Wavelength selective switch, optical switching device and optical network system

Abstract

The embodiment of the invention provides a wavelength selection switch, optical switching equipment and an optical network system, and relates to the technical field of optical communication, and the number of ports of the wavelength selection switch is large. The wavelength selection switch comprises a wave combining and separating device, a first optical modulator and a first mode conversion unit, wherein the first mode conversion unit is coupled to a plurality of branch ports of the wavelength selection switch; the wave combining and separating device receives an optical signal input from the common port of the wavelength selection switch and outputs m single-wavelength optical signals, and m is a positive integer greater than or equal to 1; the first optical modulator performs first angle deflection and mode conversion on the m single-wavelength optical signals to generate m modulated optical signals; the first mode conversion unit receives at least one modulated optical signal in the m modulated optical signals, and transmits the modulated optical signal to one branch port in the branch port group according to the mode of each modulated optical signal in the at least one modulated optical signal.

Description

Technical Field

[0001] The present application relates to the field of optical communication technology, and in particular to a wavelength selective switch, an optical switching device and an optical network system. Background Art

[0002] Optical network systems are the current mainstream communication systems. In optical network systems, optical switching equipment is usually provided, which can realize the scheduling of optical signals of different wavelengths in any direction. Common optical switching equipment includes optical cross-connect (OXC) and optical add-drop multiplexer (OADM). Among them, the core component of the optical switching equipment is the wavelength selective switch (WSS), which can transmit any wavelength of the combined optical signal based on wavelength division multiplexing (WDM) technology received by the public port to any branch port.

[0003] The larger the number of branch ports of the wavelength selective switch, the stronger the scheduling capability of the optical switching device. However, due to the limitation of the deflection angle of the optical modulator in the wavelength selective switch, it is difficult to expand the number of ports of the existing wavelength selective switch by multiples. Summary of the invention

[0004] The embodiments of the present application provide a wavelength selective switch, an optical switching device and an optical network system. The wavelength selective switch has a large number of ports.

[0005] In a first aspect, a wavelength selective switch is provided, comprising: a wavelength combiner / demultiplexer (dispersion element), a first optical modulator and a first mode conversion unit, wherein the first mode conversion unit is coupled to a plurality of branch ports of the wavelength selective switch; the wavelength combiner / demultiplexer is used to receive an optical signal input from a common port of the wavelength selective switch, output m single-wavelength optical signals, where m is a positive integer greater than or equal to 1, and transmit the m single-wavelength optical signals to the first optical modulator; the first optical modulator is used to perform a first angle deflection and mode conversion on the m single-wavelength optical signals to generate m modulated optical signals; the first mode conversion unit is used to receive at least one modulated optical signal among the m modulated optical signals, and transmit the modulated optical signal to one of the plurality of branch ports according to the mode of each modulated optical signal among the at least one modulated optical signal. In the wavelength selective switch, the wavelength combiner / demultiplexer receives the optical signal input from the common port of the wavelength selective switch and outputs m single-wavelength optical signals, where m is a positive integer greater than or equal to 1; the first optical modulator performs a first angle deflection and mode conversion on the m single-wavelength optical signals to generate m modulated optical signals, wherein each of the m modulated optical signals has a deflection angle and a mode, the deflection angle of any modulated optical signal determines whether the modulated optical signal can be transmitted to the mode conversion unit, and the mode of any modulated optical signal determines which branch port among the multiple branch ports the modulated optical signal is transmitted to. The first mode conversion unit receives at least one modulated optical signal among the m modulated optical signals, and the first mode conversion unit transmits the modulated optical signal to one of the multiple branch ports according to the mode of each modulated optical signal among the at least one modulated optical signal. Therefore, when the deflection angle of the first optical modulator cannot be increased, the single-wavelength optical signal is mode-converted by the first optical modulator, combined with the function of the first mode conversion unit transmitting the modulated optical signal to one of the multiple branch ports according to the mode of the modulated optical signal, so that the number of ports of the wavelength selective switch can be further increased.

[0006] Optionally, when m is greater than or equal to 2, the first mode conversion unit is used to transmit multiple modulated optical signals with the same mode to two different branch ports among the multiple branch ports, and transmit multiple modulated optical signals with different modes to the same branch port among the multiple branch ports. In this optional manner, the first mode conversion unit can receive two or more modulated optical signals, and the first mode conversion unit transmits the modulated optical signals to a branch port according to the mode of each modulated optical signal, wherein, when the modes of the multiple modulated optical signals received by the first mode conversion unit are different, the first mode conversion unit transmits the multiple modulated optical signals with different modes to different branch ports among the multiple branch ports; when the modes of the multiple modulated optical signals received by the first mode conversion unit are the same, the first mode conversion unit transmits the multiple modulated optical signals with the same mode to the same branch port among the multiple branch ports.

[0007] Optionally, the wavelength selective switch further includes a second mode conversion unit, which is arranged between the common port and the wavelength combiner / demultiplexer; the second mode conversion unit is used to shape the received optical signal into a shaped optical signal, and transmit the shaped optical signal to the wavelength combiner / demultiplexer; wherein the size of the light spot of the shaped optical signal in the first direction is larger than the size of the light spot of the shaped optical signal in the second direction, the first direction is the port direction of the wavelength selective switch, and the second direction is the dispersion direction of the wavelength selective switch; the wavelength combiner / demultiplexer is specifically used to receive the shaped optical signal and output m single-wavelength optical signals. In this optional manner, the second mode conversion unit is used to shape the received optical signal into a shaped optical signal, and transmit the shaped optical signal to the wavelength combiner / demultiplexer; wherein the size of the light spot of the shaped optical signal in the port direction is larger than the size of the light spot of the shaped optical signal in the dispersion direction; the wavelength combiner / demultiplexer is specifically used to receive the shaped optical signal and output m single-wavelength optical signals. When m single-wavelength optical signals are transmitted to the first optical modulator, the size of the light spot of any single-wavelength optical signal in the port direction is larger than that in the dispersion direction, that is, the size of the light spot of the single-wavelength optical signal in the port direction becomes larger. When the size of the light spot of the single-wavelength optical signal in the port direction becomes larger, the first optical modulator performs a first angle deflection and mode conversion on the single-wavelength optical signal to generate a modulated optical signal, which can reduce the crosstalk between the multiple modulated optical signals.

[0008] Optionally, the first mode conversion unit includes a first coupling region and a plurality of first optical fibers, wherein a first end of a first optical fiber is connected to an output end of the first coupling region, and a second end of a first optical fiber is connected to a branch port among a plurality of branch ports; the first optical fiber is a single-mode optical fiber; and the first coupling region is used to transmit the modulated optical signal to a first optical fiber among the plurality of first optical fibers according to the mode of the modulated optical signal. In this optional manner, the first mode conversion unit specifically includes a plurality of first optical fibers connected to a plurality of branch ports, so that the first mode conversion unit and the plurality of branch ports can be well coupled, thereby improving the coupling efficiency of the wavelength selective switch, wherein the first coupling region can specifically be a mode demultiplexer in the form of an optical waveguide, or a mode demultiplexer in the form of an optical fiber coupler.

[0009] Optionally, the first mode conversion unit further comprises a second optical fiber, the second optical fiber is connected to the input end of the first coupling region; the second optical fiber is a few-mode optical fiber. In this optional manner, the first mode conversion unit is specifically a mode demultiplexer based on a tapered form (also called a photon lantern).

[0010] Optionally, the first mode conversion unit includes a plurality of first phase plates, and the phase masks of the plurality of first phase plates are arranged on the transmission path of the modulated optical signal received by the first mode conversion unit; the phase masks of the plurality of first phase plates are used to transmit the modulated optical signal to the position of one of the plurality of branch ports according to the mode of the modulated optical signal. In this optional manner, the plurality of first phase plates may also be specifically referred to as multi-plane light conversion (MPLC). Each first phase plate may be a first phase plate made by photolithography technology, and the unit size of the phase distribution on the phase mask of the first phase plate is micrometer-level, for example, it may be 1 micrometer (μm) to 20μm. Alternatively, each first phase plate may be a first phase plate made by metasurface technology, and the unit size of the phase distribution on the phase mask of the first phase plate is nanometer-level, for example, it may be 1 nanometer (nm) to 500nm. Wherein, when the number of branch ports included in the plurality of branch ports is large, the plurality of first phase plates may make the coupling efficiency of the first mode conversion unit higher.

[0011] Optionally, the second mode conversion unit includes a second coupling region and a third optical fiber, wherein the first end of the third optical fiber is connected to the common port, and the second end of the third optical fiber is connected to the input end of the second coupling region; the third optical fiber is a single-mode optical fiber; and the second coupling region is used to shape the optical signal received by the second mode conversion unit to form a shaped optical signal. In this optional manner, the second mode conversion unit specifically includes a third optical fiber connected to the common port, so that the second mode conversion unit and the common port can be well coupled, thereby improving the coupling efficiency of the wavelength selective switch, wherein the second coupling region can specifically be a mode field converter in the form of an optical waveguide, or a mode field converter in the form of an optical fiber coupler.

[0012] Optionally, the second mode conversion unit further includes a fourth optical fiber, which is connected to the output end of the second coupling region; the fourth optical fiber is a single-mode optical fiber. In this optional manner, the fourth optical fiber can also be arranged at the output end of the second coupling region, so that the structure of the second mode conversion unit has diversity.

[0013] Optionally, the second mode conversion unit includes a plurality of second phase plates, and the phase masks of the plurality of second phase plates are arranged on the transmission path of the optical signal received by the second mode conversion unit; the phase masks of the plurality of second phase plates are used to shape the optical signal received by the second mode conversion unit to form a shaped optical signal. In this optional manner, the plurality of second phase plates may also be specifically referred to as MPLC. Each second phase plate may be a second phase plate made by photolithography technology, and the unit size of the phase distribution on the phase mask of the second phase plate is in the micron level, for example, it may be 1μm to 20μm. Alternatively, each second phase plate may be a second phase plate made by metasurface technology, and the unit size of the phase distribution on the phase mask of the second phase plate is in the nanometer level, for example, it may be 1nm to 500nm.

[0014] Optionally, the wavelength selective switch includes multiple first mode conversion units and multiple groups of branch port groups, each branch port group includes multiple branch ports; multiple first mode conversion units are coupled with multiple groups of branch port groups in a one-to-one correspondence; each first mode conversion unit includes a first coupling region and multiple first optical fibers. In this optional manner, the wavelength selective switch may include multiple mode conversion units and multiple groups of branch port groups, thereby further increasing the number of ports of the wavelength selective switch, and each mode conversion unit includes a first coupling region and multiple first optical fibers.

[0015] Optionally, the wavelength selective switch includes multiple first mode conversion units and multiple groups of branch port groups; each branch port group includes multiple branch ports, and the multiple first mode conversion units are coupled to the multiple groups of branch port groups in a one-to-one correspondence; each first mode conversion unit includes multiple first phase plates. In this optional manner, the wavelength selective switch may include multiple mode conversion units and multiple groups of branch port groups, thereby further increasing the number of ports of the wavelength selective switch, and each first mode conversion unit includes multiple first phase plates.

[0016] Optionally, the wavelength selective switch includes multiple groups of branch port groups, each of which includes multiple branch ports; each first phase plate includes multiple phase masks, and the multiple phase masks are respectively correspondingly arranged on the transmission path of the modulated optical signal transmitted to the multiple groups of branch port groups. In this optional manner, when the wavelength selective switch includes multiple groups of branch port groups, each of the multiple first phase plates may include multiple phase masks, and the multiple phase masks are respectively correspondingly arranged on the transmission path of the modulated optical signal transmitted to the multiple groups of branch port groups, thereby making the wavelength selective switch more integrated. The multiple first phase plates can integrate the functions of multiple first mode conversion units.

[0017] Optionally, the wavelength selective switch further includes a second mode conversion unit; each first phase plate further includes an input phase mask, which is correspondingly arranged on the transmission path of the optical signal input from the common port; the input phase mask is used to form the second mode conversion unit. In this optional manner, each first phase plate further includes an input phase mask, which is correspondingly arranged on the transmission path of the optical signal input from the common port; the input phase mask is used to form the second mode conversion unit, so that the wavelength selective switch can realize the function of the second mode conversion unit without setting up new devices, thereby improving the flexibility of the wavelength selective switch. The multiple first phase plates can integrate the functions of multiple first mode conversion units and the second mode conversion unit.

[0018] Optionally, the wavelength selective switch includes a second optical modulator disposed between the first optical modulator and the first mode conversion unit; the first optical modulator is specifically used to perform a first angle deflection and mode conversion on m single-wavelength optical signals to generate m first modulated optical signals, and transmit the m first modulated optical signals to the second optical modulator; the second optical modulator is used to perform a second angle deflection on the m first modulated optical signals to generate m modulated optical signals. In this optional manner, the first optical modulator performs a first angle deflection and mode conversion on the m single-wavelength optical signals to generate m first modulated optical signals, and transmits the m first modulated optical signals to the second optical modulator; the second optical modulator performs a second angle deflection on the m first modulated optical signals to generate m modulated optical signals, and the wavelength selective switch can be, for example, an M×N wavelength selective switch, wherein "M" in the M×N wavelength selective switch represents the number of common ports of the wavelength selective switch, and "N" represents the number of branch ports of the wavelength selective switch.

[0019] Optionally, the wavelength selective switch further includes a first lens or at least one third phase plate disposed between the first optical modulator and the second optical modulator, the phase mask of the third phase plate being disposed on the transmission path of the m first modulated optical signals; the first lens or at least one third phase plate is used to focus the m first modulated optical signals in a first direction, the first direction being the port direction of the wavelength selective switch. In this optional manner, the first lens or at least one third phase plate is used to focus the m first modulated optical signals in the first direction to realize an optical path of the M×N wavelength selective switch.

[0020] Optionally, the wavelength combiner / demultiplexer includes at least one fourth phase plate, and the fourth phase plate includes grating lines. In this optional manner, the wavelength combiner / demultiplexer may include a fourth phase plate provided with grating lines, thereby improving the flexibility of the wavelength selective switch.

[0021] Optionally, the wavelength selective switch further includes a second lens or at least one fifth phase plate disposed between the wavelength combiner and the first optical modulator, the phase mask of the fifth phase plate being disposed on the transmission path of the m single-wavelength optical signals; the second lens or at least one fifth phase plate is used to collimate the m single-wavelength optical signals in a second direction, and the second direction is the dispersion direction of the wavelength selective switch. In this optional manner, the dispersion angles of the m single-wavelength optical signals output by the wavelength combiner and the wavelength splitter are different, and the second lens collimates the m single-wavelength optical signals in the dispersion direction, so that the size of the first optical modulator in the dispersion direction does not need to be too large to receive the m single-wavelength optical signals.

[0022] Optionally, the wavelength selective switch further includes a third lens or at least one sixth phase plate disposed between the first optical modulator and the first mode conversion unit, the phase mask of the sixth phase plate being disposed on the transmission path of the m modulated optical signals; the third lens or at least one sixth phase plate is used to collimate the m modulated optical signals in a first direction, the first direction being the port direction of the wavelength selective switch. In this optional manner, the modulated optical signal has a deflection angle after being emitted from the first optical modulator, and the third lens or at least one sixth phase plate is disposed to collimate the m modulated optical signals in the port direction, so that the size of the first mode conversion unit in the port direction does not need to be too large to receive the m modulated optical signals.

[0023] Optionally, the wavelength selective switch further includes a fourth lens or at least one seventh phase plate arranged between the common port and the wavelength combiner / demultiplexer, and the phase mask of the seventh phase plate is arranged on the transmission path of the optical signal input from the common port; the fourth lens or at least one seventh phase plate is used to collimate the optical signal input from the common port. In this optional mode, after the fourth lens or at least one seventh phase plate collimates the optical signal received by the common port in the dispersion direction and the port direction, it can ensure that the optical signal input from the common port is transmitted to the predetermined position of the wavelength combiner / demultiplexer.

