Optical fiber optical switching system and phase distribution design method thereof

Abstract

The invention relates to an optical fiber optical switching system and a phase distribution design method thereof, the optical fiber optical switching system comprises a first optical fiber port and a second optical fiber port, and the first optical fiber port and the second optical fiber port are distributed at intervals along the axial direction of the first optical fiber port; the cascade phase plate comprises multiple layers of phase plates, the multiple layers of phase plates are distributed at intervals layer by layer in the axial direction of the first optical fiber port, and the multiple layers of phase plates are located between the first optical fiber port and the second optical fiber port; and the adjusting mechanism is connected with the at least one layer of phase plate, and the adjusting mechanism is configured to adjust the position of the phase plate. The cascade phase plate is arranged between the first optical fiber port and the second optical fiber port, and the position of the phase plate is adjusted by adopting the adjusting mechanism, so that multiple fan-in and fan-out modes can be realized, the output port can be quickly switched, and the problem that a multi-plane optical converter in the related technology can only realize a single fan-in and fan-out mode and cannot realize the single fan-in and fan-out mode is solved. And the technical problem that port switching operation cannot be carried out is solved.

Description

Technical Field

[0001] The present application relates to the field of optical switching technology, and in particular to an optical fiber optical switching system and a phase distribution design method thereof. Background Art

[0002] With the rapid development of technologies such as the Internet of Things, 5G-related services, and artificial intelligence, the growing data traffic has brought unprecedented challenges to high-performance data center interconnection networks based on electrical switching technology. In order to overcome the limitations of electrical switching networks, optical switching networks with low latency, low power consumption, low cost, and high bandwidth capacity have been proposed as a solution. Optical switching devices used for optical switching mainly include MEMS (Micro-Electro-Mechanical System) optical switches, microring resonator optical switches, optical switches based on spatial light modulators, MZI (Mach-Zehnder Interferometer) waveguide optical switches, arrayed waveguide grating routers, and semiconductor optical amplifier optical switches.

[0003] Multi-core fiber space division multiplexing technology shows great potential and prospects in solving the problem of growing data traffic. Applying multi-core fiber to high-performance data center optical interconnection can make optical switching systems more compact and miniaturized.

[0004] In the related art, a common solution for fan-in and fan-out of multi-core optical fibers is MPLC (Multiplane Light Conversion), which can theoretically realize the conversion of any input and output mode. However, the traditional MPLC design generally cascades multiple phase planes and fixes them, which can only realize a preset single fan-in and fan-out mode, and cannot perform port switching operations.

[0005] Therefore, it is necessary to design a new fiber optic switching system to overcome the above problems. Summary of the invention

[0006] The present application provides a fiber optic switching system and a phase distribution design method thereof, which can solve the technical problem in the related art that a multi-plane optical converter can only implement a single fan-in and fan-out mode and cannot perform a port switching operation.

[0007] In a first aspect, an embodiment of the present application provides a fiber optic switching system, comprising: a first fiber port and a second fiber port, wherein the first fiber port and the second fiber port are spaced apart along the axial direction of the first fiber port; a cascaded phase plate, wherein the cascaded phase plate comprises a plurality of layers of phase plates, wherein the plurality of layers of the phase plates are spaced apart layer by layer along the axial direction of the first fiber port, and the plurality of layers of the phase plates are located between the first fiber port and the second fiber port; and an adjustment mechanism, wherein the adjustment mechanism is connected to at least one layer of the phase plate, and the adjustment mechanism is configured to adjust the position of the phase plate.

[0008] In combination with the first aspect, in one embodiment, the adjustment mechanism includes a driving mechanism, the driving mechanism is connected to a first adjustment member and / or a second adjustment member and / or a third adjustment member, the first adjustment member or the second adjustment member or the third adjustment member is connected to the phase plate; the first adjustment member is configured to drive the phase plate to rotate around the axis of the first optical fiber port; the second adjustment member is configured to drive the phase plate to move in a plane perpendicular to the direction of light propagation; the third adjustment member is configured to drive the phase plate to move along the direction of light propagation.

[0009] In combination with the first aspect, in one implementation, the cascaded phase plates include 2 to 10 layers of the phase plates.

[0010] In combination with the first aspect, in one implementation, the first optical fiber port and the second optical fiber port are single-mode multi-core optical fibers, single-mode single-core optical fibers, or multi-mode multi-core optical fibers.

