Optical delay phase shifter device and method of regulating the same

Abstract

The present disclosure provides an optical delay phase-shifting device and a method for regulating the same. The device comprises a double-fiber collimator, a first MEMS mirror arranged on an outgoing light path of the double-fiber collimator, a first plane mirror and a second plane mirror, the first plane mirror and the second plane mirror constituting a Fabry-Perot cavity, a second MEMS mirror arranged on an outgoing light path of the Fabry-Perot cavity, and a driving device for driving the second plane mirror to displace along a cavity length direction of the Fabry-Perot cavity to achieve optical delay, and for driving the second MEMS mirror to displace along an incident light direction to achieve phase modulation. The device integrates a large-range continuously adjustable optical delay and a high-speed precise phase-shifting function in one through a shared light path, and has the advantages of low loss, high integration, and flexible regulation.

Description

Technical Field

[0001] This disclosure mainly relates to the field of optical communication technology, and specifically to an optical delay phase shifting device and its control method. Background Technology

[0002] In applications such as optical phased arrays, satellite-to-ground laser communication, quantum information processing, and precision measurement, it is often necessary to simultaneously possess delay and phase-shifting functions. Current technical solutions typically use the delay unit and the phase shifter as two independent devices connected in series, which has drawbacks such as large system size, accumulated insertion loss, complex synchronization control, and difficulty in achieving high integration. Summary of the Invention

[0003] This disclosure provides an optical delay and phase shifting device and its control method, aiming to solve the technical problems in the prior art where the delay and phase shifting functions are separated, resulting in large system size, high loss, complex synchronization control, and difficulty in high integration.

[0004] In a first aspect, an optical delay phase shifting device is provided, comprising: Dual fiber collimator; The first MEMS reflector is disposed on the outgoing optical path of the dual fiber collimator; A first plane mirror and a second plane mirror, which together form a Fabry-Perot cavity; The second MEMS reflector is disposed in the outgoing light path of the Fabry-Perot cavity; The driving device drives the second plane mirror to displace along the cavity length direction of the Fabry-Perot cavity to achieve optical delay; the driving device drives the second MEMS reflector to displace along the incident light direction to achieve phase modulation.

[0005] In one possible implementation, the reflection angles of the first MEMS mirror and the second MEMS mirror are adjustable.

[0006] In one possible implementation, the driving device adjusts the reflection angles of the first MEMS mirror and the second MEMS mirror according to the displacement of the second plane mirror, so as to ensure that the beam center trajectory remains closed during multiple reflections and is eventually coupled back to the dual fiber collimator.

[0007] In one possible implementation, a non-zero angle exists between the first plane mirror and the second plane mirror; the driving device adjusts the angles of the first MEMS mirror and the second MEMS mirror to compensate for the optical path deviation caused by the non-zero angle.

[0008] In one possible implementation, the driving device adjusts the distance between the first plane mirror and the second plane mirror, and simultaneously adjusts the angles of the first MEMS reflector and the second MEMS reflector to output continuously varying optical delay.

[0009] In one possible implementation, the driving device drives the second MEMS mirror to move along the direction of the incident light while keeping the reflection angles of the first MEMS mirror and the second MEMS mirror constant, so as to achieve continuous modulation of the output light phase.

[0010] In one possible implementation, the driving device includes: A first driving unit drives the second plane mirror to displace. The second driving unit drives the first MEMS mirror to rotate. A third driving unit drives the second MEMS mirror to rotate and displace. The type of the first driving unit is different from the types of the second and third driving units.

[0011] In one possible implementation, the first drive unit may be any one or a combination of piezoelectric ceramic drivers and voice coil motors.

[0012] In one possible implementation, the second and third drive units are of the types of electrostatic actuators, piezoelectric actuators, electrothermal actuators, or any combination thereof.

[0013] In one possible implementation, the driving device further includes a control unit that performs closed-loop or semi-closed-loop control on the reflection angles of the first MEMS mirror and the second MEMS mirror based on the optical power, coupling efficiency, or phase information of the optical signal output from the dual-fiber collimator.

[0014] In one possible implementation, the light beam reflected from the first MEMS mirror is transmitted through the Fabry-Perot cavity, reflected by the second MEMS mirror, transmitted through the Fabry-Perot cavity again, and reflected by the first MEMS mirror again before returning to the dual-fiber collimator.

