Broad spectrum multi-space / mode optical switching method and system supporting optical spatial modes

Abstract

The application discloses a kind of space division optical switching method and system based on optical mode label, the method with optical mode structure distribution characteristics as label (bridge), through optical wavefront phase multi-plane transformation, realize the arbitrary interconnection between multiple input ports / modes and multiple output ports / modes, the optical mode is various space mode, for example, Hermite-Gaussian, Laguerre-Gaussian, vortex, linear polarization, vector and so on mode;The multi-plane transformation can be loaded on spatial light modulator, for the light of each input port / mode is modulated according to the wavefront phase of space / mode phase distribution Multi-level (multiple) transformation, so that the light of each space port / mode is transformed to the space port / mode needed.The system structure is simple, can match various input / output interface, supports wide spectrum communication, compatible with wavelength division multiplexing system, can be used to constitute super large multi-dimensional optical switching system.

Description

Technical Field

[0001] This invention belongs to the fields of optical communication switching and information optics, specifically relating to a multi-space / mode optical switching method that supports wide spectrum optical spatial modes. Background Technology

[0002] (Space Division Multiplexing) The deep integration of cloud computing, artificial intelligence, big data technologies, and industrialization and informatization is constantly driving operators towards integrated, intelligent, and green cloud-network architectures. The transmission of single-mode fiber optic systems used in long-distance fiber optic communication is approaching its nonlinear capacity limit. Achieving ultra-high-speed, ultra-large-capacity long-distance transmission relies on continuously improving the spatial parallelism of optical fibers and the spectral efficiency of the system. Currently, the four physical dimensions of light—amplitude, time / frequency, orthogonal phase, and polarization—have been utilized to near their limits through optical transmission technologies such as high-order modulation formats, frequency division multiplexing, digital coherent reception, and polarization multiplexing. To improve transmission capacity, further reductions in fiber transmission loss, increases in fiber mode field area, high-performance amplification schemes, noise suppression, and channel equalization techniques are employed, but the potential for improvement is very small. Space Division Multiplexing (SDM) technology utilizes the multiplexing of spatial dimensions within the fiber to achieve transmission capacity expansion. After more than 10 years of research and development, it has demonstrated enormous potential for improving the transmission capacity of fiber optic communication systems. SDM mainly includes multi-core multiplexing, few-mode multiplexing, few-mode multi-core multiplexing, and multi-mode multiplexing schemes. Few-mode multi-core technology is currently the most researched solution for improving the parallelism of optical fibers in transmission channels. Short-distance interconnects using space-division multiplexing have already increased communication capacity by approximately 100 times, reaching the 10Pbps level. Space-division multiplexing is the most effective way to achieve ultra-high-speed, ultra-large-capacity communication. In recent years, countries including China, the United States, the European Union, the United Kingdom, Japan, and South Korea have conducted extensive research on mode / space-division multiplexing technologies. Currently, mode / space-division multiplexing mainly includes single-mode multi-core multiplexing, few-mode multiplexing, few-mode multi-core, and multi-mode solutions.

[0003] Space division multiplexing (SDM) multiplies bandwidth resources by introducing spatial degrees of freedom orthogonal to existing multiplexing dimensions such as wavelength division multiplexing (WDM). Recent research hotspots include mode division multiplexing in optical fibers and orbital angular momentum multiplexing in free space. How to effectively manage and allocate communication bandwidth resources based on the greater absolute communication bandwidth provided by SDM technology, and leverage its high bandwidth advantages to improve the overall network's carrying capacity and efficiency, is a crucial approach to solving the transmission capacity limitation problem. Network management based on SDM poses a significant challenge to switching-based network management capabilities. The core of optical switching technology is: at the switching node, signals are directly switched to different outputs within the optical domain without intermediate optical-to-electrical-to-optical conversion. Among existing optical switching technologies, free-space optical line switching (FLS) uses the entire optical channel as the switching granularity, offering high reliability, fast switching speed, large switching granularity, simplified network management, and significantly improved switching speed and capacity at switching nodes. Furthermore, free-space optical switching is not constrained by waveguides. It utilizes effects such as refraction, reflection, and diffraction from elements like prisms, lenses, beam splitters, or holographic optical components to alter the direction of light propagation in space, allowing the beam to path from one array plane to another, thus achieving optical switching between different ports. It also possesses inherent compatibility with space-division multiplexing optical communication. Free-space optical switching technologies mainly include beam-oriented optical switching based on dynamic holographic diffraction and shutter-selective optical switching. However, since ordinary signal beams lack distinguishability, these optical switching technologies must process each beam separately in space. This severely limits the scalability of switching ports and the increase in spatial port density, contradicting the future requirements for supporting more optical paths and higher port density. Similar to wavelength selection in optical switching, the key to overcoming spatial separation limitations and achieving overlapping free-space optical switching lies in finding a new mechanism to provide a physical distinguishing parameter for spatial beams. This parameter should be used to filter and arbitrarily orient different overlapping beams, overcoming the spatial separation limitations.

