Array waveguide grating and router

Abstract

The invention discloses an array waveguide grating and a router, relates to the technical field of signal transmission, and aims to solve the problems of how to reduce the optical loss of the array waveguide grating router and improve the transmission efficiency of optical signals. The array waveguide grating comprises a first waveguide structure, a second waveguide structure and a connecting waveguide, the connecting waveguide comprises a first waveguide section and a second waveguide section which are connected in sequence, the first waveguide section is connected with the first waveguide structure, and the second waveguide section is connected with the second waveguide structure; the width of the first waveguide section and the width of the second waveguide section are gradually reduced in the direction from the first waveguide section to the second waveguide section, the two surfaces of the first waveguide section in the width direction are first cambered surfaces, and the two surfaces of the second waveguide section in the width direction are first planes. The present application is used for transmitting signals.

Description

Technical Field

[0001] The present application relates to the technical field of signal transmission, and particularly to an arrayed waveguide grating and a router. Background Art

[0002] An arrayed waveguide grating router is a passive optical device based on the principle of wavelength division multiplexing, and is used for demultiplexing and multiplexing optical signals. The arrayed waveguide grating router has a high optical signal transmission efficiency and is widely applied in intelligent computer networks, industrial Internet and large-scale data centers.

[0003] In the prior art, the sizes and modes of different waveguides in an arrayed waveguide grating router may not match, which may cause a drastic change in the optical field distribution when the optical signal is transmitted between different waveguides, resulting in loss of the optical signal during the transmission process and still having a great impact on the transmission efficiency of the optical signal. Summary of the Invention

[0004] The present application provides an arrayed waveguide grating and a router, which solve the problem of how to reduce the optical loss of the arrayed waveguide grating router and improve the transmission efficiency of the optical signal.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides an arrayed waveguide grating, which includes a first waveguide structure, a second waveguide structure and a connecting waveguide. The connecting waveguide includes a first waveguide section and a second waveguide section connected in sequence. The first waveguide section is connected to the first waveguide structure, and the second waveguide section is connected to the second waveguide structure. Along the direction from the first waveguide section to the second waveguide section, the widths of both the first waveguide section and the second waveguide section gradually decrease, and the two surfaces of the first waveguide section in the width direction are first arc surfaces, and the two surfaces of the second waveguide section in the width direction are first flat surfaces.

[0007] The arrayed waveguide grating provided by the present application enables the optical signal to transition from wide to narrow when transmitting in the first waveguide section and also from wide to narrow when transmitting in the second waveguide section during the process of transmitting from the first waveguide section to the second waveguide section; during the process of transmitting from the second waveguide section to the first waveguide section, the optical signal can transition from narrow to wide when transmitting in the second waveguide section and also from narrow to wide when transmitting in the first waveguide section. Thus, the transition of the optical signal can be relatively smooth, making the optical field distribution more stable when the optical signal transmits between the first waveguide structure and the second waveguide structure, thereby reducing the loss of the optical signal and improving the transmission efficiency of the optical signal. Moreover, the gradual change modes of the first waveguide section and the second waveguide section are different, which can make the first waveguide section and the second waveguide section more reasonably adapt to the first waveguide structure and the second waveguide structure, and further make the transmission transition of the optical signal smoother, reducing the optical loss.

[0008] Optionally, along the length direction of the connecting waveguide, the first waveguide section includes a first end and a second end, the second waveguide section includes a third end and a fourth end, the first end is connected to the first waveguide structure, the second end is connected to the third end, and the fourth end is connected to the second waveguide structure; the widths of the second end and the third end are equal. In this way, the optical signal can also transition more smoothly between the first waveguide section and the second waveguide section, reducing the optical loss and improving the transmission efficiency of the optical signal.

[0009] Optionally, the thicknesses of the first waveguide section and the second waveguide section are equal. In this way, the smoothness of the optical signal transmission between the first waveguide section and the second waveguide section can be further improved, further reducing the optical loss.

[0010] Optionally, any position in the length direction of the first waveguide section is the first position, the length of the part of the connecting waveguide between the first end and the first position is the first length, the width of the connecting waveguide at the first position is the first width, and the first length and the first width satisfy an exponential function relationship.

[0011] Since the exponential function curve gradually becomes steeper as the independent variable changes, the first length and the first width satisfying the exponential function relationship can make the width change of the first waveguide section gradually increase, that is, the closer to the second waveguide section, the greater the width change degree of the first waveguide section. In this way, the closer the optical signal is to the second waveguide section in the first waveguide section, the better the focusing effect, so that more optical signals can be transmitted to the second waveguide section to improve the transmission efficiency of the optical signal.

[0012] Optionally, the first length and the first width satisfy: where 0 ≤ x 1 ≤ L 1 , W 1 (x 1 ) is the first width, Winput is the width of the first end, W mid is the width of the second end, L 1 is the length of the first waveguide section, x 1 is the first length. In this way, the relationship between the first length and the first width can be defined according to the width of the first end of the first waveguide section, the width of the second end, and the length of the first waveguide section, so that the width change of the first waveguide section is more appropriate, thereby enabling the optical signal to better transition in the first waveguide section and improving the transmission efficiency of the optical signal.

[0013] Optionally, any position in the length direction of the second waveguide section is the second position, the length of the connecting waveguide located between the first end and the second position is the second length, and the second width is the width of the connecting waveguide at the second position. The second length and the second width satisfy: where L 1 ≤x 2 ≤L), W 2 (x 2 ) is the second width, W mid is the width of the second end, W output is the width of the fourth end, L 2 is the length of the second waveguide section, L 1 is the length of the first waveguide section, x 2 is the second length. In this way, the relationship between the second length and the second width can be defined according to the width of the second end of the first waveguide section, the width of the fourth end of the second waveguide section, the length of the first waveguide section, and the length of the second waveguide section, so that the width change of the second waveguide section is more appropriate, thereby enabling the optical signal to better transition in the second waveguide section and improving the transmission efficiency of the optical signal.