[0015] In one possible implementation, both the first MEMS mirror and the second MEMS mirror are located outside the Fabry-Perot cavity.

[0016] In one possible implementation, the total number of reflections experienced by the light beam is 2× Next, among them It is an integer greater than or equal to 2.

[0017] In a second aspect, an optical modulation method is provided, applied to the optical delay and phase shifting device described in this disclosure, comprising: achieving optical delay by driving the second plane mirror to displace along the cavity length direction of the Fabry-Perot cavity; and achieving phase modulation by driving the second MEMS reflector to displace along the incident light direction.

[0018] This disclosed optical delay and phase shifting device and its control method employ a dual-fiber collimator, two MEMS mirrors, and a Fabry-Perot cavity composed of fixed and movable plane mirrors. A driving device is used to drive the movable plane mirror along the cavity length to achieve optical delay and to drive the second MEMS mirror along the incident light direction to achieve phase modulation. This integrates a wide range of continuously adjustable delay and high-speed, precise phase shifting functions within a single compact optical path structure. It avoids the problems of large size, accumulated insertion loss, and complex synchronization control associated with traditional discrete device series connections, achieving low loss, high integration, and flexible control. This device can directly meet the core requirements for joint delay and phase control in applications such as optical phased arrays, space-to-ground laser communication, quantum information processing, and precision measurement.

[0019] It should be understood that the summary section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0020] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of some embodiments thereof in the accompanying drawings, in which: Figure 1 A schematic diagram of an optical delay phase shifting device according to some embodiments of the present disclosure is shown.

[0021] Figure 2 A schematic diagram of a delay adjustment mode according to some embodiments of the present disclosure is shown.

[0022] Figure 3 A schematic diagram of a phase-shifting mode according to some embodiments of the present disclosure is shown.

[0023] Figure 4 A schematic diagram is shown showing two plane mirrors that are not parallel, according to some embodiments of the present disclosure.

[0024] Figure 5 A schematic diagram showing the change in optical path difference caused by the displacement of the second plane mirror is shown.

[0025] Figure 6A schematic diagram showing the angular changes of M1 and M2 during the displacement of the second plane mirror is shown.

[0026] Figure 7 A schematic diagram showing the change in the displacement of the second MEMS mirror and the optical path difference is shown.

[0027] Figure 8 A flowchart of an optical control method according to some embodiments of the present disclosure is shown. Detailed Implementation

[0028] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0029] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0030] To facilitate understanding, the technical terms involved in the embodiments of this disclosure will be explained first.

[0031] Dual-fiber collimator: An integrated optical element containing two optical fibers and a shared collimating lens. The end faces of the two fibers are located symmetrically on opposite sides of the lens's focal plane; one fiber serves as the input and the other as the output. Diverging light from the input fiber is collimated into a parallel beam after passing through the lens; the parallel beam from space is converged by the lens and coupled to the output fiber.

[0032] MEMS mirrors are miniature mirrors fabricated using Micro-Electro-Mechanical System (MEMS) technology, with mirror dimensions typically ranging from hundreds of micrometers to several millimeters. They can be rotated (adjusting the reflection angle) and / or translated (displaced along a specific direction) by electrostatic, piezoelectric, or electrothermal actuation methods, offering advantages such as fast response speed, high resolution, and low power consumption. In this disclosure, the first and second MEMS mirrors are used for optical path guidance and phase modulation, respectively.

[0033] A Fabry-Pérot cavity (FP cavity) is a standard interference cavity structure in optics, consisting of two parallel or nearly parallel reflecting mirrors. The light beam undergoes multiple reflections and interferences between the two mirrors, and its transmission characteristics are closely related to the distance between the two mirrors (cavity length). By changing the position of one of the reflecting mirrors, the cavity length can be continuously adjusted, thereby controlling the optical path and phase of the transmitted beam. In this embodiment, this cavity is used to achieve a wide range of continuously adjustable optical delay.

[0034] Cavity length: The perpendicular distance between two plane mirrors in a Fabry-Perot cavity, denoted as d. Changing the cavity length alters the optical path of the beam traveling back and forth within the cavity, thereby adjusting the time delay.