[0024] Optionally, the common port of the wavelength selective switch and the multiple branch ports of the wavelength selective switch are arranged on the same side of the first optical modulator; or, the common port of the wavelength selective switch and the multiple branch ports of the wavelength selective switch are arranged on different sides of the first optical modulator.

[0025] In a second aspect, an optical switching device is provided, comprising a wavelength selective switch as described in any one of the first aspects above.

[0026] According to a third aspect, an optical network system is provided, comprising a plurality of optical switching devices as described in the second aspect connected by optical fibers.

[0027] In a fourth aspect, a method for transmitting an optical signal is provided, comprising: receiving an optical signal, outputting m single-wavelength optical signals, where m is a positive integer greater than or equal to 1; performing a first angle deflection and mode conversion on the m single-wavelength optical signals to generate m modulated optical signals; receiving at least one modulated optical signal among the m modulated optical signals, and transmitting the modulated optical signal to one of a plurality of branch ports according to the mode of each modulated optical signal among the at least one modulated optical signal.

[0028] Optionally, when m is greater than or equal to 2, the modulated optical signal is transmitted to one of the multiple branch ports according to the mode of each modulated optical signal in at least one modulated optical signal, including: transmitting multiple modulated optical signals with different modes to different branch ports among the multiple branch ports, and transmitting multiple modulated optical signals with the same mode to the same branch port among the multiple branch ports.

[0029] Optionally, before receiving the optical signal and outputting m single-wavelength optical signals, the method further includes: shaping the optical signal into a shaped optical signal, wherein a size of a light spot of the shaped optical signal in a first direction is larger than a size of a light spot of the shaped optical signal in a second direction, the first direction is a port direction in which a plurality of branch ports are arranged, and the second direction is a dispersion direction of the m single-wavelength optical signals; receiving the optical signal and outputting m single-wavelength optical signals specifically includes: receiving the shaped optical signal and outputting m single-wavelength optical signals.

[0030] Optionally, the optical signal transmission method includes: collimating the optical signal; shaping the optical signal into a shaped optical signal, wherein the size of the light spot of the shaped optical signal in the first direction is larger than the size of the light spot of the shaped optical signal in the second direction, the first direction is the port direction in which a plurality of branch ports are arranged, and the second direction is the dispersion direction of m single-wavelength optical signals; receiving the shaped optical signal, outputting m single-wavelength optical signals, where m is a positive integer greater than or equal to 1; collimating the m single-wavelength optical signals in the dispersion direction; performing a first angle deflection and mode conversion on the m single-wavelength optical signals to generate m first modulated optical signals; focusing the m first modulated optical signals in the port direction; performing a second angle deflection on the m first modulated optical signals to generate m modulated optical signals; collimating the m modulated optical signals in the port direction; receiving at least one modulated optical signal among the m modulated optical signals, and transmitting the modulated optical signal to one of the plurality of branch ports according to the mode of each modulated optical signal among the at least one modulated optical signal.

[0031] Among them, the technical effects brought about by any possible implementation method of the second to fourth aspects can refer to the technical effects brought about by different implementation methods in the above-mentioned first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1A schematic diagram of the structure of an optical network system provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of the structure of an optical add / drop multiplexer provided in an embodiment of the present application;

[0034] Figure 3 A schematic diagram of the structure of an optical cross-connect provided in an embodiment of the present application;

[0035] Figure 4 A schematic diagram of the structure of a wavelength selective switch provided in an embodiment of the present application;

[0036] Figure 5 for Figure 4 Schematic diagram of optical field distribution of the combined optical signal received by the wavelength selective switch shown;

[0037] Figure 6 A schematic diagram of a light spot of a Gaussian-distributed combined optical signal and a rectangular-distributed combined optical signal transmitted to an optical modulator according to an embodiment of the present application;

[0038] Figure 7 A schematic diagram of the structure of a wavelength selective switch provided in another embodiment of the present application;

[0039] Figure 8 for Figure 7 The light intensity cross section of the modulated optical signal output by the optical modulator in the wavelength selective switch shown in FIG. Figure 1 ;

[0040] Fig. 9 for Figure 7 The light intensity cross section of the modulated optical signal output by the optical modulator in the wavelength selective switch shown in FIG. Figure 2 ;

[0041] Fig.10 for Figure 7 The light intensity cross section of the modulated optical signal output by the optical modulator in the wavelength selective switch shown in FIG. Figure 3 ;

[0042] Fig.11 for Figure 7 Phase distribution of the region of the optical modulator covered by a single wavelength optical signal in a wavelength selective switch Figure 1 ;

[0043] Fig.12 A graph showing the relationship between the number of iterations and the mode conversion efficiency of an optical modulator provided in an embodiment of the present application;

[0044] Fig.13 A schematic diagram of the structure of the first mode conversion unit provided in the embodiment of the present application Figure 1 ;

[0045] Fig.14 for Figure 7 Phase distribution of the region of the optical modulator covered by a single wavelength optical signal in a wavelength selective switch Figure 2 ;

[0046] Fig.15 for Figure 7 The light intensity cross section of the modulated optical signal output by the optical modulator in the wavelength selective switch shown in FIG. Figure 4 ;

[0047] Fig.16 for Figure 7 Phase distribution of the region of the optical modulator covered by a single wavelength optical signal in a wavelength selective switch Figure 3 ;

[0048] Fig.17 for Fig.16 The ideal light intensity cross section diagram of the modulated light signal output by the light modulator shown;

[0049] Fig.18 for Fig.16 The light intensity cross-sectional diagram of the modulated light signal output by the light modulator shown;

[0050] Fig.19 A schematic diagram of the structure of the first mode conversion unit provided in the embodiment of the present application Figure 2 ;

[0051] Fig. 20 for Fig.17 The light field distribution diagram of the modulated light signal output by the first mode conversion unit shown;

[0052] Fig.21 A schematic diagram of the structure of a wavelength selective switch provided in yet another embodiment of the present application;

[0053] Fig. 22 for Fig.21 The light intensity cross-sectional diagram of the optical signal inputted from the common port and received by the wavelength selective switch and the light intensity cross-sectional diagram of the shaped optical signal outputted by the second mode conversion unit are shown;

[0054] Fig.23 A schematic diagram of the structure of the second mode conversion unit provided in the embodiment of the present application Figure 1 ;

[0055] Fig.24 A schematic diagram of the structure of the second mode conversion unit provided in the embodiment of the present application Figure 2 ;

[0056] Fig.25 A schematic diagram of the structure of a wavelength selective switch provided in yet another embodiment of the present application;

[0057] Fig.26 A schematic diagram of the structure of a wavelength selective switch provided in another embodiment of the present application;

[0058] Fig. 27 for Fig.26 A schematic diagram of the arrangement of light spots of a single wavelength optical signal received by an optical modulator in a wavelength selective switch is shown;

[0059] Fig.28 A schematic diagram of the structure of a wavelength selective switch provided in yet another embodiment of the present application;

[0060] Fig.29 A schematic diagram of the structure of a wavelength selective switch provided in yet another embodiment of the present application;

[0061] Fig.30 A schematic diagram of the structure of a wavelength selective switch provided in another embodiment of the present application;

[0062] Fig.31 A schematic diagram of the structure of a wavelength selective switch provided in yet another embodiment of the present application;

[0063] Fig.32 A schematic diagram of the structure of a wavelength selective switch provided in yet another embodiment of the present application;

[0064] Fig.33 A schematic diagram of the structure of a wavelength selective switch provided in another embodiment of the present application;

[0065] Fig.34 for Fig.33 The schematic diagram of the light spot arrangement of the single wavelength optical signal received by the optical modulator in the wavelength selective switch is shown. DETAILED DESCRIPTION

[0066] The technical solutions in the embodiments of the present application will be 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, rather than all the embodiments.

[0067] Unless otherwise defined, all scientific and technological terms used herein have the same meaning as those known to those of ordinary skill in the art. In the embodiments of the present application, "at least one" refers to one or more, and "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B, which may represent: A exists alone, A and B exist at the same time, and B exists alone, wherein A and B may be singular or plural. The character " / " generally indicates that the associated objects before and after are a kind of "or" relationship. "At least one of the following (individuals)" or its similar expressions refers to any combination of these items, including any combination of single items (individuals) or plural items (individuals). For example, at least one of a, b or c (individuals) may represent: a, b, c, a and b, a and c, b and c or a, b and c, wherein a, b and c may be single or multiple. In addition, in the embodiments of the present application, the words "first", "second" and the like do not limit the quantity and order.

[0068] In addition, in the embodiments of the present application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they may change accordingly according to changes in the orientation of the components in the drawings.

[0069] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0070] The technical solutions in the embodiments of the present application will be 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, rather than all of the embodiments.

[0071] Optical fiber transmission uses light as carrier and optical fiber as transmission medium to transmit signals. With the development of optical fiber transmission, optical network systems based on optical fiber transmission have gradually become the mainstream communication system. Figure 1 As shown, an embodiment of the present application provides a structural schematic diagram of an optical network system 10, in which the optical network system 10 includes a network 1 and a network 2, and the network 1 includes a plurality of optical switching devices connected by optical fibers, and the optical switching devices are used to control a predetermined area (e.g. Figure 1 The predetermined area shown may be a small building or an area covered by a large building) and / or a network (e.g. Figure 1The network 2 shown in FIG. 1 provides optical communication services, wherein the optical switching equipment includes an optical cross-connect (OXC) and an optical add-drop multiplexer (OADM). An optical cross-connect is usually used to provide optical communication services to different networks, such as Figure 1 In the example, network 2 communicates with the optical cross-connection in network 1 through the optical cross-connection in network 2, so that network 2 receives the optical signal transmitted in network 1, or transmits the optical signal generated in network 2 to network 1. Both the optical cross-connection and the optical add-drop multiplexer can provide optical communication services to a predetermined area, for example, Figure 1 In the present invention, an optical cross-connect is used in network 1 to provide optical communication services for the area covered by a large building or a small building, an optical cross-connect is used in network 2 to provide optical communication services for the area covered by a large building, and an optical add / drop multiplexer is used in network 2 to provide optical communication services for the area covered by a small building.

[0072] Among them, local communication equipment is set in the area covered by the large building and the small building, the optical switching equipment communicates with the local communication equipment, and the local communication equipment receives the network (such as Figure 1 The optical signal transmitted in the network 1 or network 2 shown, or the optical signal generated by the local communication device is transmitted to the network through the optical switching device.

[0073] In some embodiments, reference Figure 1 As shown, the optical network system 10 also includes multiple optical amplifiers. Figure 1 As shown, at least one optical amplifier is arranged between any two optical switching devices, and the optical amplifier is used to amplify the optical signal transmitted in the optical fiber. In other embodiments, the optical network system 10 further includes devices such as an optical performance monitor, and the optical performance monitor is used to detect the signal-to-noise ratio and power of the optical signal transmitted in a certain number of optical amplifiers and / or optical switching devices.

[0074] Figure 1 The core component of the optical switching device shown is a wavelength selective switch (WSS), which can realize the scheduling of optical signals of different wavelengths in any direction, as well as the adding or dropping of optical signals of different wavelengths. The structure of the optical cross-connect including the wavelength selective switch and the optical add / drop multiplexer will be described in detail below.

[0075] For example, Figure 2 A schematic diagram of the structure of an optical add / drop multiplexer provided in an embodiment of the present application is shown in FIG. Figure 2As shown, a typical C (colorless) D (directionless) C (contentionless) optical add / drop multiplexer 20 includes a line side device 21 and a client side device 22. Figure 2 As shown, the line-side device 21 in the optical add / drop multiplexer 20 can realize the transmission of an optical signal of any wavelength from one line direction to another line direction; the client-side device 22 in the optical add / drop multiplexer 20 can realize the downlink of an optical signal in any line direction to a local communication device, and uplink an optical signal generated by a local communication device to any line direction. The line-side device 21 includes a plurality of wavelength selective switches (WSS), and the plurality of WSSs are cross-connected to realize the transmission of an optical signal of any wavelength from one line direction to another line direction. Figure 2 The line side device 21 shown specifically includes three wavelength selection switches, namely WSS1, WSS2 and WSS3. WSS1, WSS2 and WSS3 are cross-connected, specifically, one port of WSS1 is connected to one port of WSS2, one port of WSS1 is connected to one port of WSS3, and one port of WSS2 is connected to one port of WSS3. Among them, Figure 2 The WSSs shown are all cross-connected via optical fibers.

[0076] In other embodiments, Figure 2 The optical add / drop multiplexer 20 shown also includes more functional devices. For example, the optical add / drop multiplexer 20 also includes an optical amplifier, which is coupled to the wavelength selective switch. The optical amplifier can amplify the optical signal transmitted to the wavelength selective switch, or amplify the optical signal output by the wavelength selective switch.

[0077] Reference Figure 2 As shown, Figure 2 Any wavelength selective switch shown includes four ports, and two ports of the wavelength selective switch are connected to the client-side device 22, and the other two ports are connected to other wavelength selective switches. Figure 2 When any wavelength selective switch shown includes 8 ports, the number of ports of the wavelength selective switch connected to the client-side device 22 and / or the number of ports connected to other wavelength selective switches will increase, thereby increasing the scheduling capability of the optical add / drop multiplexer for optical signals.

[0078] For example, Figure 3 A schematic diagram of the structure of an optical cross-connect 30 provided in an embodiment of the present application is shown in FIG. Figure 3As shown, the optical cross-connect 30 includes an optical line device 31, an optical backplane 32, and an optical branch device 33, wherein the optical line device 31 may be one or more, and the optical branch device 33 may be one or more. Figure 3 The optical line device 31 shown is specifically two, Figure 3 There are two optical branch devices 33 shown. The main components of the optical line device 31 and the optical branch device 33 are wavelength selection switches. The optical line device 31 is used to transmit an optical signal of any wavelength from one line direction to another line direction through the wavelength selection switch provided therein. The optical backplane 32 is used to interconnect the optical line device 31 with the optical branch device 33. The optical branch device 33 receives an optical signal of any line direction through the optical backplane 32. The optical branch device 33 is used to transmit an optical signal of any line direction to a local communication device through the wavelength selection switch provided therein, or transmit an optical signal generated by a local communication device to any line direction. Exemplarily, Figure 3 The optical line device 31 shown is specifically provided with WSS4 and WSS5. Figure 3 The optical branch device 33 shown in the figure is specifically provided with WSS6 and WSS7. Figure 3 The optical backplane 32 shown generally includes an optical circuit board and an optical connector. The optical connector on the side of the optical backplane 32 close to the optical line device 31 is connected to the port of WSS4 and also to the port of WSS5. The optical connector on the side of the optical backplane 32 close to the optical branch device 33 is connected to the port of WSS6 and also to the port of WSS7.

[0079] In other embodiments, Figure 3 The optical cross-connect 30 shown also includes more functional devices, for example, the optical cross-connect 30 also includes an optical amplifier and a filter. For example, in the optical line device 31, an optical amplifier and a filter may be provided, the filter is coupled to the optical amplifier, and the optical amplifier is coupled to the wavelength selective switch in the optical line device 31; the optical amplifier may amplify the optical signal transmitted to the wavelength selective switch or the optical signal output by the wavelength selective switch; the filter may filter out the interference optical signal in the optical line device 31. For another example, in the optical branch device 33, an optical amplifier may be provided, the optical amplifier is coupled to the wavelength selective switch in the optical branch device 33, and the optical amplifier may amplify the optical signal transmitted to the wavelength selective switch or the optical signal output by the wavelength selective switch.