[0011] In a second aspect, an embodiment of the present application provides a phase distribution design method for the above-mentioned optical fiber optical switching system, which comprises the following steps:

[0012] Calculating the light field mode of each phase plate when the light propagates along a first direction; wherein the first direction is a direction from the first optical fiber port to the second optical fiber port or a direction from the second optical fiber port to the first optical fiber port;

[0013] The light field pattern of each phase plate when light propagates along a second direction is calculated, and the phase distribution of each phase plate is calculated based on the light field pattern of each phase plate when light propagates along a first direction and a second direction; wherein the second direction is opposite to the first direction.

[0014] In combination with the second aspect, in one implementation, the calculating the light field pattern of each phase plate when the light propagates along the first direction includes:

[0015] Starting from n=1, determining whether the nth target light field mode needs to adjust the position of the mth phase plate when the light propagates along the first direction; wherein n and m are both positive integers;

[0016] If yes, then adjust the position of the mth phase plate and sequentially calculate the light field mode of each phase plate along the first direction; otherwise, directly calculate the light field mode of each phase plate along the first direction;

[0017] Determine whether n is equal to N; wherein N is the total number of target light field modes when the light propagates along the first direction, and n is less than or equal to N;

[0018] If n is not equal to N, n=n+1 is set, and the above steps of determining and calculating the light field mode of each phase plate are continuously performed until n is equal to N.

[0019] In combination with the second aspect, in one embodiment, calculating the light field pattern of each phase plate when the light propagates along the second direction, and calculating the phase distribution of each phase plate based on the light field pattern of each phase plate when the light propagates along the first direction and the second direction, includes:

[0020] Step a: calculating the light field mode of each phase plate when the light propagates along the second direction, and calculating the phase distribution of each phase plate based on the light field mode of each phase plate when the light propagates along the first direction and the second direction;

[0021] Step b: based on the phase distribution of each phase plate calculated in step a, calculating the light field mode of each phase plate when the light propagates along the first direction, and calculating the phase distribution of each phase plate based on the light field mode of each phase plate when the light propagates along the first direction and the second direction;

[0022] Step c: Repeat the above steps a and b until a sufficient number of iterations or convergence is reached.

[0023] In conjunction with the second aspect, in one implementation, step a includes:

[0024] Starting from n=1, determining whether the nth target light field mode needs to adjust the position of the mth phase plate when the light propagates along the second direction; wherein n and m are both positive integers;

[0025] If yes, then adjust the position of the mth phase plate and sequentially calculate the light field mode of each phase plate along the second direction; otherwise, directly calculate the light field mode of each phase plate along the second direction;

[0026] calculating a phase distribution of each phase plate based on a light field pattern of each phase plate when light propagates along a first direction and a second direction;

[0027] Determine whether n is equal to N; wherein N is the total number of target light field modes when the light propagates along the second direction, and n is less than or equal to N;

[0028] If n is not equal to N, n=n+1 is set, and the above steps of determining and calculating the light field mode of each phase plate are continuously performed until n is equal to N.

[0029] In conjunction with the second aspect, in one implementation, step b includes:

[0030] Starting from n=1, determining whether the nth target light field mode needs to adjust the position of the mth phase plate when the light propagates along the first direction; wherein n and m are both positive integers;

[0031] If yes, then adjust the position of the mth phase plate and sequentially calculate the light field mode of each phase plate along the first direction; otherwise, directly calculate the light field mode of each phase plate along the first direction;

[0032] calculating a phase distribution of each phase plate based on a light field pattern of each phase plate when light propagates along a first direction and a second direction;

[0033] Determine whether n is equal to N; wherein N is the total number of target light field modes when the light propagates along the first direction, and n is less than or equal to N;

[0034] If n is not equal to N, n=n+1 is set, and the above steps of determining and calculating the light field mode of each phase plate are continuously performed until n is equal to N.

[0035] In combination with the second aspect, in one implementation, before calculating the light field pattern of each phase plate when the light propagates along the first direction, the method further includes:

[0036] Initialize the phase distribution of all phase plates and normalize the phase distribution of all phase plates to a matrix of all 1s.

[0037] The beneficial effects brought by the technical solution provided in the embodiments of the present application include:

[0038] By arranging a cascade phase plate between the first optical fiber port and the second optical fiber port and using an adjustment mechanism to adjust the position of the phase plate, a variety of fan-in and fan-out modes can be realized, and the output port can be quickly switched, which solves the technical problem in the related art that the multi-plane optical converter can only realize a single fan-in and fan-out mode and cannot perform port switching operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 A schematic diagram of the structure of a fiber optic switching system provided in an embodiment of the present application;

[0041] Figure 2 Phase distribution diagram of a three-layer phase plate provided in an embodiment of the present application;

[0042] Figure 3 (1) is a diagram showing the incident light field and the light field distribution after passing through each phase plate provided in an embodiment of the present application; (2) is a diagram showing the incident light field and the light field distribution after passing through each phase plate obtained by rotating the second layer of phase plate 90° around the axis of the first optical fiber port compared to FIG (1);

[0043] Figure 4 A flow chart of a phase distribution design method provided in an embodiment of the present application;

[0044] Figure 5 A flowchart of another phase distribution design method provided in an embodiment of the present application.

