A 100-picosecond true-delay MEMS fiber delay line and its array

Abstract

The present invention provides a 100-picosecond true-delay MEMS fiber delay line and its array. The 100-picosecond true-delay MEMS fiber delay line is optically collimated by coupling a long-stroke MEMS vertical motion micromirror with a multi-reflection fiber collimator. By setting a motion amplification lever structure, the out-of-plane motion stroke of the long-stroke MEMS vertical motion micromirror can reach the millimeter level, and the vertical movement accuracy can reach the nanometer level, thus breaking through the limitation of the existing technology that the MEMS vertical motion micromirror has a stroke of only tens of microns and reducing the preparation cost. In addition, the present invention greatly improves the delay amount of the fiber delay line, makes the fiber delay line highly precise and rapidly tunable, and realizes the arraying of the fiber delay line to a certain extent, thereby meeting the application requirements of high-end optical systems such as optical phased arrays.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber delay lines, and in particular to a 100-picosecond true delay MEMS optical fiber delay line and an array thereof. Background Art

[0002] Microwave phased array technology has been widely used in both military and civilian applications, achieving particular success in microwave phased array radars. With the development of microwave phased array radars, improving ranging accuracy has necessitated the development of "true delay" technology based on optical carriers. With technological advancements, the wavelength of the carrier used in microwave phased array technology has expanded into the optical band. To achieve ultra-wideband (e.g., dense wavelength division multiplexing of dozens of wavelengths or single-wavelength transmission rates of hundreds of Gbps) space laser communications, high-precision, adjustable true delay compensation is required for each phased sub-beam in the optical phased array.

[0003] Optical delay lines, as high-end optical devices that provide optical signal time delay, are widely used in optical systems such as optical phased arrays and microwave phased arrays with optical carriers, and have broad market prospects. Optical delay lines can provide tunable optical signal time delay and are also known as optical tunable delay lines. They are typically implemented using optical fiber waveguides and are therefore also referred to in the field as fiber delay lines. Unlike optical phase modulators, which only have a tuning range of a few wavelengths, fiber delay lines typically provide optical signal time delays on the order of 1 to 10 picoseconds (ps), meaning they can extend over thousands of optical wavelengths. Based on the tuning step size, fiber delay lines can be categorized as fiber digital delay lines and fiber analog delay lines. Fiber digital delay lines offer larger optical delay step sizes, but improving tuning accuracy requires more optical switches in series, significantly increasing the insertion loss, size, and cost of the fiber delay line. Consequently, there are no mature commercial products for fiber digital delay lines to date. The fiber-optic analog delay line has a higher delay tuning accuracy, especially the optical delay line with a large delay, which is more difficult to realize technically. Although it is possible to obtain a larger microwave delay by periodic extension of microwaves, this limits the radar signal bandwidth of the microwave phased array, that is, only narrowband microwave signals can be realized. At present, the main realization technologies of the fiber-optic analog delay line are as follows: the fiber-optic tunable delay line based on tunable laser and fiber dispersion, which uses the dispersion characteristics of the fiber and the tuning of the laser wavelength to change the refractive index of the fiber to achieve the tuning of the fiber delay. However, due to the small tuning range of the laser wavelength and the fiber dispersion, its optical delay is small, usually only in the order of sub-ps to 1ps, and the tunable laser is expensive and costly, so its application scenarios are greatly limited; the fiber-optic tunable delay line based on thermo-optic tuning, which uses the thermo-optic effect of the fiber to control the temperature of the fiber to change the refractive index of the fiber to achieve the tuning of the fiber delay, but its optical delay is small, usually only in the order of sub-ps to 1ps, and due to the high power consumption and slow speed of the fiber temperature control, its application scenarios are greatly limited; The optical fiber adjustable delay line based on mechanical stretching of the optical fiber wraps the optical fiber around a piezoelectric ceramic ring and stretches the optical fiber through the deformation of the piezoelectric ceramic to achieve tuning of the optical fiber delay. However, its optical delay is small, usually only on the order of sub-ps to 1ps, and its driving voltage is very high. In addition, piezoelectric ceramics have serious "hysteresis" characteristics, making it difficult to achieve high-precision control, and therefore its application is also greatly limited. The optical fiber adjustable delay line based on precision mechanical displacement uses a linear motor to drive a precision mechanical guide to drive the optical reflector to move linearly, and realizes electric tuning of the optical fiber delay through fiber collimator coupling. However, due to the use of motor drive and mechanical guide, it has the disadvantages of high power consumption, slow speed, large size and heavy weight. In addition, there is motion hysteresis due to mechanical friction, which makes it difficult to control its driving accuracy.

[0004] Therefore, how to develop optical fiber delay lines and their arrays with large delay, high precision, small size, low power consumption, fast tuning, and low cost to meet the growing demand for optical phased array technology has become a difficult problem that needs to be solved urgently. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a hundred-picosecond true-delay MEMS fiber delay line and its array, which are used to solve the problems of low delay, low precision, large size, high power consumption and high cost of fiber delay lines and their arrays in the prior art, as well as the inability to perform rapid tuning.