[0035] Plane mirror: An optical reflecting mirror with a flat surface. In this disclosure, the first plane mirror is a fixed reflecting mirror, and the second plane mirror is a movable reflecting mirror that is displaced along the cavity length direction by a driving device.

[0036] Optical delay: The amount of time an optical signal takes to travel relative to a reference path after passing through this device. By changing the cavity length of the FP cavity, the optical path length can be varied, thus achieving a continuously adjustable delay.

[0037] Phase modulation: By changing the minute displacement of the reflector, the optical path of the reflected light is altered, thereby producing a phase change. In this disclosure, high-speed and precise phase shifting is achieved by displacing the second MEMS reflector along the incident light direction.

[0038] Figure 1 This is a structural diagram of an optical delay and phase shifting device according to an embodiment of this disclosure. Figure 1 As shown, the optical delay phase shifting device includes: a dual fiber collimator 1, a first MEMS mirror 2, a first plane mirror 3, a second plane mirror 4, a second MEMS mirror 5, and a driving device (not shown).

[0039] The dual-fiber collimator 1 has a first port 11 and a second port 12. The first port 11 is used to transmit the collimated beam, and the second port 12 is used to receive the returned collimated beam.

[0040] The first MEMS mirror 2 is disposed in the output optical path of the dual-fiber collimator 1. The function of the first MEMS mirror 2 is to guide the collimated beam from the dual-fiber collimator 1 into the Fabry-Perot cavity, and to reflect the beam back to the second port 12 of the dual-fiber collimator when the beam returns from the cavity.

[0041] The first plane mirror 3 and the second plane mirror 4 constitute a Fabry-Perot cavity. The first plane mirror 3 is a fixed reflector, and the second plane mirror 4 is a movable reflector. The two mirrors are opposite each other and parallel or nearly parallel, both coated with a high-reflectivity film. The second plane mirror 4 is displaced along the cavity length direction D1 by a driving device, thereby continuously changing the distance between the first plane mirror 3 and the second plane mirror 4. The light beam undergoes multiple reflections between the two mirrors within the cavity, and its total optical path increases linearly with the cavity length, thus achieving optical path multiplication and a large-range continuously adjustable delay.

[0042] The second MEMS mirror 5 is positioned in the exit light path of the Fabry-Perot cavity. Structurally similar to the first MEMS mirror, the second MEMS mirror additionally possesses a translational degree of freedom along the incident light direction. The second MEMS mirror can rotate about its axis (adjusting the reflection angle) and also make minute displacements (typically 0–3 μm) along the incident light direction. Translation is typically driven by independent electrostatic combs or electrothermal actuators, exhibiting sub-nanometer resolution and sub-microsecond response speed. The function of the second MEMS mirror is to reflect the light beam exiting the Fabry-Perot cavity back into the cavity and achieve high-speed, precise phase modulation through its own axial displacement.

[0043] The driving device drives the second plane mirror 4 to move along the cavity length direction D1 of the Fabry-Perot cavity to achieve optical delay; the driving device drives the second MEMS reflector 5 to move along the incident light direction D2 to achieve phase modulation.

[0044] The delay and phase-shifting functions of the optical delay and phase-shifting device disclosed herein are implemented in the same optical structure through different driving modes. The two do not interfere with each other, which avoids the insertion loss and system complexity caused by the series connection of traditional discrete devices, and significantly improves the system integration, stability and scalability. It is particularly suitable for high-performance optical systems with strict requirements for size, power consumption and dynamic performance.

[0045] In this embodiment, both the first MEMS mirror 2 and the second MEMS mirror 5 are located outside the Fabry-Perot cavity (FPC). This ensures that the rotation or translation of the MEMS mirrors does not affect the parallelism and cavity length stability between the two plane mirrors within the FPC. Conversely, adjusting the cavity length of the FPC does not interfere with the angle or position of the MEMS mirrors, achieving spatial decoupling of the functional modules and reducing the complexity of system control. Secondly, if the MEMS mirrors were placed inside the FPC, each reflection would introduce additional absorption and scattering losses, which would be amplified by multiple reflections. The external layout ensures that the MEMS mirrors only reflect once, significantly reducing the total insertion loss. Furthermore, the external layout allows for independent assembly, calibration, and replacement of the MEMS mirrors and the FPC without disassembling the entire optical path.