[0045] In the figure:

[0046] 1. First optical fiber port; 2. Second optical fiber port; 3. Phase plate. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] The current problems with optical switching technology are:

[0049] 1. Microring resonator optical switches, MZI waveguide optical switches, and arrayed waveguide grating routers have high crosstalk.

[0050] 2. The scalability of semiconductor optical amplifiers is affected by gain noise.

[0051] 3. In an optical switching system implemented by a spatial light modulator controlled by an electrical signal, the speed of optical switching is limited due to the delay of the control circuit of the liquid crystal molecules in the spatial light modulator.

[0052] 4. In the optical switching system implemented by spatial light modulator or MEMS, a complex fiber output collimating lens group is required to ensure that the light irradiated on the spatial light modulator or MEMS is planar light, and to ensure efficient coupling of the light to the output fiber.

[0053] 5. The size of the spatial light modulator and MEMS devices is large, which makes the overall size of the system larger and is not conducive to installation.

[0054] There is an urgent need for a solution to be applied to high-performance data center interconnection networks, which can not only ensure the system size is miniaturized, easy to integrate, and fast port switching, but also retain the MPLC's ability to convert arbitrary input and output modes and make the system easy to expand to other homogeneous and heterogeneous optical fiber interconnections.

[0055] The embodiment of the present application provides a fiber optic switching system and a phase distribution design method thereof, which can solve the technical problem in the related art that a multi-plane optical converter can only implement a single fan-in and fan-out mode and cannot perform port switching operations.

[0056] See also Figure 1 As shown, a fiber optic switching system provided by an embodiment of the present application may include: a first fiber port 1 and a second fiber port 2, wherein the first fiber port 1 and the second fiber port 2 are spaced apart along the axial direction of the first fiber port 1; a cascaded phase plate, wherein the cascaded phase plate includes a plurality of layers of phase plates 3, wherein the plurality of layers of the phase plates 3 are spaced apart layer by layer along the axial direction of the first fiber port 1, and the plurality of layers of the phase plates 3 are located between the first fiber port 1 and the second fiber port 2; and an adjustment mechanism, wherein the adjustment mechanism is connected to at least one layer of the phase plate 3, and the adjustment mechanism is configured to adjust the position of the phase plate 3.

[0057] In the above embodiment, the first optical fiber port 1 can be used as a transmitting port or a receiving port. When used as a transmitting port, it transmits optical signals, and when used as a receiving port, it receives optical signals converted by the phase plate 3. The second optical fiber port 2 can also be used as a transmitting port or a receiving port. When the first optical fiber port 1 is used as a transmitting port, the second optical fiber port 2 is used as a receiving port. The above cascaded phase plate can include two layers of phase plates 3, or more than two layers of phase plates 3, each of which has a certain interval and is arranged in sequence between the first optical fiber port 1 and the second optical fiber port 2. In the cascaded phase plate, some phase plates 3 can be set to be fixed, and some phase plates 3 can be set to be adjustable, for example, one layer or a base layer of phase plates 3 is mechanically adjustable; or all phase plates 3 can be set to be adjustable. When all phase plates 3 are adjustable, all phase plates 3 need to be connected to the adjustment mechanism so that the adjustment mechanism can arbitrarily adjust the position or state of each phase plate 3; when some phase plates 3 are adjustable, the phase plates 3 that need to be adjusted can be connected to the adjustment mechanism, and the phase plates 3 that do not need to be adjusted do not need to be connected to the adjustment mechanism. Figure 1 As shown in the figure, three layers of phase plates 3 are provided, and the phase plate 3 located in the middle is connected to the adjustment mechanism, so that the adjustment mechanism can adjust the position or state of the phase plate 3, while the phase plates 3 located in the first and third layers are fixed.

[0058] In this embodiment, a cascaded phase plate is arranged between the first optical fiber port 1 and the second optical fiber port 2, and an adjustment mechanism is set to be connected to the phase plate 3, so that the position and state of the phase plate 3 can be adjusted by the adjustment mechanism. By adjusting the position or state of one layer or multiple layers of phase plates 3 at the same time, cascaded phase plates with multiple position states can be obtained, thereby realizing multiple fan-in and fan-out modes, realizing the switching of the optical signal of the first optical fiber port 1 to the second optical fiber port 2, and using the adjustment mechanism to realize mechanical adjustment, the output port can be quickly switched, which solves the technical problem that the multi-plane optical converter in the related art can only realize a single fan-in and fan-out mode and cannot perform port switching operation.