[0004] Mode-multiplexed optical communication refers to utilizing the differences in the intrinsic modes of electromagnetic waves as a new coding / multiplexing dimension resource. That is, different mode beams represent different signals / channels, thus opening up new avenues for improving the spectral efficiency of optical communication. This application introduces the photonic dimension of optical spatial modes into optical switching, providing a new manipulation parameter and solving the problem of the lack of distinguishing parameters for overlapping light in the aforementioned optical switching. Optical modes possess both a huge capacity for carrying optical signal transmission and the "tag" characteristic used to distinguish different optical carriers. Introducing the concept of optical modes as both optical multiplexing channels and physical tags for those channels into optical switching offers the following advantages: First, the mutual orthogonality and distinguishability of different optical modes allow them to overlap spatially as intermediate bridges in optical switching. Since crosstalk between modes can be minimized, excessive signal degradation is avoided during application, increasing the port density of the switching space. Second, in optical switching based on optical mode tags, each input beam is coaxial after the mode tag, with the same spatial position. This greatly enhances the scalability of the switching ports and significantly reduces the difficulty of phase modulation design. Furthermore, in the mode tag-based optical switching proposed in this application, the output of each input beam is completed by the same set of phase transformation sequences, simplifying the architecture and improving stability. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a method and system for supporting broadband multi-spatial / mode optical switching, which greatly improves the scalability of the switching port, while also significantly reducing the difficulty of phase modulation design, simplifying the architecture, and improving stability.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a broadband multi-space / mode optical switching method supporting optical spatial modes. Multiple input optical ports are located in different spatial positions or spatial modes, having the same or different spatial modes. After optical spatial mode labeling and driver delabeling, the signals are output from multiple optical output ports. The method is applied to a space-division optical switching system based on optical mode labeling. The system includes: an input fiber array; a multi-plane mode multiplexer that performs spatial mode labeling on spatial channels; a reconfigurable demultiplexer that enables multi-plane phase map switching and demultiplexes spatial / mode channels with different labels to a specific space; and an output fiber array.

[0008] Preferably, the optical spatial mode refers to various transverse spatial mode sets formed by different spatial orthogonal basis modes, including: Hermite-Gaussian mode, Laguerre-Gaussian mode, spatial vector mode, spatial linear polarization mode (LP mode), and spatial vortex mode (OAM mode). Specifically, a mode basis corresponding to the number of spatial / mode channels to be exchanged is selected from one of the mode sets as the label of each space / mode and as the target label for multiplexing each space / mode.

[0009] Preferably, the support for wide-spectrum multi-space / mode means that each mode of the spatial mode is a signal light mode that supports wide bands or multiple wavelengths; the wide bands include C, S, L, O, and U bands, as well as a portion or the whole of several of these bands; the multi-wavelength signals supported are multi-wavelength signal light multiplexed from multi-wavelength signal light.

[0010] Preferably, the multi-space / mode optical switching comprises three layers: first, the switching channel consists of multiple spatial channels, which are single-mode or few-mode / multi-mode spatial channels; second, as a spatial optical switching system, it includes an input unit, an output unit, and a spatial optical switching control unit; and third, it enables arbitrary connections from any input spatial / mode port to any output spatial / mode port.

[0011] Preferably, the input fiber array and the output fiber array are independent input port arrays and output port arrays of a switching unit matched with the communication system. The input fiber array and the output fiber array are single-mode fiber arrays, few-mode / multi-mode fiber arrays, single-mode fibers, and few-mode / multi-mode hybrid fiber arrays. The various fiber modes are not limited to conventional refractive index structures, but include various corresponding microstructure fibers, such as: ring-core fiber, photonic crystal fiber, hollow-core photonic bandgap fiber, and anti-resonant fiber.

