the film layer 20;

[0053] - conductive wiring 26, coupling the conductive contact pads 24 on the film layer 20 to the conductive leads 14 in the support base 12; and

[0054] - an optical element 30, such as a lens, configured to direct light emitted from a source at the input end of the optical element 30 (not visible in the figure) along an optical path aiming at the film 20, and the optical element 30 is coupled to the package base 12 via the orifice 120 in the package base 12. For example, the optical element may have a diameter of about 2.5 mm and a length of about the same size.

[0055] As Figure 1 illustrated, for example, the device 10 can be sealed via a jacket 90 (e.g., a cover).

[0056] In one or more embodiments, when light is focused on the film layer 20, the opto-mechanical device 10 can convert an optical signal into an electrical signal via mechanical vibration of the film layer 20.

[0057] As Figure 2 illustrated, a GRIN lens is an example of the optical element 30, which can be advantageously used in the embodiments discussed herein.

[0058] As background, it can be recalled that, asFigure 2A The "optical object" 30A shown is configured to focus a beam of parallel rays from a light source S and "squeeze" it to a focal point FP at a certain focal depth or distance F from the object 30. The "optical object" 30A is called a focusing lens 30A. The corresponding position along the propagation axis Z (where the beam spot reaches its minimum radius) is called the "focus" FP (or beam waist).

[0059] Conversely, as Figure 2B shown by the optical object 30B, which receives a divergent beam from a light source S and generates a beam with no remaining angular divergence (in a conceptually ideal scenario) or a beam with Gaussian behavior (in a more realistic scenario). The optical object 30B is called a collimating lens 30B. The collimating lens 30B can have a collimation length, i.e., the distance between the light source S and the lens 30B, so that the beam from the light source is collimated.

[0060] As Figure 2 illustrated, the GRIN lens 30 can include a cylindrical or rod-shaped body that extends linearly (i.e., longitudinally) between two flat ends 306, 308 and is suitable for fiber coupling.

[0061] The optical behavior of the GRIN lens 30 can be based on the refractive index of the lens material, which varies spatially with a gradient profile in a manner well-known to those skilled in the art.

[0062] Figure 2 Shows a ray trace diagram within the GRIN rod 30 designed to be a focusing lens. The linear rod-shaped body 30 can have a length also indicated as one "pitch" P, i.e., the length for obtaining a 1:1 image without inversion, which is related to the refractive index change of each GRIN lens.

[0063] As is known to those skilled in the art, a GRIN lens can act as a focusing lens or a collimating lens (or a diverging lens) depending on its pitch P.

[0064] For example, shortening the rod to a length of 1 / 2 or 1 / 4 of the full pitch P, as Figure 2 illustrated by the arrows, can vary the optical characteristics of the optical element 30.

[0065] In the device 10 illustrated as Figure 1 shown, a GRIN lens can be used at 30 to focus a beam (as Figure 2A illustrated) on the bottom surface 200 of the membrane.

[0066] On the other hand, as mentioned above, accurately aligning the focused beam so that its waist is located at the position corresponding to the bottom surface 200 can be a challenging task.

[0067] As Figure 3 illustrated in an example, one or more embodiments may use an optical element 30 based on the GRIN lens concept, which includes a focusing lens portion 32 and a collimating lens portion 34 embedded in a single optical piece (e.g., a single (optical) fiber block).

[0068] For example, since they are formed together in a single fiber block having a certain length, such an optical element 30 can be designed so that both the focusing lens portion 32 and the collimating lens portion 34 have corresponding (focal lengths) lengths F that are related to each other.

[0069] As Figure 3 illustrated in an example, such an optical element 30 can be used in conjunction with a reference reflective surface 40, e.g., included in a film layer 20, as a peripheral portion 400 around the center portion 200 of its bottom surface, or as a pattern of non-connected reflective surfaces, operating as a fiducial mark. Such a reference reflective surface 40 coplanar with the bottom surface of the film 20 can help perform improved optical alignment of the focal length F of the focusing lens portion 32.

[0070] For example, a light beam emitted by a light source S can be simultaneously focused 32 and collimated 34 when passing through the optical element 30. As a result, the collimated rays emitted from the light source S can impinge on the reflective reference surface 40.

