Multi-channel distributor and multi-channel distributor temperature control system

Abstract

The invention provides a multi-channel distributor and a multi-channel distributor temperature control system, which can improve the temperature control precision and range, reduce the device preparation difficulty and reduce the cost. The multiplexer is integrated on a silicon substrate, and comprises an input free propagation region provided with an input side silicon waveguide; an output free propagation region in which an output-side silicon waveguide is disposed; a phase difference structure constituting a grating and disposed between the input free propagation region and the output free propagation region; and the temperature control structures are respectively configured at the tops of the input side silicon waveguide and the output side silicon waveguide, and the width of the temperature control structures and the position of the grating are in an equal difference change relationship.

Description

Technical Field

[0001] The present invention relates to a multiplexer and a multiplexer temperature control system, in particular to a multiplexer integrated on a silicon substrate and a multiplexer temperature control system for controlling the temperature of the multiplexer. Background Art

[0002] A demultiplexer (Demux) is a module used to split a single signal into multiple signals. It can be used to split a single signal into multiple signals and then connect these signals to subsequent signal processing modules. Demux devices are widely used in high-speed digital communications, signal processing, data transmission, and other fields.

[0003] In the application field of on-chip demux devices, there is a physical phenomenon known as the "thermo-optic effect," which is the ability to change the optical properties of a medium by changing its temperature. This phenomenon has important applications in many fields, such as infrared radiation detection and the study of molecular layered structures in biology. The essence of the "thermo-optic effect" is to change the refractive index of the crystal, which causes changes in the propagation direction and intensity of the light beam. The thermo-optic modulation principle of silicon-based optical waveguides is also based on the thermo-optic effect. By controlling the current or voltage applied to the medium under the optical waveguide, heat is generated, which in turn changes the real-time temperature of the waveguide, thereby changing the waveguide's refractive index. This causes the phase of the light beam emitted by the waveguide to change, thereby achieving beam scanning.

[0004] However, for demultiplexers, especially Demux devices integrated on silicon substrates, the performance of the Demux devices will change with changes in ambient temperature due to the photothermal effect during operation, which can lead to unstable performance.

[0005] In the past, in order to eliminate the influence of thermo-optical effect on the performance of Demux devices, the following three temperature control methods have been proposed: (1) by using discrete heating elements or cooling elements to heat or cool the Demux devices to achieve the desired temperature control effect; (2) by using discrete thermistors or heat sinks to heat or dissipate heat from the Demux devices to achieve the desired temperature control effect; and (3) by integrating heating elements, cooling elements, thermistors and heat sinks into the Demux devices through doping processes to achieve the desired temperature control effect. Summary of the Invention

[0006] Technical problems to be solved by the present invention

[0007] However, the temperature control method (1) mentioned above requires the independent provision of additional energy sources and heat dissipation devices, which increases the complexity and cost of the system.

[0008] In addition, for the above-mentioned temperature control method (2), since a discrete thermistor or heat sink is used, the accuracy and range of temperature control are limited and are greatly affected by the stress in the phase sensitive area.

[0009] In addition, for the above-mentioned temperature control method (3), since the heating element, cooling element, thermistor and heat sink are integrated into the Demux device by using a doping process, the technical difficulty is relatively high, which will increase the difficulty and cost of device integration.

[0010] As mentioned above, existing temperature control methods have many problems, such as low temperature control efficiency, high cost, high integration difficulty, and significant influence of stress in phase-sensitive areas.

[0011] The present invention is completed in view of the above problems, and its purpose is to provide a multiplexer and a multiplexer temperature control system that can improve the temperature control accuracy and range, reduce the difficulty of device preparation, and reduce costs.

[0012] Technical solutions to technical problems

[0013] In order to solve the above problems, the first aspect of the present invention relates to a multiplexer, which is integrated on a silicon substrate and includes: an input free propagation area, which is configured with an input-side silicon waveguide; an output free propagation area, which is configured with an output-side silicon waveguide; a phase difference structure, which constitutes a grating and is configured between the input free propagation area and the output free propagation area; and a temperature control structure, which is respectively configured at the top of the input-side silicon waveguide and the output-side silicon waveguide, and its width varies in an arithmetically differential relationship with the position of the grating.