[0046] In one embodiment, the driving device includes a first driving unit, a second driving unit, a third driving unit, and a control unit. The first driving unit is connected to the second plane mirror and is used to drive the second plane mirror to move along the cavity length direction. The type of the first driving unit includes, but is not limited to, a piezoelectric ceramic driver and a voice coil motor. The first driving unit features a large stroke, sub-micron resolution, and millisecond-level response speed, making it suitable for coarse adjustment over a wide range of delays.

[0047] The second driving unit is integrated into the first MEMS mirror and is used to drive the first MEMS mirror to rotate, thereby changing the reflection angle of the first MEMS mirror. The types of the second driving unit include electrostatic comb actuators, piezoelectric benders, electrothermal actuators, etc., and they are usually characterized by small angle range, high resolution, and microsecond to submicrosecond response speed.

[0048] The third driving unit is integrated into the second MEMS mirror and is used to drive the rotation of the second MEMS mirror and its translational motion along the incident light direction. The rotation part is similar to the second driving unit, while the translational part is an independent axial actuator (such as an electrostatic comb linear drive). The translational stroke is 0~3μm, the resolution is better than 1 nm, and the response speed can reach the sub-microsecond level, which is used for high-speed phase shifting.

[0049] Based on the optical power, coupling efficiency, or phase information of the optical signal output from the dual fiber collimator, the control unit performs closed-loop or semi-closed-loop control on the reflection angles of the first and second MEMS mirrors. It can automatically correct the reflection angles of the first and second MEMS mirrors to compensate for environmental drift and mechanical errors without manual intervention.

[0050] The optical path sequence of the optical delay-phase shifting device is as follows: The collimated beam emitted from the first port 11 of the dual-fiber collimator first strikes the center of the first MEMS mirror 2. After being reflected by the first MEMS mirror 2, the beam strikes the first plane mirror 3 of the Fabry-Perot cavity at a predetermined incident angle. After undergoing multiple reflections between the first plane mirror 3 and the second plane mirror 4, the beam exits from the second plane mirror 4 of the Fabry-Perot cavity and strikes the center of the second MEMS mirror 5. After being reflected by the second MEMS mirror 5, the beam re-enters the Fabry-Perot cavity and undergoes multiple reflections in the opposite direction. The beam exits from the Fabry-Perot cavity and strikes the first MEMS mirror 2 again. After being reflected by the first MEMS mirror 2, the beam returns to the second port 12 of the dual-fiber collimator.

[0051] The operating modes of the optical delay and phase shifting device disclosed herein include delay adjustment mode and phase shift adjustment mode.

[0052] In delay adjustment mode, the driving device adjusts the distance between the first and second plane mirrors and simultaneously adjusts the angles of the first and second MEMS reflectors to output continuously varying optical delays. For example... Figure 2 As shown, in this embodiment, the first MEMS mirror is denoted as M1, and the second MEMS mirror is denoted as M2. There is a fixed non-zero angle γ0 between the beam emitted from the first port and the beam incident at the second port of the dual-fiber collimator. This angle γ0 is determined by the fiber core spacing and lens focal length of the dual-fiber collimator and is fixed after the device is manufactured, and does not change with the working state.

[0053] In the ideal case where the first and second plane mirrors are parallel, when the FP cavity spacing is d, the angles of M1 and M2 are respectively θ 1 and β 1. When the second plane mirror moves Δd along the cavity length, in order to ensure that the output light still shines at an angle γ0 toward the second port 12, the angles of M1 and M2 need to be adjusted synchronously. The essence of this adjustment is to compensate for the lateral drift of the beam caused by the change in cavity length, ensuring the optical path is closed. When the FP cavity spacing is d ± Δd, the angles of M1 and M2 are respectively... θ 2 and β 2. In this embodiment, the light beam undergoes 2... Secondary reflection, in which The value is an integer greater than or equal to 2. The above angles should satisfy the following relationship: (1) (2) (3) (4) Where H is the length of the plane mirror, r M1 r is the distance from the center of mirror M1 to the top of the plane mirror. M2 The distance from the center of M2 to the top of the plane mirror.

[0054] The angle setting should also meet the following constraints to ensure that the beam can be reflected by the two plane mirrors: (5) in, r gmax This represents the maximum value of the beam waist during the propagation of a Gaussian beam after collimation by a collimator.

