An on-chip ultra-compact wavelength multiplexer-demultiplexer device and a manufacturing method

Abstract

The application discloses an on-chip ultra-compact wavelength multiplexing-demultiplexing device and a manufacturing method thereof, and relates to the technical field of optical communication, wherein the on-chip ultra-compact wavelength multiplexing-demultiplexing device comprises a substrate layer, a waveguide layer arranged on the substrate layer, the waveguide layer comprising an incident waveguide and two exit waveguides arranged at a certain angle, and a wavelength multiplexing-demultiplexing area arranged between the incident waveguide and the two exit waveguides, the wavelength multiplexing-demultiplexing area being configured to enable transmission light of a second wavelength transmitted through the incident waveguide to directly penetrate to be output from one exit waveguide and enable transmission light of a first wavelength transmitted through the incident waveguide to be reflected to be output from the other exit waveguide. The application can effectively solve the on-chip wavelength (de)multiplexing problem.

Description

Technical Field

[0001] This invention relates to the field of photonic integrated device technology, specifically to an on-chip ultra-compact wavelength multiplexing-demultiplexing device and its manufacturing method. Background Technology

[0002] Integrated photonic devices play a crucial role in optical interconnects, optical sensing, and quantum computing. One of the key functions of silicon photonics is wavelength division multiplexing, which multiplies the data capacity of a single optical waveguide or fiber by the number of wavelength channels used.

[0003] However, traditional wavelength demultiplexers, such as arrayed waveguide gratings and microring resonator arrays, are quite large, ranging in size from tens to hundreds of micrometers. Therefore, it is necessary to propose an on-chip ultracompact and ultraminiature wavelength (de)multiplexing structure and its fabrication method. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the first aspect of this invention provides an on-chip ultra-compact wavelength multiplexing-demultiplexing device, which can effectively solve the on-chip wavelength (de)multiplexing problem.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An on-chip ultracompact wavelength multiplexing-demultiplexing device includes:

[0007] Substrate layer;

[0008] A waveguide layer disposed on the substrate layer, the waveguide layer including an incident waveguide and two outgoing waveguides arranged at a certain angle; and

[0009] A wavelength multiplexing-demultiplexing region is disposed between the incident waveguide and the two outgoing waveguides. The wavelength multiplexing-demultiplexing region is configured to allow transmitted light of a second wavelength transmitted through the incident waveguide to pass directly through and be output from one outgoing waveguide, and to allow transmitted light of a first wavelength transmitted through the incident waveguide to be reflected and be output from the other outgoing waveguide.

[0010] In some embodiments, the wavelength multiplexing-demultiplexing region includes a plurality of spaced refractive index structure layers, the width of the refractive index structure layer being one-quarter of the second wavelength, and the spacing between two adjacent refractive index structure layers also being one-quarter of the second wavelength.

[0011] In some embodiments, each of the low-refractive-index structural layers is shaped as part of a parabola, and the focus of the parabola is on the same horizontal line as the center of the incident waveguide.

[0012] In some embodiments, the two outgoing waveguides are arranged vertically, and one of the outgoing waveguides is on the same horizontal line as the center of the incoming waveguide.

[0013] In some embodiments, each of the low-refractive-index structural layers is shaped as part of an elliptic curve, and the focus of the elliptic curve is on the same horizontal line as the center of the incident waveguide.

[0014] In some embodiments, the wavelength multiplexing-demultiplexing region includes N ≥ 2 spaced refractive index structure layers.

[0015] In some embodiments, an insulating structure layer is further provided between the substrate layer and the waveguide layer.

[0016] In some embodiments, a waveguide cladding layer is also provided on the waveguide layer.

[0017] The second aspect of the present invention provides a method for manufacturing an on-chip ultra-compact wavelength multiplexing-demultiplexing device, which can effectively solve the problem of on-chip wavelength (de)multiplexing.

[0018] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0019] A method for manufacturing an on-chip ultracompact wavelength multiplexing-demultiplexing device, the method comprising the following steps:

[0020] A substrate layer, an insulating structure layer, and a waveguide layer are deposited sequentially, and an incident waveguide and two outgoing waveguides of the waveguide layer are fabricated.