[0012] Preferably, the optical spatial mode tagging of the multi-space / mode ports refers to selecting an orthogonal mode base of a specific mode set to establish a one-to-one mapping relationship with different spatial / mode ports. Then, based on the differences between the distribution of each spatial mode and the target mode, a multi-plane transformation method is used to perform mode transformation on the input port beams / modes, transforming them into coaxial multi-mode multiplexed beams. This process is implemented through a multi-plane optical transformation device and is a spatial mode tagging process for the spatial channel.

[0013] Preferably, the optical spatial mode driver de-labels the coaxial (spatially overlapping) modes after spatial mode labeling, and demultiplexes them, so that each mode is transformed back into spatially separated spatial / mode beams. The demultiplexing process is a reconfigurable process, and the reconfiguration process corresponds to the spatial redistribution of the spatial / mode beams. The port distribution control scheme of the distribution is determined by needs, and its implementation is accomplished by switching the multi-plane phase transformation map loaded on the reconfigurable demultiplexer. This process corresponds to the inverse process of the mode label, which is a demultiplexing and de-labeling process. However, the difference is that the spatial flow of the mode energy after de-labeling, i.e., the output port / mode, is flexibly controlled by the reconfigurable loaded multi-plane phase transformation map. Here, the reconfigurable demultiplexer is executed by various spatial light modulators.

[0014] Preferably, the specific process of the port distribution control scheme, which is accomplished by switching the multi-plane phase transformation map loaded on the reconfigurable demultiplexer, includes: port allocation scheme, construction of demultiplexing multi-plane transformation phase map sets corresponding to various schemes, and selection of the corresponding phase map to be loaded as needed. Here, each phase map refers to a phase map sequence consisting of multiple phase maps containing the corresponding multi-plane transformation.

[0015] Preferably, the phase map sequence is generated by any method that can achieve corresponding mode transformation demultiplexing control.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] This invention provides a broadband multi-space / mode optical switching method and system that supports optical spatial modes. Multiple input optical ports are located in different spatial positions or spatial modes, possessing the same or different spatial modes. After optical spatial mode labeling and driver delabeling, the signals are output from multiple optical output ports. The method is applied to a space-division optical switching system based on optical mode labeling. The system includes: an input fiber array; a multi-plane mode multiplexer that performs spatial mode labeling on spatial channels; a reconfigurable demultiplexer that enables multi-plane phase map switching and demultiplexes spatial / mode channels with different labels to a specific space; and an output fiber array. This significantly improves the scalability of the switching ports while greatly reducing the difficulty of phase modulation design, simplifying the architecture, and improving stability. Attached Figure Description

[0018] Figure 1 : Schematic diagram of the pattern tag swapping method process;

[0019] Figure 2 Diagram of a single-mode array input / single-mode array output switching system with independent mode labels and switching processes;

[0020] Figure 3Diagram of a multimode multiplexed input single-mode array output switching system;

[0021] Figure 4 Diagram of a demultiplexing, multimode multiplexing input, multimode multiplexing output mode switching system;

[0022] Figure 5 Diagram of a single-mode array input and single-mode array output switching system integrating the mode label switching process;

[0023] Figure 6 Diagram of a multimode multiplexed input and multimode multiplexed output mode switching system integrating demultiplexing and transformation;

[0024] Figure 7(a): Schematic diagram of multiplane transform phase sequence for normal demultiplexing through-connection;

[0025] Figure 7(b): Schematic diagram of multiplane transform phase sequence of switched demultiplexing connection;

[0026] Figure 8 Port identification diagram showing the effects of pass-through and switched connections corresponding to the input. Detailed Implementation

[0027] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] This invention provides a broadband multi-space / mode optical switching method supporting optical spatial modes. Multiple input optical ports are located in different spatial positions or spatial modes, having the same or different spatial modes. After optical spatial mode labeling and driver delabeling, the signals are output from multiple optical output ports. The method is applied to a space-division optical switching system based on optical mode labeling. The system includes: an input fiber array; a multi-plane mode multiplexer that performs spatial mode labeling on spatial channels; a reconfigurable demultiplexer that enables multi-plane phase map switching and demultiplexes spatial / mode channels with different labels to a specific space; and an output fiber array.

[0029] Furthermore, the optical spatial mode refers to various transverse spatial mode sets formed by different spatial orthogonal basis modes, including: Hermite-Gaussian mode, Laguerre-Gaussian mode, spatial vector mode, spatial linear polarization mode (LP mode), and spatial vortex mode (OAM mode). Specifically, a mode basis corresponding to the number of spatial / mode channels to be exchanged is selected from one of the mode sets as the label of each space / mode and as the target label for multiplexing each space / mode.