[0006] To achieve the above and other related objectives, the present invention provides a 100-picosecond true-delay MEMS optical fiber delay line, which comprises at least:

[0007] A lower base and an upper base arranged opposite to the lower base, wherein support grooves are provided on both sides of the lower base and the upper base, and a fiber collimator hole is provided at the center of the upper base;

[0008] A support column, wherein the support column comprises an upper support column and a lower support column that match each other, wherein the lower support column is located in the support column groove of the lower base, and the upper support column is located in the support column groove of the upper base;

[0009] A large-stroke MEMS vertical motion micromirror, the large-stroke MEMS vertical motion micromirror being fixedly connected to the pillar, comprising a MEMS vertical motion micromirror chip and a driver package, wherein the MEMS vertical motion micromirror chip comprises a fixed outer frame, a vertical motion micromirror located within the fixed outer frame, a first elastic hinge distributed around the vertical motion micromirror, a uniaxial torsion driver connected to the vertical motion micromirror, and a motion amplifying lever structure connecting the uniaxial torsion driver and the first elastic hinge;

[0010] A multi-reflection fiber collimator, comprising a fixed sleeve, a multi-fiber array connected to the fixed sleeve, and a rod-shaped plano-convex lens located at the bottom of the fixed sleeve, wherein the fixed sleeve is fixed through the fiber collimator hole so that the flat surface of the rod-shaped plano-convex lens is coupled to the end face of the multi-fiber array, and the convex surface of the rod-shaped plano-convex lens is collimated and coupled to the vertically moving micromirror;

[0011] The multi-fiber array includes at least an input fiber and an output fiber, so that an optical signal is input through the input fiber, collimated and expanded by the rod-shaped plano-convex lens, and then incident on the large-stroke MEMS vertical motion micromirror. The optical signal is reflected multiple times on the mirror surface of the large-stroke MEMS vertical motion micromirror, and then optically coupled multiple times with the multi-reflection fiber collimator, and then output from the output fiber, thereby achieving continuous tuning of the optical signal's time delay in the hundreds of picoseconds.

[0012] Optionally, the number of the uniaxial torsion actuators is an even number and is at least 2, and they are symmetrically distributed on both sides of the vertical motion micromirror.

[0013] Optionally, the single-axis torsional drive is an electromagnetically driven single-axis torsional drive or an electrostatically driven single-axis torsional drive.

[0014] Optionally, the electromagnetically driven single-axis torsional drive is one of a "rotating magnet" electromagnetically driven single-axis torsional drive or a "rotating coil" electromagnetically driven single-axis torsional drive.

[0015] Optionally, the "rotating magnet" electromagnetically driven uniaxial torsional driver includes a permanent magnet supporting platform, a torsional elastic beam supporting the permanent magnet supporting platform, and a permanent magnet fixed on the permanent magnet supporting platform. A coil is arranged around the permanent magnet and a soft magnetic core is provided in the center of the coil to generate electromagnetic torque, thereby driving the permanent magnet supporting platform to twist around the torsional elastic beam. The coil is arranged in a non-contact manner with the permanent magnet and an air gap of a certain size is provided in the coil, thereby providing a movable space for the torsional movement of the permanent magnet.

[0016] Optionally, the permanent magnet is a neodymium iron boron permanent magnet, a samarium cobalt permanent magnet or other types of permanent magnets.

[0017] Optionally, the material type of the soft magnetic core is nanomagnetic crystal, Permalloy or other soft magnetic materials with low hysteresis loss.

[0018] Optionally, the torsional elastic beam is a symmetrical serpentine torsion beam.

[0019] Optionally, the electrostatically driven uniaxial torsional actuator is an electrostatically driven uniaxial torsional actuator having a vertical comb-tooth structure.

[0020] Optionally, the motion amplification lever structure includes a first high-rigidity beam, a second elastic hinge and a second high-rigidity beam with a torsion axis, the second high-rigidity beam with a torsion axis is connected to the fixed outer frame, one end of the first high-rigidity beam is fixedly connected to the uniaxial torsion driver, and the other end is connected to the second elastic hinge, wherein the second high-rigidity beam includes a short arm with an arm length of L2 and a long arm with an arm length of L3, the arm length of the first high-rigidity beam is L1, and the arm length of the first high-rigidity beam is greater than the short arm length of the second high-rigidity beam, and the length of the long arm is at least 10 times the length of the broken arm, ultimately realizing the conversion of the torsion angle of the vertical motion micromirror to vertical displacement and the amplification of the stroke.

[0021] Optionally, the thickness of the MEMS vertical motion micromirror chip is 200 μm to 350 μm.

[0022] Optionally, the first elastic hinge is a plurality of rectangles fixedly connected in the middle, and is deformed by twisting and stretching along the long sides of the rectangles.

[0023] Optionally, the shape of the vertically moving micromirror may be circular, rectangular or square and the size of the vertically moving micromirror may be 1 mm to 5 mm.

[0024] Optionally, the surface of the vertically moving micromirror is coated with a reflective film, and the reflective film is a gold film, an aluminum film or other dielectric film.

[0025] Optionally, a torsion angle sensor is further provided on the uniaxial torsion actuator, which can detect the motion displacement of the MEMS vertical motion micromirror and perform feedback control and monitoring output on the delay time of the true delay MEMS optical fiber delay line.

[0026] Optionally, the torsion angle sensor is a piezoresistive angle sensor or a capacitive angle sensor.

[0027] Optionally, the multi-fiber array is single-mode optical fibers, and the single-mode optical fibers are arranged in a centrally symmetrical and closely spaced manner.

[0028] Optionally, the diameter of the collimated light spot of the multi-reflection optical fiber collimator is 500 μm to 2500 μm and the number of reflections of the multi-reflection optical fiber collimator is 1 to 9 times.

[0029] The present invention also provides a 100-picosecond true-delay MEMS optical fiber delay line array, which is composed of N of the aforementioned 100-picosecond true-delay MEMS optical fiber delay lines.