[0014] Optionally, the two first arc surfaces are symmetrically arranged. In this way, when the optical signal is transmitted in the first waveguide section, the two first arc surfaces can make the optical signal gradually converge towards the middle of the first waveguide section, so that the optical signal can be transmitted to the second waveguide section more smoothly, thereby improving the transmission efficiency of the optical signal between the first waveguide section and the second waveguide section.

[0015] Optionally, the two first planes are symmetrically arranged. In this way, when the optical signal is transmitted in the second waveguide section, the two first planes can make the optical signal gradually converge towards the middle of the second waveguide section, so that the optical signal can be transmitted to the second waveguide structure more smoothly, thereby improving the transmission efficiency of the optical signal between the second waveguide section and the second waveguide structure.

[0016] Optionally, the arrayed waveguide grating further includes an input waveguide, an input coupler, an array of waveguides, an output coupler, and an output waveguide that are connected in sequence; wherein, one of the first waveguide structure and the second waveguide structure is the input waveguide, and the other is the input coupler. In this way, the optical signal can smoothly transition during the process of being transmitted from the input waveguide to the input coupler.

[0017] Optionally, one of the first waveguide structure and the second waveguide structure is the input coupler, and the other is the array of waveguides. In this way, the optical signal can smoothly transition during the process of being transmitted from the input coupler to the array of waveguides.

[0018] Optionally, one of the first waveguide structure and the second waveguide structure is the array of waveguides, and the other is the output coupler. In this way, the optical signal can smoothly transition during the process of being transmitted from the array of waveguides to the output coupler.

[0019] Optionally, one of the first waveguide structure and the second waveguide structure is the output coupler, and the other is the output waveguide. In this way, the optical signal can smoothly transition during the process of being transmitted from the output coupler to the output waveguide.

[0020] Optionally, the array of waveguides includes Euler bend segments, and each Euler bend segment includes two arc segments that are symmetrically arranged. The ends of the two arc segments that are far from each other are connection ends. One connection end is connected to the input coupler, and the other connection end is connected to the output coupler; any position on the arc segment is the third position, and the length of the part of the arc segment between the connection end and the third position is the third length. The curvature of the arc segment at the third position and the third length satisfy: where k(s) is the curvature of the arc segment at the third position, R min is the radius of curvature of the arc segment at the connection end, L 3 is the total length of the Euler bend segment, and s is the third length. In this way, the curvatures at different positions in the arc segment can be reasonably set so that the curvatures at different positions in the arc segment are different and gradually increase, and the change is smoother, avoiding that the curvature at each position of the Euler bend segment is relatively small, so that the optical signal can transition more smoothly during transmission in the Euler bend segment, further improving the transmission efficiency of the optical signal.

[0021] Optionally, the total length of the Euler bend segment satisfies: where θ is the bending angle of the Euler bend segment. Determining the total length of the Euler bend segment through the radius of curvature of the arc segment at the connection end and the bending angle of the Euler bend segment can make the total length of the Euler bend segment within a more appropriate range, so as to facilitate smoother transition of the Euler bend segment and improve the transmission efficiency of the optical signal in the Euler bend segment.

[0022] Second aspect, the present application also provides a router, which includes a housing and the above-mentioned arrayed waveguide grating, and the arrayed waveguide grating is disposed inside the housing. Description of the Drawings

[0023] Figure 1 FIG. is a schematic structural diagram of a router provided by an embodiment of the present application;

[0024] Figure 2 For Figure 1 FIG. is a schematic structural diagram of the arrayed waveguide grating in the router shown;

[0025] Figure 3 For Figure 2 FIG. is a schematic diagram of the working principle of the arrayed waveguide grating shown;

[0026] Figure 4 For Figure 2 FIG. is a schematic diagram of the principle of the input coupler in the arrayed waveguide grating shown;

[0027] Figure 5 FIG. is a schematic structural diagram of the curved section of the arrayed waveguide when the curved section in the related art is an arc curve;

[0028] Figure 6 FIG. is a schematic structural diagram of the Euler curved section provided by an embodiment of the present application;

[0029] Figure 7 For Figure 2 FIG. is a schematic structural diagram of the connecting waveguide shown.

[0030] Reference Signs:

[0031] 100, router; 10, housing; 20, arrayed waveguide grating;

[0032] 1, input waveguide;

[0033] 2, input coupler; 21, groove surface;

[0034] 3, arrayed waveguide; 31, Euler curved section; 311, first Euler curved section; 312, second Euler curved section; 313, arc section; 3131, connection end; 32, curved section; 33, straight section;

[0035] 4, output coupler;

[0036] 5, output waveguide;

[0037] 6, substrate;

[0038] 7, connecting waveguide; 71, first waveguide section; 711, first end; 712, second end; 713, first arc surface; 72, second waveguide section; 721, third end; 722, fourth end; 723, first plane. Detailed implementation manners

[0039] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0040] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0041] The terms "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0042] In the description of the present application, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations. In addition, when describing pipelines or channels, the terms "connected" and "coupled" used in the present application have the meaning of conducting. The specific meaning needs to be understood in combination with the context.

[0043] In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific manner.