[0030] Furthermore, the support for wide-spectrum multi-space / mode means that each mode of the spatial mode is a signal light mode that supports wide-band or multi-wavelength signals; the wide-band includes C, S, L, O, and U bands, as well as a portion or the whole of several of these bands; the multi-wavelength signals supported are multi-wavelength signal lights after multiplexing of multi-wavelength signal lights.

[0031] Furthermore, the multi-space / mode optical switching comprises three layers: first, the switching channel consists of multiple spatial channels, which can be single-mode or few-mode / multi-mode spatial channels; second, as a spatial optical switching system, it includes an input unit, an output unit, and a spatial optical switching control unit; and third, it enables arbitrary connections from any input spatial / mode port to any output spatial / mode port.

[0032] Furthermore, the input fiber array and the output fiber array are independent input port arrays and output port arrays of switching units matched with the communication system. The input fiber array and the output fiber array are single-mode fiber arrays, few-mode / multi-mode fiber arrays, single-mode fibers, and few-mode / multi-mode hybrid fiber arrays. The various modes of fibers are not limited to conventional refractive index structures, but include various corresponding microstructure fibers, such as: ring-core structure fibers, photonic crystal fibers, hollow-core photonic bandgap fibers, and anti-resonant fibers.

[0033] Furthermore, the optical spatial mode tagging of the multi-space / mode ports refers to selecting an orthogonal mode base of a specific mode set to establish a one-to-one mapping relationship with different spatial / mode ports. Then, based on the differences between the distribution of each spatial mode and the target mode, a multi-plane transformation method is used to perform mode transformation on the input port beams / modes, transforming them into coaxial multi-mode multiplexed beams. This process is implemented through a multi-plane optical transformation device and is a spatial mode tagging process for the spatial channel.

[0034] Furthermore, the optical spatial mode driver de-labels the coaxial (spatially overlapping) modes after spatial mode labeling, and demultiplexes them, so that each mode is transformed back into spatially separated spatial / mode beams. The demultiplexing process is a reconfigurable process, and the reconfiguration process corresponds to the spatial redistribution of the spatial / mode beams. The port distribution control scheme of the distribution is determined by needs, and its implementation is accomplished by switching the multi-plane phase transformation map loaded on the reconfigurable demultiplexer. This process corresponds to the inverse process of the mode label, which is a demultiplexing and de-labeling process. However, the difference is that the spatial flow of the mode energy after de-labeling, i.e., the output port / mode, is flexibly controlled by the reconfigurable multi-plane phase transformation map. Here, the reconfigurable demultiplexer is executed by various spatial light modulators.

[0035] Furthermore, the specific process of the port distribution control scheme, which is accomplished by switching the multi-plane phase transformation map loaded on the reconfigurable demultiplexer, includes: port allocation scheme, construction of demultiplexing multi-plane transformation phase map sets corresponding to various schemes, and selection of the corresponding phase map to be loaded as needed. Here, each phase map refers to a phase map sequence consisting of multiple phase maps containing the corresponding multi-plane transformation.

[0036] Furthermore, the phase map sequence can be generated using any method that can achieve corresponding mode transformation demultiplexing control.

[0037] This invention provides a broadband multi-space / mode optical switching method and system that supports optical spatial modes. Multiple input optical ports are located in different spatial positions or spatial modes, possessing the same or different spatial modes. After optical spatial mode labeling and driver delabeling, the signals are output from multiple optical output ports. The method is applied to a space-division optical switching system based on optical mode labeling. The system includes: an input fiber array; a multi-plane mode multiplexer that performs spatial mode labeling on spatial channels; a reconfigurable demultiplexer that enables multi-plane phase map switching and demultiplexes spatial / mode channels with different labels to a specific space; and an output fiber array. This significantly improves the scalability of the switching ports while greatly reducing the difficulty of phase modulation design, simplifying the architecture, and improving stability.