[0071] At least a portion of the impinging collimated rays will be reflected from the reflective reference surface 40. Such reflected rays R can travel back along the optical element 30 and be capable of being sensed, e.g., via an optical circulator 31 disposed at the "far" end (i.e., the end away from the reflective surface 40) of the element 30. For example, the circulator 31 can provide the reflected rays R to a user circuit A, e.g., an actuator A, which is configured to perform feedback on the alignment of the optical element 30 relative to the reference surface 40.

[0072] Due to a larger spot size at the focal point FP, the alignment of the collimating lens 34 can be facilitated.

[0073] The focusing lens 32 is incorporated together with the collimating lens 34 in a common optical assembly 30, thus facilitating (in a substantially "passive" manner) the alignment of the focusing lens 32.

[0074] It is noteworthy that the reflected light R provides a passive alignment feedback, in the absence of an active opto-mechanical transducer per se, i.e., without powering the device 10.

[0075] As previously mentioned, such a passive alignment process is relatively fast and easy.

[0076] For example, optical element 30 , once aligned with assembly 10 , may be directly attached (eg, bonded) to assembly 10 .

[0077] Alternatively, when the membrane 20 is assembled in the housing, it may be attached to the aperture 120 of the housing.

[0078] In such Figures 4 to 7 In the illustrated optical alignment systems 30, 40, for example, the reference surface 40 may include a plurality of planar reflective surfaces (or facets) 400A, 400B symmetrically arranged relative to the film layer 20, the plurality of planar reflective surfaces being at the same distance from the target focus FP of the active surface 200 of the film 20; and the optical element 30 may include a plurality of collimating lens portions 34A, 34B, which are symmetrically arranged relative to the focusing lens portion 32 (the optical axis thereof) of the optical element 30.

[0079] As discussed herein, a “target” reference surface 40 , 400 may be located on an exposed surface portion of an optically transparent layer 16 , 18 of the assembly 10 , such as a surface portion aligned with an aperture 120 in the housing 12 of the device 10 .

[0080] For simplicity, the following discusses the arrangement of a pair of planar reflective surfaces (or facets) 400A, 400B and a corresponding pair of collimating lens portions 34A, 34B. In addition, it should be understood that such numbers in the exemplary arrangement are not limiting in any way, as almost any number of planar reflective surfaces (or facets) 400A, 400B and collimating lens portions 34A, 34B can be used in one or more embodiments.

[0081] like Figure 5 As shown in the example (this is along the Figure 4 Cross-sectional view along line VV): The focusing lens portion 32 of the optical element 30 can be incorporated in an optical fiber including a focusing GRIN lens portion 320 and an optical spacer portion 322; and a pair of collimating lens portions 34A, 34B can include a first collimating lens portion 34A and a second collimating lens portion 24B, each of which includes a collimating GRIN lens portion 340 and another optical spacer portion 342.

[0082] For a particular wavelength of light, the focusing GRIN lens 320 may be obtained for a certain pitch P, eg, P=500 microns, while the collimating GRIN lens 340 may be obtained for a fraction of the pitch, eg, P'=½*P.

[0083] Since the collimating lens 340 is shorter than the focusing lens 320, the collimating GRIN lens 340 can be coupled to an optical spacer or "buffer" such that the total length L0 given by the sum of the lengths of the respective lenses 340, 342 and the lengths of the respective spacers 342, 344 is the same for both the focusing 32 and collimating 34A, 34B sections, facilitating the coupling of the optical element 30 to the light source S and the optically transparent layer 18.

[0084] Using GRIN lenses 320, 340 with different pitch lengths can provide advantageous and easy assembly of the optical component 30 and can facilitate the focal point FP reaching the target spot size at the central surface 200 of the film 20.

[0085] As Figure 6 illustrated (which is a cross-sectional view along line VI-VI of Figure 4 ), the optical fibers respectively embedded in the focusing section 32 and the collimating sections 34A, 34B can be assembled in a housing that includes: a support layer 60 including a plurality of V-grooves 600 in which the optical fibers 32, 34A, 34B can be arranged to be respectively received in the corresponding V-grooves (in a manner known to those skilled in the art); a cover layer 64 configured to be arranged over the optical fibers 32, 34A, 34B to hold them in the corresponding V-grooves 600; and a filling layer 62, such as an epoxy resin layer, sandwiched between the support layer 60 and the cover layer 64 and filling the gap spaces between the V-grooves 600, the optical fibers 32, 34A, 34B and the cover layer 64.