[0044] With the rapid development of intelligent computing networks, industrial Internet infrastructures, and large-scale data centers, data traffic shows a high growth trend. The growth of traffic not only poses higher performance requirements on the existing network architecture but also poses a huge challenge to traditional electrical interconnection methods. Especially in terms of bandwidth, power consumption, and signal integrity, electrical interconnection is difficult to meet the needs of future high-speed and high-capacity communications. In contrast, optical interconnection technology, with its inherent advantages in transmission speed, working bandwidth, energy consumption efficiency, and signal quality, has become a key technology to address this challenge and is widely used in large data centers, intelligent network nodes, and high-speed on-chip interconnections. The low latency, high throughput, and high anti-interference characteristics of optical interconnection technology make it particularly important in large-scale distributed computing environments and can effectively support new-generation artificial intelligence, cloud computing, and big data processing tasks.

[0045] Among many optical interconnection technologies, the optical interconnection architecture based on Arrayed Waveguide Grating Router (AWGR) has gradually received wide attention due to its excellent performance and scalability. AWGR is a passive optical device based on the principle of wavelength division multiplexing and is used to implement the functions of demultiplexing and multiplexing optical signals. AWGR has the advantages of low insertion loss, high channel isolation, wide wavelength coverage, and high stability, and can effectively meet the needs of high-density and high-bandwidth communications. In large data centers, AWGR can achieve fast optical switching between different nodes through wavelength routing, which not only significantly reduces the number of optoelectronic conversions, thereby reducing power consumption, but also greatly improves the throughput capacity of the network. In high-speed on-chip interconnections, AWGR can achieve low-latency optical computing and communication through its compact design and high wavelength utilization efficiency.

[0046] However, in related technologies, the arrayed waveguide grating router usually couples and connects waveguides with various different sizes, shapes, and modes. During the transmission of optical signals between different waveguides, when passing through the transition region between adjacent waveguides, it will cause a drastic change in the optical field distribution, thereby causing the problem of optical field mode mismatch. This will increase the loss of optical signals and affect the transmission efficiency of optical signals.

[0047] And at least part of the arrayed waveguides in the arrayed waveguide grating router will be set as a bent structure to facilitate the connection between the arrayed waveguides and other components. In related technologies, the bent section of the arrayed waveguide is usually bent into a circular arc structure with a fixed curvature. In the case of a small bending radius, it is easy to cause optical field mode mismatch, resulting in a high bending loss of optical signals and affecting the transmission efficiency of optical signals.

[0048] Based on this, please refer to Figure 1 , Figure 1Schematic diagram of the structure of a router 100 provided by an embodiment of the present application. The present application provides a router 100. The router 100 includes a chassis 10 and an arrayed waveguide grating 20. The arrayed waveguide grating 20 is disposed inside the chassis 10 and is used for transmitting optical signals, and the chassis 10 is used for protecting the arrayed waveguide grating 20.

[0049] In some embodiments, please refer to Figure 2 , Figure 2 is Figure 1 Schematic diagram of the structure of the arrayed waveguide grating 20 in the router 100 shown. The arrayed waveguide grating 20 may include an input waveguide 1, an input coupler 2, an array of waveguides 3, an output coupler 4, and an output waveguide 5 connected in sequence. Among them, the number of the array of waveguides 3 may be multiple, and the multiple arrays of waveguides 3 are arranged side by side. The number of the output waveguides 5 may be multiple and is used for outputting multiple optical signals. The number of the input waveguides 1 may be one or multiple. In the present application, an example is given with the number of the input waveguides 1 being multiple.

[0050] The input waveguide 1 is used for receiving optical signals. The input waveguide 1 is connected to the input end of the input coupler 2 and is used for transmitting the received optical signals to the input coupler 2. The output end of the input coupler 2 is connected to the input ends of the multiple arrays of waveguides 3 and is used for distributing the received optical signals into each array of waveguides 3 so that the optical signals are transmitted in each array of waveguides 3. The output ends of the multiple arrays of waveguides 3 are connected to the input end of the output coupler 4 and are used for transmitting the optical signals in each array of waveguides 3 to the output coupler 4. The output end of the output coupler 4 is connected to the input end of the output waveguide 5. The output coupler 4 is used for converging the optical signals of the multiple arrays of waveguides 3 and distributing the converged optical signals to the output waveguide 5 for output through the output waveguide 5.

[0051] Exemplarily, please refer to Figure 3 , Figure 3 is Figure 2 Schematic diagram of the working principle of the arrayed waveguide grating 20 shown. The number of the input waveguides 1 is 8, and the numbers of the 8 input waveguides 1 in Figure 3 are respectively 1-8. The number of the output waveguides 5 is also 8, and the numbers of the 8 output waveguides 5 in Figure 3 are respectively a-g.

[0052] Each input waveguide 1 inputs optical signals of 8 wavelengths, and the 8 wavelengths of optical signals are respectively Figure 3 in 1 -λ 8 , and after being converted by the input coupler 2, the multiple arrays of waveguides 3, and the output coupler 4, the 8 optical signals in any one input waveguide 1 can all be output on the 8 output waveguides 5. For example, the 8 optical signals λ 1 -λ8 After being converted by the input coupler 2, the multiple array waveguides 3, and the output coupler 4, the λ 1 optical signal will be output on the output waveguide 5 numbered d, λ 2 optical signal will be output on the output waveguide 5 numbered e, λ 3 optical signal will be output on the output waveguide 5 numbered f, and so on, λ 8 optical signal will be output on the output waveguide 5 numbered c, that is, there is a misalignment of three channels between the input signal and the output signal. The output modes of the 8 optical signals in the other input waveguides 1 after conversion are similar to those of the input waveguide 1 numbered 4.

[0053] In this way, 8 optical signals of different wavelengths will also be output on each output waveguide 5, thus realizing a non-blocking 64-channel communication link and reducing the number and cost of optical switches.