[0059] Furthermore, in one embodiment, the adjustment mechanism may include a driving mechanism, the driving mechanism is connected to a first adjustment member and / or a second adjustment member and / or a third adjustment member, the first adjustment member or the second adjustment member or the third adjustment member is connected to the phase plate 3; the first adjustment member is configured to drive the phase plate 3 to rotate around the axis of the first optical fiber port 1; the second adjustment member is configured to drive the phase plate 3 to move in a plane perpendicular to the direction of light propagation; the third adjustment member is configured to drive the phase plate 3 to move along the direction of light propagation.

[0060] In this embodiment, the driving mechanism can be, for example, a high-speed motor, and the driving mechanism can be connected to the first adjusting member, the second adjusting member or the third adjusting member alone; it can also be connected to the second adjusting member and / or the third adjusting member while being connected to the first adjusting member; or the driving mechanism can be connected to the second adjusting member and the third adjusting member, or the driving mechanism can be connected to the first adjusting member while also being connected to the second adjusting member and the third adjusting member. When the driving mechanism is connected to a first adjustment member, the driving mechanism can control the movement of the first adjustment member, and then drive the phase plate 3 directly or indirectly connected to the first adjustment member to rotate through the first adjustment member, for example, it can rotate around the axis of the first optical fiber port 1 by any angle such as 90° or 180°; when the driving mechanism is connected to a second adjustment member, the driving mechanism can control the movement of the second adjustment member, and then drive the phase plate 3 directly or indirectly connected to the second adjustment member to move in a plane perpendicular to the light propagation direction through the second adjustment member, wherein the phase plate 3 can move horizontally in the plane perpendicular to the light propagation direction, and can also move vertically in the plane perpendicular to the light propagation direction; when the driving mechanism is connected to a third adjustment member, the driving mechanism can control the movement of the third adjustment member, and then drive the phase plate 3 directly or indirectly connected to the third adjustment member to move along the direction of light propagation through the third adjustment member.

[0061] In this embodiment, the driving mechanism can not only drive the phase plate 3 to move along the direction of light propagation, but also drive the phase plate 3 to move horizontally or vertically in a plane perpendicular to the light propagation direction, and can also drive the phase plate 3 to rotate around the light propagation direction, so that the phase plate 3 has multi-dimensional mechanical regulation. By designing the movement mode and movement distance of one or several layers of phase plates 3 at the same time, more switching modes can be realized. The fiber optic switching system of this embodiment has more flexible and continuously adjustable degrees of freedom, and can realize more switchable port modes. At the same time, the fiber optic switching system does not require other collimating lens groups, and the system structure is compact, small in size, and easier to install and integrate.

[0062] In a preferred embodiment, the cascaded phase plate includes 2 to 10 layers of the phase plate 3. In this embodiment, in order to facilitate the arrangement of the cascaded phase plate between the first optical fiber port 1 and the second optical fiber port 2, the number of layers of the phase plate 3 arranged between the first optical fiber port 1 and the second optical fiber port 2 is preferably 2 to 10 layers. Of course, in other embodiments, the number of phase plates 3 may not be limited to 10 layers, and a larger number of phase plates 3 may be arranged according to actual needs.

[0063] Furthermore, in some embodiments, the first optical fiber port 1 and the second optical fiber port 2 are single-mode multi-core optical fibers, single-mode single-core optical fibers or multi-mode multi-core optical fibers. That is, the first optical fiber port 1 in this embodiment can adopt single-mode multi-core optical fibers, single-mode single-core optical fibers or multi-mode multi-core optical fibers, and the second optical fiber port 2 can also adopt single-mode multi-core optical fibers, single-mode single-core optical fibers or multi-mode multi-core optical fibers. Since MPLC also has the ability of mode conversion, the present application can be applied not only to the optical exchange between single-mode multi-core optical fibers and single-mode single-core optical fibers, but also to the optical exchange between multi-mode multi-core optical fibers and any other heterogeneous single-mode or multi-mode multi-core optical fibers, and any combination of single-mode or multi-mode single-core optical fibers, and the number of input and output ports can be different.