[0014] Optionally, the width of the temperature control structure increases as the optical path difference on the grating increases.

[0015] Optionally, the width of the temperature control structure is linearly related to the optical path difference.

[0016] Optionally, the width of the temperature control structure has a nonlinear relationship with the optical path difference.

[0017] Optionally, the temperature control structure is made of tungsten or titanium nitride.

[0018] Optionally, a difference between a refractive index of the input-side silicon waveguide and the output-side silicon waveguide and a refractive index of a covering layer covering the input-side silicon waveguide and the output-side silicon waveguide is 1.5 to 2.5.

[0019] Optionally, the input-side silicon waveguide and the output-side silicon waveguide respectively adopt a ridge waveguide structure.

[0020] Optionally, the input-side silicon waveguide and the output-side silicon waveguide are respectively arranged on top of the silicon substrate, and the silicon substrate is an SOI substrate.

[0021] In addition, in order to solve the above-mentioned problem, the second aspect of the present invention relates to a multiplexer temperature control system, characterized in that it includes: the multiplexer involved in the first aspect of the present invention; a temperature sensing unit, which detects the on-chip temperature information of the grating; and a control circuit, which obtains the on-chip temperature information from the temperature sensing unit and adjusts the temperature of the temperature control structure based on the on-chip temperature information.

[0022] Optionally, the control circuit regulates the temperature of the temperature control structure by adjusting the voltage or current applied to the temperature control structure.

[0023] Optionally, the temperature sensing unit and the control circuit are integrated into the multiplexer.

[0024] Optionally, the temperature sensing unit and the control circuit are electrically connected to the multiplexer as external components.

[0025] Effects of the Invention

[0026] The multiplexer and multiplexer temperature control system according to the present invention can improve the temperature control accuracy and range, reduce the difficulty of device preparation, and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present application but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

[0028] Figure 1 It is a schematic diagram showing the structure of the demultiplexer involved in the present invention.

[0029] Figure 2 This is a top view showing an example of the structure of the free propagation area.

[0030] Figure 3 Yes Figure 2 Cross-sectional view of section AA in FIG.

[0031] Figure 4 Schematic diagram showing the structure of a multiplexer temperature control system according to the present invention. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0033] In the description of the present disclosure, it should be noted that, unless otherwise specified, "plurality" means more than two; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating directions or positional relationships, are merely for the purpose of facilitating the description of the present disclosure and simplifying the description, and do not indicate or imply that the devices or components referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present disclosure. "Vertical" does not mean vertical in the strict sense, but is within the allowable error range. "Parallel" does not mean parallel in the strict sense, but is within the allowable error range.

[0034] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the present disclosure. In the description of the present disclosure, it should also be noted that, unless otherwise clearly specified and limited, the terms "assemble", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances.

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0036] Figure 1 Schematic diagram showing the structure of the demultiplexer involved in this embodiment. Figure 1 This is just an abstract structural diagram for facilitating understanding of the location of the temperature control structure in the multiplexer. The shapes of the various components of the multiplexer of the present invention are not limited to Figure 1 In addition, those skilled in the art should be able to understand that Figure 1 The abstract structure of the demultiplexer shown can be applied to various different demultiplexer components integrated on-chip.

[0037] like Figure 1As shown, a demultiplexer (hereinafter also referred to as a "Demux device") includes an input free propagation region, a phase difference structure, and an output free propagation region. The phase difference structure is disposed between the input free propagation region and the output free propagation region, and is connected to the input free propagation region and the output free propagation region, respectively.

[0038] In actual operation, input light (not shown) enters the input free propagation zone from the left side of the input free propagation zone, undergoes diffraction propagation, and then enters the phase difference structure. In the phase difference structure, the optical signals with different diffraction angles generate phase differences and enter the output free propagation zone. The optical signals with phase differences propagate in the output free propagation zone and, after experiencing the coherence effect, are output from the right side of the output free propagation zone to form an image. Here, due to the phase difference generated in the phase difference structure, the image output from the right side of the output free propagation zone has a dispersion effect. That is, optical signals of different wavelengths are imaged at different locations, thus completing the optical signal splitting. The right side of the demultiplexer is connected to multiple signal processing modules (not shown). The split optical signals are output to each signal processing module, thereby achieving the optical signal multi-path distribution function.