[0054] In some other examples, the number of array waveguides 3 can also be one, and only one optical signal is transmitted at this time. This application takes the number of array waveguides 3 being multiple as an example for illustration.

[0055] In some examples, the arrayed waveguide grating 20 may further include a substrate 6, and the input waveguide 1, the input coupler 2, the array waveguides 3, the output coupler 4, and the output waveguide 5 are all connected to the substrate 6 to support the input waveguide 1, the input coupler 2, the array waveguides 3, the output coupler 4, and the output waveguide 5 through the substrate 6.

[0056] In some embodiments, the input coupler 2 may be a Rowland circle grating structure. Specifically, please refer to Figure 4 Figure 4 which is Figure 2 a schematic diagram of the principle of the input coupler 2 in the shown arrayed waveguide grating 20. The groove surface 21 of the input coupler 2 is located on a circle with a radius of R (i.e., Figure 4 the large circle with the center C in Figure 4 ), and after the input waveguide 1 is connected to the input coupler 2, the incident point of the optical signal output from the input waveguide 1 in the input coupler 2 is located on a circle with a radius of r (i.e., Figure 4 the small circle with the center M in 1 ), for example, the incident point is P in

[0057] wherein, R = 2r, and the circle with a radius of R is tangent to the circle with a radius of r, and the tangent point is the midpoint O of the groove surface 21, then the circle with a radius of r is the Rowland circle. 1 The optical signal is transmitted from the incident point P Figure 4 to the groove surface 21, and after diffraction by the groove surface 21, the exit point (such as the point P in 2 ​) is also on a circle with a radius of r. After the array waveguide 3 is connected to the input coupler 2, the receiving point of the array waveguide 3 for receiving the optical signal can be located at P 2 position. In this way, by setting the input coupler 2 as a Rowland circle grating structure, the phase matching and transmission efficiency of the optical path can be ensured, and efficient wavelength beam splitting and multiplexing can be achieved.

[0058] Among them, the groove pitch d of the groove surface 21 of the input coupler 2 (i.e., Figure 4 the pitch d shown in) satisfies the grating equation: mλ = d(sinθ + sinα), and the optical path difference ΔL between two adjacent array waveguides 3 when the optical signal is transmitted in the multiple array waveguides 3 needs to satisfy: ΔL = mλ, where m is the diffraction order, λ is the wavelength of light; α is the incident angle of the incident light (such as Figure 4 the light ray P in) 1 O), that is, Figure 4 the included angle between P 1 O and OC in, O is the intersection point of the incident light ray P 1 O and the groove surface 21. θ is the diffraction angle of the reflected light ray (such as Figure 4 the light ray OP in) 2 ), that is, Figure 4 the included angle between OP 2 and OC in. In this way, the optical path difference ΔL between two adjacent array waveguides 3 and the groove pitch of the groove surface 21 can be reasonably set according to the above formula to ensure that optical signals of different wavelengths can be effectively separated. By setting the input coupler 2 as a Rowland circle grating structure, the diffraction and focusing of the light beam can be precisely controlled, thereby realizing wavelength separation and signal multiplexing.

[0059] And, the radius r of the Rowland circle can be calculated according to the formula: where n eff is the effective refractive index of the arrayed waveguide grating 20, L is the optical path length from the input waveguide 1 to the array waveguide 3, λ 0 is the central wavelength, and the central wavelength λ 0 is the operating wavelength of the router 100. In this way, the positions of the incident point of the input waveguide 1 and the receiving point of the array waveguide 3 can be reasonably set to ensure the transmission efficiency of the optical signal.

[0060] In some other embodiments, the input coupler 2 can also be other couplers that can distribute the received optical signal to each array waveguide 3, such as a star coupler, etc.

[0061] In some embodiments, the structure of the output coupler 4 can be the same as that of any of the above input couplers 2, and will not be elaborated here.

[0062] In addition, in the design of the arrayed waveguide grating 20, the central wavelength λ also needs to be determined according to the usage requirements of the router 1000 The channel spacing Δλ, the number of channels N, and the free spectral range (FSR). The channel spacing Δλ is the wavelength interval between adjacent channels; the number of channels N is the total number of wavelength channels that the router 100 can multiplex / demultiplex; the free spectral range (FSR) is the spectral range within which the router 100 can correctly split / combine light beams.

[0063] Among them, the free spectral range (FSR) and the optical path difference ΔL between two adjacent array waveguides 3 among the multiple array waveguides 3 satisfy: Among them, n eff is the effective refractive index of the arrayed waveguide grating 20.

[0064] In order to calculate the optical path difference ΔL between two adjacent array waveguides 3 among the multiple array waveguides 3, the phase delay Δφ introduced by the optical path difference between two adjacent array waveguides 3 can be made to satisfy: Among them, λ is the wavelength of light.

[0065] Moreover, in order to make the optical signal undergo constructive interference at the output end of the array waveguide 3, the phase matching condition must be satisfied: Δφ = 2π*m. From this, it can be obtained that the optical path difference ΔL between two adjacent array waveguides 3 among the multiple array waveguides 3 satisfies: The basic parameters of the arrayed waveguide grating 20 can be determined through the above formula to ensure that the optical signal can be effectively split and multiplexed through the arrayed waveguide grating 20.

[0066] In some embodiments, in order to reduce the relatively high bending loss that occurs when the bending radius of the array waveguide 3 is small, thereby affecting the transmission efficiency of the optical signal. Please continue to refer to Figure 2 , the array waveguide 3 may include an Euler bending section 31, that is, each of the multiple array waveguides 3 may include an Euler bending section 31. Among them, the Euler bending section 31 conforms to the Euler bending curve.