[0038] The core of this method is to utilize the distinguishability of orthogonal modes within various spatial mode sets, introducing each mode as a label for each spatial input port into the optical switching process. Through optical mode transformation of the optical spatial ports / modes, each mode is mapped to different coaxial modes. This process can be described as a mode labeling and mode multiplexing process for each input port. Then, based on the differences in mode structure and system requirements, specific mode transformation, demultiplexing, and beam splitting are performed on the modes, allowing the corresponding output ports to establish connections with the input ports as needed. The mode transformation, demultiplexing, and beam splitting scheme is reconfigurable, allowing for switching of multi-plane transformation phase sequences as needed, reconstructing the correspondence between output and input ports, and realizing the switching of port spatial / mode channels. Figure 1 As shown, the core of its implementation process mainly includes: matching with the input space port

[100] , a high-efficiency and low-loss multi-path optical mode tagging process based on multi-plane transformation

[200] , corresponding to the coaxial multiplexing of each port mode

[300] ; various multi-plane transformation phase generation processes based on the port corresponding mode transformation demultiplexing according to requirements, corresponding to the key routing layout of optical space mode channel output; dynamically loading the corresponding multi-plane transformation phase sequence as needed, realizing a low-crosstalk and flexible multi-path optical mode de-tag routing output process

[400] , and finally realizing the spatial output after spatial channel switching

[500] .

[0039] Optical spatial modes, serving as labels for spatial port channels / modes, can be any orthogonal basis from various spatial mode sets, such as Hermit-Gaussian (HG) modes, Laguerre-Gaussian (LG) modes, spatial vector modes (VM) modes, spatial linear polarization modes (LP) modes, and spatial vortex modes (OAM) modes. The key characteristic is that a mode basis corresponding to the number of spatial / mode channels to be exchanged is selected from one of the mode sets, serving as the label for each spatial / mode and also as the destination label for multiplexing each spatial / mode. The core principle here is that after selecting the orthogonal basis, each mode in the orthogonal basis is orthogonal to all other modes, and the radial and angular parameters of the corresponding modes must differ. Simultaneously, each spatial port is transformed into its corresponding specific mode, coaxially overlapping in space. This process is essentially the transformation and multiplexing process of modes under the corresponding basis.

[0040] Regarding the differences in interfaces compatible with actual space division multiplexing systems, this space optical switching method can be specifically divided into three basic switching units: I is a single-mode interface switching unit with multiple input and output ports, such as... Figure 2 As shown; II is an input few-mode multi-port and output single-mode multi-port switching unit, such as... Figure 3 As shown; III is a switching unit with few-mode ports for both input and output, such as... Figure 4 As shown. From the input port perspective, all input ports are spatially multi-channel. I is a single-mode (which can be the fundamental mode or any consistent higher-order mode) port array; II and III are both multi-order overlapping orthogonal modes after coaxial multiplexing. For case I, the input spatial port / mode labels can be arbitrarily selected from orthogonal basis modes such as HG, LG, VM, LP, and OAM. Then, mode transformation is performed to load mode labels onto the input light of each port and transform it to the same spatial position, forming a coaxial multiplexed mode. The key here is the correspondence between the spatial position of the input port and different modes (generally represented by the difference in radial and angular indices of the mode). For cases II and III, their inputs are already multiplexed modes, and their corresponding mode basis is already given. No mode label loading is required at the input end. The scheme directly transforms the output pointing operation based on the existing corresponding mode information. From the output port perspective, I and II are both multi-single-mode port arrays, and III is a multi-mode multiplexed port. For the outputs of I and II, only reconfigurable mode transformation and demultiplexing are needed, and the output ports are switched according to the required mode multi-plane transformation phase sequence. For the multiplexed output of III, the spatial port needs to be switched as needed before mode multiplexing to match the output port requirements. It should be noted that the implementation of the switching processes for both I and III transformations can be achieved by optimizing the transformation phase sequence, completing the mode multiplexing labeling and mode demultiplexing labeling processes in one step. The corresponding unit simplifies to, as shown below. Figure 5 and Figure 6 As shown, this situation reduces the degrees of freedom in mode transformation spatial operations, increases the difficulty of generating transformation phase sequences, and places higher demands on devices (spatial light modulators) that can realize reconfigurable phase sequences.

[0041] For the input and output interfaces of the switching unit, they are typically independent fiber optic arrays matched to the communication system. These can be single-mode fiber arrays, few-mode / multi-mode fiber arrays, single-mode fiber, or few-mode / multi-mode hybrid fiber arrays. The various fiber modes are not limited to conventional refractive index structures; they include corresponding microstructure fibers, such as: ring-core fiber, photonic crystal fiber, hollow-core photonic bandgap fiber, anti-resonant fiber, etc. Simultaneously, the input and output ports can also be more flexible free-space coupling interfaces.

