Dense wavelength division device for improving planar optical waveguide edge channel isolation
By depositing a multilayer bandpass filter film with alternating high and low refractive index materials at the output end of the AWG device, the problem of insufficient isolation of the edge channel of the AWG device is solved, the isolation of the optical signal is enhanced, signal crosstalk is reduced, and the performance of the communication system is improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2026-03-06
AI Technical Summary
The poor edge channel isolation of AWG devices leads to a decrease in the performance of communication systems.
A bandpass filter film is deposited at the output end of the AWG device. By utilizing the alternating structure of multiple high-refractive-index and low-refractive-index materials, the light signal transmittance of the edge channel is reduced and the isolation is enhanced.
It improves the optical isolation between edge channels and adjacent channels, reduces signal crosstalk, and enhances the performance of the communication system.
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Figure CN223977372U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical communication technology, and in particular to a dense wavelength division multiplexing (DWDM) device for improving the isolation of edge channels in planar optical waveguides. Background Technology
[0002] Arrayed waveguide gratings (AWGs) are key components in wavelength division multiplexing (WDM) systems and are widely used in dense wavelength division multiplexing (DWDM) systems. They can multiplex and demultiplex 40 or more optical wavelengths within the C-band, multiplexing optical signals of different wavelengths onto a single optical fiber, or separating multiple optical channels multiplexed on the same fiber according to wavelength. However, AWG devices face a significant challenge in practical applications: the isolation of their edge channels is relatively poor.
[0003] The working principle of AWG devices is based on waveguide grating technology. It uses a series of waveguide arrays with progressively increasing lengths to interfere and diffract the input optical signal, thereby achieving multiplexing and separation of optical signals of different wavelengths. When an AWG device needs to process multiple wavelengths, the optical isolation of the edge channels (e.g., the channel for the 40th wavelength is the edge channel) is poor. This makes the signal in the edge channel susceptible to crosstalk from the optical signals in adjacent channels, leading to a decrease in the transmission performance of the edge channels.
[0004] In chip design, while the performance of AWG devices can be improved by optimizing waveguide structures and adjusting waveguide length differences, enhancing isolation while maintaining filtering bandwidth becomes particularly challenging. On one hand, increasing waveguide length differences can improve wavelength resolution, thereby improving isolation, but this also increases chip size and manufacturing costs. On the other hand, reducing spectral interference by optimizing waveguide shape and materials can improve isolation to some extent, but the effect is limited and often accompanied by other problems such as increased insertion loss.
[0005] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Utility Model Content
[0006] The technical problem this invention aims to solve is the issue of poor isolation of the edge channels of AWG devices, which leads to a decrease in the performance of the communication system.
[0007] The present invention adopts the following technical solution:
[0008] On the one hand, a dense wavelength division multiplexing (WDM) device for improving the isolation of edge channels of a planar optical waveguide is provided, comprising: an AWG device 1 and a bandpass filter 2, wherein the bandpass filter 2 is deposited at the output end of the AWG device 1; the bandpass filter 2 is composed of a high refractive index material and a low refractive index material;
[0009] The bandpass filter 2 is used to reduce the transmittance of the optical signal in the edge channel at the output end of the AWG device 1 and improve the isolation of the edge channel.
[0010] Preferably, the bandpass filter film 2 includes multiple stacked interference layers, each interference layer consisting of a high-refractive-index layer and a low-refractive-index layer, wherein the high-refractive-index layer is formed by depositing the high-refractive-index material and the low-refractive-index layer is formed by depositing the low-refractive-index material.
[0011] Preferably, the bandpass filter film 2 includes a first interference layer 21, a second interference layer 22, a third interference layer 23, a fourth interference layer 24, a fifth interference layer 25, a sixth interference layer 26 and a seventh interference layer 27 stacked together;
[0012] The first interference layer 21 is deposited at the output end of the AWG device 1.
[0013] Preferably, the first layer of the first interference layer 21 is a first composite layer, the second-to-last layer is a second composite layer, and the last layer is the low-refractive layer. A high-refractive layer and a low-refractive layer are alternately deposited between the first composite layer and the second composite layer.
