Planar optical waveguide, wavelength selection switch and communication equipment

Abstract

The invention discloses a planar optical waveguide, a wavelength selective switch and communication equipment. The planar optical waveguide comprises a transition waveguide and a grating waveguide. Wherein one end of the transition waveguide is connected with an external optical fiber array, and the other end of the transition waveguide is connected with the grating waveguide. The grating waveguide comprises a core layer and a cladding layer, the cladding layer is used for surrounding the core layer, the first length and / or the second length change along a first direction, the first direction is the direction from the optical fiber array to the grating waveguide, the first length is the interval length among the plurality of core layers, and the second length is the length of the plurality of core layers along the first direction. The grating waveguide is used for realizing spot expansion in the vertical direction, so that the planar optical waveguide which is simple to process can be used for replacing an array lens, and the processing difficulty of a light spot shaping module is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical communication technology, and specifically to a planar optical waveguide, a wavelength selective switch, and a communication device. Background Art

[0002] Wavelength selective switch (WSS) is an important component of large-scale optical cross-connection and all-optical network, which can realize wavelength-level optical link scheduling. In WSS, the input and output ports of the light spot are fixed in the form of fiber array (FA), and the spot size used by the scheduling engine based on liquid crystal on silicon (LCOS) cannot be directly matched with the spot size of FA, so a special spot shaping module is required.

[0003] The commonly used spot shaping module uses lenses to transform the light beam. For example, the mode field radius of a conventional single-mode optical fiber is 4.8 microns, and the required mode field radius is 14 microns × 100 microns, which are expanded by 2.9 times and 20.9 times respectively. The array lens and array cylindrical lens method can be used to first expand the spot to 14 microns and then expand it to 100 microns.

[0004] Since WSS has a large number of ports and the alignment accuracy of FA is required to be at the sub-micron level, spot shaping requires the use of one or more array lenses processed by semiconductor processes to match it for optical coupling. The high coupling accuracy requirements lead to a sharp increase in processing difficulty. Summary of the invention

[0005] The embodiment of the present application provides a planar optical waveguide for reducing the difficulty of processing a light spot shaping module. The embodiment of the present application also provides a corresponding wavelength selective switch and communication equipment.

[0006] In a first aspect, the present application provides a planar optical waveguide, which includes a transition waveguide and a grating waveguide; one end of the transition waveguide is used to connect to an external optical fiber array, and the other end of the transition waveguide is connected to the grating waveguide; the grating waveguide includes a cladding and multiple core layers, the cladding is used to surround the multiple core layers, and the first length and / or the second length changes along a first direction; wherein the first direction is the direction from the optical fiber array to the grating waveguide, the first length is the interval length between the multiple core layers, and the second length is the length of the multiple core layers along the first direction.

[0007] In the present application, the planar optical waveguide can be used as an optical connection module in optical devices such as wavelength selective switches, spatial filters and spatial isolators. One end of the planar optical waveguide is connected to the optical fiber array, and the other end is exposed in space. The light spot input by the optical fiber array will expand in diameter after passing through the planar optical waveguide, and will be output as spatial light from the end face of the planar optical waveguide.

[0008] In the present application, the planar optical waveguide can also receive spatial light from the external space, reduce the spot radius of the spatial light, and output it to the optical fiber array.

[0009] In the present application, the optical fiber array is an optical fiber array with a polishing angle matching that of the planar optical waveguide, and the end face angle of the optical fiber array connected to the planar optical waveguide is 0 to 8 degrees. Before using the planar optical waveguide provided in the embodiment of the present application, the planar optical waveguide and the optical fiber array need to be assembled and matched.

[0010] In the present application, the planar optical waveguide is a single-layer waveguide structure. In order to more conveniently describe the planar optical waveguide provided in the embodiment of the present application, the direction from the optical fiber array to the grating waveguide is defined as the first direction, the direction horizontally perpendicular to the first direction is defined as the second direction (horizontal direction), and the direction from the bottom to the top of the planar optical waveguide is defined as the third direction (vertical direction), and the third direction is perpendicular to both the first direction and the second direction.