[0080] Compared with the optical add / drop multiplexer 20, the optical cross-connect 30 has a higher integration level, and the optical line device 31 and the optical branch device 33 in the optical cross-connect 30 are interconnected through the optical backplane 32, which reduces the use of optical fibers and the transmission loss of optical signals.

[0081] Reference Figure 3 As shown, when the number of ports of the wavelength selective switch in the optical line device 31 increases, the optical line device 31 can dispatch more optical signals in different line-side directions through the wavelength selective switch arranged therein, and when the number of ports of the wavelength selective switch in the optical branch device 33 increases, the optical branch device 33 can dispatch more optical signals to add or drop wavelengths through the wavelength selective switch arranged therein. It can be seen that the increase in the number of ports of the wavelength selective switch can increase the dispatching capability of the optical cross-connect 30 for optical signals.

[0082] For example, Figure 4 A schematic diagram of the structure of a wavelength selective switch 40 is provided for an embodiment of the present application, wherein Figure 4 In the wavelength selective switch 40 shown, the z-axis direction is the transmission direction of the optical signal in the wavelength selective switch 40, the y-axis direction is the port arrangement direction of the wavelength selective switch 40, and the x-axis direction is the dispersion direction of the wavelength selective switch 40. The plane formed by the y-axis direction and the z-axis direction is the port plane of the wavelength selective switch 40. Figure 4 (a) is specifically a schematic diagram of a port plane of the wavelength selective switch 40; the plane formed by the x-axis direction and the z-axis direction is the dispersion plane of the wavelength selective switch 40, Figure 4 (b) is specifically a schematic diagram of the dispersion plane of the wavelength selective switch 40.

[0083] The wavelength selective switch 40 includes a port array 41 and an optical modulator 45. A multi-plane light conversion (MPLC) 42, a wavelength combiner / demultiplexer 43, a lens 46 and a lens 44 are arranged on the optical path between the port array 41 and the optical modulator 45. The wavelength combiner / demultiplexer 43 is also called a dispersion element. The splitting direction of the wavelength combiner / demultiplexer 43 is parallel to the x-axis direction. The lens plane of the lens 46 is parallel to the port plane of the wavelength selective switch 40. The lens plane of the lens 44 is parallel to the dispersion plane of the wavelength selective switch 40. Exemplarily, in the wavelength selective switch 40, the wavelength combiner / demultiplexer 42 and the lens 46 are mounted together. The port array 41 includes a common port com, a branch port f1, a branch port f2, a branch port f3 and a branch port f4, and each port in the port array 41 is arranged along the y-axis direction. Exemplarily, the common port com is connected to the input optical fiber of the wavelength selective switch 40, and each branch port is connected to an output optical fiber of the wavelength selective switch 40.

[0084] Among them, an optical signal of any wavelength among the multiplexed optical signals input from the common port com to the wavelength selective switch 40 is output through the branch port f1 , the branch port f2 , the branch port f3 , or the branch port f4 .

[0085] In one example, the combined optical signal input from the common port com to the wavelength selective switch 40 includes an optical signal S1 with a wavelength of λ1, an optical signal S2 with a wavelength of λ2, an optical signal S3 with a wavelength of λ3, and an optical signal S4 with a wavelength of λ4. The functions of the various components in the wavelength selective switch 40 are described by taking the example that the optical signal S1 is output through the branch port f1, the optical signal S2 is output through the branch port f2, the optical signal S3 is output through the branch port f3, and the optical signal S4 is output through the branch port f4.

[0086] Specifically, refer to Figure 4 As shown, when the combined optical signal input from the common port com to the wavelength selection switch 40 is transmitted to the optical modulator 45, in the dispersion direction, the wavelength combiner / demultiplexer 43 is used to demultiplex the combined optical signal to generate an optical signal S1 with a wavelength of λ1, an optical signal S2 with a wavelength of λ2, an optical signal S3 with a wavelength of λ3 and an optical signal S4 with a wavelength of λ4, wherein the dispersion angles of the optical signal S1, the optical signal S2, the optical signal S3 and the optical signal S4 are all different, wherein the dispersion angle is the angle between the direction in which the optical signal is emitted from the wavelength combiner / demultiplexer 43 and the z-axis direction in the dispersion plane; the lens 44 is used to collimate the optical signal S1, the optical signal S2, the optical signal S3 and the optical signal S4 in the x-axis direction and then transmit them to the optical modulator 45.

[0087] In the port direction, MPLC42 is used to shape the combined optical signal. Figure 5 As shown, Figure 5 (a) shows the light field distribution of the combined optical signal transmitted to MPLC42 and the light field distribution of the combined optical signal output by MPLC42, wherein the light field distribution of the combined optical signal transmitted to MPLC42 is Gaussian distribution, and after being shaped by MPLC42, the light field distribution of the combined optical signal output by MPLC42 is sinc distribution. Lens 46 is used to focus and Fourier transform the optical signal S1, optical signal S2, optical signal S3 and optical signal S4, focusing so that each optical signal is transmitted to a predetermined position in the y-axis direction of the optical modulator 45, and Fourier transforming so that the light field distribution of each optical signal transmitted to the optical modulator 45 is rectangular distribution, refer to Figure 5 As shown in (b), the MPLC 42 and the lens 46 change the light field distribution of the optical signal S1, the optical signal S2, the optical signal S3 and the optical signal S4 from a Gaussian distribution to a rectangular distribution.

[0088] Reference Figure 6 As shown, the size of the light spot of the light signal S1 with Gaussian light field distribution transmitted to the light modulator 45 in the y-axis direction is L1, and the size of the light spot of the light signal S1 with rectangular light field distribution transmitted to the light modulator 45 in the y-axis direction is L2, L2<L1.

[0089] The optical modulator 45 is used to perform angular deflection on the optical signal S1, the optical signal S2, the optical signal S3 and the optical signal S4, specifically, to change the angles at which the optical signals S1, the optical signal S2, the optical signal S3 and the optical signal S4 are emitted from the optical modulator 45, so that the optical signal S1 is transmitted to the branch port f1, the optical signal S2 is transmitted to the branch port f2, the optical signal S3 is transmitted to the branch port f3, and the optical signal S4 is transmitted to the branch port f4.

[0090] In the process of transmitting any optical signal to the branch port, in the dispersion direction, the lens 44 focuses the optical signal S1, the optical signal S2, the optical signal S3 and the optical signal S4. In the port direction, the lens 46 is used to collimate and Fourier transform the optical signal S1, the optical signal S2, the optical signal S3 and the optical signal S4. The collimation allows each optical signal to be transmitted to the location of the corresponding branch port, and the Fourier transform allows the light field distribution of each optical signal transmitted to the MPLC42 to change from a rectangular distribution to a Sinc distribution; the MPLC42 is used to shape the optical signal S1, the optical signal S2, the optical signal S3 and the optical signal S4, and the light field distribution of any optical signal transmitted to the MPLC42 is a sinc distribution. After being shaped by the MPLC42, the light field distribution of any optical signal output by the MPLC42 is a Gaussian distribution.

[0091] exist Figure 4 In the wavelength selective switch 40 shown, when the optical signals S1, S2, S3 and S4 are compressed by MPLC 42 and transmitted to the optical modulator 45, the size of the light spot in the y-axis direction is reduced, so that the optical modulator 45 can arrange more optical signals along the y-axis direction. However, for the 1×N wavelength selective switch, the size of the compressed optical signal in the y-axis direction when transmitting to the optical modulator 45 cannot increase the number of ports of the wavelength selective switch. In addition, the size of the optical signal in the y-axis direction is reduced when the optical signal is transmitted to the optical modulator 45, which will increase the diffraction angle of the optical signal, make the optical signal more divergent, and increase the crosstalk. In order to reduce the crosstalk, it is necessary to increase the deflection angle of the adjacent branch ports, which will reduce the number of ports of the wavelength selective switch 40. Among them, "1" in the 1×N wavelength selective switch represents the number of common ports of the wavelength selective switch, and "N" represents the number of branch ports of the wavelength selective switch.

[0092] To this end, some embodiments of the present application provide a wavelength selective switch, which has a large number of ports and can be arranged at Figure 2 In the optical add / drop multiplexer 20 shown in FIG. Figure 3 The optical cross-connect 30 is shown.

[0093] For example, Figure 7 The schematic diagram of the structure of the wavelength selection switch 50 provided in the embodiment of the present application is shown in FIG. Figure 7 As shown, the wavelength selective switch 50 includes a wavelength multiplexer / demultiplexer 51, an optical modulator 52 (also referred to as a first optical modulator) and a mode conversion unit 53. Figure 7 The z-axis direction represents the transmission direction of the optical signal in the wavelength selective switch 50 , and the wavelength multiplexer / demultiplexer 51 and the optical modulator 52 are arranged along the z-axis direction. Figure 7 The x-axis direction is used to represent the dispersion direction of the wavelength selective switch 50, and the wavelength multiplexer / demultiplexer 51 in the wavelength selective switch 50 disperses the optical signals of different wavelengths along the x-axis direction; Figure 7 In the figure, the y-axis direction is used to represent the port direction of the wavelength selective switch 50, the y-axis direction is perpendicular to the x-axis direction, and the y-axis direction is perpendicular to the z-axis direction, wherein the common ports and / or branch ports in the wavelength selective switch 50 may be arranged along the y-axis direction, or the common ports and / or branch ports in the wavelength selective switch 50 may be arranged in an array in a plane formed by the x-axis direction and the y-axis direction, and each column of ports is arranged along the y-axis direction. The plane formed by the y-axis direction and the z-axis direction is the port plane of the wavelength selective switch 50, Figure 7 (a) is specifically a schematic diagram of a port plane of the wavelength selective switch 50; the plane formed by the x-axis direction and the z-axis direction is the dispersion plane of the wavelength selective switch 50, Figure 7 (b) is specifically a schematic diagram of the dispersion plane of the wavelength selective switch 50.

[0094] The mode conversion unit 53 in the wavelength selective switch 50 is coupled to a plurality of branch ports of the wavelength selective switch 50. For example, Figure 7 As shown, the wavelength selective switch 50 includes a plurality of branch ports. Figure 7 The multiple branch ports specifically include branch port f1 and branch port f2, and the mode conversion unit 53 is coupled to the branch port f1 and the branch port f2. In other embodiments, the multiple branch ports may also include more than two branch ports, and the embodiments of the present application do not limit the number of branch ports included in the multiple branch ports.

[0095] Reference Figure 7 As shown in (b), the wavelength combiner / demultiplexer 51 is used to receive the optical signal S1 input from the common port com of the wavelength selection switch 50, output m single-wavelength optical signals, m is a positive integer greater than or equal to 1, and transmit the m single-wavelength optical signals to the optical modulator 52; the optical modulator 52 is used to perform a first angle deflection and mode conversion on the m single-wavelength optical signals to generate m modulated optical signals; the mode conversion unit 53 is used to receive at least one modulated optical signal among the m modulated optical signals, and transmit the modulated optical signal to one of the multiple branch ports according to the mode of each modulated optical signal in the at least one modulated optical signal.

[0096] Exemplarily, when m is 1, the m single-wavelength optical signals include a single-wavelength optical signal S11. The optical modulator 52 is used to perform a first angle deflection and mode conversion on the single-wavelength optical signal S11 to generate a modulated optical signal S11'. In particular, since the optical modulator 52 performs a first angle deflection on the single-wavelength optical signal S11, the modulated optical signal S11' has a deflection angle when it is emitted from the optical modulator 52; and since the optical modulator 52 performs mode conversion on the single-wavelength optical signal S11, the modulated optical signal S11' has a mode when it is emitted from the optical modulator 52. In particular, the magnitude of the deflection angle of the modulated optical signal S11' determines whether the modulated optical signal S11' can be transmitted to the mode conversion unit 53, and the mode of the modulated optical signal S11' determines to which branch port of the multiple branch ports the modulated optical signal S11' is transmitted. Exemplarily, when the deflection angle of the modulated light signal S11 ′ is the first angle, the modulated light signal S11 ′ is transmitted to the mode conversion unit 53 after being emitted from the optical modulator 52 .

[0097] The modulated optical signal S11' is transmitted to the mode conversion unit 53 after being emitted from the optical modulator 52. When the mode of the modulated optical signal S11' is the first mode, the mode conversion unit 53 transmits the modulated optical signal S11' to the branch port f1; when the mode of the modulated optical signal S11' is the second mode, the mode conversion unit 53 transmits the modulated optical signal S11' to the branch port f2. The first mode is different from the second mode.

[0098] In some embodiments, the first mode is the fundamental mode, which is denoted as TEM. 00 or HG 00 , refer to Figure 8 As shown, there is only one light spot in the intensity cross-section of the fundamental mode; the second mode mentioned above is a high-order mode, specifically TEM 01 or HG 01 This higher-order mode, refer to Fig. 9 As shown, TEM 01 or HG 01 In the intensity cross-sectional diagram of FIG. 1 , there are two light spots, and the two light spots are arranged along the y-axis direction. In some other embodiments, the second mode may also be TEM 10 or HG 10 This higher-order mode, refer to Fig.10 As shown, TEM 10 or HG 10 In the intensity cross-sectional diagram of TEM, there are two light spots, which are arranged along the x-axis. 10 With TEM 01 For example, the first mode and the second mode may also be two different high-order modes, which is not limited in the embodiments of the present application.

[0099] exist Figure 7In the wavelength selective switch 50 shown, the wavelength multiplexer / demultiplexer 51 receives the optical signal S1 input from the common port com of the wavelength selective switch 50, and outputs m single-wavelength optical signals, where m is a positive integer greater than or equal to 1, and the m single-wavelength optical signals include the single-wavelength optical signal S11; the optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S11 to generate a modulated optical signal S11', wherein the modulated optical signal S11' has a deflection angle and a mode, the deflection angle of the modulated optical signal S11' determines whether the modulated optical signal S11' can be transmitted to the mode conversion unit 53, and the mode of the modulated optical signal S11' determines to which branch port of the multiple branch ports the modulated optical signal S11' is transmitted. For example, when the modulated optical signal S11' can be transmitted to the mode conversion unit 53, specifically, the mode conversion unit 53 receives the modulated optical signal S11', and the mode conversion unit 53 transmits the modulated optical signal S11' to one of the multiple branch ports according to the mode of the modulated optical signal S11'. Therefore, when the deflection angle of the optical modulator 52 cannot be increased, the single-wavelength optical signal is mode-converted by the optical modulator 52, and the mode conversion unit 53 transmits the modulated optical signal S11' to one of the multiple branch ports according to the mode of the modulated optical signal S11', thereby further increasing the number of ports of the wavelength selection switch 50.

[0100] For example, Figure 7 The optical modulator 52 shown can perform a first angle deflection and mode conversion on the single-wavelength optical signal S11. The optical modulator 52 can be, for example, liquid crystal on silicon (LCoS). By applying a voltage to the LCoS so that the phase change direction of the LCoS meets the requirement for performing a first angle deflection on the single-wavelength optical signal S11, the modulated optical signal S11' emitted from the LCoS can have a deflection angle. In addition, when applying a voltage to the LCoS, the phase distribution in the area of ​​the LCoS covered by the single-wavelength optical signal S11 can also be adjusted so that the modulated optical signal S11' emitted from the LCoS has a mode. For example, refer to Fig.11 As shown in (a), when the phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11 is all phase 0, the mode of the modulated optical signal S11' emitted from the LCoS is specifically the fundamental mode; Fig.11 As shown in (b), when the phase distribution in the region of LCoS covered by the single-wavelength optical signal S11 happens to be one part with phase 0 and the other part with phase π along the y-axis direction, the mode of the modulated optical signal S11' emitted from the LCoS is specifically TEM 01 or HG 01 This higher order mode.