[0014] The first composite layer is formed by alternatingly depositing the high-refractive layer and the low-refractive layer a first preset number of times, and the second composite layer is formed by alternatingly depositing the low-refractive layer and the high-refractive layer a second preset number of times.
[0015] Preferably, the third interference layer 23 is formed by repeatedly depositing nested layers a third preset number of times, and the fifth interference layer 25 is formed by repeatedly depositing nested layers a fourth preset number of times;
[0016] The first layer of the nested layers is the first composite layer, the second-to-last layer is the second composite layer, and the last layer is the low-refractive layer. High-refractive layers and low-refractive layers are alternately deposited between the first composite layer and the second composite layer.
[0017] Preferably, the first layer of the seventh interference layer 27 is the high refractive layer, the second to last layer is the first composite layer, and the last layer is the high refractive layer, with the low refractive layer and the high refractive layer alternately deposited between the high refractive layer and the first composite layer.
[0018] Preferably, the device includes an input waveguide 10, an input star coupler 11, an array waveguide 12, an output star coupler 13, and an output waveguide 14. The input waveguide 10 is used to introduce optical signals into the array waveguide 12. The input star coupler 11 is used to evenly distribute optical signals to each of the array waveguides 12. The output star coupler 13 is used to concentrate the optical signals processed by the array waveguides 12 and guide them to different output waveguides 14. The output waveguide 14 is used to output the demultiplexed optical signals from the AWG device 1. The bandpass filter 2 is deposited at the output end of the output waveguide 14.
[0019] Preferably, the array waveguide 12 comprises a plurality of waveguides with successively increasing lengths of ΔL.
[0020] Preferably, the waveguide isolation at the edge of the array waveguide 12 is greater than 20 dB.
[0021] Preferably, the high refractive index material is Ta2O5 with a refractive index of 2.08±0.01, and the low refractive index material is SiO2 with a refractive index of 1.48±0.01.
[0022] Compared with the prior art, the beneficial effects of this utility model are as follows: by depositing a bandpass filter film 2 on the output end surface of the AWG device 1, the bandpass filter film 2 is used to reduce the transmittance of the optical signal in the edge channel of the output end of the AWG device 1, thereby reducing the spectral overlap between the optical signal in the edge channel and the optical signal in the adjacent channel, thus enhancing the optical isolation between the edge channel and the adjacent channel, reducing the signal crosstalk in the edge channel. Moreover, the bandpass filter film 2 can allow all the signal light in the middle channel to pass through, so that the signal light in the middle channel of the AWG device 1 is not affected, thereby improving the performance of the communication system. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments of this utility model will be briefly described below. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.
[0024] Figure 1 This is a schematic diagram of a dense wavelength division multiplexing (DWDM) device for improving the isolation of edge channels in a planar optical waveguide, provided by an embodiment of this utility model.
[0025] Figure 2 This is a schematic diagram of a film structure for improving the isolation of edge channels in a planar optical waveguide, provided by an embodiment of the present invention.
[0026] Figure 3 This is a schematic diagram of the edge channel spectrum of an AWG device without a bandpass filter film, which is provided by an embodiment of the present invention to improve the isolation of the edge channel of a planar optical waveguide.
[0027] Figure 4 This is a spectral schematic diagram of a bandpass filter film for a dense wavelength division multiplexing (DWDM) device that improves the isolation of edge channels in a planar optical waveguide, according to an embodiment of this utility model.
[0028] Figure 5 This is a schematic diagram of a dense wavelength division multiplexing (WDM) device for improving the isolation of edge channels of a planar optical waveguide, provided by an embodiment of this utility model.
[0029] Figure 6 This is a schematic diagram of an AWG device for improving the isolation of edge channels of a planar optical waveguide, provided by an embodiment of this utility model. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0031] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as openly inclusive, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples; that is, although they may be incorporated into embodiments or examples using the above terms for reasons such as order and position, it does not limit them to be incorporated in combination by a single embodiment or example.
[0032] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.