[0042] The selection of optical tags for optical mode tagging-based optical switching is crucial to technical implementation and performance. In practice, selection should be based on existing foundations for transforming various mode multiplexing and demultiplexing bases, but in principle, the aforementioned orthogonal bases are equivalent. Here, different spatial / mode ports undergoing spatial optical mode tagging refer to selecting orthogonal mode bases from a specific set of modes to establish a one-to-one mapping relationship with different spatial / mode ports. Then, based on the differences between the spatial mode distribution and the target mode, a multi-plane transformation method is used to transform the input beams / modes at each port into coaxial multi-mode multiplexed beams. This process is implemented through, but is not limited to, multi-plane optical transformation devices; it is a spatial mode tagging process for the spatial channel.

[0043] After the aforementioned spatial / mode port tags are multiplexed, the spatial channels of each mode overlap in space. To achieve spatial channel switching, the original spatial input / output ports / modes must be exchanged. This process involves de-tagging the multiplexed, overlapping spatial optical modes and performing a spatial position mode-driven transformation. This demultiplexing process de-tagging the coaxial (spatially overlapping) modes generated with spatial mode tags, transforming each mode back into spatially separated spatial / mode beams. This demultiplexing process is reconfigurable, corresponding to the spatial redistribution of the spatial / mode beams. The port distribution control scheme is determined by needs and is implemented by switching the multi-plane phase transform map loaded on the reconfigurable demultiplexer. This process corresponds to the reverse of the mode tagging process, a demultiplexing and tagging process, but the difference lies in the spatial flow of mode energy after tagging, i.e., the output port / mode, which is flexibly controlled by the reconfigurable multi-plane phase transform map. The reconfigurable demultiplexer can be executed by various spatial light modulators.

[0044] The port distribution control scheme described above, achieved by switching the multi-plane phase transform diagram loaded onto the reconfigurable demultiplexer, includes the following specific processes: possible port allocation schemes, construction of demultiplexed multi-plane transform phase diagram sets corresponding to each scheme, and selection of the appropriate phase diagram to load as needed. Each phase diagram here refers to a sequence of phase diagrams containing multiple phase diagrams of the corresponding multi-plane transform. The generation of each multi-plane transform phase diagram sequence can be achieved using any method capable of implementing demultiplexing control of the corresponding mode transform.

[0045] Based on the aforementioned optical mode tag optical switching process, the switching units can be expanded or combined in parallel to meet the needs of the switching system. For example, the combination of input terminals I and II, and the combination of output terminals I and III, can build a switching system with more ports, greater complexity, higher throughput, and better performance, realizing arbitrary connection from any input space / mode port to the output space / mode port.

[0046] The spatial optical switching described in this application is compatible with wavelength division multiplexing (WDM), and each spatial port mode supports broadband. Broadband support here means that each spatial mode can be a signal light mode that supports wide bands or multiple wavelengths; wide bands can be C, S, L, O, U, etc., or a part or the whole of several of these bands; multiple wavelengths can be the signal light supported by multiplexed multi-wavelength signal light.

[0047] Space-division multiplexing optical paths take two basic forms: spatial parallel alignment (e.g., single-mode multi-core fiber) and orthogonal overlap (different modes in few-mode fiber), as well as composite forms derived from these. Spatial parallel alignment often does not require differentiation of beams or optical mode lines; they form different channels based on their spatial positions. In the case of orthogonal overlap, since the optical paths overlap in space, the modes of each optical path need to be orthogonal to each other. The mode-label-based optical switching method proposed in this invention is based on the orthogonality of modes in optical mode classes and the differences in mode structures. It achieves reusability and demultiplexability based on the mode differences and orthogonality of orthogonal base modes within a mode class, performing mode transformation and spatial position control at the mode-by-mode unit level. Here, the mode class can be any orthogonal base in various spatial mode sets, such as: Hermit-Gaussian mode (HG mode), Laguerre-Gaussian mode (LG mode), spatial vector mode (VM mode), spatial linear polarization mode (LP mode), spatial vortex mode (OAM mode), etc.

[0048] The following example illustrates the implementation process of pattern tag optical switching. Figure 2 As shown, taking optical path switching with m×n input ports as an example, the optical field distribution of the input ports is represented by I. m,n This indicates that the optical field at the output port is represented by O.p,q This indicates that the middle label pattern is represented by M. m,n This is illustrated by the most common case: a single-mode array where the number of output ports is the same as the number of input ports.