[0011] In the present application, the grating waveguide is a structure loaded on an ordinary planar optical waveguide, and other structures may or may not be loaded in the transition waveguide. When other structures are not loaded, the transition waveguide is the planar optical waveguide itself.

[0012] In the present application, the grating waveguide is used to achieve the expansion of the light spot in the third direction (vertical direction), that is, the first length and / or the second length changes along the first direction, the interval length between the multiple core layers and / or the length of the multiple core layers along the first direction changes along the first direction, that is, the duty cycle of the core layer and the cladding is changed, so that the effective refractive index difference of the light spot in the grating waveguide changes, and the waveguide refractive index difference is 0-10%, thereby achieving the expansion of the light spot radius by 2 to 3 times in the third direction, that is, the effective refractive index difference of the waveguide is adjusted by changing the duty cycle of the cladding and the core layer in the grating waveguide, and the shape and refractive index change of the waveguide itself are used to adjust the size of the light spot, thereby realizing periodic refractive index modulation, eliminating the processing of the microlens array, and the precise assembly requirements.

[0013] In the present application, in the grating waveguide, only the interval length between the multiple core layers may change along the first direction, or only the length of the multiple core layers along the first direction may change along the first direction, or both the interval length between the multiple core layers and the length of the multiple core layers along the first direction may change along the first direction. In addition, the length of the multiple core layers along the first direction changing along the first direction may be understood as the length becoming larger or smaller, etc., but the overall length increases, and the change may be regular (periodic) or irregular.

[0014] In the first aspect, the planar optical waveguide includes a transition waveguide and a grating waveguide. One end of the transition waveguide is used to connect to an external optical fiber array, and the other end is connected to the grating waveguide. The grating waveguide includes a core layer and a cladding, the cladding is used to surround the core layer, and the first length and / or the second length changes along a first direction, the first direction is the direction from the optical fiber array to the grating waveguide, wherein the first length is the interval length between multiple core layers, and the second length is the length of multiple core layers along the first direction. The grating waveguide is used to achieve vertical spot expansion, so that the array lens can be replaced with the simple-to-process planar optical waveguide, reducing the processing difficulty of the spot shaping module.

[0015] In a possible implementation manner of the first aspect, the transition waveguide includes n transition regions, areas of the n transition regions vary along a first direction, and n is an integer greater than 1.

[0016] In this possible implementation, the spot expansion in the second direction is achieved by changing the area of ​​multiple transition regions in the transition waveguide, thereby expanding the spot radius in the horizontal direction. As a result, the array lens can be replaced by the planar optical waveguide, which is easy to process, thereby reducing the difficulty of processing the spot shaping module.

[0017] In a possible implementation manner of the first aspect, areas of the n transition regions change by a first preset value along a first direction, and the first preset value of each transition region in the n transition regions is different.

[0018] In this possible implementation, the n transition regions in the transition waveguide have different changes, but the area of ​​the first transition region (close to the optical fiber array) is smaller than the area of ​​the last transition region (close to the grating waveguide), and the changes in the areas of the intermediate transition regions should be transitional, that is, the overall area change trend is getting larger and larger, which improves the feasibility of the solution.

[0019] In a possible implementation manner of the first aspect, sides of the n transition regions along the first direction are curves.

[0020] In this possible implementation, the n transition regions may be rectangular, trapezoidal or irregular in shape. For example, the edges of the n transition regions along the first direction (the same direction as the first direction) are curves, which improves the feasibility of the solution.

[0021] In a possible implementation manner of the first aspect, the grating waveguide includes a transmitting part and a receiving part, and a periodic variation amount of the transmitting part is different from a periodic variation amount of the receiving part.

[0022] In this possible implementation, since the goal of the emitting part is to expand the small light spot into a large light spot, the change speed of the light spot size can be slower, so the interval between the core layers of the emitting part is larger and the periodic variation is smaller. The goal of the receiving part is to reduce the large light spot to a small light spot. In order to prevent the leakage of the large light spot and reduce the insertion loss, the change speed of the light spot size needs to be faster. Therefore, the interval between the core layers of the receiving part is smaller, denser, and the periodic variation is larger. While reducing the insertion loss, the use of an emitting part with a smaller periodic variation also reduces the manufacturing difficulty and process requirements of the entire planar optical waveguide.