[0067] Please refer to Figure 5 and Figure 6 , Figure 5 is a schematic structural diagram of the bending section 32 of the array waveguide in the related art when the bending section 32 is an arc bending, Figure 6 is a schematic structural diagram of the Euler bending section 31 provided by the embodiment of the present application. As can be seen from Figure 5 , the radius of the arc bending is equal everywhere, so the curvature does not change either. When the installation position of the array waveguide 3 is restricted by space and the radius of the arc bending is small, the curvature of the arc bending is small everywhere, and relatively high bending loss is likely to occur, affecting the transmission efficiency of the optical signal. Among them, Figure 5 and Figure 6The dashed circles shown are for reference when comparing the bent section 32 with the Euler bent section 31, rather than the actual structure.

[0068] Compared with arc bending, as can be seen from Figure 6 the curvature of the Euler bent section 31 can vary smoothly, that is, the curvatures at different positions are different, and the overall bending of the Euler bent section 31 is relatively gentle, so as to avoid that the curvature at each position of the Euler bent section 31 is relatively small. In this way, when the optical signal is transmitted through the Euler bent section 31, the transition is smoother, thereby reducing the leakage of the optical field, reducing the mode mismatch and loss of the optical signal, and improving the transmission efficiency of the optical signal.

[0069] In some examples, the array waveguide 3 can be entirely the Euler bent section 31, or some waveguide sections of the array waveguide 3 can be the Euler bent section 31. In some examples, the number of the Euler bent sections 31 can be one section or multiple sections.

[0070] This application is exemplified by taking the number of the Euler bent sections 31 as two sections. Specifically, please continue to refer to Figure 2 The two Euler bent sections 31 are respectively the first Euler bent section 311 and the second Euler bent section 312, and the array waveguide 3 includes a straight section 33. The first Euler bent section 311 is connected between the output end of the input coupler 2 and the straight section 33. The second Euler bent section 312 is connected between the straight section 33 and the input end of the output coupler 4. In this way, during the process of the optical signal being transmitted from the input coupler 2 to the array waveguide 3 and from the array waveguide 3 to the output coupler 4, the transition of the optical signal can be made smoother, and the transmission efficiency of the optical signal can be improved.

[0071] In some examples, please continue to refer to Figure 6 the Euler bent section 31 includes two arc sections 313 that are symmetrically arranged. The ends of the two arc sections 313 away from each other are connection ends 3131, one connection end 3131 is connected to the input coupler 2, and the other connection end 3131 is connected to the output coupler 4.

[0072] Exemplarily, the two arc sections 313 in the first Euler bent section 311 are respectively the first arc section and the second arc section. The connection end 3131 of the first arc section is connected to the input coupler 2, and the connection end 3131 of the second arc section is connected to the output coupler 4 through the straight section 33 and the second Euler bent section 312. The two arc sections 313 in the second Euler bent section 312 are respectively the third arc section and the fourth arc section. The connection end 3131 of the third arc section is connected to the input coupler 2 through the straight section 33 and the first Euler bent section 311, and the connection end 3131 of the fourth arc section is connected to the output coupler 4.

[0073] Since the shapes of the first arc segment, the second arc segment, the third arc segment, and the fourth arc segment are the same, for convenience of description, they are collectively referred to as arc segment 313 in the following description.

[0074] In some embodiments, the total length of the Euler bending segment 31 satisfies: wherein, R min is the radius of curvature of the arc segment 313 at the connection end 3131, that is, the minimum radius of curvature of the arc segment 313. β is the bending angle of the Euler bending segment 31, that is, the angle between the tangent line at the connection end 3131 of one of the arc segments 313 and the tangent line at the connection end 3131 of the other arc segment 313.

[0075] Determining the total length of the Euler bending segment 31 through the radius of curvature of the arc segment 313 at the connection end 3131 and the bending angle of the Euler bending segment 31 can make the total length of the Euler bending segment 31 within a more appropriate range, thereby facilitating a smoother transition of the Euler bending segment 31 to improve the transmission efficiency of the optical signal in the Euler bending segment 31.

[0076] Moreover, the coordinates (x, y) at any position s in the Euler bending segment 31 can be calculated through the above formula for the total length of the Euler bending segment 31, that is where x(s) is the abscissa at any position s in the Euler bending segment 31, y(s) is the ordinate at any position s in the Euler bending segment 31, and t is the integration variable, that is, the length of the part of the Euler bending segment 31 between any position s and the connection end 3131. In this way, the radius of curvature at different positions of the Euler bending segment 31 can be controlled more precisely to make the transition of the optical signal smoother.

[0077] In some examples, the incident direction of the optical signal output by the input coupler 2 at the first arc segment of the first Euler bending segment 311 can be tangent to the first arc segment, and the tangent point is the connection end 3131 of the first arc segment. The second arc segment can be tangent to the straight line segment 33, and the tangent point is the connection end 3131 of the second arc segment. In this way, the transition of the optical signal during transmission in the input coupler 2, the first Euler bending segment 311, and the straight line segment 33 can be relatively smooth, improving the transmission efficiency of the optical signal.

[0078] The third arc segment of the second Euler bending segment 312 can be tangent to the straight line segment 33, and the tangent point is the connection end 3131 of the third arc segment. The outgoing direction of the optical signal transmitted to the output coupler 4 at the fourth arc segment can be tangent to the fourth arc segment, and the tangent point is the connection end 3131 of the fourth arc segment. In this way, the transition of the optical signal during transmission in the straight line segment 33, the second Euler bending segment 312, and the output coupler 4 can be relatively smooth, improving the transmission efficiency of the optical signal.