[0049] Light field I at each input port m,n The mode M is transformed into a selected mode orthogonal basis using a multiplane mode transformation table. m,n The single-mode optical fields at the input ports here form a non-overlapping array in space, such as a collimated single-mode fiber array. The optical field at each port is transformed to a corresponding mode M through a multi-plane phase transform. m,n This establishes a one-to-one correspondence between ports and modes, with different ports corresponding to different modes. Here, the transformed m×n modes overlap spatially, forming coaxial multiplexing of the optical paths at each port. The relationship between the mode optical field and the input port optical field can be expressed as M... m,n =I m,n T, where T is the phase transformation matrix of the light field, represents a series of transformations of the light field, T = F1T1F2T2…F n T n F n+1 F i The transmission matrix corresponding to the light field, T i The phase distribution of the i-th plane in the multiplane transformation corresponds to the phase sequence shown in Figure 7(a). Figure 2 This is implemented on the phase board shown in Figure 2.1. This achieves mode multiplexing tags for the signal light at the m×n spatial input ports, where each signal after the tag corresponds to an orthogonal mode.

[0050] Based on the reversibility of optical paths, an inverse transformation of the above-mentioned mode multiplexing tag multiplexing process can achieve the demultiplexing of the multiplexed optical path, re-obtaining the single-mode optical field array, and realizing, as Figure 8 The input shown in (a) is similar to... Figure 8 (b) shows the straight-through connection of the output port.

[0051] Multiplane transformation M of corresponding mode m,n =I m,n For T, the one-to-one correspondence sequence between the spatial location port optical field and a certain mode in the orthogonal modes is arbitrary, and M can be fully realized. m,n =I p,q The correspondence of T' is simply the transformation phase sequence T at this time. i The phase sequence can be similar to that shown in Figure 7(b). Different demultiplexing transformation sequences result in different arrangements of the demultiplexed single-mode output array, thus enabling the output port O... p,q Different correspondences to input ports O p,q =I m,nT'. This achieves the switching of signal light from the same input port to different output ports, or in other words, the switching of different input signal light from the same output port. In fact, there are m×n permutations of the output ports, each requiring a specific multiplane transform phase sequence. This transform phase sequence is directly related to the type and mode of the selected orthogonal basis, and the spatial arrangement of the input and output ports. Correspondingly, when the phase sequence is in... Figure 2 When the through phase sequence (Fig. 7(a)) loaded on the spatial light modulator in section 4.2 is switched to the exchanged phase sequence (Fig. 7(b)), the corresponding input optical path port ( Figure 8 (a), corresponding to Figure 2 The signal light from the input port of (1) will be drawn from Figure 2 The output port of 5 is as follows Figure 8 (b) The direct connection state is switched to the state shown in the figure. Figure 8 (c) Switching state. Similarly, by switching the phase diagram, any output optical path can be switched.

[0052] This invention provides a broadband multi-space / mode optical switching method and system that supports optical spatial modes. Multiple input optical ports are located in different spatial positions or spatial modes, possessing the same or different spatial modes. After optical spatial mode labeling and driver delabeling, the signals are output from multiple optical output ports. The method is applied to a space-division optical switching system based on optical mode labeling. The system includes: an input fiber array; a multi-plane mode multiplexer that performs spatial mode labeling on spatial channels; a reconfigurable demultiplexer that enables multi-plane phase map switching and demultiplexes spatial / mode channels with different labels to a specific space; and an output fiber array. This significantly improves the scalability of the switching ports while greatly reducing the difficulty of phase modulation design, simplifying the architecture, and improving stability.

[0053] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of this invention. Therefore, if these modifications and variations of this invention fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for supporting broadband multi-spatial / mode optical switching, characterized in that, The input multiple optical ports are located in different spatial locations or spatial modes. After passing through optical spatial mode tags and driving de-tags, they are output from multiple optical output ports. The method is applied to a space-division optical switching system based on optical mode tags. The system includes: an input fiber array, a multi-plane mode multiplexer for spatial mode labeling of spatial channels, a reconfigurable demultiplexer that enables multi-plane phase map switching and demultiplexes spatial / mode channels with different labels to a specific space, and an output fiber array. The optical signal originates from the input fiber array, is processed by the multi-plane mode multiplexer and becomes a coaxial multiplexed beam. The coaxial multiplexed beam enters the reconfigurable demultiplexer and achieves routing and spatial separation through phase diagram switching, forming a spatially discrete beam coupled to the output fiber array.