[0064] See also Figure 1 As shown, this embodiment shows that the first optical fiber port 1 uses a multi-core optical fiber, the second optical fiber port 2 uses a single-core optical fiber array, and the mechanically adjustable cascade phase plate between the first optical fiber port 1 and the second optical fiber port 2 converts the light field modes of different transmitting ports into the coupled light field modes of the receiving port, respectively, to achieve mechanically adjustable light exchange between the transmitting port and the receiving port. The multilayer phase plate 3 can use the wavefront matching method or the inverse design method to obtain the phase distribution according to the design method of MPLC, wherein the algorithm flow chart of the wavefront matching algorithm is shown in Figure 5 As shown. Figure 2 The figure shows a specific embodiment of the phase distribution of a three-layer cascaded phase plate of the present application. Figure 2The three figures in FIG. 1 respectively represent the phase distribution of the first to third layers (from left to right) of the phase plate 3 calculated by the modified wavefront matching method. In this embodiment, the output port can be switched by rotating the second layer of the phase plate 3 90 degrees around the light propagation direction. The incident light field and the light field distribution after passing through each phase plate 3 obtained by simulation calculation are shown in FIG. Figure 3 As shown. Among them, the illustrations in the first column represent the input light field distribution, and the illustrations in the second to fourth columns represent the light field distribution after passing through the first to third layers of phase plates 3, respectively. By comparison, it can be seen that after the second layer of phase plate 3 is rotated 90 degrees around the light propagation direction, the position of the output single-mode light field in the fourth column changes, and the output port is switched from the single-mode single-core optical fiber on the right to the single-mode single-core optical fiber on the left. The fiber optic optical switching system controlled by the phase plate 3 that can actually be designed includes but is not limited to rotating 90 degrees around the light propagation direction, and can also be moved in a plane perpendicular to the light propagation direction, or moved along the direction of light propagation, or controlling more than one phase plate 3 to undergo mechanical movement, so that multi-dimensional mechanical regulation can achieve more switching methods.

[0065] Compared to an optical switching system implemented by a spatial light modulator controlled by an electrical signal, the optical fiber optical switching system controlled by the mechanical phase plate 3 of the present application has a faster switching speed, a smaller system size, and a higher degree of integration; and compared to an optical switching system implemented by a spatial light modulator or MEMS, the present application does not need to use a complex light output collimating lens group, the system complexity is reduced, the system size is also smaller, and the integration is higher.

[0066] See also Figure 4 As shown, the embodiment of the present application also provides a phase distribution design method for the above-mentioned optical fiber optical switching system, which may include the following steps:

[0067] S1: Calculate the light field mode of each phase plate 3 when light propagates along a first direction; wherein the first direction is a direction from the first optical fiber port 1 to the second optical fiber port 2 or a direction from the second optical fiber port 2 to the first optical fiber port 1.

[0068] S2: Calculate the light field pattern of each phase plate 3 when light propagates along the second direction, and calculate the phase distribution of each phase plate 3 based on the light field pattern of each phase plate 3 when light propagates along the first direction and the second direction; wherein the second direction is opposite to the first direction.

[0069] In a preferred embodiment, before step S1, the phase distributions of all phase plates 3 are initialized and normalized to an all-1 matrix.

[0070] This embodiment is described by taking the first direction as the direction from the second optical fiber port 2 to the first optical fiber port 1 as an example. In other embodiments, the first direction may also be the direction from the first optical fiber port 1 to the second optical fiber port 2.

[0071] In step S1, when the first direction is the direction from the second optical fiber port 2 to the first optical fiber port 1 (i.e., from right to left), the second optical fiber port 2 emits a light beam, the first optical fiber port 1 receives the light beam, and the light field mode of each phase plate 3 is calculated from right to left in sequence (if the first optical fiber port 1 is a transmitting port when the optical fiber optical switching system is in normal use, it is also referred to as the output light field mode of the phase plate 3 here). In step S2, the first optical fiber port 1 emits a light beam, the second optical fiber port 2 receives the light beam, and the light field mode of each phase plate 3 is calculated from left to right in sequence (if the first optical fiber port 1 is a transmitting port when the optical fiber optical switching system is in normal use, it is also referred to as the input light field mode of the phase plate 3 here). After calculating the input light field mode and the output light field mode of each phase plate 3, the phase distribution of each phase plate 3 can be calculated.

[0072] In the above embodiment, if the entire optical fiber optical switching system is provided with i phase plates 3, the phase distribution of the i-th phase plate 3 is φ i =∠A i B i * , where φ i A is the phase distribution of the i-th phase plate 3; i is the light field mode of the i-th phase plate 3 when the light propagates along the first direction; B i is the light field mode of the i-th phase plate 3 when the light propagates along the second direction.