[0021] A wavelength multiplexing-demultiplexing region is created between the incident waveguide and the two exiting waveguides. The wavelength multiplexing-demultiplexing region is configured to allow transmitted light of a second wavelength transmitted through the incident waveguide to pass directly through and exit from one exiting waveguide, and to allow transmitted light of a first wavelength transmitted through the incident waveguide to be reflected and exit from the other exiting waveguide.

[0022] In some embodiments, a wavelength multiplexing-demultiplexing region is formed between the incident waveguide and the two exiting waveguides. This wavelength multiplexing-demultiplexing region is configured to allow transmitted light of a second wavelength passing through the incident waveguide to directly penetrate and exit from one exiting waveguide, and to allow transmitted light of a first wavelength passing through the incident waveguide to be refracted and exit from the other exiting waveguide, including:

[0023] A wavelength multiplexing-demultiplexing region is fabricated at the junction of the incident waveguide and the two outgoing waveguides using a photoresist mask, and multiple etching grooves with a width and spacing of one-quarter of the second wavelength are formed by etching.

[0024] Each etched groove is filled with a refractive index material lower than the waveguide's refractive index to form a set of refractive index structure layers.

[0025] Compared with the prior art, the advantages of the present invention are as follows:

[0026] The on-chip ultra-compact wavelength multiplexing-demultiplexing device of this invention includes a substrate layer, a waveguide layer, and a wavelength multiplexing-demultiplexing region. The waveguide layer is disposed on the substrate layer and includes an incident waveguide and two outgoing waveguides arranged at a certain angle. The wavelength multiplexing-demultiplexing region is disposed between the incident waveguide and the two outgoing waveguides. The wavelength multiplexing-demultiplexing region is configured to allow the transmitted light of the second wavelength transmitted through the incident waveguide to directly pass through and exit from one outgoing waveguide, and to allow the transmitted light of the first wavelength transmitted through the incident waveguide to be reflected and exit from the other outgoing waveguide. The on-chip ultra-compact wavelength multiplexing-demultiplexing device of this invention is easy to fabricate, has low structural loss, and a large bandwidth. It can effectively solve the on-chip wavelength (de)multiplexing problem, has a smaller size than traditional wavelength division multiplexing schemes, and can effectively improve channel capacity. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the on-chip ultra-compact wavelength multiplexing-demultiplexing device in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the waveguide layer structure in one embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the waveguide layer structure in another embodiment of the present invention;

[0030] Figure 4 This is a flowchart of a method for manufacturing an on-chip ultra-compact wavelength multiplexer-demultiplexer device according to an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] See Figure 1 As shown, an embodiment of the present invention discloses an on-chip ultra-compact wavelength multiplexing-demultiplexing device, which includes: a substrate layer 6, a waveguide layer and a wavelength multiplexing-demultiplexing region 4.

[0033] The waveguide layer is disposed on the substrate layer 6, and includes an incident waveguide 1 and two outgoing waveguides arranged at a certain angle: a first outgoing waveguide 2 and a second outgoing waveguide 3. Furthermore, in some embodiments, an insulating structure layer 5 is provided between the substrate layer 6 and the waveguide layer. A waveguide capping layer 7 is also provided on the waveguide layer.

[0034] The wavelength multiplexing-demultiplexing region 4 is located between the incident waveguide 1 and the two outgoing waveguides. The wavelength multiplexing-demultiplexing region 4 is configured to allow the transmitted light of the second wavelength transmitted through the incident waveguide 1 to pass directly through and be output from one outgoing waveguide, and to allow the transmitted light of the first wavelength transmitted through the incident waveguide 1 to be reflected and be output from the other outgoing waveguide.

[0035] To achieve the above objectives, the wavelength multiplexing-demultiplexing region 4 in this embodiment includes multiple spaced refractive index structure layers. The width of each refractive index structure layer is one-quarter of the second wavelength, and the spacing between two adjacent refractive index structure layers is also one-quarter of the second wavelength. Preferably, the wavelength multiplexing-demultiplexing region 4 includes N≥2 spaced refractive index structure layers, for example, six spaced refractive index structure layers can be provided. The number of refractive index structure layers is not limited in this embodiment and can be reasonably set according to requirements.