[0033] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, for example, the description may use the prefix "A" or "B" to describe the same type of nouns as two independent entities. In this case, the features defined with "A" and "B" are used only to distinguish between similar entities and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.
[0034] In describing some embodiments, the terms "coupled," "coupled," and "connected," and their derivative expressions, may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other. Similarly, the term "coupled" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact. However, the terms "connected" or "coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other, such as "optical coupling" or "wireless connection." The embodiments disclosed herein are not necessarily limited to the scope of this invention.
[0035] In the description of this utility model, the expression "A and / or B" (where A and B are used to formally represent specific features) will be involved. The corresponding expression includes the following three combinations: only A, only B, and a combination of A and B.
[0036] As used in this invention, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the specified value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the specified quantity (i.e., the limitations of the measurement system).
[0037] Furthermore, the technical features involved in the various embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.
[0038] Example 1:
[0039] Embodiment 1 of this utility model provides a dense wavelength division multiplexing (WDM) device for improving the isolation of edge channels in planar optical waveguides, such as... Figure 1As shown, it includes: an AWG device 1 and a bandpass filter 2, wherein the bandpass filter 2 is deposited on the output end of the AWG device 1; the bandpass filter 2 is composed of a high refractive index material and a low refractive index material; the bandpass filter 2 is used to reduce the transmittance of the light signal of the edge channel at the output end of the AWG device 1 and improve the isolation of the edge channel.
[0040] By depositing a bandpass filter film 2 on the output surface of the AWG device 1, the bandpass filter film 2 reduces the transmittance of the optical signal in the edge channel of the AWG device 1 output, improves the isolation of the edge channel, and thus reduces the spectral overlap between the optical signal in the edge channel and the optical signal in its adjacent channels. This enhances the optical isolation between the edge channel and its adjacent channels, reduces signal crosstalk in the edge channel, and allows all signal light in the middle channel to pass through without being affected, thereby improving the performance of the communication system. In this embodiment, the solution is used to transmit coherent signals; therefore, reducing the transmittance of the optical signal in the edge channel of the AWG device 1 output does not affect the performance of the optical device.
[0041] The principle behind reducing signal crosstalk and improving isolation in the output of the AWG device 1 by depositing a bandpass filter film 2 is that when light shines on the film surface, it is reflected on the upper and lower surfaces. Since the film thickness is typically a fraction to a few tens of times the wavelength of light, a certain optical path difference is generated between the two reflected beams. According to the principle of light interference, when the optical path difference is an integer multiple of the wavelength, the two beams will enhance each other, forming bright fringes; when the optical path difference is an odd multiple of half the wavelength, the two beams will cancel each other out, forming dark fringes. By controlling the film thickness and refractive index, light of a specific wavelength can be enhanced or weakened, thereby achieving the control of light reflection, transmission, and absorption properties.
[0042] Based on this, the bandpass filter film 2 is formed by stacking multiple optical films. Specifically, the bandpass filter film 2 includes multiple stacked interference layers, each interference layer consisting of a high refractive index layer and a low refractive index layer. The high refractive index layer is formed by depositing the high refractive index material, and the low refractive index layer is formed by depositing the low refractive index material.
[0043] In one embodiment, such as Figure 2 As shown, the bandpass filter 2 includes a first interference layer 21, a second interference layer 22, a third interference layer 23, a fourth interference layer 24, a fifth interference layer 25, a sixth interference layer 26, and a seventh interference layer 27 stacked together; the first interference layer 21 is deposited at the output terminal of the AWG device 1. Similarly, the seventh interference layer 27 is deposited on the surface of the bandpass filter 2. In the film structure mentioned later, the first layer is always located at the bottom of the film structure, and the last layer is always located on the surface of the film structure.
[0044] In this first interference layer 21, the first layer is a first composite layer, the second-to-last layer is a second composite layer, and the last layer is the low-refractive-index layer. High-refractive-index layers and low-refractive-index layers are alternately deposited between the first and second composite layers. The first composite layer is formed by alternately depositing the high-refractive-index layer and the low-refractive-index layer a first preset number of times, and the second composite layer is formed by alternately depositing the low-refractive-index layer and the high-refractive-index layer a second preset number of times. The first preset number of layers in the first interference layer 21 can be 4 layers or other numbers, which can be designed according to actual conditions. The second preset number of layers in the first interference layer 21 can be 3 layers or other numbers, which can be designed according to actual conditions and are not specifically limited here.