[0086] Figure 7 is Figure 4 an exemplary plan view showing fiducial regions 400A, 400B, such as two metallic square regions 400A, 400B having side length C, and the center of the exemplary plan view is located at the same distance H from the central region 200 of the film 20 targeted at the focal point FP.

[0087] For example, the value of the distance H can have a value of approximately 500 micrometers.

[0088] Figure 7 Also shown respectively, represented by dashed lines superimposed on the reference reflection regions 400A, 400B and 20, are the spot sizes BSf, BSc output from the focusing section 32 and the collimating section 34 of the optical element 30.

[0089] For example, as Figure 7 illustrated: the focusing beam spot size BSf can achieve a waist size of less than 20 μm, ideally 10 μm (1 μm = 10 -6 m = 1 micrometer); and the collimated beam spot size BSc can be approximately 300 μm at the corresponding fiducial regions 400A, 400B.

[0090] During the optical alignment operation, since the signal R is reflected back from the reflection surfaces of the reference reflection regions 400A, 400B, the alignment error δc of the collimated beam BSc with respect to the reference regions 400A, 400B can be detected. Such an alignment error δc can indicate the corresponding alignment error δf of the focused beam with respect to the target focus FP.

[0091] In one or more embodiments, when the collimated beam spot size BSc is (completely) adapted within the reference reflection regions 400A, 400B, that is, when the alignment error δc is negligible, up to zero, the optical element 30 can be considered aligned with respect to the reference surface 40. As a result, it can also be considered that the focus FP is aligned with respect to the target position, corresponding to a negligible (ideally, up to zero) focusing alignment error δf when the collimated beam spot size BSc is completely adapted within the reference reflection regions 400A, 400B, that is, the collimation alignment error δc is negligible (ideally, up to zero).

[0092] Figure 8 is an enlarged view of the focusing portion 32 of the optical element 30, showing the ray trajectory in which the beam propagates and exits at the optical interface 330 (such as an optical window having a certain thickness T).

[0093] As Figure 8 illustrated, the focusing portion 32 can have a total length L0 given by the sum of the length Pf of the focusing GRIN lens 320 and the length Bf of the focusing buffer 322 (e.g., L0 = Pf + Bf), the length Pf of the focusing GRIN lens 320 being equal to, for example, the full pitch and approximately 500 microns, and the focusing buffer 322 being made of, for example, fused silica.

[0094] For example, the GRIN lens 320 can have a substantially cylindrical shape with a constant diameter E (e.g., between 350 microns and 500 microns).

[0095] Figure 8A is a plot of the RMS focused beam spot size BSf (in microns) as a function of the distance (in millimeters) from the ideal focus FP taken as the abscissa origin.

[0096] As Figure 9 illustrated, the total length L0 of the collimating portion 34 can be given by the sum of the length Pc of the collimating GRIN lens 340, for example, approximately half of the lens pitch, and the length Bc of the collimating buffer 342, for example, made of fused silica, e.g., L0 = Pc + Bc.

[0097] In one or more embodiments, such a total length L0 is the same for the focusing section 32 and the collimating section 34, e.g., L0 = Pc + Bc = Pf + Bf.

[0098] For example, the GRIN focusing lens 320 may have a corresponding length Pf of approximately 5.35 mm, the collimating GRIN lens 324 may have a second length Pc of approximately 3.07 mm, and the optical buffer 342 may have a third length Bc of approximately 2.28 mm such that the total length Pc + Bc of the collimating GRIN lens and the collimating optical buffer 342 is equal to the length of the focusing GRIN lens Pf.

[0099] Figure 9A It is a diagram showing the RMS collimated beam spot size BSc (in microns) as a function of the distance (in millimeters) from the reference surface 40 taken as the abscissa origin.

[0100] Figure 10 It is a diagram showing the amount of optical power LP reaching one of the reference surfaces 40, 400, 400A, 400B as a function of the alignment error δc calculated for each value of the length C of the reference surface. In the example considered, for the simplicity of performing the power loss calculation, the total power of the light emitted into the optical element 30 is considered equal to 1 watt.