[0030] As described above, the 100-picosecond true-delay MEMS fiber delay line and its array of the present invention have the following beneficial effects: the 100-picosecond true-delay MEMS fiber delay line is optically collimated by a large-stroke MEMS vertical motion micromirror and a multi-reflection fiber collimator, and through the setting of a motion amplification lever structure, the off-plane motion stroke of the large-stroke MEMS vertical motion micromirror can reach the millimeter level, and the vertical movement accuracy can reach the nanometer level, thus breaking through the limitation of the MEMS vertical motion micromirror in the prior art that the stroke is only tens of microns, and reducing the preparation cost; in addition, the present invention greatly improves the delay amount of the fiber delay line, and makes the fiber delay line high-precision and fast-tunable, and realizes the arraying of the fiber delay line to a certain extent, thereby being able to meet the application requirements of high-end optical systems such as optical phased arrays. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Shown is a schematic diagram of the three-dimensional structure of the 100-picosecond true-delay MEMS optical fiber delay line of the present invention.

[0032] Figure 2 Shown is a schematic diagram of the exploded structure of the 100-picosecond true-delay MEMS optical fiber delay line of the present invention.

[0033] Figure 3 Schematic diagram showing the arrangement of a uniaxial torsion actuator and a vertically moving micromirror in the optical fiber delay line of the present invention.

[0034] Figure 4 Shown is a schematic diagram of the motion amplifying lever structure in the optical fiber delay line of the present invention.

[0035] Figure 5 It is a schematic diagram showing the driving principle of the electromagnetically driven uniaxial torsional actuator in the optical fiber delay line of the present invention.

[0036] Figure 6 Shown is a schematic structural diagram of the "rotating magnet" electromagnetically driven uniaxial torsional actuator in the optical fiber delay line of the present invention.

[0037] Figure 7 Shown is a schematic structural diagram of the "turning coil" electromagnetically driven uniaxial torsional actuator in the optical fiber delay line of the present invention.

[0038] Figure 8 Shown is a schematic structural diagram of an electrostatically driven uniaxial torsional actuator in the optical fiber delay line of the present invention.

[0039] Figure 9 It is a schematic diagram showing the end face arrangement of a multi-fiber array in the optical fiber delay line of the present invention.

[0040] Figure 10 Shown is a three-dimensional schematic diagram of a large-stroke MEMS vertical motion micromirror in the optical fiber delay line of the present invention.

[0041] Figure 11 Shown is a front view of the structure of a large-stroke MEMS vertical motion micromirror in the optical fiber delay line of the present invention.

[0042] Figure 12 It is a schematic structural diagram of a multi-reflection optical fiber collimator in an optical fiber delay line of the present invention.

[0043] Figure 13 Shown is a schematic diagram of the structure of the 100-picosecond true-delay MEMS fiber delay line array of the present invention.

[0044] Component number description

[0045] 10. Lower base; 101. Support slot; 11. Upper base; 111. Fiber collimator hole; 12. Lower support; 13. Upper support; 14. Multi-reflection fiber collimator; 141. Fixed sleeve; 142. Rod-shaped plano-convex lens; 1421. Optical reflective film; 143. Multi-fiber array; 144. Input fiber port; 145. Output fiber port; 15. Large-stroke MEMS vertical motion micromirror; 151. MEMS vertical motion micromirror chip; 1511. Single-axis torsion actuator; 1512. Vertical motion micromirror; 1513. First elastic hinge; 1514. Motion amplification lever Rod structure; 1514-1, first high-rigidity beam; 1514-2, second elastic hinge; 1514-3, second high-rigidity beam; 1514-4, torsion axis; 1515, fixed outer frame; 152, driver package; 1521, permanent magnet support platform; 1522, permanent magnet; 1523, torsional elastic beam; 1524, coil; 1524-1, soft magnetic core; 1525, copper electroplated coil; 1526, vertical comb structure; 1071, dummy optical fiber; 1072, first layer; 1073, second layer; 1074, third layer; 108, optical fiber delay line array. DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0047] For convenience, spatially relative terms such as "under," "below," "below," "below," "above," and "on" may be used herein to describe the relationship of one element or feature to other elements or features shown in the drawings. It will be understood that these spatially relative terms are intended to encompass orientations of the device in use or operation in addition to the orientation depicted in the drawings. Additionally, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

[0048] It should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the above components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0049] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0050] See also Figures 1 to 13 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components relevant to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be arbitrarily changed, and the component layout may also be more complex.

[0051] like Figures 1 to 2 as well as Figure 10 and Figure 11As shown, this embodiment provides an electromagnetically driven 100-picosecond true-delay MEMS fiber delay line, which includes: a lower base 10 and an upper base 11 arranged opposite to the lower base 10, wherein both sides of the lower base 10 and the upper base 11 are provided with support grooves 101 and the center of the upper base 11 is provided with a fiber collimator hole 111; supports, including an upper support 13 and a lower support 12 that match each other, wherein the lower support 12 is located in the support groove 101 of the lower base 10, and the upper support 13 is located in the support groove 101 of the upper base 11; a large-stroke MEMS vertical motion micromirror 15, which is fixedly connected to the support, including a MEMS vertical motion micromirror chip 151 and a driver package 152, and the MEMS vertical motion micromirror chip 151 includes a fixed outer frame 1515 , a vertical motion micromirror 1512 located in a fixed outer frame 1515, a first elastic hinge 1513 distributed around the vertical motion micromirror 1512, a uniaxial torsion driver 1511 connected to the vertical motion micromirror 1512, and a motion amplifying lever structure 1514 connecting the uniaxial torsion driver 1511 and the first elastic hinge 1513; a multi-reflection fiber collimator 14, the multi-reflection fiber collimator 14 includes a fixed sleeve 141, a multi-fiber array 143 connected to the fixed sleeve 141, and a rod-shaped plano-convex lens 142 located at the bottom of the fixed sleeve 141, the fixed sleeve 141 is fixed through the fiber collimator hole 111 so that the plane of the rod-shaped plano-convex lens 142 is coupled with the end face of the multi-fiber array 143, and the convex surface of the rod-shaped plano-convex lens 142 is collimated and coupled with the large-stroke MEMS vertical motion micromirror 15.