[0073] Further, see Figure 5 As shown, in some embodiments, the step of calculating the light field pattern of each phase plate 3 when the light propagates along the first direction may include the following steps:

[0074] S11: Determine whether the nth target light field mode needs to adjust the position of the mth phase plate 3 when the light propagates along the first direction; wherein n and m are both positive integers, and the initial value of n is 1. In this embodiment, if the entire optical fiber optical switching system is provided with i phase plates 3, then m is less than or equal to i, and m can be any integer value from 1 to i, and the specific value of m can be set according to actual needs.

[0075] S12: If yes, adjust the position of the mth phase plate 3 and then go to step S13; otherwise, go directly to step S13.

[0076] S13: Calculate the light field mode of each phase plate 3 in sequence along the first direction.

[0077] S14: Determine whether n is equal to N; wherein N is the total number of target light field modes when the light propagates along the first direction, and n is less than or equal to N.

[0078] S15: If n is not equal to N, n=n+1 is set, and the above steps of judging and calculating the light field mode of each phase plate 3 are continued until n is equal to N. In this step, if n is not equal to N, steps S11 to S15 are continued until n is equal to N, the loop is terminated, and step S2 is continued.

[0079] In this embodiment, before step S11, N target light field patterns can be preset. When n=2, the light field pattern calculated in step S13 will be superimposed on the light field pattern calculated when n=1; when n=3, the light field pattern calculated in step S13 will be superimposed on the light field pattern calculated when n=2; and so on, after multiple cycles of calculation, when n=N, the initial value of the light field pattern of each phase plate 3 is calculated, and the light field pattern calculated when n=N is used in step S2. The multiple cycles of calculation in this embodiment are to obtain the initial value of the light field distribution pattern on each phase plate 3 when light propagates along the first direction.

[0080] In the above step S12, the position of the m-th phase plate 3 may be adjusted by driving the m-th phase plate 3 to move along the direction of light propagation, or by driving the m-th phase plate 3 to move horizontally or vertically in a plane perpendicular to the direction of light propagation, or by driving the m-th phase plate 3 to rotate around the direction of light propagation, etc.

[0081] Further, in one embodiment, the calculating of the light field mode of each phase plate 3 when the light propagates along the second direction, and the calculating of the phase distribution of each phase plate 3 based on the light field mode of each phase plate 3 when the light propagates along the first direction and the second direction may include:

[0082] Step a: Calculate the light field mode of each phase plate 3 when light propagates along the second direction, and calculate the phase distribution of each phase plate 3 based on the light field mode of each phase plate 3 when light propagates along the first direction and the second direction.

[0083] Step b: Based on the phase distribution of each phase plate 3 calculated in step a, calculate the light field mode of each phase plate 3 when the light propagates along the first direction, and calculate the phase distribution of each phase plate 3 based on the light field mode of each phase plate 3 when the light propagates along the first direction and the second direction.

[0084] Step c: Repeat the above steps a and b until a sufficient number of iterations or convergence is reached.

[0085] In this embodiment, in the first iteration, step b will use the phase distribution calculated in step a in this iteration to calculate the light field mode and phase distribution; in the second iteration, step a will use the phase distribution calculated in step b in the previous iteration to calculate the light field mode and phase distribution, so the cycle is repeated to gradually optimize the phase distribution of each phase plate 3.

[0086] Preferably, see Figure 5 As shown, step a may include:

[0087] Step a1: Determine whether the nth target light field mode needs to adjust the position of the mth phase plate 3 when the light propagates along the second direction; wherein n and m are both positive integers, and the initial value of n is 1. In this embodiment, if the entire optical fiber optical switching system is provided with i phase plates 3, then m is less than or equal to i, and m can be any integer value from 1 to i, and the specific value of m can be set according to actual needs.

[0088] Step a2: If yes, adjust the position of the mth phase plate 3 and then proceed to step a3; otherwise, directly proceed to step a3.

[0089] Step a3: Calculate the light field mode of each phase plate 3 in sequence along the second direction.

[0090] Step a4: Calculating the phase distribution of each phase plate 3 based on the light field pattern of each phase plate 3 when the light propagates along the first direction and the second direction.

[0091] Step a5: Determine whether n is equal to N; wherein N is the total number of target light field modes when the light propagates along the second direction set in step a, and n is less than or equal to N.

[0092] Step a6: If n is not equal to N, set n=n+1, and continue to perform the above steps of judging and calculating the light field mode of each phase plate 3 until n is equal to N. In this step, if n is not equal to N, continue to perform steps a1 to a6 until n is equal to N, end the loop, and continue to perform step b.