[0045] The third interference layer 23 is formed by repeatedly depositing nested layers a third preset number of times, and the fifth interference layer 25 is formed by repeatedly depositing nested layers a fourth preset number of times. The third preset number of times can be 8 times or other layers, and the fourth preset number of times can be 7 times or other layers. These can be designed according to actual conditions and are not specifically limited here.
[0046] The first layer of the nested layers is the first composite layer, the second-to-last layer is the second composite layer, and the last layer is the low-refractive layer. High-refractive layers and low-refractive layers are alternately deposited between the first composite layer and the second composite layer.
[0047] The first layer of the seventh interference layer 27 is the high refractive layer, the second to last layer is the first composite layer, and the last layer is the high refractive layer. The low refractive layer and the high refractive layer are alternately deposited between the high refractive layer and the first composite layer.
[0048] It should be noted that the aforementioned high-refractive-index layer and low-refractive-index layer are defined from a functional perspective. The high-refractive-index layer and low-refractive-index layer achieve constructive interference between reflected light and transmitted light of a specific wavelength by using the refractive index of the coating material and the pre-designed thickness, thereby reducing its transmittance.
[0049] The following is a specific example of a bandpass filter film, with the specific structure of the first interference layer 21, the second interference layer 22, the third interference layer 23, the fourth interference layer 24, the fifth interference layer 25, the sixth interference layer 26, and the seventh interference layer 27 as follows:
[0050] The film structure of the first interference layer 21 is: (HL)^4H4LHLHL3H(LH)^3L;
[0051] The film structure of the second interference layer 22 is: 3HLHLH10LH(LH)^4L;
[0052] The film structure of the third interference layer 23 is: ((HL)^3H12LH(LH)^4L)^8;
[0053] The film structure of the fourth interference layer 24 is: (HL)^3H12LH5L3HLHLHLH L;
[0054] The film structure of the fifth interference layer 25 is: ((HL)^3H12LH(LH)^4L)^7;
[0055] The film structure of the sixth interference layer 26 is: (HL)^3H10LHLHL3H(LH)^3L;
[0056] The film structure of the seventh interference layer 27 is: 3HLHLH4L(HL)^3H.
[0057] In this context, H represents a high-refractive-index layer and L represents a low-refractive-index layer. For example, (HL)^4 indicates that the first composite layer, consisting of a high-refractive-index layer and a low-refractive-index layer, was repeatedly deposited four times. 4L indicates that four layers of low-refractive-index layer were deposited, and so on.
[0058] For the first interference layer 21, the first layer of the first interference layer 21 is a first composite layer, the second-to-last layer is a second composite layer, and the last layer is the low refractive layer. High refractive layers and low refractive layers are alternately deposited between the first composite layer and the second composite layer. Among them, one high refractive layer, four low refractive layers, one high refractive layer, one low refractive layer, one high refractive layer, one low refractive layer, and three high refractive layers are deposited sequentially between the first composite layer and the second composite layer.
[0059] For the second interference layer 22, the film structure of the second interference layer 22 is: 3 high refractive layers, 1 low refractive layer, 1 high refractive layer, 1 low refractive layer, 1 high refractive layer, 10 low refractive layers, 1 high refractive layer, 4 second composite layers and 1 low refractive layer.
[0060] For the third interference layer 23 and the fifth interference layer 25, the third interference layer 23 is formed by repeatedly depositing nested layers 8 times, and the fifth interference layer 25 is formed by repeatedly depositing nested layers 7 times. The first layer of the nested layers is the first composite layer, the second-to-last layer is the second composite layer, and the last layer is the low-refractive layer. High-refractive layers and low-refractive layers are alternately deposited between the first composite layer and the second composite layer. Between the first composite layer and the second composite layer, one high-refractive layer, 12 low-refractive layers, and one high-refractive layer are deposited sequentially.