[0036] It is worth noting that the shape of the refractive index structure layer affects the angle at which the waveguide outputs from the other waveguide during reflection. Two specific examples illustrate this below:

[0037] See Figure 2 As shown, the first wavelength of the first transmitted light passing through the incident waveguide 1 is λ1, and the second wavelength of the second transmitted light is λ2, where λ1 < λ2. The width of the refractive index structure layer is λ2 / 4, and the spacing between two adjacent refractive index structure layers is also λ2 / 4.

[0038] This structure resembles an on-chip thin-film filter. Light with a wavelength of λ2 can completely pass through the low-refractive-index layer. The optical thickness of the entire HLHL layer (high-low-high-low refractive-index layer) is λ2, so light with a wavelength of λ2 is also completely transmitted. Thus, for the entire λ2 / 4 film system, regardless of the number of layers, light with a wavelength of λ2 can pass through. However, for other wavelengths λ≠λ2, each layer reflects the light, and the transmittance decreases. Because smaller wavelengths are more prone to total internal reflection, under certain structural layer width conditions, λ1 is reflected, and λ2 is transmitted.

[0039] In other words, the second transmitted light will pass directly through the refractive index structure layer, while the first transmitted light will be reflected when it encounters the refractive index structure layer.

[0040] In this embodiment, each low-refractive-index structural layer is shaped as part of a parabola, with the focus of the parabola aligned horizontally with the center of the incident waveguide. This ensures that the first transmitted light will be reflected perpendicularly from the refractive-index structural layer. Therefore, in this embodiment, the first exiting waveguide 2 is positioned horizontally with the incident waveguide, and the second exiting waveguide 3 is positioned perpendicularly to the first exiting waveguide 2. Consequently, the second transmitted light passes through the refractive-index structural layer and exits from the first exiting waveguide 2, while the first transmitted light, after reflection from the refractive-index structural layer, exits perpendicularly from the second exiting waveguide 3.

[0041] See Figure 3 As shown, and Figure 2 The difference is that the shape of each of the low-refractive-index structural layers is part of an elliptical curve, and the focus of the elliptical curve is on the same horizontal line as the center of the incident waveguide.

[0042] In this way, the first transmitted light will be reflected at a certain angle when it encounters the refractive index structure layer. Specifically, the reflected light will pass through the other focus of the elliptic curve. Therefore, this can be used as a basis to set the angle between the first outgoing waveguide 2 and the second outgoing waveguide 3.

[0043] It is worth noting that Wavelength Division Multiplexing (WDM) is a technique that combines two or more optical carrier signals of different wavelengths (carrying various information) at the transmitting end using a multiplexer (also called a multiplexer) and couples them into the same optical fiber for transmission. At the receiving end, the various wavelengths of optical carriers are separated by a demultiplexer (also called a demultiplexer), and then further processed by an optical receiver to recover the original signal. This technique of simultaneously transmitting two or more different wavelength optical signals in the same optical fiber is called wavelength division multiplexing.

[0044] Based on the above description, in the embodiments of the present invention, the first and second transmitted light passing through the incident waveguide 1 can be reflected by the wavelength multiplexing-demultiplexing region 4 to be output from the second output waveguide 3, and the second transmitted light can be transmitted to be output from the first output waveguide 2, thereby effectively solving the on-chip wavelength (demultiplexing) problem.

[0045] In summary, the on-chip ultra-compact wavelength multiplexing-demultiplexing device of this invention includes a substrate layer 6, a waveguide layer, and a wavelength multiplexing-demultiplexing region 4. The waveguide layer is disposed on the substrate layer 6 and includes an incident waveguide 1 and two outgoing waveguides arranged at a certain angle. The wavelength multiplexing-demultiplexing region 4 is disposed between the incident waveguide 1 and the two outgoing waveguides. The wavelength multiplexing-demultiplexing region is configured to allow the transmitted light of the second wavelength transmitted through the incident waveguide 1 to directly pass through and exit from one outgoing waveguide, and to allow the transmitted light of the first wavelength transmitted through the incident waveguide to be reflected and exit from the other outgoing waveguide. The on-chip ultra-compact wavelength multiplexing-demultiplexing device of this invention is easy to fabricate, has low structural loss, and a large bandwidth. It can effectively solve the on-chip wavelength (de)multiplexing problem, has a smaller size than traditional wavelength division multiplexing schemes, and can effectively improve channel capacity.