[0055] When the FP cavity is d, the corresponding optical path is... The optical path length from port 11 to M2 L 1t The optical path reflected from M2 back to the second port 12 L 1bThe sum, since the included angle γ0 of the dual-fiber collimators is generally small, the corresponding optical path can be approximately expressed as: (6) in, This is the distance from the collimator port to the first plane mirror.

[0056] When the FP cavity is d±Δd, the corresponding optical path L2 is the optical path L from the emitted light from the first port 11 to M2. 2t The optical path L reflected from M2 back to the second port 12 2b The sum can be expressed as: (7) The change in optical path difference It can be represented as: (8) First, determine the required change in optical path difference based on the delay requirements. Then, based on formulas (1) to (8), calculate , θ 1. β 1. θ 2. β 2 and Δd. The calculated parameters satisfy that, under any Δd movement of the second plane mirror, the angle between the beam emitted from the first port and the beam incident at the second port is always γ0, so as to ensure that the beam center trajectory remains closed during multiple reflections and is eventually coupled back to the dual fiber collimator.

[0057] In phase-shift modulation mode, the driving device drives the second MEMS reflector to move along the direction of the incident light while keeping the reflection angles of the first and second MEMS reflectors constant, thereby achieving continuous modulation of the output light phase. For example... Figure 3 As shown, in this embodiment, the first MEMS mirror is denoted as M1, and the second MEMS mirror is denoted as M2. A fixed non-zero angle γ0 exists between the beam emitted from the first port and the beam incident at the second port of the dual-fiber collimator. In the ideal case where the first and second plane mirrors are parallel, when the FP cavity spacing is d, the angles of M1 and M2 are respectively... θ 1 and β 1. In phase-shifting mode, keeping the angle between M1 and M2 constant, drive M2 to move Δ along the direction of the incident light. l .like Figure 3As shown, the reflected light after moving M2 is parallel to the reflected light when M2 is not moved. This indicates that the second MEMS mirror can not only achieve angle deflection to cooperate with delay adjustment, but also achieve submicron-level longitudinal translation in the direction decoupled from angle deflection. It introduces a controllable equivalent optical path change without changing the spatial propagation direction of the reflected beam, so that phase shift adjustment does not depend on large-stroke mechanical displacement, thereby improving phase shift bandwidth and reducing driving power consumption, which is suitable for high-frequency optical phase modulation scenarios.

[0058] In this embodiment, when M2 does not move, the corresponding optical path can be obtained using formula (6). When M2 moves Δ l， Its corresponding optical path The optical path length from port 11 to M2 The optical path reflected from M2 back to the second port 12 The sum, expressed as: (9) Then the corresponding optical path difference It can be represented as: (10) Optical path difference The relationship with the phase shift amount PS is as follows: (11) in λ is the wavelength of the incident light.

[0059] Based on the required phase shift PS, and combining formulas (10) and (11), the displacement Δ of M2 along the incident light direction can be calculated. l .

[0060] Due to manufacturing or assembly errors, the first and second plane mirrors may not be perfectly parallel. In this case, without compensation, the light beam will deviate from the ideal trajectory after multiple reflections within the cavity, resulting in a decrease in output power. The driving device disclosed herein compensates for the optical path deviation caused by the non-parallelism of the first and second plane mirrors by adjusting the reflection angles of the first and second MEMS mirrors. Figure 4 As shown, in this embodiment, there is a non-zero included angle between the first plane mirror and the second plane mirror. a By changing the included angle of M1 θ The angle between M1 and M2 β 1. To compensate for non-zero included angles a This causes optical path deviation. Specifically, taking a beam undergoing 2 × 7 = 14 reflections as an example, at this time... θ 1 and β 1. The following conditions must be met: (12) (13) Based on formulas (12) and (13), it can be calculated that there is a non-zero angle between the first plane mirror and the second plane mirror. a At that time, the included angle of M1 θ The angle between M1 and M2 β 1. This ensures that the beam can still enter and exit the FP cavity in the correct direction and eventually couple back to the dual fiber collimator at an angle γ0.

[0061] To verify the performance of the optical delay phase shifting device disclosed herein, optical simulations were performed based on the following parameters. This embodiment aims to demonstrate the key performance indicators of the device during the delay adjustment process, including the variation patterns of optical path difference, spot offset, and MEMS mirror angle.