[0093] In this embodiment, before performing step a1 for the first time, N target light field modes may be preset. When n=2, the phase distribution calculated when n=1 is used to calculate the light field mode of each phase plate 3, and the light field mode calculated in step a3 covers the light field mode calculated when n=1, and when n=2, step a4 uses the light field mode calculated in this step a3 and the light field mode calculated in S13 or step b in the previous iteration to calculate the phase distribution, and covers the phase distribution calculated when n=1; when n=3, the phase distribution calculated when n=2 is used to calculate the light field mode of each phase plate 3, and the light field mode calculated in step a3 covers the light field mode calculated when n=2, and when n=3, step a4 uses the light field mode calculated in this step a3 and the light field mode calculated in S13 or step b in the previous iteration to calculate the phase distribution, and covers the phase distribution calculated when n=2; and so on, after multiple cycles of calculation, when n=N, the light field mode and phase distribution of each phase plate 3 calculated are optimal, and the light field mode and phase distribution calculated when n=N are used in step b.

[0094] Further, in some optional embodiments, see Figure 5 As shown, step b may include:

[0095] Step b1: Determine whether the nth target light field mode needs to adjust the position of the mth phase plate 3 when the light propagates along the first direction; wherein n and m are both positive integers, and the initial value of n is 1. In this embodiment, if the entire optical fiber optical switching system is provided with i phase plates 3, then m is less than or equal to i, and m can be any integer value from 1 to i, and the specific value of m can be set according to actual needs.

[0096] Step b2: If yes, adjust the position of the mth phase plate 3 and then proceed to step b3; otherwise, directly proceed to step b3.

[0097] Step b3: Calculate the light field mode of each phase plate 3 in sequence along the first direction.

[0098] Step b4: Calculating the phase distribution of each phase plate 3 based on the light field pattern of each phase plate 3 when the light propagates along the first direction and the second direction.

[0099] Step b5: Determine whether n is equal to N; wherein N is the total number of target light field modes when the light propagates along the first direction set in step b, and n is less than or equal to N.

[0100] Step b6: If n is not equal to N, set n=n+1, and continue to perform the above steps of judging and calculating the light field mode of each phase plate 3 until n is equal to N. In this step, if n is not equal to N, continue to perform steps b1 to b6 until n is equal to N, end the loop, and continue to perform step c to judge whether a sufficient number of iterations or convergence is reached.

[0101] In this embodiment, before performing step b1 for the first time, N target light field modes may be preset. When n=2, the phase distribution calculated when n=1 is used to calculate the light field mode of each phase plate 3, and the light field mode calculated in step b3 covers the light field mode calculated when n=1, and when n=2, step b4 uses the light field mode calculated in this step b3 and the light field mode calculated in step a in this iteration to calculate the phase distribution, and covers the phase distribution calculated when n=1; when n=3, the phase distribution calculated when n=2 is used to calculate the light field mode of each phase plate 3, and the light field mode calculated in step b3 covers the light field mode calculated when n=2, and when n=3, step b4 uses the light field mode calculated in this step b3 and the light field mode calculated in step a in this iteration to calculate the phase distribution, and covers the phase distribution calculated when n=2; and so on, after multiple cycles of calculation, when n=N, the light field mode and phase distribution of each phase plate 3 calculated are optimal, and the light field mode and phase distribution calculated when n=N are used in step a of the next cycle.

[0102] The above phase distribution design method uses a wavefront matching method to design the phase distribution of each phase plate 3 .

[0103] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0104] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0105] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A fiber optical switching system, characterized in that: It includes: A first optical fiber port (1) and a second optical fiber port (2), wherein the first optical fiber port (1) and the second optical fiber port (2) are spaced apart and distributed along the axial direction of the first optical fiber port (1); A cascade phase plate, the cascade phase plate comprising a plurality of phase plates (3), the plurality of phase plates (3) being spaced apart layer by layer along the axial direction of the first optical fiber port (1), and the plurality of phase plates (3) being located between the first optical fiber port (1) and the second optical fiber port (2); An adjustment mechanism, the adjustment mechanism is connected to at least one layer of the phase plate (3), and the adjustment mechanism is configured to adjust the position of the phase plate (3).

2. The fiber optical switching system according to claim 1, characterized in that: The adjustment mechanism comprises a driving mechanism, the driving mechanism is connected to a first adjustment member and / or a second adjustment member and / or a third adjustment member, the first adjustment member or the second adjustment member or the third adjustment member is connected to the phase plate (3); The first adjustment member is configured to drive the phase plate (3) to rotate around the axis of the first optical fiber port (1); The second adjustment member is configured to drive the phase plate (3) to move in a plane perpendicular to the light propagation direction; The third adjusting member is configured to drive the phase plate (3) to move along the direction of light propagation.