[0101] Figure 11 It is a diagram of the difference ΔLP between the power value at zero deviation (e.g., δc = 0) and the power value with the maximum misalignment (e.g., δc = 0.1 micron), and this difference is plotted as a function of the corresponding reflecting surface length C.

[0102] As Figure 10 and Figure 11 As exemplified in, values of the length C of the reflecting surfaces 400A, 400B between 250 and 300 microns can improve the accuracy of detecting misalignment, where 250 microns is the nominal optimum value.

[0103] Figures 12 to 20 It illustrates possible stages of assembling the sensor 10 along the line discussed previously.

[0104] As Figure 12 As exemplified in, such a sensor assembly 10 may include:

[0105] - An optical chip layer 18, e.g., an optically transparent fused silica layer;

[0106] - An active film 20, e.g., a nanofilm of a piezoelectric material;

[0107] - A pair of conductive bonding pads 24, coupled to the membrane, wherein the working area of the membrane 20 is located between the bonding pads 24, and the bonding pads 24 are configured to provide an electrical connection between the leads and the membrane 20; and

[0108] - A pair of reference surfaces 400A, 400B, symmetrically arranged on the sides of the membrane 20 such that their positions relative to the membrane 20 are well-defined, and the pair of reference surfaces may include metal or a reflective coating provided in the chip by lithography in other known ways.

[0109] In one or more embodiments, the optical element 30 can be directly aligned with and coupled (e.g., bonded) to the component 100.

[0110] Alternatively, as Figure 13 、 Figure 14 illustrated, the component 10 can be included in a package 12 having a glass window 120, and the optical element 30 can be coupled to such a package window. For example, Figure 12 the chip component of Figure 13 and Figure 14 can be mounted inside the package of

[0111] Figure 13 and Figure 14 are examples of (e.g., ceramic) chip support packages 12 that include an array of conductive leads 14 and vias 120 that carry a glass window on the bottom surface of the support 12. Figure 14 is Figure 13 a flipped perspective view of the package, showing the back surface 12a of the planar support 12 with the glass window 120.

[0112] As Figure 15 illustrated, the component 10 can be placed and attached (e.g., glued) on top of the glass window 120, with a portion of the optical chip layer 18 exposed or aligned therewith. As Figure 15 and Figure 17 illustrated, for the electrical connection between the opto-mechanical component 10 and the outside of the package, wire bonding can be performed to electrically couple the bonding pads 24 that are coupled to the membrane 22 and the lead array 14 in the support 12.

[0113] In one or more embodiments as Figure 16 illustrated, a protective cover 90 can be attached to the package support 12 to seal the volume therein, thereby protecting the chip component 100 from the external environment.

[0114] Figure 17The back surface 12a of the support member 12 is shown, where the film 20 and the reference surfaces 400A, 400B are visible through the optically transparent glass window 120.

[0115] Figure 18 is a perspective view of an optical component 30, which may include a set of three optical fibers 32, 34A, 34B, inserted into the same optical fiber block 30 or coupled therebetween via a mechanical bracket (not visible in the figure).

[0116] Aligning the optical element 30 with respect to the film 20 may include, on the side of the window 120 exposed on the back surface of the package 12 as exemplified in Figure 19 coupling the free output end of the optical element 30 to the window 120.

[0117] Figure 20 is shown as an enlarged view of the portion indicated by the Figure 19 arrow XX.

[0118] In the arrangement illustrated herein, the process of aligning the optical element 30 with respect to the film 20 by δc, δf may include, before fixedly coupling the optical element 30 to the window 120:

[0119] - emitting a pair of collimated beams BSc towards the reflective reference surfaces 400A, 400B, while emitting a focused beam BSf towards the film 20;

[0120] - receiving the optical signal R reflected back from the reflective surfaces 40, 400, 400A, 400B, 200; and

[0121] - changing the position of the optical element 30 relative to the glass window 120 (and the film 20) according to the reflected signal R, for example, via the actuator A.

[0122] As a result, it is possible to align the collimating lenses 34A, 34B with respect to the reference surfaces 400A, 400B by δc, δf.

[0123] Since the positions of the reference reflective surfaces 400A, 400B are known relative to the working area of the film 20, and since the optical fibers 32, 34A, 34B are aligned with each other due to being integrated in 30, the focusing portion 32 is aligned with the working area of the film 20 by design.