[0023] In a possible implementation manner of the first aspect, one end of the grating waveguide is connected to the transition waveguide, the other end of the grating waveguide is exposed in space, and the angle between the end face of the other end of the grating waveguide and the horizontal plane is 0 degrees to 8 degrees.

[0024] In this possible implementation, the end face angle where the optical fiber array connects to the planar optical waveguide is 0 to 8 degrees, and the angle between the end face of the other end of the grating waveguide and the horizontal plane is also 0 to 8 degrees, which improves the feasibility of the solution.

[0025] In a possible implementation manner of the first aspect, the planar optical waveguide further includes a first alignment channel, and the first alignment channel is used to match with a second alignment channel of the optical fiber array.

[0026] In this possible implementation, the first alignment channel is the first and last transition regions in the transition waveguide, that is, the first transition region and the last transition region along the second direction. Similarly, the second alignment channel is the first and last fiber ports in the fiber array, that is, the first fiber port and the last fiber port along the second direction, because the first alignment channel and the second alignment channel are one-to-one corresponding and are arranged periodically. During assembly, it is sufficient to track the optical path insertion loss of the first alignment channel at the edge, adjust the position of the fiber array and the planar optical waveguide, and when the insertion loss of the first alignment channel at the edge is the lowest, the coupling position of the fiber array and the planar optical waveguide is optimal, and then fix it. Because all the fiber ports of the fiber array are arranged periodically, when the coupling insertion loss of the first and last channels is the lowest, the middle channel (the middle transition region and the fiber port) is also in the corresponding position. Specifically, the overall insertion loss of the planar optical waveguide is less than or equal to 0.3dB, which further reduces the process difficulty and assembly difficulty of the planar optical waveguide.

[0027] In a possible implementation manner of the first aspect, n is greater than or equal to 12.

[0028] In this possible implementation, in order to expand the spot radius by 24 times or more in the second direction, the transition waveguide includes greater than or equal to 12 transition regions, thereby improving the feasibility of the solution.

[0029] A second aspect of the present application provides a wavelength selective switch, which includes the planar optical waveguide in the first aspect or any possible implementation of the first aspect.

[0030] A third aspect of the present application provides a communication device, which includes the planar optical waveguide in the above-mentioned first aspect or any possible implementation of the first aspect.

[0031] In an embodiment of the present application, the planar optical waveguide includes a transition waveguide and a grating waveguide. One end of the transition waveguide is used to connect to an external optical fiber array, and the other end is connected to the grating waveguide. The grating waveguide includes a core layer and a cladding, the cladding is used to surround the core layer, and the first length and / or the second length changes along a first direction, the first direction is the direction from the optical fiber array to the grating waveguide, wherein the first length is the interval length between multiple core layers, and the second length is the length of multiple core layers along the first direction. The grating waveguide is used to achieve vertical spot expansion, so that the array lens can be replaced with the simple-to-process planar optical waveguide, reducing the processing difficulty of the spot shaping module. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the wavelength selection switch;

[0033] Figure 2 Schematic diagram of light spot shaping in wavelength selection switch;

[0034] Figure 3 A schematic diagram of an embodiment of a planar optical waveguide provided in an embodiment of the present application;

[0035] Figure 4 A schematic diagram of a grating waveguide in a planar optical waveguide provided in an embodiment of the present application;

[0036] Figure 5 A schematic diagram of a transition guide in a planar optical waveguide provided in an embodiment of the present application;

[0037] Figure 6 A schematic diagram of an embodiment of a wavelength selective switch provided in an embodiment of the present application;

[0038] Figure 7 A schematic diagram of an embodiment of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] The following describes the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the described embodiments are only embodiments of a part of the present application, rather than all embodiments. It is known to those skilled in the art that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0040] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0042] In addition, in order to better illustrate the present application, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0043] The following is an example of the application scenario involved in the embodiments of the present application.

[0044] With the development of optical communication technology, the application of wavelength selective switch (WSS) is becoming more and more extensive. WSS is an important component of large-scale optical cross-connection and all-optical networks, which can realize wavelength-level optical link scheduling.