[0061] For the fourth interference layer 24, the film structure of the fourth interference layer 24 is as follows: 3 first composite layers, one high refractive layer, 12 low refractive layers, one high refractive layer, 5 low refractive layers, 3 high refractive layers, one low refractive layer, one high refractive layer, one low refractive layer, one high refractive layer, one low refractive layer, one high refractive layer, one low refractive layer, one high refractive layer, and one low refractive layer.
[0062] For the sixth interference layer 26, the film structure of the sixth interference layer 26 is 3 first composite layers, 1 high refractive layer, 10 low refractive layers, 1 high refractive layer, 1 low refractive layer, 1 high refractive layer, 1 low refractive layer, 3 high refractive layers, 3 second composite layers and 1 low refractive layer.
[0063] For the seventh interference layer 27, the first layer of the seventh interference layer 27 is the high-refractive-index layer, the second-to-last layer is the first composite layer, and the last layer is the high-refractive-index layer. The low-refractive-index layer and the high-refractive-index layer are alternately deposited between the high-refractive-index layer and the first composite layer. The specific structure is 3 high-refractive-index layers, 1 low-refractive-index layer, 1 high-refractive-index layer, 1 low-refractive-index layer, 1 high-refractive-index layer, 4 low-refractive-index layers, 3 first composite layers, and 1 high-refractive-index layer.
[0064] like Figure 3 As shown, the edge channel spectrum of the AWG device 1 without the bandpass filter 2 is displayed; Figure 4 As shown, the spectrum of the bandpass filter 2 is displayed. Light with wavelengths less than or equal to 1567 nm is unaffected when passing through the bandpass filter 2, while the transmittance of light with wavelengths greater than 1567 nm is reduced when passing through the bandpass filter 2. Since light with wavelengths greater than 1567 nm is located in the edge channel of the AWG device 1, reducing its transmittance when passing through the bandpass filter 2 increases its isolation from adjacent channels and reduces crosstalk. Light from the original spectrum of the AWG passes through the bandpass filter 2, and the spectrum of the bandpass filter 2 is superimposed with the edge channel spectrum of the AWG device 1 without the bandpass filter 2. Figure 5 As shown, curve A is the edge channel spectrum of AWG device 1 without bandpass filter 2, curve B is the transmission spectrum, and curve C is the spectrum after superimposing curves A and B. It can be seen that when light with wavelength greater than 1567nm passes through bandpass filter 2, it is affected by bandpass filter 2. Compared with curve A, curve C shows that the transmittance of light with wavelength greater than 1567nm is reduced and the isolation is increased.
[0065] In one embodiment, the high-refractive-index material is Ta₂O₅ with a refractive index of 2.08 ± 0.01, and the low-refractive-index material is SiO₂ with a refractive index of 1.48 ± 0.01. The high-refractive-index material is Ta₂O₅ with a refractive index of 2.08. The low-refractive-index material is SiO₂ with a refractive index of 1.48.
[0066] For AWG device 1 itself, such as Figure 6 As shown, the device includes an input waveguide 10, an input star coupler 11, an array waveguide 12, an output star coupler 13, and an output waveguide 14. The input waveguide 10 introduces optical signals into the array waveguide 12. The input star coupler 11 evenly distributes the optical signals to each of the array waveguides 12. The output star coupler 13 concentrates the optical signals processed by the array waveguides 12 and guides them to different output waveguides 14. The output waveguide 14 outputs the demultiplexed optical signals from the AWG device 1. The bandpass filter 2 is deposited at the output end of the output waveguide 14. The array waveguide 12 comprises multiple waveguides with successively increasing lengths of ΔL. The specific value of ΔL can be set according to actual needs and is not limited here. The array waveguide 12 contains multiple waveguides with successively increasing lengths of ΔL, which generate equal optical path differences for optical signals passing through the waveguides. Its function is equivalent to a grating. Diffraction occurs at the output position of the array waveguide 12, with different wavelengths diffracted to different angles. After passing through the output star coupler 13, they are focused into different output waveguides.