[0052] As an example, the number of the single-axis torsion actuators 1511 is an even number and is at least 2, and they are symmetrically distributed on both sides of the vertical motion micromirror 1512 .

[0053] like Figure 3 As shown, the number of the single-axis torsional actuators 1511 is an even number and at least 2. Specifically, as shown in FIG. Figure 3 As shown in FIG. 2 , the number of the uniaxial torsion actuators 1511 is 4, and the uniaxial torsion actuators 1511 are symmetrically distributed around the vertical motion micromirror 1512; Figure 3 As shown in a, preferably, the number of uniaxial torsion drivers 1511 is 2, and the two uniaxial torsion drivers 1511 are symmetrically distributed on both sides of the vertical motion micromirror 1512. When the number of uniaxial torsion drivers 1511 is 2, on the one hand, the area of the MEMS vertical motion micromirror chip 151 can be greatly reduced, and on the other hand, it is more conducive to forming a compact array of vertical motion micromirrors 1512, thereby forming a MEMS optical fiber delay line array 108, so that the MEMS optical fiber delay line array 108 meets the optical phased array's requirement for the number of MEMS optical fiber delay lines under the premise of meeting the minimum volume, minimum weight and minimum cost.

[0054] As an example, the single-axis torsional drive 1511 is an electromagnetically driven single-axis torsional drive or an electrostatically driven single-axis torsional drive.

[0055] Specifically, in this embodiment, the uniaxial torsion driver 1511 is preferably an electromagnetically driven uniaxial torsion driver. Of course, in other embodiments, the uniaxial torsion driver 1511 may also be an electrostatically driven uniaxial torsion driver.

[0056] As an example, the electromagnetically driven single-axis torsional drive is one of a “rotating magnet” electromagnetically driven single-axis torsional drive or a “rotating coil” electromagnetically driven single-axis torsional drive.

[0057] As an example, the "rotating magnet" electromagnetically driven uniaxial torsional driver includes a permanent magnet supporting platform 1521, a torsional elastic beam 1523 supporting the permanent magnet supporting platform 1521, and a permanent magnet 1522 fixed on the permanent magnet supporting platform 1521. A coil 1524 is arranged around the permanent magnet 1522 and a soft magnetic core 1524-1 is provided at the center of the coil 1524 to generate an electromagnetic torque, thereby driving the permanent magnet supporting platform 1521 to twist around the torsional elastic beam 1523. The coil 1524 is arranged in a non-contact manner with the permanent magnet 1522 and the coil 1524 is provided with an air gap of a certain size, thereby providing a movable space for the torsional movement of the permanent magnet 1522.

[0058] Specifically, in this embodiment, the single-axis torsion driver 1511 is a "rotating magnet" electromagnetically driven single-axis torsion driver, and its structural diagram is shown as follows: Figure 6 As shown, it includes a permanent magnet support platform 1521, a permanent magnet 1522, a coil 1524 and a torsional elastic beam 1523, wherein one end of the torsional elastic beam 1523 is fixedly connected to the fixed outer frame 1515, and the other end of the torsional elastic beam 1523 is fixedly connected to the permanent magnet support platform 1521 so that the permanent magnet support platform 1521 is suspended and fixed. The permanent magnet support platform 1521 is generally a rectangular frame structure, and a microstructure matching the size and shape of the permanent magnet 1522 is designed in the frame so that the permanent magnet 1522 can be embedded in the permanent magnet support platform 1521 and fixed by adhesive. Optionally, the permanent magnet 1522 is a neodymium iron boron permanent magnet, a samarium cobalt permanent magnet or other types of permanent magnets. The driving principle of the "rotating magnet" electromagnetically driven single-axis torsional actuator is as follows Figure 5 As shown in Figure a, when the permanent magnet 1522 is embedded in the permanent magnet support platform 1521, the magnetic moment vector of the permanent magnet 1522 is perpendicular to the magnetic field vector. Since coils 1524 are arranged on the upper and lower sides of the permanent magnet support platform 1521, which are equivalent to electromagnets, when the coils 1524 are energized, an electromagnetic torque of the magnitude of the magnetic moment vector × the magnetic field vector is generated, thereby driving the permanent magnet support platform 1521 to twist around the torsional elastic beam 1523. Figure 6As shown, an air gap of a certain size is also provided on the coil 1524, so that the permanent magnet 1522 is arranged non-contact with the coil 1524 and is located in the middle of the air gap, thereby ensuring that the permanent magnet 1522 can minimize the air gap of the coil 1524 to a certain extent while having a sufficiently large torsional motion space, thereby improving the electromagnetic drive efficiency and reducing the drive power consumption.