[0045] like Figure 1As shown in the figure, in the existing 1*N WSS based on the liquid crystal on silicon (LCOS) scheduling engine, N+1 ports are composed of a fiber array, which includes 1 input port and N output ports, that is, the input and output ports of the light spot are fixed in the form of a fiber array (FA). The light spot enters the WSS system from the input port in the FA. The grating, as a dispersion separation and synthesis element, will reflect the light spot incident on it at different diffraction angles according to the wavelength and focus on the LCOS to form a new light spot. Because the angles of light of different wavelengths incident on the LCOS in the dispersion direction are different, the positions of the light spots focused on the LCOS are also different. By applying different voltages to the liquid crystals in different wavelength coverage areas of the LCOS for modulation, the light beam incident on the area can be reflected back at different reflection angles. According to the position of the destination output port of different signal lights, the signal light is reflected back at different reflection angles. The reflected light returns along the original path, and after the beam combining action of the grating, it is output from the optical fiber of the destination port.

[0046] like Figure 2 As shown in the figure, because the spot size used by the scheduling engine based on liquid crystal on silicon (LCOS) cannot directly match the spot size of FA, a special spot shaping module is required to achieve spot transformation. After the spot is input from FA, it is transformed as spatial light through one or more spot shaping modules and then transmitted to the switching engine LCOS. The same is true for reverse transmission.

[0047] The commonly used spot shaping module uses a lens to transform the light beam. For example, the mode field radius of a conventional single-mode optical fiber is 4.8 microns, and the required mode field radius is 14 microns × 100 microns, which is enlarged by 2.9 times and 20.9 times respectively. The array lens and the array cylindrical lens can be used to expand the spot to 14 microns in one direction and then to 100 microns in the other direction. It should be understood that in actual applications, the expansion requirements of the spot can also be other sizes. The above expansion of the 4.8 micron × 4.8 micron spot to only 14 microns × 100 microns is only an example of a possibility.

[0048] In order to achieve faster optical switching systems to meet the upgrading of technology and higher-speed optical communications, the number of fiber ports on the fiber end face in the WSS optical system needs to be more, for example, N is 22, 34 or more, and the alignment accuracy of FA is required to be at the sub-micron level. To achieve spot shaping, one or more array lenses processed by semiconductor processes need to be matched with it for optical coupling. The high coupling accuracy requirements lead to a sharp increase in processing difficulty.

[0049] Based on this, the embodiment of the present application provides a planar optical waveguide for reducing the difficulty of processing a light spot shaping module. The embodiment of the present application also provides a corresponding wavelength selection switch and communication equipment. The following are detailed descriptions.

[0050] The planar optical waveguide provided in the embodiment of the present application is described below in conjunction with the above application scenarios.

[0051] like Figure 3 As shown, an embodiment of the present application provides a planar optical waveguide, and an embodiment of the planar optical waveguide includes a transition waveguide 310 and a grating waveguide 320 .

[0052] Specifically, one end of the transition waveguide 310 is used to connect to the external optical fiber array 330, and the other end of the transition waveguide 310 is connected to the grating waveguide 320. The grating waveguide 320 includes a cladding 321 and a plurality of core layers 322, and the cladding 321 is used to surround the plurality of core layers 322. The first length and / or the second length varies along a first direction. The first direction is the direction from the optical fiber array 330 to the grating waveguide 320, the first length is the interval length between the plurality of core layers 322, and the second length is the length of the plurality of core layers 322 along the first direction.

[0053] In order to more conveniently describe the planar optical waveguide provided in the embodiment of the present application, the direction from the optical fiber array 330 to the grating waveguide 320 is defined as a first direction, the direction horizontally and perpendicular to the first direction is defined as a second direction (horizontal direction), and the direction from the bottom to the top of the planar optical waveguide is defined as a third direction (vertical direction), and the third direction is perpendicular to both the first direction and the second direction.