[0067] In a conventional AWG device 1, the isolation of the edge channel of the array waveguide 12 is generally 14dB. Using the structure provided in this embodiment, a bandpass filter film 2 is deposited at the output end of the AWG device 1, and the waveguide isolation at the edge of the array waveguide 12 is greater than 20dB.
[0068] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A dense wavelength division device for improving the edge channel isolation of a planar optical waveguide, characterized by The application relates to an AWG device (1) and a band-pass filter film (2) plated on the output end of the AWG device (1), wherein the band-pass filter film (2) is composed of high-refractive material and low-refractive material. The band-pass filter film (2) is used for reducing the transmittance of the optical signal of an edge channel at the output end of the AWG device (1) and improving the isolation degree of the edge channel. The band-pass filter film (2) comprises a plurality of interference layers stacked, each of which is composed of a high-refractive layer and a low-refractive layer, the high-refractive layer is plated by the high-refractive material, and the low-refractive layer is plated by the low-refractive material.
2. The DWDM device for improving the isolation of the edge channel of a planar lightwave circuit according to claim 1, wherein, The band-pass filter film (2) comprises a first interference layer (21), a second interference layer (22), a third interference layer (23), a fourth interference layer (24), a fifth interference layer (25), a sixth interference layer (26) and a seventh interference layer (27) stacked.
3. The device according to claim 2, wherein the device is a dense wavelength division multiplexer. The first interference layer (21) is plated on the output end of the AWG device (1). The first layer of the first interference layer (21) is a first composite layer, the second-to-last layer is a second composite layer, and the last layer is the low-refractive layer, and high-refractive layers and low-refractive layers are alternately plated between the first composite layer and the second composite layer.
4. The device according to claim 3, wherein the device is a dense wavelength division multiplexer. The first composite layer is formed by alternately plating the high-refractive layer and the low-refractive layer for a first preset number of times, and the second composite layer is formed by alternately plating the low-refractive layer and the high-refractive layer for a second preset number of times. The third interference layer (23) is formed by repeatedly plating a nested layer for a third preset number of times, and the fifth interference layer (25) is formed by repeatedly plating a nested layer for a fourth preset number of times.
5. The device according to claim 4, wherein the device is a dense wavelength division multiplexer. The first layer of the nested layer is the first composite layer, the second-to-last layer is the second composite layer, and the last layer is the low-refractive layer, and high-refractive layers and low-refractive layers are alternately plated between the first composite layer and the second composite layer. The first layer of the seventh interference layer (27) is the high-refractive layer, the second-to-last layer is the first composite layer, and the last layer is the high-refractive layer, and the high-refractive layers and the first composite layers are alternately plated with the low-refractive layers and the high-refractive layers.
6. The device according to claim 4, wherein the device is a dense wavelength division multiplexer. The AWG device (1) comprises an input waveguide (10), an input star coupler (11), an array waveguide (12), an output star coupler (13) and an output waveguide (14), the input waveguide (10) is used for introducing an optical signal into the array waveguide (12), the input star coupler (11) is used for evenly distributing the optical signal to each array waveguide (12), the output star coupler (13) is used for concentrating and guiding the optical signal processed by the array waveguide (12) to different output waveguides (14), the output waveguide (14) is used for outputting the demultiplexed optical signal from the AWG device (1), and the band-pass filter film (2) is plated on the output end of the output waveguide (14).
7. The device according to claim 1, wherein the device is a dense wavelength division multiplexer. The array waveguide (12) comprises a plurality of waveguides with a length difference of delta L.
8. The device according to claim 7, wherein the device is a dense wavelength division multiplexer. The waveguide isolation degree at the edge of the array waveguide (12) is greater than 20 dB.
9. The device according to claim 8, wherein the device is a dense wavelength division multiplexer. 10. A DWDM device for improving the isolation of an edge channel of a planar lightwave circuit according to any of claims 1-9, characterized in that, The high refractive index material is Ta2O5, the refractive index of the high refractive index material is 2.08±0.01, the low refractive index material is SiO2, and the refractive index of the low refractive index material is 1.48±0.01.