[0101] In other embodiments, a wavefront matching method may be used to calculate the phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11, wherein the wavefront matching method specifically updates the phase distribution in the region A1 according to the optical field distribution of the input single-wavelength optical signal S11 and the optical field distribution of the output modulated optical signal S11', so as to continuously improve the mode conversion efficiency of the LCoS. Fig.12 As shown, Fig.12 : is a relationship diagram between the number of iterations and the mode conversion efficiency of LCoS, wherein when the number of iterations is 1, the mode conversion efficiency of LCoS is approximately equal to 0.86, and when the number of iterations is greater than 1, the mode conversion efficiency of LCoS is approximately equal to 0.89. Therefore, when the wavefront matching method is used to calculate the phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11, the number of iterations selected is usually greater than 1.

[0102] Exemplarily, the mode conversion unit 53 is used to receive at least one modulated optical signal among the m modulated optical signals, and transmit the modulated optical signal to one of the multiple branch ports according to the mode of each modulated optical signal among the at least one modulated optical signal. The mode conversion unit 53 may be Fig.13 or Fig.19 The mode conversion unit 53 is shown.

[0103] Reference Fig.13 As shown, the mode conversion unit 53 includes a coupling region 100 (also referred to as a first coupling region) and a plurality of optical fibers 501 (also referred to as first optical fibers), a first end of an optical fiber 501 (such as Fig.13 The a end shown in FIG. 1 is connected to an output end of the coupling region 100, and a second end of an optical fiber 501 (such as Fig.13 The b end shown in the figure is connected to one of the branch ports among the multiple branch ports; the optical fiber 501 is a single mode fiber (SMF); the coupling region 100 is used to transmit the modulated optical signal to one of the multiple optical fibers 501 according to the mode of the modulated optical signal.

[0104] For example, due to Figure 7 The mode conversion unit 53 is shown coupled to the branch port f1 and the branch port f2. Fig.13Two optical fibers 501 are shown, namely optical fiber 501-1 and optical fiber 501-2, wherein the a end of optical fiber 501-1 is connected to the first output end of the coupling region 100, and the b end of optical fiber 501-1 is connected to the branch port f1; the a end of optical fiber 501-2 is connected to the second output end of the coupling region 100, and the b end of optical fiber 501-2 is connected to the branch port f2. In some embodiments, when the multiple branch ports coupled to the mode conversion unit 53 include X branch ports, X is a positive integer greater than or equal to 2, then the mode conversion unit 53 needs to include X optical fibers 501, and the coupling region 100 includes X output ends.

[0105] Exemplarily, the coupling region 100 may be a mode demultiplexer in the form of an optical waveguide, or the coupling region 100 may be a mode demultiplexer in the form of an optical fiber coupler. The coupling region 100 transmits the modulated optical signal to one of the multiple optical fibers 501 according to the mode of the received modulated optical signal, and the mode of the modulated optical signal output by the coupling region 100 is the fundamental mode. The structure of the existing mode demultiplexer can be referred to for the mode demultiplexer in the form of an optical waveguide and the mode demultiplexer in the form of an optical fiber coupler, and will not be described in detail here.

[0106] Exemplarily, when the modulated optical signal S11 ′ is transmitted to the mode conversion unit 53 , specifically, the coupling region 100 of the mode conversion unit 53 receives the modulated optical signal S11 ′. The specific functions of the coupling region 100 are as follows: when the mode of the received modulated optical signal S11' is the first mode, the modulated optical signal S11' of the first mode is transmitted to the a-end of the optical fiber 501-1 through the first output port of the coupling region 100, and the mode of the modulated optical signal S11' of the first mode is converted into the fundamental mode, and the optical fiber 501-1 transmits the modulated optical signal S11' of the fundamental mode from the b-end of the optical fiber 501-1 to the branch port f1; when the mode of the received modulated optical signal S11' is the second mode, the modulated optical signal S11' of the second mode is transmitted to the a-end of the optical fiber 501-2 through the second output port of the coupling region 100, and the mode of the modulated optical signal S11' of the second mode is converted into the fundamental mode, and the optical fiber 501-2 transmits the modulated optical signal S11' of the fundamental mode from the b-end of the optical fiber 501-2 to the branch port f2.

[0107] In other embodiments, referring to Fig.13As shown, the mode conversion unit 53 further includes an optical fiber 502 (also referred to as a second optical fiber), which is connected to the input end of the coupling region 100; the optical fiber 502 is a few-mode fiber. When the modulated optical signal S11' is transmitted to the mode conversion unit 53, since the mode of the modulated optical signal S11' can be the first mode or the second mode, the optical fiber 502 needs to support the transmission of the modulated optical signal S11' of the first mode, and also needs to support the transmission of the modulated optical signal S11' of the second mode, and the optical fiber 502 is a few-mode fiber (FMF). The optical fiber 502 is used to transmit the modulated optical signal S11' received by the mode conversion unit 53 to the coupling region 100, so that the modulated optical signal S11' of different modes is transmitted to different optical fibers 501 through the coupling region 100, and then transmitted from different optical fibers 501 to different branch ports among the multiple branch ports.

[0108] Exemplarily, when the mode conversion unit 53 further includes an optical fiber 502 and a plurality of optical fibers 501 , the mode conversion unit 53 may be, for example, a mode demultiplexer based on a tapered form (also called a photon lantern).

[0109] In some examples, Fig.13 The mode field diameter (MFD) of the optical fiber 501 shown is 13.8 μm, and the mode field diameter of the fundamental mode of each optical fiber 502 is 18 microns; and a collimating lens with a focal length of 11.3 millimeters (mm) is provided on the light-outgoing side of the common port com, and a collimating lens with a focal length of 11.3 mm is provided on the light-incoming side of the optical fiber 502; the distance between the common port com of the wavelength selection switch 50 and the optical modulator 52 along the z-axis direction is 15 mm, and the spot radius of the optical signal S1 output by the collimating lens provided on the light-outgoing side of the common port com is 200 μm. When the optical modulator 52 is specifically LCoS, the phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11 is specifically as follows: Fig.14 As shown, Fig.14 The phase distribution shown specifically includes two parts along the y-axis direction: Fig.14 The phase distribution shown is calculated by wavefront matching method. At this time, the mode of the modulated optical signal S11' output by the optical modulator 51 is specifically TEM 01 or HG 01 This high-order mode Fig.13 The light intensity cross-sectional diagram of the modulated light signal S11′ after being collimated by the collimating lens arranged at the light incident side of the optical fiber 502 of the mode conversion unit 53 is shown in FIG. Fig.15 As shown, the modulated optical signal S11' has two light spots, and the two light spots are arranged along the y-axis direction. Fig.13The mode conversion unit 53 shown transmits the modulated optical signal S11' to the branch port f1 through the optical fiber 501-1. Through simulation, it can be seen that the modulated optical signal S11' output from the branch port f1 has an average attenuation of 0.66dB compared with the optical signal S1, and the coupling efficiency of the modulated optical signal S11' coupled into the optical fiber 502 is about 87%.

[0110] In other examples, Fig.13 The mode field diameter of the optical fiber 501 shown is 13.8 μm, and the mode field diameter of the fundamental mode of the optical fiber 502 can be 17.8 μm; a collimating lens with a focal length of 11.3 mm is arranged on the light-outgoing side of the common port com, and a collimating lens with a focal length of 11.3 mm is arranged on the light-incoming side of the optical fiber 502; and the distance between the common port com of the wavelength selective switch 50 and the optical modulator 52 along the z-axis direction is 18 mm, and the spot radius of the optical signal S1 output by the collimating lens arranged on the light-outgoing side of the common port com is 120 μm. When the optical modulator 52 is specifically LCoS, the phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11 is calculated by the wavefront matching method.

[0111] For example, the phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11 is as follows: Fig.16 As shown in (a), the phase distribution specifically includes two parts along the y-axis direction, and the mode of the output modulated optical signal S11' is specifically TEM 01 or HG 01 The light intensity cross section of the modulated optical signal S11' in an ideal state is as follows: Fig.17 As shown in (a), the actual Fig.13 The light intensity cross-sectional diagram of the modulated light signal S11′ after being collimated by the collimating lens arranged at the light incident side of the optical fiber 502 of the mode conversion unit 53 is shown in FIG. Fig.18 As shown in (a), the modulated optical signal S11' has two light spots, and the two light spots are arranged along the y-axis direction. Fig.16 The phase distribution shown in (a) can also set the deflection angle of the modulated optical signal S11' to a third angle, thereby making Fig.18 The position of the center of the light intensity cross-sectional diagram of the modulated optical signal S11 ′ shown in (a) in the x-axis direction and the y-axis direction is (x1, y1).

[0112] For example, the phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11 is as follows: Fig.16 As shown in (b), the phase distribution specifically includes three parts along the y-axis direction, and the mode of the output modulated optical signal S11' is specifically TEM 02 or HG 02 The light intensity cross section of the modulated optical signal S11' in an ideal state is as follows: Fig.17 As shown in (b), the actual Fig.13 The light intensity cross-sectional diagram of the modulated light signal S11′ after being collimated by the collimating lens arranged at the light incident side of the optical fiber 502 of the mode conversion unit 53 is shown in FIG. Fig.18 As shown in (b), the modulated optical signal S11' has three light spots, and the three light spots are arranged along the y-axis direction. Fig.16 The phase distribution shown in (b) can also set the deflection angle of the modulated optical signal S11' to a fourth angle, thereby making Fig.18 The position of the center of the light intensity cross-sectional diagram of the modulated optical signal S11' shown in (b) in the x-axis direction and the y-axis direction is (x2, y2).

[0113] For example, the phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11 is as follows: Fig.16 As shown in (c), the phase distribution specifically includes four parts along the y-axis direction, and the mode of the output modulated optical signal S11' is specifically TEM 03 or HG 03 The light intensity cross section of the modulated optical signal S11' in an ideal state is as follows: Fig.17 As shown in (c) in the figure, the actual Fig.13 The light intensity cross-sectional diagram of the modulated light signal S11′ after being collimated by the collimating lens arranged at the light incident side of the optical fiber 502 of the mode conversion unit 53 is shown in FIG. Fig.18 As shown in (c), the modulated optical signal S11' has four light spots, and the four light spots are arranged along the y-axis direction. In addition, Fig.16 The phase distribution shown in (c) can also set the deflection angle of the modulated optical signal S11' to a fifth angle, thereby making Fig.18 The center of the intensity cross-sectional diagram of the modulated optical signal S11' shown in (a) is located at (x3, y3) in the x-axis direction and the y-axis direction. Fig.18 As shown, since the third angle, the fourth angle and the fifth angle are not equal to each other, Fig.18 The position of the center of the intensity cross-sectional diagram of the modulated optical signal S11' shown in (a) is Fig.18 The position of the center of the light intensity cross-sectional diagram of the modulated light signal S11' shown in (b) is Fig.18 The positions of the centers of the light intensity cross-sectional diagrams of the modulated optical signal S11' shown in (c) are different.

[0114] For example, when simulating the modulated optical signal S11' output by the LCoS, it can be seen that when the phase distribution of the region A1 is specifically Fig.16 When the phase distribution is shown in (a), the output mode is HG 01 The output loss of the modulated optical signal S11' is 0.86 dB; when the phase distribution of region A1 is specifically Fig.16 When the phase distribution is shown in (b), the output mode is HG 02 The output loss of the modulated optical signal S11' is 1.08 dB; when the phase distribution of region A1 is specifically Fig.16 When the phase distribution is shown in (c), the output mode is HG 03 The output loss of the modulated optical signal S11' is 1.55 dB; it can be seen that when LCoS performs mode conversion on the single-wavelength optical signal S11 to generate the modulated optical signal S11', the modes of the modulated optical signal S11' are different, and the corresponding output losses are also different.

[0115] In one example, the mode of the LCoS output is HG 01 The output loss of the modulated optical signal S11' is the same as that of the LCoS output mode HG. 02 When the output loss of the modulated optical signal S11' is different, the phase distribution of LCoS can be adjusted so that the transmission losses of modulated optical signals of different modes transmitted to different branch ports are the same. For example, the output mode of LCoS is HG 01 The output loss of the modulated optical signal S11' is the first value, and the mode of the LCoS output is HG 02 The output loss of the modulated optical signal S11' of the second mode is a second value, and the first value is less than the second value. Then the phase distribution of LCoS can be adjusted so that the mode of LCoS output is HG 01 The output loss of the modulated optical signal S11 ′ is increased to a second value, thereby making the transmission losses of modulated optical signals of different modes transmitted to different branch ports the same.

[0116] In another example, the mode of the LCoS output is HG 01 The output loss of the modulated optical signal S11' is the same as that of the LCoS output mode HG. 02 When the output loss of the modulated optical signal S11' is different, it can also be adjusted Fig.13 The mode conversion unit 53 shown in the figure transmits the modulated optical signals of different modes to different branch ports, so that the loss of the modulated optical signals transmitted by the mode conversion unit 53 to each branch port is approximately equal. 01 The output loss of the modulated optical signal S11' is the first value, and the mode of the LCoS output is HG 02 The output loss of the modulated optical signal S11' in the second mode is a second value, the first value is less than the second value, and the difference between the first value and the second value is Δ1, then it can be set Fig.13 The mode conversion unit 53 shown in FIG. 01The transmission loss of the modulated optical signal S11' transmitted to the branch port f1 is a third value, and the mode conversion unit 53 changes the mode to HG 02 The transmission loss of the modulated optical signal S11 ′ transmitted to the branch port f2 is a fourth value, the third value is greater than the fourth value, and the difference between the third value and the fourth value is approximately equal to Δ1.

[0117] In other embodiments, referring to Fig.19 As shown, the mode conversion unit 53 includes a plurality of phase plates 200 (also referred to as first phase plates), and the phase masks of the plurality of phase plates 200 are arranged on the transmission path of the modulated optical signal received by the mode conversion unit 53; the phase masks of the plurality of phase plates 200 are used to transmit the modulated optical signal to the position of one of the plurality of branch ports according to the mode of the modulated optical signal, and the mode of the modulated optical signal finally output by the phase masks of the plurality of phase plates 200 is the fundamental mode.

[0118] For example, due to Figure 7 The mode conversion unit 53 is shown coupled to the branch port f1 and the branch port f2. Fig.19 The branch ports shown are branch port f1 and branch port f2. Fig.19 The multiple phase plates 200 shown are specifically four phase plates 200, namely phase plate 200-1, phase plate 200-2, phase plate 200-3 and phase plate 200-4. Among them, the phase mask P1 of the phase plate 200-1, the phase mask P2 of the phase plate 200-2, the phase mask P3 of the phase plate 200-3 and the phase mask P4 of the phase plate 200-4 are arranged on the transmission path of the modulated optical signal received by the mode conversion unit 53.

[0119] The phase distribution on the phase mask P1 of the phase plate 200-1, the phase distribution on the phase mask P2 of the phase plate 200-2, the phase distribution on the phase mask P3 of the phase plate 200-2, and the phase distribution on the phase mask P4 of the phase plate 200-4 are specifically calculated using the wavefront matching method. And the phase distribution on the phase mask of any phase plate 200 is consistent with the spacing between the phase plate and the adjacent phase plate along the z-axis direction ( Fig.19 The spacing L1, spacing L2, spacing L3 shown in the figure are related to the unit size of the phase distribution (also called pixel size), and the spot size of the modulated light signal transmitted to the phase plate 200.

[0120] in, Fig.19The multiple phase plates 200 shown may also be specifically referred to as MPLCs. In one example, each phase plate 200 may be a phase plate made by photolithography technology, and the unit size of the phase distribution on the phase mask of the phase plate 200 is micrometer-level, for example, 1 micrometer (μm) to 20μm. In another example, each phase plate 200 may be a phase plate made by metasurface technology, and the unit size of the phase distribution on the phase mask of the phase plate 200 is nanometer-level, for example, 1 nanometer (nm) to 500nm.