[0059] Specifically, in another embodiment, the single-axis torsion driver 1511 is a "rotating coil" electromagnetically driven single-axis torsion driver, and its structural diagram is shown as follows: Figure 7 As shown, the coil carrier frame is symmetrically connected to the fixed outer frame 1515 through the torsional elastic beam 1523, and the copper electroplated coil 1525 is made on the coil carrier frame using MEMS technology. Optionally, the copper electroplated coil 1525 can be a single-layer multi-turn coil or a multi-layer multi-turn coil. In order to reduce the coil resistance and thus reduce power consumption, in this embodiment, the thickness of each layer of the copper electroplated coil 1525 is preferably 10μm to 25μm. The driving principle of the "rotating coil" electromagnetically driven single-axis torsion actuator is as follows Figure 5 As shown in b, the bias magnetic field generated by the permanent magnet 1522 is in the horizontal direction. By controlling the current passing through the copper electroplating coil 1525, the copper electroplating coil 1525 energized in the bias magnetic field will be subjected to the Lorentz force and produce an electromagnetic torque, thereby driving the permanent magnet support platform 1521 to twist around the torsional elastic beam 1523.

[0060] As an example, the torsional elastic beam 1523 is a symmetrical serpentine torsion beam.

[0061] Specifically, in this embodiment, the torsional elastic beam 1523 is preferably a symmetrical serpentine torsional beam, thereby greatly reducing the length of the torsional elastic beam 1523 and reducing driving power consumption.

[0062] In order to further reduce the power consumption of the electromagnetic drive and thus improve the drive efficiency, a soft magnetic core 1524-1 is inserted in the center of the coil 1524. Optionally, the material type of the soft magnetic core 1524-1 is nanocrystalline, Permalloy, or other soft magnetic materials with low hysteresis loss. In this embodiment, soft magnetic materials with low hysteresis loss are preferred. The soft magnetic core 1524-1 can greatly increase the driving magnetic field, but the presence of the soft magnetic core 1524-1 also introduces a "hysteresis effect", which poses a great challenge to high-precision control. Furthermore, a torsion angle sensor is provided on the single-axis torsion driver 1511 to achieve high-precision delay tuning control.

[0063] As an example, the torsion angle sensor is one of a piezoresistive angle sensor or a capacitive angle sensor.

[0064] Specifically, the torsion angle sensor can be a piezoresistive angle sensor disposed on the torsional elastic beam 1523, and its torsion angle detection resolution can reach 0.01°. In other embodiments, the torsion angle sensor can also be a capacitive angle sensor disposed on the electromagnetic driver, wherein the capacitive torsion angle sensor has a torsion angle detection resolution of 0.001°. The torsion angle sensor can detect the motion displacement of the vertical motion micromirror 1512, and can provide feedback control and monitoring output of the delay time of the true delay MEMS fiber delay line, ultimately improving the tuning accuracy of the delay amount.

[0065] As an example, the electrostatically driven single-axis torsional actuator is an electrostatically driven single-axis torsional actuator having a vertical comb structure 1526 .

[0066] Specifically, such as Figure 8 As shown, in this embodiment, the electrostatically driven single-axis torsion actuator has a vertical comb tooth structure 1526, including fixed comb teeth and torsion comb teeth arranged on a fixed outer frame 1515. The fixed comb teeth serve as fixed teeth connected to an external driving power source, while the torsion comb teeth serve as movable teeth and are connected to ground. There is a certain height difference between the fixed teeth and the movable teeth, thereby achieving torsion of the electrostatically driven single-axis torsion actuator through the electrostatic force between the vertical comb tooth structure 1526. In another embodiment, bidirectional torsion of the electrostatically driven single-axis torsion actuator can be achieved by designing two sets of fixed teeth. The electrostatically driven single-axis torsion actuator cooperates with the motion amplification lever structure 1514 to achieve large-stroke displacement with higher precision. In addition, the packaging process of the electrostatically driven single-axis torsion actuator is simpler, thereby reducing production costs to a certain extent.

[0067] As an example, the motion amplification lever structure 1514 includes a first high-rigidity beam 1514-1, a second elastic hinge 1514-2, and a second high-rigidity beam 1514-3 with a torsion axis 1514-4. The second high-rigidity beam 1514-3 with the torsion axis 1514-4 is connected to the fixed outer frame 1515. One end of the first high-rigidity beam 1514-1 is fixedly connected to the uniaxial torsion driver 1511, and the other end is connected to the second elastic hinge 1514-2. The second high-rigidity beam 1514-3 includes a short arm with an arm length of L2 and a long arm with an arm length of L3. The arm length of the first high-rigidity beam 1514-1 is L1, and the arm length of the first high-rigidity beam 1514-1 is greater than the short arm length of the second high-rigidity beam 1514-3. The long arm length of the second high-rigidity beam 1514-3 is at least 10 times the short arm length of the second high-rigidity beam 1514-3, ultimately realizing the conversion of the torsion angle of the vertical motion micromirror 1512 into vertical displacement and the amplification of the stroke.

[0068] Specifically, as shown in Figure 4, in this embodiment, the motion amplification lever structure 1514 includes a first high-rigidity beam 1514-1, a second elastic hinge 1514-2, and a second high-rigidity beam 1514-3 with a torsion axis 1514-4, wherein the second high-rigidity beam 1514-3 is connected to the fixed outer frame 1515, one end of the first high-rigidity beam 1514-1 is fixedly connected to the uniaxial torsion driver 1511, and the other end is connected to the second elastic hinge 1514-2, and the first high The arm length of the rigid beam 1514-1 is L1, and the second high-rigidity beam 1514-3 includes a short arm with an arm length of L2 and a long arm with an arm length of L3, and L1>L2, thereby realizing the amplification of the angle, and L3≥10L2, thereby realizing the amplification of the stroke, that is, the motion amplification lever structure 1514 realizes the conversion of the torsion angle into the vertical displacement, and amplifies the vertical displacement of the uniaxial torsion driver 1511 by several times to dozens of times, and finally realizes the large-stroke vertical motion of the vertical motion micromirror 1512.