[0062] In this embodiment, the angle between the incident and reflected rays γ 0 = 0.3°, the distance between the first port 11 and the second port 12 h It is 600 μm. x 0 = 12 mm, d =6 mm, θ =1=4°, incident light wavelength λ=1.55μm, radii r of MEMS mirrors M1 and M2 M1 With r M2 The light is reflected 7×2=14 times by the MEMS mirror and the plane mirror.

[0063] Figure 5 A schematic diagram illustrating the change in optical path difference caused by the displacement of the second plane mirror is shown. Figure 5 As shown, when the second plane mirror is displaced by Δd along the cavity length of the Fabry-Perot cavity, the optical path difference changes linearly. Simulations show that the change in optical path difference ΔL reaches ±23.65 mm within the range of Δd from -2 mm to +2 mm. According to the relationship between delay and optical path Δτ = ΔL / c, where c is the speed of light in vacuum, the corresponding delay tuning range is ±78.8 ps. This result verifies that a small cavity length change can be amplified by about 14 times through multiple reflections within the cavity, thereby achieving a large-range continuously adjustable delay.

[0064] Figure 6 A schematic diagram illustrating the angular changes of M1 and M2 during the displacement of the second plane mirror is shown. Figure 6As shown, when the second plane mirror is displaced by Δd along the length of the Fabry-Perot cavity, during the continuous change of Δd from -2 mm to +2 mm, the angle of M1 monotonically decreases from 5.9° to 3°, with a change range of approximately 2.9°. The angle of M2 monotonically decreases from 12° to 6°, with a change range of approximately 6°. Both angle changes are less than 10°, well within the typical adjustment range of MEMS mirrors.

[0065] In addition, when the simulation conditions are d =6 mm, initial angle of M1 θ 1 = 4° γ When 0 = 0.3°, according to the calculation formulas (1) to (4) of this disclosure, it can be calculated that when Δd = -2mm, the angle of M1 is 5.95° and the angle of M2 is 12.06°; when Δd = +2mm, the angle of M1 is 3.01° and the angle of M2 is 6.17°. This result verifies the angle adjustment formula proposed in this disclosure. and The accuracy of the results reveals the quantitative relationship between cavity length variation and MEMS mirror angle, providing a theoretical basis for achieving optical path closure and efficient coupling.

[0066] Figure 7 A schematic diagram illustrating the change in displacement of the second MEMS mirror versus the optical path difference is shown. Figure 7 As shown, this embodiment aims to verify the quantitative relationship between the displacement of M2 along the incident light direction and the phase change of the output light under a given FP cavity spacing, and to confirm the amount of M2 displacement required to achieve a 0~4π phase shift.

[0067] First, the parameters are set to d =6 mm, θ 1 = 4° β 1 = 8.15° γ Given an angle of 0° = 0.3° and an incident light wavelength of λ = 1.55 μm, assuming a phase shift range of 0 to 4π is required, the corresponding optical path difference is... = 2λ = 3.1μm.

[0068] In this embodiment, the FP cavity spacing is... d -Δ d =6-2.517mm=3.483mm; FP cavity spacing is d +Δ d =6 + 2.517mm = 8.517mm. Ray tracing simulations were performed under the two extreme cavity length conditions, and the results are as follows: When the FP cavity spacing is 3.483mm, the corresponding curve S1 shows the M2 displacement required to achieve a 0~4π phase shift. = 1.51μm; When the FP cavity spacing is 8.517mm, the corresponding curve S2 corresponds to the M2 displacement required to achieve a 0~4π phase shift. = 1.54 μm. This result verifies that even if the FP cavity spacing changes by more than 5 mm, the displacement change is only 0.03 μm, and the phase shift sensitivity remains essentially unchanged. This verification example demonstrates that within the 0~4π phase tuning range, the required displacement of M2 is approximately 1.5 μm, and it exhibits high consistency across different cavity lengths. This displacement is far smaller than the typical stroke of a MEMS electrostatic comb driver, fully meeting the application requirements of high-speed, high-precision phase modulation.

[0069] This disclosure also provides an optical control method for use in the optical delay and phase shifting device of this disclosure. For example... Figure 8 As shown, the optical control methods include: Step S81: Optical delay is achieved by driving the second plane mirror to move along the cavity length direction of the Fabry-Perot cavity.