[0121] Exemplarily, when the modulated optical signal S11' is transmitted to the mode conversion unit 53, Fig.19 The phase mask of each phase plate 200 shown can be set as follows: when the mode of the received modulated optical signal S11' is the first mode, the modulated optical signal S11' will be transmitted to the position where the branch port f1 is located through the phase mask P1 of the phase plate 200-1, the phase mask P2 of the phase plate 200-2, the phase mask P3 of the phase plate 200-3, and the phase mask P4 of the phase plate 200-4, and the mode of the modulated optical signal S11' transmitted to the branch port f1 is the fundamental mode; when the mode of the received modulated optical signal S11' is the second mode, the modulated optical signal S11' will be transmitted to the position where the branch port f2 is located through the phase mask P1 of the phase plate 200-1, the phase mask P2 of the phase plate 200-2, the phase mask P3 of the phase plate 200-3, and the phase mask P4 of the phase plate 200-4, and the mode of the modulated optical signal S11' transmitted to the branch port f2 is the fundamental mode.

[0122] For example, when the optical modulator 52 is LCoS, the phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11 is as follows: Fig. 20 As shown in (a), the output modulated optical signal S11' passes through Fig.19 The light field distribution after the mode conversion unit 53 is shown as Fig. 20 As shown in (b), the position (x4, y4) corresponding to the optical field distribution in the x-axis direction and the y-axis direction coincides with the position of the branch port f1 in the x-axis direction and the y-axis direction. The phase distribution in the region A1 of the LCoS covered by the single-wavelength optical signal S11 is shown in Fig. 20 As shown in (c) in FIG. 1 , the output modulated optical signal S11′ passes through Fig.19 The light field distribution after the mode conversion unit 53 is shown as Fig. 20 As shown in (d), the position (x5, y5) of the light field distribution in the x-axis direction and the y-axis direction coincides with the position of the branch port f2 in the x-axis direction and the y-axis direction.

[0123] For example, Figure 7As shown, the wavelength selective switch 50 further includes a lens 54 (also referred to as a second lens) disposed between the wavelength multiplexer 51 and the optical modulator 52. The lens plane of the lens 54 is parallel to the dispersion plane. The lens 54 is used to collimate the m single-wavelength optical signals in the x-axis direction. The dispersion angles of the m single-wavelength optical signals output by the wavelength multiplexer 51 are different. The lens 54 collimates the m single-wavelength optical signals in the x-axis direction, so that the size of the optical modulator 52 in the x-axis direction does not need to be too large to receive the m single-wavelength optical signals.

[0124] In some embodiments, the lens 54 may be replaced by at least one fifth phase plate. For example, the phase mask of each of the at least one fifth phase plate is set on the transmission path of the m single-wavelength optical signals. The phase mask of each of the at least one fifth phase plate is calculated using a wavefront matching method, so that the at least one fifth phase plate is used to collimate the m single-wavelength optical signals in the x-axis direction.

[0125] For example, Figure 7 As shown, the wavelength selective switch 50 further includes a lens 55 (also referred to as a third lens) disposed between the optical modulator 52 and the mode conversion unit 53, the lens plane of the lens 55 being parallel to the port plane, and the lens 55 being used to collimate the m modulated optical signals outputted by the optical modulator 52 in the y-axis direction. Exemplarily, the modulated optical signal has a deflection angle after being emitted from the optical modulator 52, and the lens 55 is arranged to collimate the m modulated optical signals in the y-axis direction, so that the size of the mode conversion unit 53 in the y-axis direction does not need to be too large to receive the m modulated optical signals.

[0126] In some embodiments, the lens 55 can also be replaced by at least one sixth phase plate. For example, the phase mask of each of the at least one sixth phase plate is set on the transmission path of the m modulated optical signals; the phase mask of each of the at least one sixth phase plate is calculated using a wavefront matching method, so that the at least one sixth phase plate is used to collimate the m modulated optical signals in the y-axis direction.

[0127] For example, in Figure 7 , the focal length of lens 54 is f2, the focal length of lens 55 is f1, the light modulator 52 is disposed at the right focal plane of lens 54, and the light modulator 52 is disposed at the right focal plane of lens 55.

[0128] For example, refer to Figure 7As shown, the wavelength selective switch 50 further includes a lens 56 (also referred to as a fourth lens) disposed between the common port com of the wavelength selective switch 50 and the wavelength multiplexing / demultiplexing device 51. The lens 56 is used to collimate the optical signal input from the common port com. Exemplarily, after the lens 56 collimates the optical signal S1 input from the common port com in the x-axis direction and the y-axis direction, it can ensure that the optical signal S1 is transmitted to the predetermined position of the wavelength multiplexing / demultiplexing device 51.

[0129] In some embodiments, the lens 56 can also be replaced by at least one seventh phase plate. For example, the phase mask of each of the at least one seventh phase plate is set on the transmission path of the optical signal S1 input at the common port com; the phase mask of each of the at least one seventh phase plate is calculated by the wavefront matching method, so that the at least one seventh phase plate is used to collimate the optical signal S1 in the x-axis direction and the y-axis direction.

[0130] For example, refer to Figure 7 As shown, when m is greater than or equal to 2, for example, m may be equal to 2, then the m single-wavelength optical signals include a single-wavelength optical signal S11 and a single-wavelength optical signal S12. The optical modulator 52 is used to perform a first angle deflection and mode conversion on the single-wavelength optical signal S11 and the single-wavelength optical signal S12 to generate a modulated optical signal S11' and a modulated optical signal S12'. The modulated optical signal S11' has a deflection angle and a mode, and the modulated optical signal S12' has a deflection angle and a mode. Exemplarily, the deflection angle of the modulated optical signal S11' can enable the modulated optical signal S11' to be transmitted to the mode conversion unit 53, and the deflection angle of the modulated optical signal S12' can enable the modulated optical signal S12' to be transmitted to the mode conversion unit 53, that is, the mode conversion unit 53 receives the modulated optical signal S11' and the modulated optical signal S12'. The mode conversion unit 53 is used to transmit multiple modulated optical signals with different modes to different branch ports among the multiple branch ports, and to transmit multiple modulated optical signals with the same mode to the same branch port among the multiple branch ports. Figure 7 In the wavelength selective switch shown, the plurality of branch ports specifically include a branch port f1 and a branch port f2.

[0131] For example, when the mode conversion unit 53 receives the modulated optical signal S11' and the modulated optical signal S12', when the mode of the modulated optical signal S11' and the mode of the modulated optical signal S12' are both the first mode, the mode conversion unit 53 transmits the modulated optical signal S11' and the modulated optical signal S12' to the branch port f1 among the multiple branch ports; when the mode of the modulated optical signal S11' and the mode of the modulated optical signal S12' are both the second mode, the mode conversion unit 53 transmits the modulated optical signal S11' and the modulated optical signal S12' to the branch port f2 among the multiple branch ports.

[0132] Exemplarily, when the mode conversion unit 53 receives the modulated optical signal S11' and the modulated optical signal S12', when the mode of the modulated optical signal S11' is the first mode and the mode of the modulated optical signal S12' is the second mode, the mode conversion unit 53 transmits the modulated optical signal S11' to the branch port f1 among the multiple branch ports, and the mode conversion unit 53 transmits the modulated optical signal S12' to the branch port f2 among the multiple branch ports. Alternatively, when the mode of the modulated optical signal S11' is the second mode and the mode of the modulated optical signal S12' is the first mode, the mode conversion unit 53 transmits the modulated optical signal S11' to the branch port f2 among the multiple branch ports, and the mode conversion unit 53 transmits the modulated optical signal S12' to the branch port f1 among the multiple branch ports.

[0133] In some examples, when the modulated optical signal is transmitted from the optical modulator 52 to the mode conversion unit 53, the modulated optical signal first passes through the wavelength multiplexing / demultiplexing device 51 and then is transmitted to the mode conversion unit 53. When the deflection angle of the modulated optical signal S11' can make the modulated optical signal S11' transmitted to the mode conversion unit 53, and the deflection angle of the modulated optical signal S12' can make the modulated optical signal S12' transmitted to the mode conversion unit 53, the modulated optical signal S11' and the modulated optical signal S12' will pass through the same position of the wavelength multiplexing / demultiplexing device 51 and then be transmitted to the mode conversion unit 53, and the wavelength multiplexing / demultiplexing device 51 will combine the modulated optical signal S11' and the modulated optical signal S12' into a combined modulated optical signal, and the combined modulated optical signal includes the modulated optical signal S11' and the modulated optical signal S12'. Therefore, when the mode of the modulated optical signal S11' is the same as the mode of the modulated optical signal S12', the mode conversion unit 53 specifically transmits the combined modulated optical signal including the modulated optical signal S11' and the modulated optical signal S12' to the same branch port among the multiple branch ports. When the mode of the modulated optical signal S11' is different from the mode of the modulated optical signal S12', the mode conversion unit 53 specifically transmits the modulated optical signal S11' and the modulated optical signal S12' in the combined modulated optical signal to two different branch ports among the multiple branch ports.

[0134] Exemplarily, the mode conversion unit 53 receives the modulated optical signal S11' and the modulated optical signal S12', and the mode conversion unit 53 is Fig.19 In the mode conversion unit 53 shown, the phase mask P1 of the phase plate 200-1, the phase mask P2 of the phase plate 200-2, the phase mask P3 of the phase plate 200-3 and the phase mask P4 of the phase plate 200-4 are arranged on the transmission path of the modulated optical signal S11' and also on the transmission path of the modulated optical signal S12'.

[0135] In other embodiments, referring to Fig.21 As shown, compared to Figure 7 The wavelength selective switch 50 shown, Fig.21 The wavelength selection switch 50 shown also includes a mode conversion unit 59, which is arranged between the common port com and the wavelength combiner / demultiplexer 51; the mode conversion unit 59 is used to shape the received optical signal into a shaped optical signal, and transmit the shaped optical signal to the wavelength combiner / demultiplexer 51; wherein the size of the light spot of the shaped optical signal in the y-axis direction (also called the first direction) is larger than the size of the light spot of the shaped optical signal in the x-axis direction (also called the second direction); the wavelength combiner / demultiplexer 51 is specifically used to receive the shaped optical signal and output m single-wavelength optical signals.

[0136] For example, Fig.21 The optical signal input to the common port com of the wavelength selective switch 50 is an optical signal S1. The mode conversion unit 59 is arranged between the common port com and the wavelength multiplexing / demultiplexing filter 51. The optical signal received by the mode conversion unit 59 is specifically the optical signal S1. The mode conversion unit 59 shapes the optical signal S1 into a shaped optical signal S1'. Fig. 22 As shown, Fig. 22 (a) is a cross-sectional diagram of the light intensity of the optical signal S1 received by the common port of the wavelength selective switch 50, Fig. 22 As can be seen from (a) in the figure, the light spot of the optical signal S1 is specifically a circular light spot; Fig. 22 (b) is the intensity cross-sectional diagram of the shaped optical signal S1' output by the mode conversion unit 59, Fig. 20 As can be seen from (b) in FIG. 1 , the light spot of the shaped optical signal S1' is specifically an elliptical light spot, and the size of the light spot of the shaped optical signal S1' in the y-axis direction is w1, and the size of the light spot of the shaped optical signal S1' in the x-axis direction is w2, and w1 is larger than w2. The wavelength combiner / demultiplexer 51 is specifically used to receive the shaped optical signal S1' and output m single-wavelength optical signals. When the m single-wavelength optical signals are transmitted to the optical modulator 52, the size of the light spot of any single-wavelength optical signal in the y-axis direction is larger than that in the x-axis direction, and the size of the area of ​​the optical modulator 52 covered by any single-wavelength optical signal S11 along the y-axis direction will become larger, which makes it easier for the optical modulator 52 to perform the first angle deflection and mode conversion on the single-wavelength optical signal, and reduces the crosstalk between the modulated optical signals generated by the optical modulator 52.

[0137] Exemplarily, the mode conversion unit 59 may be used to reshape the received optical signal into a reshaped optical signal. The mode conversion unit 59 may be Fig.23 or Fig.24 The mode conversion unit shown.

[0138] Reference Fig.23As shown, the mode conversion unit 59 includes a coupling region 101 (also referred to as a second coupling region) and an optical fiber 503 (also referred to as a third optical fiber). The first end of the optical fiber 503 (as shown in FIG. Fig.23 The e end shown in FIG. 1 is connected to the common port com, and the second end of the optical fiber 503 (as shown in FIG. Fig.23 The f end shown is connected to the input end of the coupling region 101; the optical fiber 503 is a single-mode optical fiber; the coupling region 101 is used to shape the optical signal S1 received by the mode conversion unit 59 to form a shaped optical signal S1'.

[0139] Exemplarily, the coupling region 101 may be a mode field converter in the form of an optical waveguide, or the coupling region 101 may be a mode field converter in the form of an optical fiber coupler. The structure of the existing mode field converter can be referred to for the mode field converter in the form of an optical waveguide and the mode field converter in the form of an optical fiber coupler, and will not be described in detail here.

[0140] Exemplarily, when the optical signal S1 is transmitted to the mode conversion unit 59, the optical fiber 503 of the mode conversion unit 59 receives the optical signal S1, and transmits the optical signal S1 to the coupling region 101 of the mode conversion unit 59. The coupling region 101 is used to shape the optical signal S1 into a shaped optical signal S1', and the shaped optical signal S1' is transmitted to the wavelength combiner / demultiplexer 51 after being output from the mode conversion unit 59.

[0141] In other embodiments, referring to Fig.23 As shown, the mode conversion unit 59 further includes an optical fiber 504 (also referred to as a fourth optical fiber), and the optical fiber 504 is connected to the output end of the coupling region 101; the optical fiber 504 is a single-mode optical fiber.

[0142] In other embodiments, referring to Fig.24 As shown, the mode conversion unit 59 includes a plurality of phase plates 201 (also referred to as second phase plates), and the phase masks of the plurality of phase plates 201 are arranged on the transmission path of the optical signal S1 received by the mode conversion unit 59; the phase masks of the plurality of phase plates 201 shape the optical signal S1 received by the mode conversion unit 59 to form a shaped optical signal S1'.

[0143] For example, Fig.24 The multiple phase plates 201 shown are specifically three phase plates 201, namely phase plate 201-1, phase plate 201-2 and phase plate 201-3. Among them, the phase mask P5 of the phase plate 201-1, the phase mask P6 of the phase plate 201-2 and the phase mask P7 of the phase plate 201-3 are arranged on the transmission path of the optical signal S1.

[0144] The phase distribution on the phase mask P1 of the phase plate 201-1, the phase distribution on the phase mask P2 of the phase plate 201-2, and the phase distribution on the phase mask P3 of the phase plate 201-2 are specifically calculated using the wavefront matching method. And the phase distribution on the phase mask of any phase plate 201 is consistent with the spacing between the phase plate and the adjacent phase plate along the z-axis direction ( Fig.24 The spacing L4 and the spacing L5 shown are related to the unit size of the phase distribution (also called pixel size), and the spot size of the optical signal S1 transmitted to the phase plate 201.

[0145] in, Fig.24 The multiple phase plates 201 shown may also be specifically referred to as MPLC. In one example, each phase plate 201 may be a phase plate made by photolithography technology, and the unit size of the phase distribution on the phase mask of the phase plate 201 is micrometer level, for example, 1 μm to 20 μm. In another example, each phase plate 201 may be a phase plate made by metasurface technology, and the unit size of the phase distribution on the phase mask of the phase plate 201 is nanometer level, for example, 1 nm to 500 nm.