[0124] The device (e.g., 10) may include:

[0125] - an optically transparent substrate (e.g., 18), having a first surface and a second surface opposite the first surface;

[0126] - A piezoelectric film (e.g., 20), disposed on a first surface of an optically transparent substrate, the piezoelectric film being configured to oscillate due to light propagating through the optically transparent substrate and impinging on the piezoelectric film, wherein at least one reflective facet (e.g., 40, 400A, 400B) facing the optically transparent substrate is provided at the piezoelectric film; and

[0127] - An optical element (e.g., 30), configured to receive a light beam at an input end and direct the light beam toward an output end that can be coupled to a second surface of the optically transparent substrate;

[0128] - Wherein the optical element includes: a light focusing path (e.g., 32), configured to focus (e.g., 320) the light beam at a focal point (e.g., FP) of the piezoelectric film; and at least one light collimating path (e.g., 34, 34A, 34B), configured to irradiate the collimated (e.g., 340) light beam onto at least one reflective facet;

[0129] - Wherein the optical element is configured to direct the light (e.g., R, 31) reflected from at least one reflective facet toward the input end; and

[0130] - Wherein the light reflected to the input end indicates (e.g., δc, δf) the position of the optical element relative to the focal point.

[0131] In the apparatus exemplified herein:

[0132] - The piezoelectric film may include at least one reflective facet (e.g., 40), the at least one reflective facet having a central region (e.g., 200) and a peripheral region (e.g., 400), and

[0133] The light focusing path in the optical element is configured to focus the light beam at the central region (e.g., 200, FP) of at least one reflective facet, and

[0134] – At least one light collimating path in the optical element is configured to collimate (e.g., 340) the light beam at the peripheral region of at least one reflective facet.

[0135] The apparatus exemplified herein may include a plurality of reflective facets (400A, 400B), in which case the optical element may include a plurality of light collimating paths (e.g., 34A, 34B), the light collimating paths being configured to provide corresponding collimated light beams (e.g., 340) to the plurality of reflective facets.

[0136] In the apparatus exemplified herein, the plurality of reflective facets may include reflective facets arranged at the same distance (e.g., H) from the center (e.g., FP) of the piezoelectric film.

[0137] In the apparatus as exemplified herein, the plurality of reflective facets includes two facets arranged symmetrically about the center of the piezoelectric film.

[0138] In the apparatus as exemplified herein, the plurality of reflective facets may include:

[0139] - a square facet having a side length (e.g., C) between about 250 micrometers and about 300 micrometers, and / or

[0140] - a facet located at about 300 micrometers (e.g., H) from the center of the piezoelectric film.

[0141] In the apparatus as exemplified herein, the optical element may include:

[0142] - a substrate (e.g., 60) having a plurality of channels (e.g., 600) formed therein,

[0143] - a plurality of optical fibers (e.g., 32, 34, 34A, 34B) disposed in the channels (e.g., 600), and

[0144] - the optical fibers (e.g., 32, 34, 34A, 34B) providing an optical focusing path (e.g., 32) and at least one optical collimation path (e.g., 34, 34A, 34B).

[0145] In the apparatus as exemplified herein:

[0146] - the optical focusing path in the optical element may include an optical focusing gradient index, GRIN, lens (e.g., 320) having a focusing pitch (e.g., Pf), and

[0147] - at least one optical collimation path in the optical element includes an optical collimation GRIN lens (e.g., 34A, 34B) having a collimation pitch (e.g., Pc), and the optical focusing path and the optical collimation path may have the same total length (e.g., L0) and the same lens diameter (e.g., E).

[0148] In the apparatus as exemplified herein, at least one of the optical focusing path in the optical element and at least one optical collimation path may include an optical spacer portion (e.g., 322, 342).

[0149] In the apparatus as exemplified herein, the same total length may be about 500 micrometers, and / or the same lens diameter may be about 350 micrometers.

[0150] In an apparatus as exemplified herein, the apparatus may include a housing (e.g., 12, 90) having a support base (e.g., 12) with a through hole (e.g., 120) therein, the support base of the housing being coupled to a second surface of an optically transparent substrate, a portion of the second surface of the optically transparent substrate being aligned with the through hole; and an output end of an optical element being coupled to an optically transparent layer at the through hole in the support base of the housing.