[0079] In some embodiments, any position on the arc segment 313 is the third position, the length of the part of the arc segment 313 between the connection end 3131 and the third position is the third length, and the curvature of the arc segment 313 at the third position and the third length satisfy: where k(s) is the curvature of the arc segment 313 at the third position, and R min is the radius of curvature of the arc segment 313 at the connection end 3131, L 3 is the total length of the Euler bending segment 31, and s is the third length.

[0080] That is to say, the curvature at any position in the arc segment 313 and the length of the part of the arc segment 313 between this position and the connection end 3131 satisfy That is, after the total length of the Euler bending segment 31 is determined, the curvature at any position in the arc segment 313 and the length of the part of the arc segment 313 between this position and the connection end 3131 have a linear variation relationship.

[0081] In this way, the curvature at different positions in the arc segment 313 can be reasonably set according to this formula, so that the curvatures at different positions in the arc segment 313 are different, and the curvature gradually increases and the change is smoother, so as to further avoid that the curvature at each position of the Euler bending segment 31 is relatively small, so that the optical signal is more stable during transmission in the Euler bending segment 31, and the transmission efficiency of the optical signal is further improved.

[0082] In some embodiments, please continue to refer to Figure 2 , the arrayed waveguide grating 20 may further include a first waveguide structure, a second waveguide structure, and a connecting waveguide 7. The connecting waveguide 7 is used to connect the first waveguide structure and the second waveguide structure, so that the optical signal can smoothly transition when transmitting between the first waveguide structure and the second waveguide structure, and reduce the loss of the optical signal.

[0083] Please refer to Figure 7 , Figure 7 is Figure 2 the schematic structural diagram of the connecting waveguide 7 shown. The connecting waveguide 7 may include a first waveguide segment 71 and a second waveguide segment 72 connected in sequence. The first waveguide segment 71 is connected to the first waveguide structure, and the second waveguide segment 72 is connected to the second waveguide structure. Specifically, along the length direction of the connecting waveguide 7 ( Figure 7 the direction X in), the first waveguide segment 71 includes a first end 711 and a second end 712, the second waveguide segment 72 includes a third end 721 and a fourth end 722, the first end 711 is connected to the first waveguide structure, the second end 712 is connected to the third end 721, and the fourth end 722 is connected to the second waveguide structure.

[0084] It can be understood that since the width of the first end 711 of the first waveguide segment 71 (i.e., Figure 7the dimension in the width direction Y) is greater than the width of the fourth end 722 of the second waveguide section 72 (i.e., Figure 7 the dimension in the width direction Y), and the connecting waveguide 7 is used for the optical signal to transition between the first waveguide structure and the second waveguide structure. Therefore, the width of the first waveguide structure is also greater than the width of the second waveguide structure.

[0085] In some examples, the width of the first waveguide structure can be equal to the width of the first end 711 of the first waveguide section 71, and the width of the second waveguide structure can be equal to the width of the fourth end 722 of the second waveguide section 72. In this way, the optical signal can also transition more smoothly between the first waveguide structure and the connecting waveguide 7, and between the connecting waveguide 7 and the second waveguide structure, reducing optical loss.

[0086] In some examples, the thickness of the first waveguide structure can also be the same as the thickness of the first waveguide section 71 (i.e., Figure 7 the dimension in the thickness direction Z), and the thickness of the second waveguide structure can also be the same as the thickness of the second waveguide section 72 (i.e., Figure 7 the dimension in the width direction Z). In this way, the smoothness of the optical signal transition between the first waveguide structure and the connecting waveguide 7, and between the connecting waveguide 7 and the second waveguide structure can be further improved, reducing optical loss.

[0087] In some examples, one of the first waveguide structure and the second waveguide structure is the input waveguide 1, and the other is the input coupler 2. That is to say, when the dimensions of the waveguides at the input ends of the input waveguide 1 and the input coupler 2 are different, the input waveguide 1 and the input coupler 2 can be connected through a connecting structure so that the optical signal can transition smoothly during the process of transmitting from the input waveguide 1 to the input coupler 2. Among them, when there are multiple input waveguides 1, each input waveguide 1 is connected to a connecting waveguide 7.

[0088] In some examples, one of the first waveguide structure and the second waveguide structure is the input coupler 2, and the other is the array waveguide 3. That is to say, when the dimensions of the waveguides at the output end of the input coupler 2 and the array waveguide 3 are different, the input coupler 2 and the array waveguide 3 can be connected through the connecting waveguide 7 so that the optical signal can transition smoothly during the process of transmitting from the input coupler 2 to the array waveguide 3. Among them, each array waveguide 3 is connected to a connecting waveguide 7.

[0089] In some examples, one of the first waveguide structure and the second waveguide structure is the array waveguide 3, and the other is the output coupler 4. That is to say, when the dimensions of the waveguides at the input ends of the array waveguide 3 and the output coupler 4 are different, the array waveguide 3 and the output coupler 4 can be connected through the connecting waveguide 7 so that the optical signal can transition smoothly during the process of transmitting from the array waveguide 3 to the output coupler 4. Among them, each array waveguide 3 is connected to a connecting waveguide 7.

[0090] In some examples, one of the first waveguide structure and the second waveguide structure is the output coupler 4, and the other is the output waveguide 5. That is, when the waveguide at the output end of the output coupler 4 has a different size from the output waveguide 5, the output coupler 4 and the output waveguide 5 can be connected by a connecting waveguide 7 so that the optical signal can smoothly transition during the process of being transmitted from the output coupler 4 to the output waveguide 5. Among them, each output waveguide 5 is connected to a connecting waveguide 7.