[0054] In the embodiment of the present application, the grating waveguide 320 is used to achieve the expansion of the light spot in the third direction (vertical direction), that is, the first length and / or the second length changes along the first direction, and the interval length between the multiple core layers 322 and / or the length of the multiple core layers 322 along the first direction changes along the first direction, that is, the duty ratio of the core layer 322 and the cladding 321 is changed, so that the effective refractive index difference of the light spot in the grating waveguide 320 changes, thereby achieving the expansion of the light spot radius by 2 to 3 times in the third direction.

[0055] It should be understood that in the grating waveguide 320, only the interval length between the multiple core layers 322 may change along the first direction, or only the length of the multiple core layers 322 along the first direction may change along the first direction, or both the interval length between the multiple core layers 322 and the length of the multiple core layers 322 along the first direction may change along the first direction. In addition, the length of the multiple core layers 322 along the first direction changing along the first direction may be understood as the length becoming larger or smaller, etc., but the overall length increases, and the change may be regular (periodic) or irregular, and the embodiment of the present application does not limit this.

[0056] Optionally, the grating waveguide 320 includes a transmitting portion 324 and a receiving portion 323, which can also be understood as the grating waveguide 320 can be divided into a transmitting portion 324 and a receiving portion 323, wherein the periodic variation of the transmitting portion 324 is different from the periodic variation of the receiving portion 323. The periodic variation can be understood as the frequency and variation of the multiple core layers 322 changing along the first direction.

[0057] For example, Figure 4 As shown, the transmitting part 324 is used to output the light spot input by the optical fiber array 330 as spatial light, and the receiving part 323 is used to output the spatial light returned by the LCOS to the optical fiber array 330, wherein the periodic variation of the transmitting part 324 is smaller than the periodic variation of the receiving part 323, because the goal of the transmitting part 324 is to expand the small light spot into a large light spot, the speed of change of its light spot size can be slower, so the interval between the core layers 322 of the transmitting part 324 is larger, and the periodic variation is smaller, while the goal of the receiving part 323 is to reduce the large light spot to a small light spot. In order to prevent the leakage of the large light spot and reduce the insertion loss, the speed of change of its light spot size needs to be faster, so the interval between the core layers 322 of the receiving part 323 is smaller, more dense, and the periodic variation is larger. While reducing the insertion loss, the use of the transmitting part 324 with a smaller periodic variation also reduces the manufacturing difficulty and process requirements of the entire planar optical waveguide.

[0058] It should be noted that Figure 4 The transmitting part 324 corresponds to three channels, and the receiving part 323 corresponds to one channel. However, in actual situations, according to different needs of users, the transmitting part 324 can also include more or fewer channels, and the receiving part 323 can also include more channels, which will not be repeated in the embodiments of the present application.

[0059] It should be understood that the periodic variation of the transmitting part 324 and the periodic variation of the receiving part 323 may also adopt other different designs according to the actual needs of the user, and the embodiments of the present application are not limited to this.

[0060] It should be understood that the grating waveguide 320 is a structure loaded on an ordinary planar optical waveguide, and the transition waveguide 310 may or may not be loaded with other structures. When no other structures are loaded, the transition waveguide 310 is the planar optical waveguide itself.

[0061] Optional, such as Figure 5 As shown, the transition waveguide 310 includes n transition regions 311, and the areas of the n transition regions 311 vary along a first direction, where n is an integer greater than 1. The areas of the n transition regions 311 vary along the first direction by a first preset value, and the first preset value of each transition region 311 in the n transition regions 311 is different.

[0062] Exemplarily, along the first direction, there are transition region 1, transition region 2, transition region 3 and transition region 4, the area of ​​transition region 1 is 3, the first preset value of transition region 1 is 1, then the area of ​​transition region 2 is 1 larger than the area of ​​transition region 1, which is 4, the first preset value of transition region 2 is -2, then the area of ​​transition region 3 is 2 smaller than the area of ​​transition region 2, which is 2, the first preset value of transition region 3 is 4, then the area of ​​transition region 4 is 4 larger than the area of ​​transition region 2, which is 6.