[0070] In one embodiment, achieving optical delay includes: firstly performing initial calibration of the device and setting the initial cavity length of the Fabry-Perot cavity. d And based on the fixed included angle of the dual fiber collimators γ 0. Calculate and set the initial reflection angle of the first MEMS mirror. θ 1. Initial reflection angle of the second MEMS mirror β 1. This allows the light beam incident from the first port to be precisely coupled to the second port at a fixed angle after passing through the optical path, maximizing the output power.

[0071] When the optical delay needs to be changed, the required optical path difference change ΔL is calculated based on the target delay Δτ, and the required cavity length increment Δd is estimated based on the number of intracavity reflections. Using the optical path closure formula, the new reflection angles that the first and second MEMS mirrors should be adjusted to are calculated based on the cavity length increment. θ 2 and β 2. The first drive unit of the drive device moves the second plane mirror by the required displacement along the cavity length direction, while the second and third drive units rotate the two MEMS mirrors to the newly calculated angles. The control unit can perform closed-loop fine-tuning based on the output optical power to ensure maximum coupling efficiency.

[0072] Step S82: Phase modulation is achieved by driving the second MEMS mirror to displace along the direction of the incident light.

[0073] In one embodiment, phase modulation includes: maintaining the reflection angle of the first MEMS mirror before performing a phase shifting operation. θ 1. Reflection angle of the second MEMS mirror β1. With the target phase change PS unchanged, the displacement Δ that the second MEMS mirror needs to move along the incident light direction is calculated using the relationship between phase and optical path difference. l The third drive unit of the drive device drives the second MEMS mirror to move by this displacement along the direction of its incident light. Since the mirror angle remains unchanged, the direction of the reflected light remains unchanged, and the output light still enters the second port of the dual-fiber collimator at a fixed angle, so the coupling efficiency is unaffected. Continuously changing this displacement allows for continuous phase tuning.

[0074] In one embodiment, when the first plane mirror and the second plane mirror have a small included angle (i.e., not strictly parallel) due to processing or assembly, the reflection angles of the first MEMS mirror and the second MEMS mirror are adjusted according to the included angle to compensate for the optical path deviation caused by the non-parallelism.

[0075] The optical delay phase shifting device and its control method of this application have the following beneficial effects: 1. The device disclosed herein employs a shared optical path structure consisting of dual fiber collimators, two MEMS mirrors, and a Fabry-Perot (FP) cavity. It achieves delay and phase shifting functions on the same compact platform through different driving modes. This effectively avoids the additional losses and increased size caused by discrete components such as circulators, thus successfully solving key challenges in existing technologies such as discrete devices, limited performance, and difficulty in integration.

[0076] 2. This disclosure utilizes multiple reflections of the beam within a Fabry-Perot cavity to amplify the minute displacement of the second plane mirror into a total optical path change, thereby achieving a wide range of continuously adjustable delay. Simulations show that an optical path difference change of ±23.65 mm can be obtained within a ±2 mm mirror travel distance, and the delay range can be further extended by increasing the number of reflections or the travel distance, meeting the application requirements of satellite-to-ground communication, optical phased arrays, etc.

[0077] 3. This disclosure utilizes the axial displacement of a second MEMS mirror along the incident light direction to achieve phase modulation. The displacement resolution can reach the sub-nanometer level, the response speed is sub-microsecond, and the phase tuning range can reach several wavelengths or more. This phase shifting process does not change the direction of the reflected light and is completely decoupled from the delay adjustment.

[0078] 4. This disclosure can effectively compensate for the optical path deviation caused by the non-parallelism of the two plane mirrors by adaptively adjusting the angle of the MEMS reflector, which significantly reduces the requirements for precision assembly and improves the feasibility of mass production and environmental adaptability.

[0079] 5. In this disclosure, the delay and phase shift are independently controlled by different types of drive units: the first drive unit provides large stroke and slow coarse adjustment; the second and third drive units provide small angle / displacement and high-speed fine adjustment. Both can work simultaneously to achieve joint control of large-range delay coarse adjustment and high-speed phase compensation, adapting to dynamic and complex environments.