[0091] Wherein, along the direction from the first waveguide segment 71 to the second waveguide segment 72, the widths of both the first waveguide segment 71 and the second waveguide segment 72 gradually decrease, and the two surfaces of the first waveguide segment 71 in the width direction are first arc surfaces 713, and the two surfaces of the second waveguide segment 72 in the width direction are first flat surfaces 723. That is to say, the widths of both the first waveguide segment 71 and the second waveguide segment 72 are gradually changing, but the ways of gradual change are different.

[0092] In this way, during the process of the optical signal being transmitted from the first waveguide segment 71 to the second waveguide segment 72, it can transition from wide to narrow when transmitting in the first waveguide segment 71, and the optical signal can also transition from wide to narrow when transmitting in the second waveguide segment 72; during the process of the optical signal being transmitted from the second waveguide segment 72 to the first waveguide segment 71, it can transition from narrow to wide when transmitting in the second waveguide segment 72, and the optical signal can also transition from narrow to wide when transmitting in the first waveguide segment 71, so that the optical signal can have a relatively smooth transition, making the optical field distribution more stable when the optical signal is transmitted between the first waveguide structure and the second waveguide structure, thereby reducing the loss of the optical signal and improving the transmission efficiency of the optical signal.

[0093] Moreover, the different ways of gradual change of the first waveguide segment 71 and the second waveguide segment 72 can make the first waveguide segment 71 and the second waveguide segment 72 more reasonably adapt to the first waveguide structure and the second waveguide structure, and further make the transmission transition of the optical signal smoother and reduce the optical loss.

[0094] In some embodiments, please continue to refer to Figure 7 , the two first arc surfaces 713 of the first waveguide segment 71 in the width direction are symmetrically arranged. In this way, when the optical signal is transmitted in the first waveguide segment 71, the two first arc surfaces 713 can make the optical signal gradually converge towards the middle of the first waveguide segment 71, so that the optical signal can be transmitted to the second waveguide segment 72 more smoothly, thereby improving the transmission efficiency of the optical signal between the first waveguide segment 71 and the second waveguide segment 72.

[0095] In some other embodiments, the two first arc surfaces 713 of the first waveguide segment 71 in the width direction can also be asymmetric, and in this way, the optical signal can also smoothly transition in the connecting waveguide 7.

[0096] In some embodiments, please continue to refer to Figure 7 , the two first planes 723 in the width direction of the second waveguide section 72 are symmetrically arranged. In this way, when the optical signal is transmitted in the second waveguide section 72, the two first planes 723 can make the optical signal gradually converge towards the middle of the second waveguide section 72, so that the optical signal can be transmitted to the second waveguide structure more smoothly, thereby improving the transmission efficiency of the optical signal between the second waveguide section 72 and the second waveguide structure.

[0097] In some other embodiments, the two first planes 723 in the width direction of the second waveguide section 72 can also be asymmetric, and in this way, the optical signal can also make a smooth transition in the connecting waveguide 7.

[0098] In some embodiments, please continue to refer to Figure 7 , the width of the second end 712 of the first waveguide section 71 (i.e., Figure 7 the dimension in the Y direction in Figure 7 ) is equal to the width of the third end 721 of the second waveguide section 72 (i.e.,

[0099] the dimension in the Y direction in

[0100] In some embodiments, the thickness of the first waveguide section 71 (i.e., Figure 7 the dimension in the Z direction in Figure 7 ) is equal to the thickness of the second waveguide section 72 (i.e.,

[0101] In some other embodiments, the thickness of the first waveguide section 71 and the thickness of the second waveguide section 72 can also be unequal, and in the thickness direction of the connecting waveguide 7, the first waveguide section 71 and the second waveguide section 72 can also be connected by a gradually changing arc-shaped surface structure or a planar structure to make the optical signal transition smoothly.

[0102] In some embodiments, any position in the length direction of the first waveguide section 71 is the first position, the length of the part of the connecting waveguide 7 between the first end 711 and the first position is the first length, the width of the connecting waveguide 7 at the first position is the first width, and the first length and the first width satisfy an exponential function relationship.

[0103] Since the exponential function curve gradually becomes steeper as the independent variable changes, the first length and the first width satisfy an exponential function relationship, which can make the width change of the first waveguide section 71 gradually increase. That is to say, the closer to the second waveguide section 72, the greater the width change degree of the first waveguide section 71. In this way, the light signal can be better concentrated in the first waveguide section 71 closer to the second waveguide section 72, so that more light signals can be transmitted to the second waveguide section 72 to improve the transmission efficiency of the light signal.

[0104] In some embodiments, the first length and the first width satisfy: where 0 ≤ x 1 ≤ L 1 , W 1 (x 1 ) is the first width, W input is the width of the first end 711, W mid is the width of the second end 712, L 1 is the length of the first waveguide section 71, x 1 is the first length.

[0105] In this way, the relationship between the first length and the first width can be defined according to the width of the first end 711, the width of the second end 712 and the length of the first waveguide section 71 of the first waveguide section 71, so that the width change of the first waveguide section 71 is more appropriate, and the light signal can be better transitioned in the first waveguide section 71, improving the transmission efficiency of the light signal.

[0106] In some other embodiments, the first length and the first width may also satisfy other exponential function relationships that make the two surfaces of the first waveguide section 71 in the width direction be the first arc surfaces 713. The present application does not make specific limitations on this.

[0107] In some other embodiments, the first length and the first width may also satisfy other curve function relationships, so that the two surfaces of the first waveguide section 71 in the width direction are the first arc surfaces 713. For example, the first length and the first width satisfy a quadratic equation curve.