[0069] As an example, the second elastic hinge 1514 - 2 is a plurality of rectangles fixedly connected in the middle, and is deformed by twisting and stretching along the long sides of the rectangle.

[0070] Specifically, the second elastic hinge 1514-2 is a flexible structure etched from single-crystal silicon. It is structurally composed of multiple rectangular elements fixedly connected in the middle, and is easily deformed by twisting and stretching along its long sides. The second elastic hinge 1514-2, combined with the motion-amplifying lever structure 1514, ultimately achieves the conversion of torsion angles into vertical displacements without stimulating the non-operating motion modes of the vertically moving micromirror 1512. Furthermore, the second elastic hinge 1514-2 can adapt to the geometric changes caused by the torsion of the motion-amplifying lever structure 1514, thereby reducing the tensile stress on the vertically moving micromirror 1512 and the resulting deformation of the vertically moving micromirror 1512.

[0071] As an example, the thickness of the MEMS vertical motion micromirror chip 151 is 200 μm to 350 μm.

[0072] Specifically, the MEMS vertical motion micromirror chip 151 is manufactured on a single crystal silicon wafer using a MEMS deep etching process. The thickness of the MEMS vertical motion micromirror chip 151 is 200 μm to 350 μm, for example, 200 μm, 300 μm or 350 μm, which is not specifically limited here. In this embodiment, Figure 10 and Figure 11As shown, the MEMS vertical motion micromirror chip 151 includes a fixed outer frame 1515, a vertical motion micromirror 1512 located within the fixed outer frame 1515, first elastic hinges 1513 distributed around the vertical motion micromirror 1512, a uniaxial torsion actuator 1511 connected to the vertical motion micromirror 1512, and a motion amplifying lever structure 1514 connecting the uniaxial torsion actuator 1511 and the first elastic hinge 1513. The uniaxial torsion actuator 1511, the motion amplifying lever structure 1514, and the first elastic hinge 1513 are symmetrically arranged around the vertical motion micromirror 1512. The symmetrically distributed first elastic hinges 1513 suspend and support the vertical motion micromirror 1512, allowing it to move only vertically along the lateral direction of the mirror surface while maintaining its horizontal position unchanged.

[0073] As an example, the first elastic hinge 1513 is a plurality of rectangles fixedly connected in the middle, and is deformed by twisting and stretching along the long sides of the rectangle.

[0074] The first elastic hinge 1513 is a flexible structure etched on single-crystal silicon. Structurally, it is a plurality of rectangles fixedly connected in the middle, and is easily twisted and stretched along the long sides of the rectangles. The first elastic hinge 1513 serves as a link between the motion amplification lever structure 1514 and the vertical motion micromirror 1512, and can realize the key adaptation function.

[0075] As an example, the shape of the vertical motion micromirror 1512 may be circular, rectangular, or square, and the size of the vertical motion micromirror 1512 may be 1 mm to 5 mm.

[0076] As an example, the surface of the vertical motion micromirror 1512 is coated with a reflective film, and the type of the reflective film is a gold film, an aluminum film or other dielectric film.

[0077] Specifically, in this embodiment, the vertical motion micromirror 1512 is a silicon reflector made by MEMS technology, which has a nanometer-level surface roughness and a high optical flatness at the optical subwavelength level. The shape of the vertical motion micromirror 1512 can be circular, rectangular or square and the size of the vertical motion micromirror 1512 is 1 mm to 5 mm, for example, it can be 1 mm, 3 mm or 5 mm. Optionally, a reflective film is also coated on the surface of the vertical motion micromirror 1512, and the type of the reflective film is a gold film, an aluminum film or other dielectric film, and the optical reflectivity of the reflective film is ≥95%.

[0078] As an example, the multi-fiber array 143 is a single-mode optical fiber, and the single-mode optical fibers are arranged in a centrally symmetrical and closely spaced manner.

[0079] Specifically, in this embodiment, Figure 12As shown, the multi-reflection fiber collimator 14 includes a fixed sleeve 141, a multi-fiber array 143 connected to the fixed sleeve 141, and a rod-shaped plano-convex lens 142 located at the bottom of the fixed sleeve 141. The multi-fiber array 143 is an array containing 2N optical fibers (N is a positive integer) arranged tightly and centrally symmetrically, as shown in FIG. Figure 9 As shown in a, the multi-fiber array 143 is closely arranged in a regular hexagon. At this time, the axis of the multi-fiber array 143 is located at the center of the regular hexagon, and the optical fiber at the center of the regular hexagon is a dummy optical fiber 1071 that does not transmit light. The first layer 1072 has 6 optical fibers, the second layer 1073 has 6 optical fibers, and the third layer 1074 has 6 optical fibers. The transmission path of the optical signal is: the optical signal is input by the input optical fiber, and after being collimated and expanded, it is incident on the large-stroke MEMS vertical motion micromirror 15. The optical signal is reflected by the mirror surface of the vertical motion micromirror 1512 and then coupled back to other optical fibers that are symmetrical with the center of the input optical fiber. Since the optical fibers in the multi-fiber array 143 are all fused together, the optical signal is collimated and expanded again after passing through other optical fibers and is incident on the mirror surface of the vertical motion micromirror 1512. After reflection, it is focused by the rod-shaped plano-convex lens 142 and coupled back to another optical fiber. Similarly, the optical signal is output from the output optical fiber after being reflected by the mirror surface of the vertical motion micromirror 1512 multiple times. In another embodiment, as Figure 9 As shown in FIG. 2 b, the multi-fiber array 143 can also be arranged in a close-packed square pattern. In this case, the axis of the multi-fiber array 143 is located at the center of the square.