[0080] In summary, this application provides an optical delay and phase shifting device and its control method that integrates a wide range of continuously adjustable delay and high-speed precision phase shifting, is highly fault-tolerant, and easy to engineer, and has broad application prospects in fields such as optical communication, quantum information, precision measurement, and radar.

[0081] This disclosure uses flowcharts to illustrate the operations performed by a system according to embodiments of this disclosure. It should be understood that preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0082] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this disclosure. In addition, although the terminology used in this disclosure is selected from commonly known and used terms, some terms mentioned in this disclosure may have been chosen by the applicant at his or her judgment, and their detailed meanings are explained in the relevant sections of the description herein. Furthermore, this disclosure should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0083] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

[0085] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0086] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. An optical delay and phase shifting device, characterized in that, include: Dual fiber collimator; The first MEMS reflector is disposed on the outgoing optical path of the dual fiber collimator; A first plane mirror and a second plane mirror, which together form a Fabry-Perot cavity; The second MEMS reflector is disposed in the outgoing light path of the Fabry-Perot cavity; The driving device drives the second plane mirror to displace along the cavity length direction of the Fabry-Perot cavity to achieve optical delay; the driving device drives the second MEMS reflector to displace along the incident light direction to achieve phase modulation.

2. The apparatus as claimed in claim 1, characterized in that, The reflection angles of the first MEMS reflector and the second MEMS reflector are adjustable.

3. The apparatus as described in claim 2, characterized in that, The driving device adjusts the reflection angles of the first MEMS mirror and the second MEMS mirror according to the displacement of the second plane mirror, so as to ensure that the beam center trajectory remains closed during multiple reflections and is eventually coupled back to the dual fiber collimator.

4. The apparatus as claimed in claim 2, characterized in that, There is a non-zero angle between the first plane mirror and the second plane mirror; the driving device adjusts the angles of the first MEMS mirror and the second MEMS mirror to compensate for the optical path deviation caused by the non-zero angle.

5. The apparatus as described in claim 2, characterized in that, The driving device adjusts the distance between the first plane mirror and the second plane mirror, and simultaneously adjusts the angles of the first MEMS reflector and the second MEMS reflector to output continuously varying optical delay.

6. The apparatus as claimed in claim 2, characterized in that, The driving device drives the second MEMS reflector to move along the direction of the incident light while keeping the reflection angles of the first MEMS reflector and the second MEMS reflector constant, so as to achieve continuous modulation of the output light phase.

7. The apparatus as claimed in claim 2, characterized in that, The driving device includes: A first driving unit drives the second plane mirror to displace; The second driving unit drives the first MEMS mirror to rotate. A third driving unit drives the second MEMS mirror to rotate and displace. The type of the first driving unit is different from the types of the second and third driving units.

8. The apparatus as claimed in claim 7, characterized in that, The first drive unit can be any combination of one or more of the following: piezoelectric ceramic driver and voice coil motor.

9. The apparatus as claimed in claim 7, characterized in that, The types of the second and third drive units include electrostatic actuators, piezoelectric actuators, electrothermal actuators, or any combination thereof.

10. The apparatus as claimed in claim 2, characterized in that, The driving device also includes a control unit, which performs closed-loop or semi-closed-loop control on the reflection angles of the first MEMS mirror and the second MEMS mirror based on the optical power, coupling efficiency, or phase information of the optical signal output from the dual-fiber collimator.

11. The apparatus as claimed in claim 1, characterized in that, The light beam reflected from the first MEMS mirror is transmitted through the Fabry-Perot cavity, reflected by the second MEMS mirror, transmitted through the Fabry-Perot cavity again, and reflected by the first MEMS mirror again before returning to the dual-fiber collimator.

12. The apparatus as claimed in claim 11, characterized in that, Both the first MEMS mirror and the second MEMS mirror are located outside the Fabry-Perot cavity.

13. The apparatus as claimed in claim 11, characterized in that, The total number of reflections experienced by the light beam is 2× Next, among them It is an integer greater than or equal to 2.

14. An optical control method, applied to the optical delay and phase shifting device according to any one of claims 1 to 13, characterized in that, include: Optical delay is achieved by driving the second plane mirror to displace along the cavity length direction of the Fabry-Perot cavity; Phase modulation is achieved by driving the second MEMS mirror to displace along the direction of the incident light.

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