[0146] In some examples, reference Fig.25 As shown, the common port com is connected to the input optical fiber of the wavelength selective switch 50 , the input optical fiber is a single-mode optical fiber, and the mode field diameter of the input optical fiber is 13.8 μm. Fig.25 The wavelength selective switch 50 shown in the figure further includes a lens 56, which is disposed between the common port com and the mode conversion unit 59. The focal length of the lens 56 is 11.3 mm. The lens 56 specifically collimates the optical signal S1. The mode field diameter of the optical signal S1 output by the lens 56 is 400 μm. The distance between the common port com and the optical modulator 52 is 15 mm. The mode conversion unit 59 is specifically Fig.24The mode conversion unit 59 shown in the figure includes three phase plates 201, and each phase plate 201 includes a unit size of 750×50. The light spot of the shaped optical signal S1' finally output by the mode conversion unit 59 is specifically an elliptical light spot, and the size of the light spot of the shaped optical signal S1' in the y-axis direction is w1, which is 750μm, and the size of the light spot of the shaped optical signal S1' in the x-axis direction is w2, which is 150μm. When the mode conversion unit 59 shapes the optical signal S1 into the shaped optical signal S1', the shaped optical signal S1' is transmitted to the wavelength combiner / demultiplexer 51; wherein, the size of the light spot of the shaped optical signal S1' in the port direction is larger than the size of the light spot of the shaped optical signal S1' in the dispersion direction; the wavelength combiner / demultiplexer 51 receives the shaped optical signal S1', and outputs a single-wavelength optical signal S11 and a single-wavelength optical signal S12. When the single-wavelength optical signal S11 and the single-wavelength optical signal S12 are transmitted to the optical modulator 52 (specifically, LCoS), the size of the light spot of any single-wavelength optical signal in the y-axis direction is greater than the size in the x-axis direction, that is, the size of the light spot of the single-wavelength optical signal in the y-axis direction becomes larger. The optical modulator 52 generates a modulated optical signal S11' and a modulated optical signal S12', and the deflection angle of the modulated optical signal S11' can make the modulated optical signal S11' transmitted to the mode conversion unit 53, and the deflection angle of the modulated optical signal S12' can make the modulated optical signal S12' transmitted to the mode conversion unit 53, and the mode of the modulated optical signal S11' is different from the mode of the modulated optical signal S12'. The mode conversion unit 53 is specifically Fig.19 The mode conversion unit 53 shown in the figure includes four phase plates 200. The mode conversion unit 53 transmits the modulated optical signal S11' to the location of the branch port f1, and the mode conversion unit 53 transmits the modulated optical signal S12' to the location of the branch port f2. When the size of the light spot of the single-wavelength optical signal in the y-axis direction becomes larger, the simulation results show that the loss of the modulated optical signal S11' transmitted to the branch port f1 and the loss of the modulated optical signal S12' transmitted to the branch port f2 is about 0.66dB, and the crosstalk between the branch port f1 and the branch port f2 is less than -22.10dB.

[0147] For example, Fig.21 As shown, Fig.21 The wavelength selection switch 50 shown in the figure can also be provided with a lens 54, a lens 55 and a lens 56, wherein the mode conversion unit 59 is specifically Fig.23 In the mode conversion unit shown in FIG. 5 , the lens 56 is specifically arranged between the mode conversion unit 59 and the wavelength multiplexing / demultiplexing filter 51, and the lens 56 is specifically used to collimate the shaped optical signal S1 ′. Fig.24In the case of the mode conversion unit shown in FIG. 5 , the lens 56 can be disposed between the mode conversion unit 59 and the wavelength multiplexing / demultiplexing filter 51 , or between the common port com and the mode conversion unit 59 .

[0148] For example, Fig.26 A schematic diagram of the structure of a wavelength selective switch 50 provided in an embodiment of the present application, Fig.26 (a) is specifically a port plane diagram of the wavelength selective switch 50; Fig.26 (b) is a schematic diagram of the dispersion plane of the wavelength selective switch 50. Figure 7 The wavelength selective switch 50 shown, Fig.26 The wavelength selection switch 50 shown includes multiple groups of branch port groups and multiple mode conversion units 53, each branch port group includes multiple branch ports, and multiple mode conversion units 53 are coupled to the multiple groups of branch port groups in a one-to-one correspondence. Specifically, Fig.26 The wavelength selective switch 50 includes two groups of branch port groups and two mode conversion units 53 for description.

[0149] For example, Fig.26 As shown, the two branch port groups are branch port group arr1 and branch port group arr2. The branch port group arr1 includes multiple branch ports. Fig.26 Specifically, the branch port group arr1 includes the branch port f1 and the branch port f2 as an example; the branch port group arr2 includes multiple branch ports, Fig.26 Specifically, take the branch port group arr2 including the branch port f3 and the branch port f4 as an example.

[0150] like Fig.26 As shown, the two mode conversion units 53 are the mode conversion unit 53-1 and the mode conversion unit 53-2. The mode conversion unit 53-1 is coupled to the branch port group arr1, specifically, the mode conversion unit 53-1 is coupled to the branch port f1 and the branch port f2; the mode conversion unit 53-2 is coupled to the branch port group arr2, specifically, the mode conversion unit 53-2 is coupled to the branch port f3 and the branch port f4.

[0151] In one example, the mode conversion unit 53-1 may be used to receive at least one modulated optical signal among m modulated optical signals, transmit the modulated optical signal to the branch port f1 in the branch port group arr1 according to the first mode of the modulated optical signal in the at least one modulated optical signal, and transmit the modulated optical signal to the branch port f2 in the branch port group arr1 according to the second mode of the modulated optical signal in the at least one modulated optical signal. The first mode is different from the second mode. The mode conversion unit 53-2 is used to receive at least one modulated optical signal among m modulated optical signals, transmit the modulated optical signal to the branch port f3 in the branch port group arr2 according to the first mode of the modulated optical signal in the at least one modulated optical signal, and transmit the modulated optical signal to the branch port f4 in the branch port group arr2 according to the second mode of the modulated optical signal in the at least one modulated optical signal. That is, the mode conversion unit 53-1 and the mode conversion unit 53-2 can transmit the modulated optical signal of the first mode and the modulated optical signal of the second mode to different branch ports. In this example, the optical modulator 52 performs first angle deflection and mode conversion on m modulated optical signals to generate m modulated optical signals, wherein for any modulated optical signal, when the deflection angle of the modulated optical signal allows the modulated optical signal to be transmitted to the mode conversion unit 53-1, the mode of the modulated optical signal is the first mode or the second mode; when the deflection angle of the modulated optical signal allows the modulated optical signal to be transmitted to the mode conversion unit 53-2, the mode of the modulated optical signal is the first mode or the second mode. In addition, the deflection angle of the modulated optical signal transmitted to the mode conversion unit 53-1 is different from the deflection angle of the modulated optical signal transmitted to the mode conversion unit 53-2.

[0152] Specifically, Fig.26 As shown, taking the modulated optical signal S11' transmitted to the branch port f1, the modulated optical signal S12' transmitted to the branch port f2, the modulated optical signal S13' transmitted to the branch port f3, and the modulated optical signal S14' transmitted to the branch port f4 as an example, the mode conversion unit 53-1 and the mode conversion unit 53-2 can transmit the modulated optical signal of the first mode and the modulated optical signal of the second mode to different branch ports, and the function of the wavelength selection switch 50 is described.

[0153] The common port com of the wavelength selective switch 50 inputs an optical signal S1. The mode conversion unit 59 in the wavelength selective switch 50 first receives the optical signal S1, shapes the optical signal S1 into a shaped optical signal S1', and transmits the shaped optical signal S1' to the lens 56. The size of the light spot of the shaped optical signal S1' in the y-axis direction is larger than the size of the light spot of the shaped optical signal S1' in the x-axis direction. The lens 56 collimates the shaped optical signal S1' and transmits the shaped optical signal S1' to the wavelength multiplexer 51. The wavelength multiplexer 51 receives the shaped optical signal S1' and outputs four single-wavelength optical signals. The four single-wavelength optical signals include a single-wavelength optical signal S11, a single-wavelength optical signal S12, a single-wavelength optical signal S13, and a single-wavelength optical signal S14, and the dispersion angles of any two single-wavelength optical signals emitted from the wavelength multiplexer 51 are different. The lens 54 is used to collimate the four single-wavelength optical signals in the x-axis direction so that the four single-wavelength optical signals are transmitted to the optical modulator 52. Fig. 27 As shown, the light spots of four single-wavelength optical signals are arranged along the x-axis direction on the optical modulator 52 and are located at the same position along the y-axis direction.

[0154] The optical modulator 52 is used to perform a first angle deflection and mode conversion on the four single-wavelength optical signals to generate four modulated optical signals. Specifically, the optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S11 to generate a modulated optical signal S11', the deflection angle of the modulated optical signal S11' is the first angle, and the mode of the modulated optical signal S11' is the first mode; the optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S12 to generate a modulated optical signal S12', the deflection angle of the modulated optical signal S12' is the first angle, and the mode of the modulated optical signal S12' is the second mode; the optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S13 to generate a modulated optical signal S13', the deflection angle of the modulated optical signal S12' is the second angle, and the mode of the modulated optical signal S13' is the first mode; the optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S14 to generate a modulated optical signal S14', the deflection angle of the modulated optical signal S14' is the second angle, and the mode of the modulated optical signal S14' is the second mode.

[0155] The lens 55 is used to collimate the four modulated optical signals in the y-axis direction, so that the modulated optical signal S11 ′ and the modulated optical signal S12 ′ are transmitted to the mode conversion unit 53 - 1 , and the modulated optical signal S13 ′ and the modulated optical signal S14 ′ are transmitted to the mode conversion unit 53 - 2 .

[0156] The mode conversion unit 53-1 is used to receive the modulated optical signal S11' and the modulated optical signal S12' among the m modulated optical signals, and transmit the modulated optical signal S11' to the branch port f1 in the branch port group arr1 according to the mode of the modulated optical signal S11' being the first mode, and transmit the modulated optical signal S12' to the branch port f2 in the branch port group arr1 according to the mode of the modulated optical signal S12' being the second mode. The mode conversion unit 53-2 is used to receive the modulated optical signal S13' and the modulated optical signal S14' among the m modulated optical signals, and transmit the modulated optical signal S13' to the branch port f3 in the branch port group arr2 according to the mode of the modulated optical signal S13' being the first mode, and transmit the modulated optical signal S14' to the branch port f4 in the branch port group arr2 according to the mode of the modulated optical signal S14' being the second mode.

[0157] Exemplarily, the above embodiments are described by taking the modulated optical signal S11' transmitted to the branch port f1, the modulated optical signal S12' transmitted to the branch port f2, the modulated optical signal S13' transmitted to the branch port f3, and the modulated optical signal S14' transmitted to the branch port f4 as an example. In other examples, two or more of the modulated optical signals S11', S12', S13', and S14' may be transmitted to the same branch port, and the modes of the modulated optical signals transmitted to the same branch port are the same and the deflection angles are the same.

[0158] In another example, the mode conversion unit 53-1 is used to receive at least one modulated optical signal among m modulated optical signals, and transmit the modulated optical signal to the branch port f1 in the branch port group arr1 according to the first mode of the modulated optical signal in the at least one modulated optical signal, and transmit the modulated optical signal to the branch port f2 in the branch port group arr1 according to the second mode of the modulated optical signal in the at least one modulated optical signal; the mode conversion unit 53-2 is used to receive at least one modulated optical signal among m modulated optical signals, and transmit the modulated optical signal to the branch port f3 in the branch port group arr2 according to the third mode of the modulated optical signal in the at least one modulated optical signal, and transmit the modulated optical signal to the branch port f4 in the branch port group arr2 according to the fourth mode of the modulated optical signal in the at least one modulated optical signal, wherein the first mode, the second mode, the third mode and the fourth mode are different. That is, the mode conversion unit 53-1 can transmit the modulated optical signal of the first mode and the modulated optical signal of the second mode to different branch ports, and the mode conversion unit 53-2 can transmit the modulated optical signal of the third mode and the modulated optical signal of the fourth mode to different branch ports. In this example, the optical modulator 52 performs first angle deflection and mode conversion on m modulated optical signals to generate m modulated optical signals, wherein for any modulated optical signal, when the deflection angle of the modulated optical signal allows the modulated optical signal to be transmitted to the mode conversion unit 53-1, the mode of the modulated optical signal is the first mode or the second mode; when the deflection angle of the modulated optical signal allows the modulated optical signal to be transmitted to the mode conversion unit 53-2, the mode of the modulated optical signal is the third mode or the fourth mode. In addition, the deflection angle of the modulated optical signal transmitted to the mode conversion unit 53-1 is different from the deflection angle of the modulated optical signal transmitted to the mode conversion unit 53-2.

[0159] For example, refer to Fig.28 As shown, Fig.28 (a) is specifically a port plane diagram of the wavelength selective switch 50; Fig.28 (b) is a schematic diagram of the dispersion plane of the wavelength selective switch 50. Fig.26 The wavelength selective switch shown, Fig.28 In the wavelength selective switch shown in FIG. 1 , each mode conversion unit 53 includes a coupling region 100 and a plurality of optical fibers 501, and the mode conversion unit 53 may also include an optical fiber 502. The connection structure and function of the coupling region 100, the optical fiber 501 and the optical fiber 502 in the mode conversion unit 53 refer to FIG. Fig.13 As shown, no further description is given here.

[0160] Reference Fig.28As shown, when both the mode conversion unit 53-1 and the mode conversion unit 53-2 can transmit the modulated optical signal of the first mode and the modulated optical signal of the second mode to different branch ports, the physical parameters of the coupling region 100 of the mode conversion unit 53-1 and the physical parameters of the coupling region 100 of the mode conversion unit 53-2 can be the same. When the mode conversion unit 53-1 can transmit the modulated optical signal of the first mode and the modulated optical signal of the second mode to different branch ports, and the mode conversion unit 53-2 can transmit the modulated optical signal of the third mode and the modulated optical signal of the fourth mode to different branch ports, the physical parameters of the coupling region 100 of the mode conversion unit 53-1 and the physical parameters of the coupling region 100 of the mode conversion unit 53-2 are different.

[0161] Reference Fig.29 As shown, Fig.29 The wavelength selective switch 50 shown is Fig.26 The wavelength selective switch 50 is a schematic diagram of a transmission-type unfolded structure, and compared with Fig.26 The wavelength selective switch shown, Fig.29 Each mode conversion unit 53 in the wavelength selective switch 50 shown includes a plurality of phase plates 200, and Fig.29 For example, each mode conversion unit 53 includes four phase plates 200 .

[0162] Wherein, when both the mode conversion unit 53-1 and the mode conversion unit 53-2 can transmit the modulated optical signal of the first mode and the modulated optical signal of the second mode to different branch ports, the number of phase plates 200 included in the mode conversion unit 53-1 is 4, and the phase mask of each phase plate 200 is set on the transmission path of the modulated optical signal transmitted to the branch port group arr1. The number of phase plates 200 included in the mode conversion unit 53-2 is 4; the phase mask of each phase plate 200 is set on the transmission path of the modulated optical signal transmitted to the branch port group arr2. In addition, as Fig.29 As shown, the phase mask P1 of the phase plate 200-1 in the mode conversion unit 53-1 has the same structure as the phase mask P1 of the phase plate 200-1 in the mode conversion unit 53-2; the phase mask P2 of the phase plate 200-2 in the mode conversion unit 53-1 has the same structure as the phase mask P2 of the phase plate 200-2 in the mode conversion unit 53-2; the phase mask P3 of the phase plate 200-3 in the mode conversion unit 53-1 has the same structure as the phase mask P3 of the phase plate 200-3 in the mode conversion unit 53-2; the phase mask P4 of the phase plate 200-4 in the mode conversion unit 53-1 has the same structure as the phase mask P4 of the phase plate 200-4 in the mode conversion unit 53-2.