[0080] In this embodiment, the optical fibers in the multi-fiber array 143 are single-mode optical fibers. Preferably, the single-mode optical fibers are polarization-maintaining single-mode optical fibers, so that the curvature radius of the polarization-maintaining optical fiber ring during fusion connection is not too small, thereby ensuring that the polarization mode crosstalk coupling is sufficiently low, thereby meeting the polarization index requirements of the multi-reflection optical fiber collimator 14.

[0081] As an example, the diameter of the collimated light spot of the multi-reflection optical fiber collimator 14 is 500 μm to 2500 μm and the number of reflections of the multi-reflection optical fiber collimator 14 is 1 to 9 times.

[0082] Specifically, in this embodiment, the diameter of the collimated light spot of the multi-reflection fiber collimator 14 is 500μm to 2500μm, for example, it can be 500μm, 1500μm or 2500μm. In addition, since the rod-shaped plano-convex lens 142 has the characteristic of aberration and the smaller the symmetrical fiber spacing, the smaller the optical insertion loss of the multi-reflection fiber collimator 14, three reflections can be achieved using the optical fiber of the first layer 1072, and a total of up to six reflections can be achieved using the optical fibers of the second layer 1073 and the third layer 1074, thereby reducing the insertion loss of the multi-reflection fiber collimator 14.

[0083] like Figure 12As shown, in this embodiment, a plano-convex rod lens 142 is fixed within a fixed sleeve 141 by adhesive. The plano-convex rod lens 142 is preferably made of glass with a high refractive index. One end face of the plano-convex rod lens 142 is a convex spherical surface coated with an optical reflective film 1421, while the other end face is a flat surface without chamfers or optical reflective film 1421. The flat surface of the plano-convex rod lens 142 is coupled to the end face of the multi-fiber array 143. The fixed sleeve 141 passes through the fiber collimator hole 111 to align the convex surface of the plano-convex rod lens 142 with the vertically moving micromirror 1512. An optical matching liquid or matching adhesive is also injected between the flat and convex surfaces of the plano-convex rod lens 142 to minimize optical insertion loss. The multi-fiber array 143 is also fixed in the fixed sleeve 141 by adhesive and is located above the rod-shaped plano-convex lens 142, so that the optical signal input from the input optical fiber is expanded and collimated by the rod-shaped plano-convex lens 142, and then reflected by the vertically moving micromirror 1512 and re-coupled into the multi-fiber array 143. Finally, the optical signal is output from the output optical fiber after multiple reflections.

[0084] In another embodiment of the present invention, Figure 13 As shown, a 100-picosecond true-delay MEMS fiber optic delay line array 108 device is also provided. The 100-picosecond true-delay MEMS fiber optic delay line array 108 device is composed of multiple 100-picosecond true-delay MEMS fiber optic delay lines, such as 4 100-picosecond true-delay MEMS fiber optic delay lines or 8 100-picosecond true-delay MEMS fiber optic delay lines.

[0085] In summary, the present invention discloses a 100-picosecond true-delay MEMS fiber delay line and its array. The 100-picosecond true-delay MEMS fiber delay line is optically coupled by a large-stroke MEMS vertical motion micromirror and a multi-reflection fiber collimator. Through the configuration of a motion amplification lever structure, the out-of-plane motion stroke of the large-stroke MEMS vertical motion micromirror can reach the millimeter level, and the vertical movement accuracy can reach the nanometer level, thus breaking through the limitation of the existing MEMS vertical motion micromirror that only has a stroke of tens of microns and reducing the preparation cost. In addition, the present invention greatly improves the delay of the fiber delay line, makes the fiber delay line highly precise and rapidly tunable, and realizes the arraying of the fiber delay line to a certain extent, thereby meeting the application requirements of high-end optical systems such as optical phased arrays. Therefore, the present invention effectively overcomes the various shortcomings of the existing technology and has high industrial utilization value.