2. The optical spatial mode supporting broadband multi-spatial / mode optical switching method according to claim 1, characterized in that, The optical spatial mode refers to the set of various transverse spatial modes formed by different spatial orthogonal basis modes; The transverse spatial mode set includes: Hermite-Gaussian mode, Laguerre-Gaussian mode, spatial vector mode, spatial linear polarization mode, and spatial vortex mode; Select a mode base corresponding to the number of space / mode channels to be exchanged from the set of horizontal spatial modes, and use it as the label for each space / mode, and as the destination label for multiplexing each space / mode.

3. The method for supporting broadband multi-spatial / mode optical switching according to claim 1, characterized in that, The support for broadband multi-space / mode means that each spatial mode supports a wide-band or multi-wavelength signal light mode. The wideband includes: C, S, L, O, U bands, or a portion or the whole of several bands containing C, S, L, O, U bands; The signals supported by the multi-wavelength signal are multi-wavelength signal light multiplexed from multiple wavelength signal light.

4. The method for supporting broadband multi-spatial / mode optical switching according to claim 1, characterized in that, The multi-space / mode optical switching comprises three layers: first, the switching channels are multiple spatial channels, which can be single-mode or few-mode / multi-mode spatial channels; second, as a spatial optical switching system, it includes an input unit, an output unit, and a control unit for spatial optical switching; and third, it enables arbitrary connections from any input spatial / mode port to any output spatial / mode port.

5. The method for supporting broadband multi-spatial / mode optical switching according to claim 1, characterized in that, The input fiber optic array and the output fiber optic array are independent input port arrays and output port arrays of a switching unit that are matched with the communication system. The input fiber array and the output fiber array are single-mode fiber arrays, few-mode / multi-mode fiber arrays, single-mode fibers, and few-mode / multi-mode hybrid fiber arrays. Various modes of optical fiber are not limited to conventional refractive index structures; various modes of optical fiber also include: corresponding microstructure optical fiber. The microstructured optical fibers include: ring-core optical fibers, photonic crystal fibers, hollow-core photonic bandgap fibers, and anti-resonant fibers.

6. The method for supporting broadband multi-spatial / mode optical switching according to claim 1, characterized in that, The process of the multi-space / mode port passing through the optical spatial mode tag is specifically as follows: By selecting orthogonal mode bases of a specific mode set, a one-to-one mapping relationship is formed between them and different spatial / mode ports. Then, based on the difference between the spatial mode distribution and the target mode, the multi-plane transformation method is used to perform mode transformation on the input port beams / modes, transforming them into coaxial multi-mode multiplexed beams. The process of multi-space / mode ports passing through the optical spatial mode tag is achieved through a multi-plane optical transformation device, which is a process of tagging spatial modes of spatial channels.

7. The method for supporting broadband multi-spatial / mode optical switching according to claim 1, characterized in that, The process of optical spatial mode labeling and driving delabeling includes: demultiplexing each coaxial mode after spatial mode labeling, so that each mode is transformed back into spatially separated spatial / mode beams; The demultiplexing process is a reconfigurable process, and the reconfiguration process corresponds to the spatial redistribution of the space / mode beam. The specific implementation process of the reconstruction process is as follows: This is achieved by switching the multi-plane phase transformation diagram loaded on the reconfigurable demultiplexer, and the port distribution control scheme is determined according to the requirements. The demultiplexing and delabeling process is the inverse process of mode labeling, and the spatial flow of mode energy after delabeling is flexibly controlled by a reconfigurable loaded multiplane transform phase map.

8. The method for supporting broadband multi-spatial / mode optical switching according to claim 7, characterized in that, The allocated port distribution control scheme is accomplished by switching the multi-plane phase transform diagram loaded on the reconfigurable demultiplexer, specifically as follows: Port allocation schemes, construction of demultiplexing multiplane transform phase map sets corresponding to various schemes, and selection and loading of corresponding phase maps as needed; where each phase map refers to a phase map sequence composed of multiple phase maps corresponding to the multiplane transform.

9. The method for supporting broadband multi-spatial / mode optical switching according to claim 8, characterized in that, The generation process of the phase map sequence is used to realize the demultiplexing control of the corresponding mode transformation.

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