[0163] Reference Fig.29As shown, when the mode conversion unit 53-1 can transmit the modulated optical signal of the first mode and the modulated optical signal of the second mode to different branch ports, and the mode conversion unit 53-2 can transmit the modulated optical signal of the third mode and the modulated optical signal of the fourth mode to different branch ports, the number of phase plates 200 included in the mode conversion unit 53-1 is different from the number of phase plates 200 included in the mode conversion unit 53-1, and / or the structure of the phase mask on the phase plate 200 in the mode conversion unit 53-1 is different from the structure of the phase mask on the phase plate 200 in the mode conversion unit 53-1.

[0164] Reference Fig.30 As shown, Fig.30 The schematic diagram of the structure of the transmission-type expansion of the wavelength selection switch 50 is shown. When the wavelength selection switch 50 includes multiple groups of branch port groups and a mode conversion unit 53, and the mode conversion unit 53 includes multiple phase plates 200, each phase plate 200 includes multiple phase masks, and the multiple phase masks are respectively arranged on the transmission path of the modulated optical signal transmitted to the multiple groups of branch port groups. The multiple phase plates can integrate the functions of multiple mode conversion units 53.

[0165] For example, Fig.30 The wavelength selective switch 50 includes two groups of branch port groups for illustration. The two groups of branch port groups are branch port group arr1 and branch port group arr2. The branch port group arr1 includes a plurality of branch ports. Fig.30 Specifically, the branch port group arr1 includes the branch port f1 and the branch port f2 as an example; the branch port group arr2 includes multiple branch ports, Fig.30 Specifically, take the branch port group arr2 including the branch port f3 and the branch port f4 as an example.

[0166] The wavelength selective switch 50 further includes a mode conversion unit 53, wherein: Fig.30 The mode conversion unit 53 shown in the figure specifically comprises four phase plates 200. Fig.30 In the figure, the phase plate 200-1 includes a phase mask P1 and a phase mask P8; the phase plate 200-2 includes a phase mask P2 and a phase mask P9; the phase plate 200-3 includes a phase mask P3 and a phase mask P10; and the phase plate 200-4 includes a phase mask P4 and a phase mask P11.

[0167] Among them, the phase mask P1 of the phase plate 200-1, the phase mask P2 of the phase plate 200-2, the phase mask P3 of the phase plate 200-3 and the phase mask P4 of the phase plate 200-4 are used to form a first mode conversion unit, and are arranged on the transmission path of the modulated optical signal transmitted to the branch port group arr1; the phase mask P8 of the phase plate 200-1, the phase mask P9 of the phase plate 200-2, the phase mask P10 of the phase plate 200-3 and the phase mask P11 of the phase plate 200-4 are used to form a second mode conversion unit, and are arranged on the transmission path of the modulated optical signal transmitted to the branch port group arr2. In this example, when the first mode conversion unit and the second mode conversion unit can both transmit the modulated optical signal of the first mode and the modulated optical signal of the second mode to different branch ports, the phase mask P1 has the same structure as the phase mask P8, the phase mask P2 has the same structure as the phase mask P9, the phase mask P3 has the same structure as the phase mask P10, and the phase mask P4 has the same structure as the phase mask P11. When the first mode conversion unit can transmit the modulated optical signal of the first mode and the modulated optical signal of the second mode to different branch ports, and the second mode conversion unit can transmit the modulated optical signal of the third mode and the modulated optical signal of the fourth mode to different branch ports, the phase mask P1 has a different structure from the phase mask P8, and / or the phase mask P2 has a different structure from the phase mask P9, and / or the phase mask P3 has a different structure from the phase mask P10, and / or the phase mask P4 has a different structure from the phase mask P11.

[0168] For example, in Fig.26 , Fig.28 , Fig.29 as well as Fig.30 In the wavelength selective switch 50 shown in FIG. 1 , the specific structure of the mode conversion unit 59 can be referred to Fig.23 or Fig.24 As shown, no further description is given here.

[0169] Reference Fig.31 As shown, compared to Fig.30 The wavelength selective switch 50 shown, Fig.31 In the wavelength selective switch 50 shown, the common port com and the branch port are arranged on the same side of the optical modulator 52. In this case, the mode conversion unit 53 includes a plurality of phase plates 200, and each phase plate 200 includes a plurality of phase masks, which are respectively arranged on the transmission path of the modulated optical signal transmitted to the plurality of branch port groups. And each phase plate 200 also includes an input phase mask. For example, Fig.31As shown, the phase plate 200-1 further includes an input phase mask P12; the phase plate 200-2 further includes an input phase mask P13; the phase plate 200-3 further includes an input phase mask P14; and the phase plate 200-4 further includes an input phase mask P15. The input phase mask P12 of the phase plate 200-1, the input phase mask P13 of the phase plate 200-2, the input phase mask P14 of the phase plate 200-3, and the input phase mask P15 of the phase plate 200-4 are arranged on the transmission path of the optical signal S1 inputted at the common port com. The input phase mask P12 of the phase plate 200-1, the input phase mask P13 of the phase plate 200-2, the input phase mask P14 of the phase plate 200-3 and the input phase mask P15 of the phase plate 200-4 are used to form a mode conversion unit 59 to shape the received optical signal S1 into a shaped optical signal S1', and the size of the spot of the shaped optical signal S1' in the y-axis direction is larger than the size of the spot of the shaped optical signal S1' in the x-axis direction.

[0170] exist Fig.31 In the wavelength selective switch 50 shown, four phase plates 200 integrate the functions of multiple mode conversion units 53 and mode conversion units 59. Specifically, the phase mask P1 of the phase plate 200-1, the phase mask P2 of the phase plate 200-2, the phase mask P3 of the phase plate 200-3, and the phase mask P4 of the phase plate 200-4 are used to form a first mode conversion unit to achieve the function of transmitting the modulated optical signal to a branch port in the branch port group arr1 according to the mode of the received modulated optical signal; the phase mask P8 of the phase plate 200-1, the phase mask P9 of the phase plate 200-2, the phase mask P10 of the phase plate 200-3, and the phase mask P11 of the phase plate 200-4 are used to form a second mode conversion unit , so as to realize the function of transmitting the modulated optical signal to a branch port in the branch port group arr1 according to the mode of the received modulated optical signal; the input phase mask P12 of the phase plate 200-1, the input phase mask P13 of the phase plate 200-2, the input phase mask P14 of the phase plate 200-3 and the input phase mask P15 of the phase plate 200-4 are used to form a mode conversion unit 59, so as to realize the function of shaping the optical signal received by the mode conversion unit 59 into a shaped optical signal, and make the size of the spot of the shaped optical signal in the y-axis direction larger than the size of the spot of the shaped optical signal in the x-axis direction.

[0171] For example, refer to Fig.32 As shown, compared to Fig.31 The wavelength selective switch 50 shown, Fig.32 The wavelength selective switch 50 shown includes an optical modulator 52 and a plurality of phase plates. Fig.32As shown, the wavelength combiner / demultiplexer 51 includes at least one phase plate 202 (also referred to as a fourth phase plate), wherein: Fig.32 The wavelength combiner / demultiplexer 51 shown specifically includes two phase plates 202, namely phase plate 202-1 and phase plate 202-2. Grating lines are set on the phase plates 202-1 and 202-2 so that the phase plates 202-1 and 202-2 can receive the optical signal S1 or the shaped optical signal S1' and output m single-wavelength optical signals.

[0172] like Fig.32 As shown, the lens 54 includes at least one phase plate 203 (also referred to as the fifth phase plate), Fig.32 The lens 54 shown specifically includes three phase plates 203, namely phase plate 203-1, phase plate 203-2 and phase plate 203-3. Phase plates 203-1, 203-2 and 203-3 are used to collimate m single-wavelength optical signals in the x-axis direction.

[0173] like Fig.32 As shown, the lens 55 includes at least one phase plate 204 (also referred to as the sixth phase plate), Fig.32 The lens 55 shown specifically includes two phase plates 204, namely a phase plate 204-1 and a phase plate 204-2. The phase plate 204-1 and the phase plate 204-2 are used to collimate the m modulated optical signals in the y-axis direction.

[0174] like Fig.32 As shown, the lens 56 includes at least one phase plate 205 (also referred to as the seventh phase plate), Fig.32 The lens 56 shown specifically includes two phase plates 205, namely phase plate 205-1 and phase plate 205-2. Phase plate 205-1 and phase plate 205-2 are used to collimate the shaped optical signal in the x-axis direction and the y-axis direction.

[0175] For example, the wavelength selection switch 50 in the above embodiment may be a 1×N wavelength selection switch. Fig.33 As shown, the wavelength selective switch 50 may also be an M×N wavelength selective switch, wherein “M” in the M×N wavelength selective switch represents the number of common ports of the wavelength selective switch, and “N” represents the number of branch ports of the wavelength selective switch.

[0176] exist Fig.33, M is specifically equal to 3, N is specifically equal to 4, wherein the common port of the wavelength selective switch 50 includes a common port com1, a common port com2, and a common port com3; the wavelength selective switch 50 includes two groups of branch port groups, namely, a branch port group arr1 and a branch port group arr2. The branch port group arr1 includes a branch port f1 and a branch port f2; the branch port group arr2 includes a branch port f3 and a branch port f4.

[0177] in, Fig.33 The wavelength selective switch 50 shown includes three mode conversion units 59 and two mode conversion units 53. Specifically, the three mode conversion units 59 are mode conversion unit 59-1, mode conversion unit 59-2 and mode conversion unit 59-3, mode conversion unit 59-1 is coupled to common port com1, mode conversion unit 59-2 is coupled to common port com2, and mode conversion unit 59-3 is coupled to common port com3. The two mode conversion units 53 are mode conversion unit 53-1 and mode conversion unit 53-2, mode conversion unit 53-1 is coupled to branch port group arr1, and mode conversion unit 53-2 is coupled to branch port group arr2.

[0178] Fig.33 The wavelength selection switch 30 shown also includes an optical modulator 57 (also called a second optical modulator) arranged between the optical modulator 52 and the mode conversion unit 53; the optical modulator 52 is specifically used to perform a first angle deflection and mode conversion on m single-wavelength optical signals to generate m first modulated optical signals, and transmit the m first modulated optical signals to the optical modulator 57; the optical modulator 57 is used to perform a second angle deflection on the m first modulated optical signals to generate m modulated optical signals.

[0179] For example, Fig.33 As shown, the wavelength selective switch 50 further includes a lens 58 (also referred to as a first lens) disposed between the optical modulator 52 and the optical modulator 57, wherein the lens plane of the lens 58 is parallel to the port plane, and the lens 58 is used to focus the m first modulated optical signals in the y-axis direction.

[0180] In some embodiments, the lens 58 can also be replaced by at least one third phase plate. For example, the phase mask of each of the at least one third phase plate is set on the transmission path of the m first modulated optical signals; the phase mask of each of the at least one third phase plate is calculated using a wavefront matching method, so that the at least one third phase plate is used to focus the m first modulated optical signals in the y-axis direction.

[0181] exist Fig.33In the embodiment, the mode conversion unit 53-1 can transmit the modulated optical signal with the first mode to the branch port f1, the mode conversion unit 53-1 can transmit the modulated optical signal with the second mode to the branch port f2, the mode conversion unit 53-2 can transmit the modulated optical signal with the first mode to the branch port f3, and the mode conversion unit 53-2 can transmit the modulated optical signal with the second mode to the branch port f4.

[0182] The common port com1 of the wavelength selective switch 50 inputs an optical signal S1 ; the common port com2 of the wavelength selective switch 50 inputs an optical signal S2 ; and the common port com3 of the wavelength selective switch 50 inputs an optical signal S3 .

[0183] The mode conversion unit 59-1 receives the optical signal S1, shapes the optical signal S1 into a shaped optical signal S1', and transmits the shaped optical signal S1' to the lens 56, wherein the size of the light spot of the shaped optical signal S1' in the y-axis direction is larger than the size of the light spot of the shaped optical signal S1' in the x-axis direction; the mode conversion unit 59-2 receives the optical signal S2, shapes the optical signal S2 into a shaped optical signal S2', and transmits the shaped optical signal S2' to the lens 56, wherein the size of the light spot of the shaped optical signal S2' in the y-axis direction is larger than the size of the light spot of the shaped optical signal S2' in the x-axis direction; the mode conversion unit 59-3 receives the optical signal S3, shapes the optical signal S3 into a shaped optical signal S3', and transmits the shaped optical signal S3' to the lens 56, wherein the size of the light spot of the shaped optical signal S3' in the y-axis direction is larger than the size of the light spot of the shaped optical signal S3' in the x-axis direction.

[0184] The lens 56 collimates the shaped optical signal S1' and transmits the shaped optical signal S1' to the wavelength multiplexer / demultiplexer 51. The wavelength multiplexer / demultiplexer 51 receives the shaped optical signal S1' and outputs two single-wavelength optical signals, which include a single-wavelength optical signal S11 and a single-wavelength optical signal S12, and the dispersion angles of the two single-wavelength optical signals emitted from the wavelength multiplexer / demultiplexer 51 are different.

[0185] The lens 56 collimates the shaped optical signal S2' and transmits the shaped optical signal S2' to the wavelength multiplexer / demultiplexer 51. The wavelength multiplexer / demultiplexer 51 receives the shaped optical signal S2' and outputs two single-wavelength optical signals, which include a single-wavelength optical signal S21 and a single-wavelength optical signal S22, and the dispersion angles of the two single-wavelength optical signals emitted from the wavelength multiplexer / demultiplexer 51 are different.

[0186] The lens 56 collimates the shaped optical signal S3' and transmits the shaped optical signal S3' to the wavelength multiplexer / demultiplexer 51. The wavelength multiplexer / demultiplexer 51 receives the shaped optical signal S3' and outputs two single-wavelength optical signals, which include a single-wavelength optical signal S31 and a single-wavelength optical signal S32, and the dispersion angles of the two single-wavelength optical signals emitted from the wavelength multiplexer / demultiplexer 51 are different.

[0187] The lens 54 is used to collimate the six single-wavelength optical signals in the x-axis direction so that the six single-wavelength optical signals are transmitted to the optical modulator 52. Fig.34 As shown, the light spots of 6 single-wavelength optical signals are arranged in an array on the optical modulator 52, wherein the single-wavelength optical signal S11 and the single-wavelength optical signal S12 are arranged along the x-axis direction and are located at a first position y1 along the y-axis direction; the single-wavelength optical signal S21 and the single-wavelength optical signal S22 are arranged along the x-axis direction and are located at a second position y2 along the y-axis direction; the single-wavelength optical signal S31 and the single-wavelength optical signal S32 are arranged along the x-axis direction and are located at a third position y3 along the y-axis direction.

[0188] The optical modulator 52 is used to perform a first angle deflection and mode conversion on the single wavelength optical signal to generate a first modulated optical signal. The lens 58 is used to focus the first modulated optical signal in the y-axis direction. The optical modulator 57 is used to perform a second angle deflection on the first modulated optical signal to generate a modulated optical signal.