[0046] See Figure 4 As shown in the figure, this invention also discloses a method for manufacturing an on-chip ultra-compact wavelength multiplexing-demultiplexing device, the method comprising the following steps:

[0047] S1. Sequentially deposit the substrate layer 6, the insulating structure layer 5, and the waveguide layer, and fabricate the incident waveguide 1 and two outgoing waveguides using a photoresist mask.

[0048] It is worth noting that the two outgoing waveguides are the first outgoing waveguide 2 and the second outgoing waveguide 3, which are set at an angle to each other.

[0049] S2. A wavelength multiplexing-demultiplexing region 4 is fabricated between the incident waveguide 1 and the two outgoing waveguides using a photoresist mask. The region is located at the junction of the three waveguides. N etching grooves with a width and spacing of λ2 / 4 are formed by etching.

[0050] In this embodiment of the invention, the first wavelength of the first transmitted light passing through the incident waveguide 1 is λ1, and the second wavelength of the second transmitted light is λ2, where λ1 < λ2. The width of the refractive index structure layer is λ2 / 4, and the spacing between two adjacent refractive index structure layers is also λ2 / 4.

[0051] This structure resembles an on-chip thin-film filter. Light with a wavelength of λ2 can completely pass through the low-refractive-index layer. The optical thickness of the entire HLHL layer (high-low-high-low refractive-index layer) is λ2, so light with a wavelength of λ2 is also completely transmitted. Thus, for the entire λ2 / 4 film system, regardless of the number of layers, light with a wavelength of λ2 can pass through. However, for other wavelengths λ≠λ2, each layer reflects the light, and the transmittance decreases. Because smaller wavelengths are more prone to total internal reflection, under certain structural layer width conditions, λ1 is reflected, and λ2 is transmitted.

[0052] Furthermore, the shape of the refractive index structure layer affects the angle at which the waveguide outputs from the other waveguide during reflection. Two specific examples illustrate this below:

[0053] One approach is to shaped each low-refractive-index structural layer (etched groove) as part of a parabola, with the focus of the parabola aligned horizontally with the center of the incident waveguide. This ensures that the first transmitted light will be reflected perpendicularly from the refractive-index structural layer. Therefore, in this embodiment, the first exiting waveguide 2 is positioned horizontally with the incident waveguide, and the second exiting waveguide 3 is positioned perpendicularly to the first exiting waveguide 2. Consequently, the second transmitted light, after passing through the refractive-index structural layer, exits from the first exiting waveguide 2, while the first transmitted light, after reflection from the refractive-index structural layer, exits perpendicularly from the second exiting waveguide 3.

[0054] Another approach is that each of the low-refractive-index structural layers is part of an elliptic curve, with the focal point of the elliptic curve aligned with the center of the incident waveguide. In this way, the first transmitted light will be reflected at a certain angle upon encountering the refractive-index structural layer; specifically, the reflected light will pass through the other focal point of the elliptic curve. Therefore, this can be used as a basis for setting the angle between the first exiting waveguide 2 and the second exiting waveguide 3.

[0055] S3. Fill N etching grooves with different refractive index materials in sequence. The refractive index of each material is lower than that of the waveguide, forming a set of refractive index structure layers.

[0056] It should be noted that filling with materials of different refractive indices in sequence is to better adjust the refraction and transmission relationship between the two wavelengths.

[0057] S4. Deposit waveguide capping layer 7 to wrap the waveguide layer and refractive index structure layer.