[0063] Optionally, other methods may be used to represent the change in the area of ​​the n transition regions 311 along the first direction. Assuming that the lengths of the n transition regions 311 along the first direction remain unchanged, let x be the coordinate value of the transition waveguide 310 along the first direction, let y be the length of the transition waveguide 310 along the second direction at x, we have:

[0064] y=Ax 2 +Bx+C

[0065] Among them, A, B and C are all constants. That is, the length of the transition region 311 along the second direction is different at different coordinate values ​​along the first direction, and the length of the transition region 311 along the second direction will change with the change of x, that is, the lengths of the n transition regions 311 along the second direction are changing, so the areas of the n transition regions 311 change along the first direction, and the functions of x and y are nonlinear.

[0066] It should be understood that no matter whether the areas of the n transition regions 311 increase or decrease, the area of ​​the first transition region 311 (close to the optical fiber array 330) is smaller than the area of ​​the last transition region 311 (close to the grating waveguide 320), and the changes in the areas of the intermediate transition regions 311 should be transitional, that is, the overall area change trend is getting larger and larger.

[0067] In addition, the n transition regions 311 may be rectangular, trapezoidal or irregular in shape, for example, the edges of the n transition regions 311 along the first direction (the same direction as the first direction) are curves, which is not limited in this embodiment of the present application.

[0068] Optionally, n is greater than or equal to 12, that is, the transition waveguide 310 includes greater than or equal to 12 transition regions 311, so as to achieve an expansion of the spot radius by 24 times or more in the second direction.

[0069] Before using the planar optical waveguide provided in the embodiment of the present application, the planar optical waveguide needs to be assembled and matched with the optical fiber array. Optionally, the planar optical waveguide includes a first alignment channel, which is used to match the second alignment channel of the optical fiber array.

[0070] Specifically, the first alignment channel is the first and last transition regions in the transition waveguide, that is, the first transition region and the last transition region along the second direction. Similarly, the second alignment channel is the first and last fiber ports in the fiber array, that is, the first fiber port and the last fiber port along the second direction, because the first alignment channel and the second alignment channel are one-to-one corresponding and are arranged periodically. During assembly, it is sufficient to track the optical path insertion loss of the first alignment channel at the edge, and adjust the position of the fiber array and the planar optical waveguide. When the insertion loss of the first alignment channel at the edge is the lowest, the coupling position of the fiber array and the planar optical waveguide is optimal, and then fixed. Because all the fiber ports of the fiber array are arranged periodically, when the coupling insertion loss of the first and last channels is the lowest, the middle channel (the middle transition region and the fiber port) is also in the corresponding position. Specifically, the overall insertion loss of the planar optical waveguide is less than or equal to 0.3dB.

[0071] Optionally, the first alignment channel may also be an additional alignment channel in the planar optical waveguide, and the second alignment channel may also be an additional alignment channel in the optical fiber array. It is only necessary to ensure that after the first alignment channel and the second alignment channel are matched, the coupling position of the optical fiber array and the planar optical waveguide is optimal and the insertion loss is minimum. The embodiments of the present application do not impose any restrictions on this.

[0072] It should also be noted that the optical fiber array used in the embodiment of the present application is an optical fiber array with a grinding angle that matches the planar optical waveguide, and the end face angle (the angle between the end face and the horizontal plane) where the optical fiber array connects to the planar optical waveguide is 0 to 8 degrees, one end of the grating waveguide is connected to the transition waveguide, and the other end of the grating waveguide is exposed in space, and the end face angle of the other end of the grating waveguide is 0 to 8 degrees.

[0073] In the embodiment of the present application, the planar optical waveguide is used as an optical connection module (or as a light spot shaping module), which is a single-layer waveguide structure, and the waveguide refractive index difference is 0-10%. The device using the planar optical waveguide can achieve the expansion of the spatial large mode field light spot without using a lens. One end of the planar optical waveguide is connected to the optical fiber array, and the other end is the spatial light. The effective refractive index difference of the waveguide is adjusted by changing the duty ratio of the cladding and the core layer in the grating waveguide to achieve vertical expansion of the spot. The area change of multiple transition areas in the transition waveguide is used to achieve horizontal expansion of the spot, and the 4.8 micron × 4.8 micron light spot is expanded to 14 microns (vertical direction) × 100 microns (horizontal direction) or larger. The shape and refractive index change of the waveguide itself are used to adjust the size of the light spot, and the periodic refractive index modulation is realized, eliminating the processing of the microlens array and the precision assembly requirements.