[0086] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A 100-picosecond true delay MEMS fiber delay line, characterized by: The optical fiber delay line comprises at least: A lower base and an upper base arranged opposite to the lower base, wherein support grooves are provided on both sides of the lower base and the upper base, and a fiber collimator hole is provided at the center of the upper base; A support column, wherein the support column comprises an upper support column and a lower support column that match each other, wherein the lower support column is located in the support column groove of the lower base, and the upper support column is located in the support column groove of the upper base; A large-stroke MEMS vertical motion micromirror, wherein the large-stroke MEMS vertical motion micromirror is fixedly connected to the pillar, and comprises a MEMS vertical motion micromirror chip and a driver package, wherein the MEMS vertical motion micromirror chip comprises a fixed outer frame, a vertical motion micromirror located in the fixed outer frame, a first elastic hinge distributed around the vertical motion micromirror, a uniaxial torsion driver connected to the vertical motion micromirror, and a motion amplifying lever structure connecting the uniaxial torsion driver and the first elastic hinge, wherein the motion amplifying lever structure comprises a first high-rigidity beam, a second elastic hinge, and a a second high-rigidity beam with a torsion axis, wherein the second high-rigidity beam with a torsion axis is connected to the fixed outer frame, one end of the first high-rigidity beam is fixedly connected to the uniaxial torsion actuator, and the other end is connected to the second elastic hinge, wherein the second high-rigidity beam includes a short arm with an arm length of L2 and a long arm with an arm length of L3, the arm length of the first high-rigidity beam is L1, and the arm length of the first high-rigidity beam is greater than the short arm length of the second high-rigidity beam, and the length of the long arm is at least 10 times the length of the short arm, thereby ultimately achieving the conversion of the torsion angle of the vertical motion micromirror into a vertical displacement and the amplification of the stroke; A multi-reflection fiber collimator, comprising a fixed sleeve, a multi-fiber array connected to the fixed sleeve, and a rod-shaped plano-convex lens located at the bottom of the fixed sleeve, wherein the fixed sleeve is fixed through the fiber collimator hole so that the flat surface of the rod-shaped plano-convex lens is coupled to the end face of the multi-fiber array, and the convex surface of the rod-shaped plano-convex lens is collimated and coupled to the vertically moving micromirror; The multi-fiber array includes at least an input fiber and an output fiber, so that an optical signal is input through the input fiber, collimated and expanded by the rod-shaped plano-convex lens, and then incident on the large-stroke MEMS vertical motion micromirror. The optical signal is reflected multiple times on the mirror surface of the large-stroke MEMS vertical motion micromirror, and then optically coupled multiple times with the multi-reflection fiber collimator, and then output from the output fiber, thereby achieving continuous tuning of the optical signal's time delay in the hundreds of picoseconds.

2. The optical fiber delay line according to claim 1, wherein: The number of the uniaxial torsion actuators is an even number and is at least 2, and the actuators are symmetrically distributed on both sides of the vertical motion micromirror.

3. The optical fiber delay line according to claim 1, wherein: The single-axis torsion drive is an electromagnetically driven single-axis torsion drive or an electrostatically driven single-axis torsion drive.

4. The optical fiber delay line according to claim 3, wherein: The electromagnetically driven single-axis torsion actuator is one of a "rotating magnet" electromagnetically driven single-axis torsion actuator or a "rotating coil" electromagnetically driven single-axis torsion actuator.

5. The optical fiber delay line according to claim 4, wherein: The "rotating magnet" electromagnetically driven uniaxial torsional driver includes a permanent magnet supporting platform, a torsional elastic beam supporting the permanent magnet supporting platform, and a permanent magnet fixed on the permanent magnet supporting platform. A coil is arranged around the permanent magnet and a soft magnetic core is provided in the center of the coil to generate electromagnetic torque, thereby driving the permanent magnet supporting platform to twist around the torsional elastic beam. The coil is arranged in a non-contact manner with the permanent magnet and an air gap of a certain size is provided with the coil, thereby providing a movable space for the torsional movement of the permanent magnet.

6. The optical fiber delay line according to claim 5, wherein: The permanent magnet is a neodymium iron boron permanent magnet, a samarium cobalt permanent magnet or other types of permanent magnets.

7. The optical fiber delay line according to claim 5, wherein: The material type of the soft magnetic core is nanomagnetic crystal, Permalloy or other soft magnetic materials with low hysteresis loss.

8. The optical fiber delay line according to claim 5, wherein: The torsional elastic beam is a symmetrical serpentine torsion beam.

9. The optical fiber delay line according to claim 3, wherein: The electrostatically driven single-axis torsion actuator is an electrostatically driven single-axis torsion actuator with a vertical comb-tooth structure.

10. The optical fiber delay line according to claim 1, wherein: The thickness of the MEMS vertical motion micromirror chip is 200 μm to 350 μm.

11. The optical fiber delay line according to claim 1, wherein: The first elastic hinge is a plurality of rectangles fixedly connected in the middle, and is deformed by twisting and stretching along the long sides of the rectangles.

12. The optical fiber delay line according to claim 1, wherein: The shape of the vertical motion micromirror can be circular, rectangular or square and the size of the vertical motion micromirror is 1 mm to 5 mm.

13. The optical fiber delay line according to claim 1, wherein: The surface of the vertically moving micromirror is coated with a reflective film, and the type of the reflective film is a gold film, an aluminum film or other dielectric film.

14. The optical fiber delay line according to claim 1, wherein: The uniaxial torsion driver is also provided with a torsion angle sensor, which can detect the motion displacement of the MEMS vertical motion micromirror and perform feedback control and monitoring output on the delay time of the true delay MEMS optical fiber delay line.

15. The optical fiber delay line according to claim 14, wherein: The torsion angle sensor is a piezoresistive angle sensor or a capacitive angle sensor.

16. The optical fiber delay line according to claim 1, wherein: The multi-fiber array is single-mode optical fibers, and the single-mode optical fibers are arranged in a centrally symmetrical and closely spaced manner.

17. The optical fiber delay line according to claim 1, wherein: The diameter of the collimated light spot of the multi-reflection optical fiber collimator is 500 μm to 2500 μm and the number of reflections of the multi-reflection optical fiber collimator is 1 to 9 times.

18. A 100-picosecond true-delay MEMS fiber delay line array, characterized by: It is composed of N hundred-picosecond true-delay MEMS optical fiber delay lines as described in any one of claims 1 to 17.

Images