[0151] A method as exemplified herein may include:

[0152] - Emitting (e.g., S) a light beam aimed at at least one reflective facet (e.g., 40, 400A, 400B) into an input end of an optical element (e.g., 30) of an opto-mechanical device (e.g., 10) as exemplified herein; and

[0153] - Sensing (e.g., 31) light (e.g., R) reflected toward the input end of the optical element (e.g., 30); and

[0154] - Aligning (e.g., A) the optical element relative to a focal point at a piezoelectric film of the device based on the sensed reflected light.

[0155] In addition, it should be understood that the selection of the various individual embodiments exemplified in the figures of this description is not necessarily intended to be employed in the same combinations as those exemplified in the figures. One or more embodiments may thus employ these (otherwise non-mandatory) options individually and / or in different combinations with respect to the combinations exemplified in the figures.

[0156] Without prejudice to the underlying principles, details and embodiments may vary, even significantly, from what has been described by way of example only, without departing from the scope of protection. The scope of protection is defined by the appended claims.

Claims

1. An optomechanical device, comprising: An optically transparent substrate having a first surface and a second surface opposite to the first surface; A piezoelectric film disposed at the first surface of the optically transparent substrate, the piezoelectric film being configured to oscillate due to a light beam propagating through the optically transparent substrate and impinging on the piezoelectric film, wherein at least one reflective facet facing the optically transparent substrate is disposed at the piezoelectric film; And An optical element configured to receive the light beam at an input end and direct the light beam towards an output end coupled to the second surface of the optically transparent substrate; Wherein, the optical element comprises: A light focusing path configured to focus the light beam at a focal point located at the piezoelectric film; and At least one light collimation path configured to collimate the light beam onto the at least one reflective facet; Wherein, the optical element is configured to direct the light reflected from the at least one reflective facet to the input end; and Wherein, the light reflected to the input end indicates the position of the optical element relative to the focal point.

2. The optomechanical device according to claim 1, wherein: The piezoelectric film includes the at least one reflective facet, and the at least one reflective facet has a central region and a peripheral region; The light focusing path in the optical element is configured to focus the light beam at the central region of the at least one reflective facet; And The at least one light collimation path in the optical element is configured to collimate the light beam at the peripheral region of the at least one reflective facet.

3. The optomechanical device according to claim 1, further comprising: A plurality of the reflective facets; Wherein the optical element includes a plurality of light collimation paths configured to provide corresponding collimated light beams to the plurality of the reflective facets.

4. The optomechanical device according to claim 3, wherein the plurality of the reflective facets include reflective facets disposed at the same distance from the center of the piezoelectric film.

5. The optomechanical device according to claim 4, wherein the plurality of the reflective facets include: A square facet having a side length between 250 microns and 300 microns; and / or A facet at a distance of 300 microns from the center of the piezoelectric film.

6. The optomechanical device according to claim 3, wherein the plurality of the reflective facets include two facets arranged symmetrically with respect to the center of the piezoelectric film in a mirror image manner.

7. The optomechanical device according to claim 1, wherein the optical element includes: A substrate having a plurality of channels formed therein; And A plurality of optical fibers disposed in the channels; Wherein the optical fibers provide the light focusing path and the at least one light collimation path.

8. The optomechanical device according to claim 1, wherein: The light focusing path in the optical element includes a light focusing gradient index (GRIN) lens having a focusing pitch; and The at least one light collimation path in the optical element includes a light collimation GRIN lens having a collimation pitch, and the light focusing path and the light collimation path have the same total length and the same lens diameter.

9. The optical-mechanical device according to claim 8, wherein at least one of the light focusing path in the optical element and the at least one light collimation path includes an optical spacer portion.

10. The optical-mechanical device according to claim 8, wherein: the same total length is 500 micrometers; and / or the same lens diameter is 350 micrometers.

11. The optical-mechanical device according to claim 1, wherein: the device further includes: a housing having a support base with a through hole therein, the support base of the housing being coupled to the second surface of the optically transparent substrate, wherein a portion of the second surface of the optically transparent substrate is aligned with the through hole; and the output end of the optical element is coupled to the optically transparent substrate at the through hole in the support base of the housing.