[0058] The on-chip ultra-compact wavelength multiplexing-demultiplexing device manufactured in the above manner can effectively solve the on-chip wavelength (de)multiplexing problem by allowing the first and second transmission light to pass through the first transmission light and the second transmission light to pass through the wavelength multiplexing-demultiplexing region 4 to reflect the first transmission light and output it from the second output waveguide 3, and allowing the second transmission light to pass through and output it from the first output waveguide 2.

[0059] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An on-chip ultra-compact wavelength multiplexing-demultiplexing device, characterized in that, include: Substrate layer; A waveguide layer disposed on the substrate layer, the waveguide layer including an incident waveguide and two outgoing waveguides disposed at a certain angle; as well as A wavelength multiplexing-demultiplexing region is disposed between the incident waveguide and the two outgoing waveguides. The wavelength multiplexing-demultiplexing region is configured to allow the transmitted light of the second wavelength transmitted through the incident waveguide to pass directly through and be output from one outgoing waveguide, and to allow the transmitted light of the first wavelength transmitted through the incident waveguide to be reflected and be output from the other outgoing waveguide. The wavelength multiplexing-demultiplexing region includes multiple spaced refractive index structure layers, the width of which is one-quarter of the second wavelength, and the spacing between two adjacent refractive index structure layers is also one-quarter of the second wavelength. Each of the refractive index structure layers is part of a parabola, and the focus of the parabola is on the same horizontal line as the center of the incident waveguide, or; Each of the refractive index structure layers is shaped as part of an elliptic curve, and the focus of the elliptic curve is on the same horizontal line as the center of the incident waveguide.

2. The on-chip ultra-compact wavelength multiplexing-demultiplexing device according to claim 1, characterized in that: When the shape of each of the refractive index structure layers is part of a parabola, and the focus of the parabola is on the same horizontal line as the center of the incident waveguide, the two outgoing waveguides are arranged vertically, and one of the outgoing waveguides is on the same horizontal line as the center of the incident waveguide.

3. The on-chip ultra-compact wavelength multiplexing-demultiplexing device according to claim 1, characterized in that, The wavelength multiplexing-demultiplexing region includes N≥2 refractive index structure layers spaced apart.

4. The on-chip ultra-compact wavelength multiplexing-demultiplexing device according to claim 1, characterized in that: An insulating structure layer is also provided between the substrate layer and the waveguide layer.

5. The on-chip ultra-compact wavelength multiplexing-demultiplexing device according to claim 4, characterized in that: A waveguide cladding layer is also provided on the waveguide layer.

6. A method for manufacturing an on-chip ultracompact wavelength multiplexing-demultiplexing device, characterized in that, The method includes the following steps: A substrate layer, an insulating structure layer, and a waveguide layer are deposited sequentially, and an incident waveguide and two outgoing waveguides of the waveguide layer are fabricated. A wavelength multiplexing-demultiplexing region is created between the incident waveguide and the two exit waveguides. The wavelength multiplexing-demultiplexing region is configured to allow transmitted light of a second wavelength transmitted through the incident waveguide to pass directly through and exit from one exit waveguide, and to allow transmitted light of a first wavelength transmitted through the incident waveguide to be reflected and exit from the other exit waveguide. A wavelength multiplexing-demultiplexing region is created between the incident waveguide and the two exiting waveguides. This wavelength multiplexing-demultiplexing region is configured to allow transmitted light of a second wavelength, transmitted through the incident waveguide, to directly pass through and exit from one exiting waveguide, and to allow transmitted light of a first wavelength, transmitted through the incident waveguide, to be refracted and exit from the other exiting waveguide. This includes: A wavelength multiplexing-demultiplexing region is fabricated at the junction of the incident waveguide and the two outgoing waveguides using a photoresist mask, and multiple etching grooves with a width and spacing of one-quarter of the second wavelength are formed by etching. Each etched groove is filled with a refractive index material lower than the waveguide's refractive index to form a set of refractive index structure layers; Each of the refractive index structure layers is part of a parabola, and the focus of the parabola is on the same horizontal line as the center of the incident waveguide, or; Each of the refractive index structure layers is shaped as part of an elliptic curve, and the focus of the elliptic curve is on the same horizontal line as the center of the incident waveguide.

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