3. The fiber optical switching system according to claim 1, wherein: The cascaded phase plate comprises 2 to 10 layers of the phase plates (3).

4. The fiber optical switching system according to claim 1, wherein: The first optical fiber port (1) and the second optical fiber port (2) are single-mode multi-core optical fibers, single-mode single-core optical fibers or multi-mode multi-core optical fibers.

5. A method for designing phase distribution of a fiber optical switching system as claimed in claim 1, characterized in that: It includes the following steps: Calculating the light field mode of each phase plate (3) when light propagates along a first direction; wherein the first direction is a direction from the first optical fiber port (1) to the second optical fiber port (2) or a direction from the second optical fiber port (2) to the first optical fiber port (1); The light field pattern of each phase plate (3) when light propagates along a second direction is calculated, and the phase distribution of each phase plate (3) is calculated based on the light field pattern of each phase plate (3) when light propagates along a first direction and a second direction; wherein the second direction is opposite to the first direction.

6. The phase distribution design method according to claim 5, characterized in that: The method of calculating the light field pattern of each phase plate (3) when the light propagates along the first direction comprises: Starting from n=1, determining whether the nth target light field mode needs to adjust the position of the mth phase plate (3) when the light propagates along the first direction; wherein n and m are both positive integers; If yes, then after adjusting the position of the mth phase plate (3), the light field mode of each phase plate (3) is calculated in sequence along the first direction; otherwise, the light field mode of each phase plate (3) is directly calculated in sequence along the first direction; Determine whether n is equal to N; wherein N is the total number of target light field modes when the light propagates along the first direction, and n is less than or equal to N; If n is not equal to N, then n=n+1 is set, and the above steps of judging and calculating the light field mode of each phase plate (3) are continued until n is equal to N.

7. The phase distribution design method according to claim 5, characterized in that: The method of calculating the light field pattern of each phase plate (3) when the light propagates along the second direction, and calculating the phase distribution of each phase plate (3) based on the light field pattern of each phase plate (3) when the light propagates along the first direction and the second direction, comprises: Step a: calculating the light field pattern of each phase plate (3) when light propagates along the second direction, and calculating the phase distribution of each phase plate (3) based on the light field pattern of each phase plate (3) when light propagates along the first direction and the second direction; Step b: based on the phase distribution of each phase plate (3) calculated in step a, calculating the light field mode of each phase plate (3) when light propagates along the first direction, and calculating the phase distribution of each phase plate (3) based on the light field mode of each phase plate (3) when light propagates along the first direction and the second direction; Step c: Repeat the above steps a and b until a sufficient number of iterations or convergence is reached.

8. The phase distribution design method according to claim 7, characterized in that: Step a includes: Starting from n=1, determining whether the nth target light field mode needs to adjust the position of the mth phase plate (3) when the light propagates along the second direction; wherein n and m are both positive integers; If yes, then after adjusting the position of the mth phase plate (3), the light field mode of each phase plate (3) is calculated in sequence along the second direction; otherwise, the light field mode of each phase plate (3) is directly calculated in sequence along the second direction; Calculating the phase distribution of each phase plate (3) based on the light field pattern of each phase plate (3) when light propagates along the first direction and the second direction; Determine whether n is equal to N; wherein N is the total number of target light field modes when the light propagates along the second direction, and n is less than or equal to N; If n is not equal to N, then n=n+1 is set, and the above steps of judging and calculating the light field mode of each phase plate (3) are continued until n is equal to N.

9. The phase distribution design method according to claim 7, characterized in that: Step b includes: Starting from n=1, determining whether the nth target light field mode needs to adjust the position of the mth phase plate (3) when the light propagates along the first direction; wherein n and m are both positive integers; If yes, then after adjusting the position of the mth phase plate (3), the light field mode of each phase plate (3) is calculated in sequence along the first direction; otherwise, the light field mode of each phase plate (3) is directly calculated in sequence along the first direction; Calculating the phase distribution of each phase plate (3) based on the light field pattern of each phase plate (3) when light propagates along the first direction and the second direction; Determine whether n is equal to N; wherein N is the total number of target light field modes when the light propagates along the first direction, and n is less than or equal to N; If n is not equal to N, then n=n+1 is set, and the above steps of judging and calculating the light field mode of each phase plate (3) are continued until n is equal to N.

10. The phase distribution design method according to claim 5, characterized in that: Before calculating the light field pattern of each phase plate (3) when the light propagates along the first direction, the method further comprises: Initialize the phase distribution of all phase plates (3), and normalize the phase distribution of all phase plates (3) to an all-1 matrix.

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