[0108] In some embodiments, any position in the length direction of the second waveguide section 72 is the second position, the length of the part of the connecting waveguide 7 between the first end 711 and the second position is the second length, and the second width of the width of the connecting waveguide 7 at the second position. The second length and the second width satisfy:

[0109] where L 1 ≤ x 2 ≤ L, W 2 (x 2) is the second width, W mid is the width of the second end 712, W output is the width of the fourth end 722, L 2 is the length of the second waveguide section 72, L 1 is the length of the first waveguide section 71, x 2 is the second length.

[0110] In this way, the relationship between the second length and the second width can be defined according to the width of the second end 712 of the first waveguide section 71, the width of the fourth end 722 of the second waveguide section 72, the length of the first waveguide section 71, and the length of the second waveguide section 72, so that the width change of the second waveguide section 72 is more appropriate, thereby enabling the optical signal to better transition in the second waveguide section 72 and improving the transmission efficiency of the optical signal.

[0111] In some other embodiments, the second length and the second width may also have other linear variation relationships, so that the two surfaces of the second waveguide section 72 in the width direction are the first planes 723. The present application does not make specific limitations on this.

[0112] Although the present application has been described in connection with various embodiments, however, in the process of implementing the claimed present application, those skilled in the art can understand and achieve other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions recited in the claims. Certain measures are recited in mutually different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0113] Although the present application has been described in connection with specific features and their embodiments, it is obvious that various modifications and combinations can be made without departing from the spirit and scope of the present application. Accordingly, the present specification and the drawings are merely exemplary illustrations of the present application defined by the appended claims, and are considered to have covered any and all modifications, variations, combinations, or equivalents within the scope of the present application. Obviously, those skilled in the art can make various changes and modifications 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 equivalent technologies, the present application is also intended to include these changes and modifications.

[0114] The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An arrayed waveguide grating, characterized in that: It comprises a first waveguide structure, a second waveguide structure and a connecting waveguide, wherein the connecting waveguide comprises a first waveguide segment and a second waveguide segment connected in sequence, the first waveguide segment is connected to the first waveguide structure, and the second waveguide segment is connected to the second waveguide structure; Along the direction from the first waveguide segment to the second waveguide segment, the width of the first waveguide segment and the width of the second waveguide segment both gradually decrease, and two surfaces of the first waveguide segment in the width direction are first curved surfaces, and two surfaces of the second waveguide segment in the width direction are first planes.

2. The arrayed waveguide grating according to claim 1, characterized in that: Along the length direction of the connecting waveguide, the first waveguide segment includes a first end and a second end, the second waveguide segment includes a third end and a fourth end, the first end is connected to the first waveguide structure, the second end is connected to the third end, and the fourth end is connected to the second waveguide structure; The second end and the third end have the same width, and / or the first waveguide segment and the second waveguide segment have the same thickness.

3. The arrayed waveguide grating according to claim 2, characterized in that: Any position of the first waveguide segment in the length direction is a first position, the length of the portion of the connecting waveguide between the first end and the first position is a first length, the width of the connecting waveguide at the first position is a first width, and the first length and the first width satisfy an exponential function relationship.

4. The arrayed waveguide grating according to claim 3, characterized in that: The first length and the first width satisfy: Where, 0≤x1≤L1, W1(x1) is the first width, W input is the width of the first end, W mid is the width of the second end, L1 is the length of the first waveguide segment, and x1 is the first length.

5. The arrayed waveguide grating according to any one of claims 2 to 4, characterized in that: Any position of the second waveguide segment in the length direction is a second position, the length of the portion of the connecting waveguide between the first end and the second position is a second length, the width of the connecting waveguide at the second position is a second width, and the second length and the second width satisfy: Wherein, L1≤x2≤L, W2(x2) is the second width, W mid is the width of the second end, W output is the width of the fourth end, L2 is the length of the second waveguide segment, L1 is the length of the first waveguide segment, and x2 is the second length.

6. The arrayed waveguide grating according to any one of claims 1 to 4, characterized in that: The two first arcuate surfaces are symmetrically arranged, and / or the two first planes are symmetrically arranged.

7. The arrayed waveguide grating according to any one of claims 1 to 4, characterized in that: It also includes an input waveguide, an input coupler, an array waveguide, an output coupler and an output waveguide connected in sequence; wherein one of the first waveguide structure and the second waveguide structure is the input waveguide, and the other is the input coupler; And / or, one of the first waveguide structure and the second waveguide structure is the input coupler, and the other is the arrayed waveguide; And / or, one of the first waveguide structure and the second waveguide structure is the arrayed waveguide, and the other is the output coupler; And / or, one of the first waveguide structure and the second waveguide structure is the output coupler, and the other is the output waveguide.

8. The arrayed waveguide grating according to claim 7, characterized in that: The array waveguide includes an Euler bending section, and the Euler bending section includes two arc sections that are symmetrically arranged, and one end of the two arc sections away from each other is a connecting end, one of the connecting ends is connected to the input coupler, and the other connecting end is connected to the output coupler; Any position of the arc segment is a third position, the length of the portion of the arc segment between the connection end and the third position is a third length, and the curvature of the arc segment at the third position and the third length satisfy: Wherein, k(s) is the curvature of the arc segment at the third position, R min is the radius of curvature of the arc segment at the connecting end, L3 is the total length of the Euler bending segment, and s is the third length.

9. The arrayed waveguide grating according to claim 8, characterized in that: The total length of the Euler bending segment satisfies: Wherein, θ is the bending angle of the Euler bending segment.

10. A router, characterized in that: The invention comprises a housing and the arrayed waveguide grating according to any one of claims 1 to 9, wherein the arrayed waveguide grating is arranged in the housing.

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