[0189] Exemplarily, for the single-wavelength optical signal S11, the optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S11 to generate a first modulated optical signal S111, and the first modulated optical signal S111 has a deflection angle and a mode. The lens 58 focuses the first modulated optical signal S111 in the y-axis direction, and the optical modulator 57 is used to perform a second angle deflection on the first modulated optical signal S111 to generate a modulated optical signal S11'. Assuming that the deflection angle of the first modulated optical signal S111 is the sixth angle and the mode of the first modulated optical signal S111 is the first mode, the modulated optical signal S11' will be transmitted to the mode conversion unit 53-1, and the mode conversion unit 53-1 transmits the modulated optical signal S11' to the branch port f1 according to the mode of the modulated optical signal S11' being the first mode; Assuming that the deflection angle of the first modulated optical signal S111 is the sixth angle and the mode of the first modulated optical signal S111 is the second mode, the modulated optical signal S11' will be transmitted to the mode conversion unit 53-1, and the mode conversion unit 53-1 transmits the modulated optical signal S11' to the branch port f2 according to the mode of the modulated optical signal S11' being the second mode; Assuming that the deflection angle of the first modulated optical signal S111 is the seventh angle and the mode of the first modulated optical signal S111 is the first mode, the modulated optical signal S11' will be transmitted to the mode conversion unit 53-2, and the mode conversion unit 53-2 transmits the modulated optical signal S11' to the branch port f3 according to the mode of the modulated optical signal S11' being the first mode; Assuming that the deflection angle of the first modulated optical signal S111 is the seventh angle and the mode of the first modulated optical signal S111 is the second mode, the modulated optical signal S11' will be transmitted to the mode conversion unit 53-2, and the mode conversion unit 53-2 transmits the modulated optical signal S11' to the branch port f4 according to the mode of the modulated optical signal S11' being the second mode. That is, the modulated optical signal S11' can be transmitted to any one of the branch ports f1, f2, f3 and f4.

[0190] Similarly, the optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S12 to generate a first modulated optical signal S121. The first modulated optical signal S121 has a deflection angle and a mode. The deflection angle of the first modulated optical signal S121 can be the sixth angle or the seventh angle, and the mode of the first modulated optical signal S121 can be the first mode or the second mode. The lens 58 focuses the first modulated optical signal S121 in the y-axis direction. The optical modulator 57 is used to perform a second angle deflection on the first modulated optical signal S121 to generate a modulated optical signal S12', which can be transmitted to any one of the branch ports f1, f2, f3, and f4.

[0191] The optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S21 to generate a first modulated optical signal S211. The first modulated optical signal S211 has a deflection angle and a mode. The deflection angle of the first modulated optical signal S211 can be the sixth angle or the seventh angle, and the mode of the first modulated optical signal S211 can be the first mode or the second mode. The lens 58 focuses the first modulated optical signal S211 in the y-axis direction. The optical modulator 57 is used to perform a second angle deflection on the first modulated optical signal S211 to generate a modulated optical signal S21', which can be transmitted to any one of the branch ports f1, f2, f3 and f4.

[0192] The optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S22 to generate a first modulated optical signal S221. The first modulated optical signal S221 has a deflection angle and a mode. The deflection angle of the first modulated optical signal S221 can be the sixth angle or the seventh angle, and the mode of the first modulated optical signal S221 can be the first mode or the second mode. The lens 58 focuses the first modulated optical signal S221 in the y-axis direction. The optical modulator 57 is used to perform a second angle deflection on the first modulated optical signal S221 to generate a modulated optical signal S22', which can be transmitted to any one of the branch ports f1, f2, f3, and f4.

[0193] The optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S31 to generate a first modulated optical signal S311. The first modulated optical signal S311 has a deflection angle and a mode. The deflection angle of the first modulated optical signal S311 can be the sixth angle or the seventh angle, and the mode of the first modulated optical signal S311 can be the first mode or the second mode. The lens 58 focuses the first modulated optical signal S311 in the y-axis direction. The optical modulator 57 is used to perform a second angle deflection on the first modulated optical signal S311 to generate a modulated optical signal S31', which can be transmitted to any one of the branch ports f1, f2, f3 and f4.

[0194] The optical modulator 52 performs a first angle deflection and mode conversion on the single-wavelength optical signal S32 to generate a first modulated optical signal S321. The first modulated optical signal S321 has a deflection angle and a mode. The deflection angle of the first modulated optical signal S321 can be the sixth angle or the seventh angle, and the mode of the first modulated optical signal S321 can be the first mode or the second mode. The lens 58 focuses the first modulated optical signal S321 in the y-axis direction. The optical modulator 57 is used to perform a second angle deflection on the first modulated optical signal S321 to generate a modulated optical signal S32'. The modulated optical signal S32' can be transmitted to any one of the branch ports f1, f2, f3, and f4.

[0195] For example, Fig.33 Any of the mode conversion units 53 shown may be Fig.13 or Fig.19 The mode conversion unit 53 shown; Fig.33 Any of the mode conversion units 59 shown may be Fig.23 or Fig.24 The mode conversion unit shown.

[0196] In other examples, it may be Fig.33 A plurality of eighth phase plates are arranged, and each of the eighth phase plates includes a first phase mask and a second phase mask. The first phase mask of each eighth phase plate is used to form a mode conversion unit 53-1, and is arranged on the transmission path of the modulated optical signal transmitted to the branch port group arr1, so as to realize the function of transmitting the modulated optical signal to different branch ports according to the mode of the modulated optical signal; the second phase mask of each eighth phase plate is used to form a mode conversion unit 53-2, and is arranged on the transmission path of the modulated optical signal transmitted to the branch port group arr2, so as to realize the function of transmitting the modulated optical signal to different branch ports according to the mode of the modulated optical signal. Fig.33 A plurality of ninth phase plates are arranged in the optical transmission line, and the ninth phase plate includes a third phase mask, a fourth phase mask and a fifth phase mask. The third phase mask of each ninth phase plate is used to form a mode conversion unit 59-1, and is arranged on the transmission path of the optical signal S1, so as to realize the function of shaping the optical signal S1 into a shaped optical signal S1'; the fourth phase mask of each ninth phase plate is used to form a mode conversion unit 59-2, and is arranged on the transmission path of the optical signal S2, so as to realize the function of shaping the optical signal S2 into a shaped optical signal S2'; the fifth phase mask of each ninth phase plate is used to form a mode conversion unit 59-3, and is arranged on the transmission path of the optical signal S3, so as to realize the function of shaping the optical signal S3 into a shaped optical signal S3'.

[0197] In some other embodiments, when the multiple branch ports and the multiple common ports of the wavelength selective switch 50 are located on the same side of the optical modulator 52, it can be Fig.33 A plurality of tenth phase plates are arranged in the optical transmission optical system, and each of the eighth phase plates includes a first phase mask, a second phase mask, a third phase mask, a fourth phase mask, and a fifth phase mask. The first phase mask of each tenth phase plate is used to form a mode conversion unit 53-1, and is arranged on the transmission path of the modulated optical signal transmitted to the branch port group arr1, so as to realize the function of transmitting the modulated optical signal to different branch ports according to the mode of the modulated optical signal; the second phase mask of each tenth phase plate is used to form a mode conversion unit 53-2, and is arranged on the transmission path of the modulated optical signal transmitted to the branch port group arr2, so as to realize the function of transmitting the modulated optical signal to different branch ports according to the mode of the modulated optical signal. The third phase mask of each tenth phase plate is used to form a mode conversion unit 59-1, and is arranged on the transmission path of the optical signal S1 to achieve the function of shaping the optical signal S1 into a shaped optical signal S1'; the fourth phase mask of each tenth phase plate is used to form a mode conversion unit 59-2, and is arranged on the transmission path of the optical signal S2 to achieve the function of shaping the optical signal S2 into a shaped optical signal S2'; the fifth phase mask of each tenth phase plate is used to form a mode conversion unit 59-3, and is arranged on the transmission path of the optical signal S3 to achieve the function of shaping the optical signal S3 into a shaped optical signal S3'.

[0198] For example, Figure 7 , Fig.21 , Fig.26 , Figure 28 to Figure 33 In the wavelength selective switch 50 shown in any of the figures, the branch port and the common port can be arranged on the same side of the optical modulator 52, or on different sides of the optical modulator 52, wherein the branch port and the common port do not affect the functions of each device in the wavelength selective switch 50. When the branch port and the common port are arranged at different positions, the wavelength selective switch 50 can also include more or fewer devices.

[0199] Although the present application has been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely exemplary illustrations of the present application as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A wavelength selective switch, characterized in that: include: A wavelength combiner / demultiplexer, a first optical modulator and a first mode conversion unit; The first mode conversion unit is coupled to a plurality of branch ports of the wavelength selective switch; The wavelength multiplexer / demultiplexer is used to receive the optical signal input from the common port of the wavelength selective switch, output m single-wavelength optical signals, where m is a positive integer greater than or equal to 1, and transmit the m single-wavelength optical signals to the first optical modulator; The first optical modulator is used to perform a first angle deflection and mode conversion on the m single-wavelength optical signals to generate m modulated optical signals; The first mode conversion unit is used to receive at least one modulated optical signal among the m modulated optical signals, and transmit the modulated optical signal to one branch port among the multiple branch ports according to a mode of each modulated optical signal among the at least one modulated optical signal.

2. The wavelength selective switch according to claim 1, characterized in that: When m is greater than or equal to 2; the first mode conversion unit is used to transmit the multiple modulated optical signals with different received modes to different branch ports among the multiple branch ports, and transmit the multiple modulated optical signals with the same received mode to the same branch port among the multiple branch ports.

3. The wavelength selective switch according to claim 1 or 2, characterized in that: The wavelength selective switch further comprises a second mode conversion unit, and the second mode conversion unit is arranged between the common port and the wavelength combiner / demultiplexer; The second mode conversion unit is used to shape the received optical signal into a shaped optical signal, and transmit the shaped optical signal to the wavelength combination and demultiplexing device; wherein the size of the light spot of the shaped optical signal in the first direction is larger than the size of the light spot of the shaped optical signal in the second direction, the first direction is the port direction of the wavelength selective switch, and the second direction is the dispersion direction of the wavelength selective switch; The wavelength combiner / demultiplexer is specifically configured to receive the shaped optical signal and output the m single-wavelength optical signals.

4. The wavelength selective switch according to any one of claims 1 to 3, characterized in that: The first mode conversion unit includes a first coupling region and a plurality of first optical fibers, a first end of one of the first optical fibers is connected to an output end of the first coupling region, and a second end of one of the first optical fibers is connected to one of the plurality of branch ports; The first optical fiber is a single-mode optical fiber; The first coupling region is used to transmit the modulated optical signal to one of the first optical fibers according to a mode of the modulated optical signal.

5. The wavelength selective switch according to claim 4, characterized in that: The first mode conversion unit further includes a second optical fiber connected to an input end of the first coupling region; The second optical fiber is a few-mode optical fiber.

6. The wavelength selective switch according to any one of claims 1 to 3, characterized in that: The first mode conversion unit includes a plurality of first phase plates, and phase masks of the plurality of first phase plates are arranged on a transmission path of the modulated optical signal received by the first mode conversion unit; The phase masks of the plurality of first phase plates are used to transmit the modulated optical signal to a position where one of the plurality of branch ports is located according to a pattern of the modulated optical signal.

7. The wavelength selective switch according to claim 3, characterized in that: The second mode conversion unit comprises a second coupling region and a third optical fiber, a first end of the third optical fiber is connected to the common port, and a second end of the third optical fiber is connected to an input end of the second coupling region; The third optical fiber is a single-mode optical fiber; The second coupling region is used to shape the optical signal received by the second mode conversion unit to form the shaped optical signal.

8. The wavelength selective switch according to claim 7, characterized in that: The second mode conversion unit further comprises a fourth optical fiber, and the fourth optical fiber is connected to the output end of the second coupling region; The fourth optical fiber is a single-mode optical fiber.

9. The wavelength selective switch according to claim 3, characterized in that: The second mode conversion unit comprises a plurality of second phase plates, and phase masks of the plurality of second phase plates are arranged on a transmission path of an optical signal received by the second mode conversion unit; The phase masks of the plurality of second phase plates are used to shape the optical signal received by the second mode conversion unit to form the shaped optical signal.

10. The wavelength selective switch according to claim 4, characterized in that: The wavelength selective switch comprises a plurality of the first mode conversion units and a plurality of branch port groups, each of the branch port groups comprises a plurality of branch ports; the plurality of the first mode conversion units are coupled to the plurality of branch port groups in a one-to-one correspondence; Each of the first mode conversion units includes the first coupling region and the plurality of first optical fibers.

11. The wavelength selective switch according to claim 6, characterized in that: The wavelength selective switch includes a plurality of the first mode conversion units and a plurality of branch port groups, each of the branch port groups includes a plurality of branch ports; the plurality of the first mode conversion units are coupled to the plurality of branch port groups in a one-to-one correspondence; and each of the first mode conversion units includes the plurality of first phase plates.

12. The wavelength selective switch according to claim 6, characterized in that: The wavelength selective switch comprises a plurality of branch port groups, each of the branch port groups comprises a plurality of branch ports; Each of the first phase plates includes a plurality of phase masks, and the plurality of phase masks are respectively and correspondingly arranged on a transmission path of the modulated optical signal transmitted to the plurality of groups of branch port groups.

13. The wavelength selective switch according to claim 12, characterized in that: The wavelength selective switch further comprises a second mode conversion unit; Each of the first phase plates further includes an input phase mask, and the input phase mask is correspondingly arranged on the transmission path of the optical signal inputted from the common port; the input phase mask is used to form the second mode conversion unit.

14. The wavelength selective switch according to any one of claims 1 to 13, characterized in that: The wavelength selective switch includes a second optical modulator disposed between the first optical modulator and the first mode conversion unit; The first optical modulator is specifically used to perform a first angle deflection and mode conversion on the m single-wavelength optical signals to generate m first modulated optical signals, and transmit the m first modulated optical signals to the second optical modulator; The second optical modulator is used to perform a second angle deflection on the m first modulated optical signals to generate the m modulated optical signals.

15. The wavelength selective switch according to claim 14, characterized in that: The wavelength selective switch further comprises a first lens or at least one third phase plate arranged between the first optical modulator and the second optical modulator, and a phase mask of the third phase plate is arranged on a transmission path of the m first modulated optical signals; The first lens or at least one of the third phase plates is used to focus the m first modulated optical signals in a first direction, where the first direction is a port direction of the wavelength selective switch.

16. The wavelength selective switch according to any one of claims 1 to 15, characterized in that: The wavelength combiner / demultiplexer comprises at least one fourth phase plate, and the fourth phase plate comprises grating lines.

17. The wavelength selective switch according to any one of claims 1 to 16, characterized in that: The wavelength selective switch further comprises a second lens or at least one fifth phase plate arranged between the wavelength combiner / demultiplexer and the first optical modulator, and a phase mask of the fifth phase plate is arranged on the transmission path of the m single-wavelength optical signals; The second lens or at least one of the fifth phase plates is used to collimate the m single-wavelength optical signals in a second direction, where the second direction is the dispersion direction of the wavelength selective switch.

18. The wavelength selective switch according to any one of claims 1 to 17, characterized in that: The wavelength selective switch further comprises a third lens or at least one sixth phase plate arranged between the first optical modulator and the first mode conversion unit, and a phase mask of the sixth phase plate is arranged on a transmission path of the m modulated optical signals; The third lens or at least one of the sixth phase plates is used to collimate the m modulated optical signals in a first direction, where the first direction is a port direction of the wavelength selective switch.

19. The wavelength selective switch according to any one of claims 1 to 18, characterized in that: The wavelength selective switch further comprises a fourth lens or at least one seventh phase plate arranged between the common port and the wavelength combiner / demultiplexer, wherein the phase mask of the seventh phase plate is arranged on the transmission path of the optical signal inputted from the common port; The fourth lens or at least one of the seventh phase plates is used to collimate the optical signal input from the common port.

20. The wavelength selective switch according to any one of claims 1 to 19, characterized in that: The common port of the wavelength selective switch and the plurality of branch ports of the wavelength selective switch are arranged on the same side of the first optical modulator; Alternatively, the common port of the wavelength selective switch and the plurality of branch ports of the wavelength selective switch are arranged on different sides of the first optical modulator.

21. An optical switching device, characterized in that: Comprising the wavelength selective switch according to any one of claims 1-20.

22. An optical network system, characterized in that: A plurality of optical switching devices as claimed in claim 21 comprising optical fiber connections.

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