12. A method of operating an optical engine device, the optical engine device comprising: An optically transparent substrate having a first surface and a second surface opposite the first surface, a piezoelectric film disposed at the first surface, at least one reflecting facet disposed at the piezoelectric film facing the substrate, and an optical element having an input end and an output end, and the output end being coupled to the second surface of the optically transparent substrate, the method includes: receiving, through the input end of the optical element, a light beam directed to at least one reflecting facet; guiding, through the optical element, the light beam toward the output end of the optical element; oscillating, through the piezoelectric film, in response to the light beam propagating through the optically transparent substrate and impinging on the piezoelectric film; guiding, through the optical element, the light reflected from the at least one reflecting facet to the input end of the optical element; sensing the light reflected to the input end of the optical element; and aligning the optical element relative to the focal point at the piezoelectric film according to the sensed reflected light.

13. The method according to claim 12, wherein the guiding of the light beam toward the output end includes: focusing, through the light focusing path of the optical element, the light beam at the focal point located at the piezoelectric film.

14. The method according to claim 13, wherein the guiding of the light beam toward the output end further includes: collimating, through at least one light collimation path of the optical element, the light beam onto the at least one reflecting facet.

15. The method according to claim 14, wherein the piezoelectric film includes the at least one reflecting facet, the at least one reflecting facet having a central region and a peripheral region, and the method further includes: focusing, through the light focusing path, the light beam at the central region of the at least one reflecting facet; and collimating, through the at least one light collimation path, the light beam at the peripheral region of the at least one reflecting facet.

16. The method according to claim 14, wherein the optical element includes a plurality of optical fibers disposed in a plurality of channels, and the method further includes: providing, through the optical fibers, the light focusing path and the at least one light collimation path.

17. The method according to claim 12, wherein the device includes a plurality of the reflective facets, and the method further includes: Collimating corresponding light beams onto the plurality of the reflective facets through a plurality of light collimation paths of the optical element.

18. The method according to claim 17, wherein the plurality of the reflective facets include reflective facets arranged at the same distance from the center of the piezoelectric film.

19. The method according to claim 18, wherein the plurality of the reflective facets include: Square facets having a side length between 250 micrometers and 300 micrometers; and / or Facets at a distance of 300 micrometers from the center of the piezoelectric film.

20. The method according to claim 17, wherein the plurality of the reflective facets include two facets arranged symmetrically with respect to the center of the piezoelectric film in a mirror image manner.

21. An opto-mechanical device, comprising: An optically transparent substrate, including: A first surface; and A second surface opposite to the first surface; A piezoelectric film disposed at the first surface of the optically transparent substrate; At least one reflective facet disposed at the piezoelectric film or disposed in the same plane on one side of the piezoelectric film, and the at least one reflective facet faces the optically transparent substrate; and An optical element, including: An input end configured to receive a light beam; An output end coupled to the second surface of the optically transparent substrate; A light focusing lens having a focus for the light beam at the piezoelectric film; and A light collimating lens oriented to collimate the light beam onto the at least one reflective facet so as to be reflected back to the input end.

22. The opto-mechanical device according to claim 21, wherein: The piezoelectric film includes the at least one reflective facet, and the at least one reflective facet has a central region and a peripheral region; The light focusing lens has the focus for the light beam at the central region of the at least one reflective facet; And The light collimating lens is oriented to collimate the light beam at the peripheral region of the at least one reflective facet.

23. The opto-mechanical device according to claim 21, further comprising: A plurality of the reflective facets; Wherein the optical element includes a plurality of light collimating lenses oriented to collimate corresponding light beams onto the plurality of the reflective facets.

24. The opto-mechanical device according to claim 21, wherein the optical element includes: A substrate having a plurality of channels formed therein; And A plurality of optical fibers arranged in the channels; Wherein the optical fibers provide light focusing paths for the light focusing lens and light collimation paths for the light collimating lens.

25. The opto-mechanical device according to claim 21, wherein: The light focusing lens is a light focusing gradient index (GRIN) lens having a focusing pitch; and The light collimating lens is a light collimating GRIN lens having a collimating pitch, and wherein the light focusing lens and the light collimating lens have the same lens diameter.

26. The opto-mechanical device according to claim 21, wherein: The device further includes: a housing having a support base with a through hole therein, the support base of the housing being coupled to the second surface of the optically transparent substrate, a portion of the second surface of the optically transparent substrate being aligned with the through hole; and The output end of the optical element is coupled to the optically transparent substrate at the through hole in the support base of the housing.

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