[0074] The planar optical waveguide provided in the embodiment of the present application is introduced above. The following describes the related devices provided in the embodiment of the present application in conjunction with the accompanying drawings.

[0075] like Figure 6 As shown, the embodiment of the present application provides a wavelength selection switch 600, the wavelength selection switch 600 includes the above Figures 3 to 5 The planar optical waveguide 601, FA 602, grating 603 and LCOS 604 described in some embodiments, the wavelength selective switch 600 and Figure 1 The wavelength selective switch shown corresponds to .

[0076] It should be understood that the planar optical waveguide provided in the embodiment of the present application can be used not only in wavelength selective switches, but also in optical devices such as spatial filters and spatial isolators.

[0077] like Figure 7 As shown, the embodiment of the present application provides a communication device 700, the communication device 700 includes the above Figures 3 to 5 Some embodiments describe a planar optical waveguide 701.

[0078] Exemplarily, the communication device 700 is a reconfigurable optical add-drop multiplexer (ROADM), and the communication device 700 includes: Figure 6 The wavelength selection switch 702 shown in FIG. 1 includes the wavelength selection switch 702 Figures 3 to 5 Some embodiments describe a planar optical waveguide 701.

[0079] Those of ordinary skill in the art will appreciate that the structural units of the examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or in a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0080] In several embodiments provided in the present application, it should be understood that the disclosed structure can be implemented in other ways. For example, the embodiments described above are merely schematic. For example, the division of the structure can be divided in other ways in actual implementation, such as multiple units or components can be combined or integrated into another structure, or some features can be ignored. Some or all of the structures can be selected according to actual needs to achieve the purpose of the present embodiment. Another point is that the coupling or direct coupling or communication connection between each other shown or discussed can be an indirect coupling or communication connection through some interfaces, structures or units, which can be electrical, mechanical or other forms.

[0081] In addition, each structure in the embodiment of the present application may be integrated into one structure, or each structure may exist physically separately, or two or more structures may be integrated into one structure.

[0082] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A planar optical waveguide, characterized in that: Including transition waveguides and grating waveguides; One end of the transition waveguide is used to connect to an external optical fiber array, and the other end of the transition waveguide is connected to the grating waveguide; The grating waveguide comprises a cladding layer and a plurality of core layers, the cladding layer is used to surround the plurality of core layers, and the first length and / or the second length varies along the first direction; The first direction is the direction from the optical fiber array to the grating waveguide, the first length is the spacing length between the multiple core layers, and the second length is the length of the multiple core layers along the first direction.

2. The planar optical waveguide according to claim 1, characterized in that The transition waveguide includes n transition regions, areas of the n transition regions vary along the first direction, and n is an integer greater than 1.

3. The planar optical waveguide according to claim 2, characterized in that The areas of the n transition regions vary by a first preset value along the first direction, and the first preset value of each transition region in the n transition regions is different.

4. The planar optical waveguide according to claim 2 or 3, characterized in that: The sides of the n transition regions along the first direction are curved lines.

5. The planar optical waveguide according to any one of claims 1 to 4, characterized in that: The grating waveguide includes a transmitting part and a receiving part, and the periodic variation amount of the transmitting part is different from the periodic variation amount of the receiving part.

6. The planar optical waveguide according to any one of claims 1 to 5, characterized in that: One end of the grating waveguide is connected to the transition waveguide, the other end of the grating waveguide is exposed in space, and the angle between the end face of the other end of the grating waveguide and the horizontal plane is 0 to 8 degrees.

7. The planar optical waveguide according to any one of claims 1 to 6, characterized in that: Also included is a first alignment channel for mating with a second alignment channel of the optical fiber array.

8. The planar optical waveguide according to any one of claims 2 to 7, characterized in that: n is greater than or equal to 12.

9. A wavelength selective switch, characterized in that: The invention comprises a planar optical waveguide as claimed in any one of claims 1 to 8.

10. A communication device, characterized in that: The invention comprises a planar optical waveguide as claimed in any one of claims 1 to 8.

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