[0039] When the Demux device is integrated on a silicon substrate, the device performance will change with the change of ambient temperature due to the thermal optical effect generated during operation. Figure 1 As shown, temperature control structures 3 are respectively provided in the input free propagation area and the output free propagation area of ​​the Demux device. When the ambient temperature of the Demux device changes, the temperature control structure 3 can be used to heat the free propagation area, thereby changing the refractive index of the crystal in the free propagation area, thereby being able to use the temperature control structure 3 to compensate for the ambient temperature change.

[0040] Below, Figure 2 and Figure 3 For example, Figure 1 A structural example of the input free propagation area and the output free propagation area in is described.

[0041] Figure 2 is a top view showing a structural example of a free propagation area. Figure 3 Yes Figure 2 Cross-sectional view of section AA in FIG. Figure 2 and Figure 3 The structure example shown can be applied to both the input free propagation area and the output free propagation area, so the input free propagation area and the output free propagation area are sometimes collectively referred to as the "free propagation area" below. Figure 2 、 Figure 3This is just an abstract diagram for facilitating understanding of the structure of the free propagation region. The shape of the free propagation region in the demultiplexer of the present invention is not limited to Figure 2 、 Figure 3 The shape shown.

[0042] like Figure 2 As shown, a silicon waveguide 1 is configured in the free propagation region. Specifically, an input-side silicon waveguide is configured in the input free propagation region, and an output-side silicon waveguide is configured in the output free propagation region. Hereinafter, the input-side silicon waveguide and the output-side silicon waveguide are sometimes collectively referred to as "silicon waveguide 1." Here, a "silicon waveguide" is a silicon-based optical waveguide device primarily used for optical signal transmission and control in integrated photonic circuits and optical communication systems. Silicon waveguides offer advantages such as low loss, high integration density, and low cost. Their operating principle is to utilize the refractive index and sidewall roughness of silicon to confine and control the propagation of light waves.

[0043] On one side of the silicon waveguide 1 ( Figure 2 The left side of the figure is connected to grating 2. The position of grating 2 is equivalent to Figure 1 The phase difference structure in the image is located at the position where the phase difference structure is located, that is, the phase difference structure constitutes grating 2. Here, the so-called "grating" is an optical device composed of a large number of parallel slits of equal width and equal spacing. It can be used to analyze, transmit or generate optical signals. It is usually composed of a series of equidistant parallel lines or thin planes, and can diffract, interfere or deflect light in various ways. One of the main functions of gratings is spectral analysis, which can be used to separate light of different wavelengths. In addition, gratings can also be used to produce specific optical effects, such as displaying three-dimensional images on a flat surface, smooth animation clips, and magic effects.

[0044] Temperature control structures 3 are respectively arranged on the top of the input side silicon waveguide and the output side silicon waveguide, that is, the silicon waveguide 1. The temperature control structure 3 can heat the silicon waveguide 1 based on the ambient temperature of the multiplexer, thereby compensating for changes in ambient temperature.

[0045] Regarding the specific composition structure of the free propagation area, such as Figure 3 As shown, an SOI (Silicon-On-Insulator) substrate 4 is provided in the free propagation region. The height of the SOI substrate 4 can be set to 0.2 to 5 μm. From bottom to top, the SOI substrate 4 is composed of a silicon wafer, an insulator, and a thin silicon layer on the surface. This substrate material is widely used in integrated circuit manufacturing, with advantages including reduced power consumption, increased speed, and enhanced anti-interference capabilities. In this embodiment, the SOI substrate 4 is used as an example of a silicon substrate for illustration. However, the silicon substrate of the present invention is not limited to this substrate. The structure of the present invention can also be applied to Demux devices integrated on other types of silicon substrates.

[0046] A silicon waveguide 1 is positioned atop an SOI substrate 4, sandwiching a buried layer 5 composed, for example, of silicon oxide. The height of the silicon waveguide 1 can be adjusted based on the device's actual needs. Its operating principle is to utilize the refractive index and sidewall roughness of the silicon material to restrict and control the propagation of light waves. In other words, light waves can propagate in a specific direction and intensity within the silicon waveguide 1, and their propagation direction and intensity vary with changes in the refractive index due to thermo-optical effects. Silicon waveguides also offer advantages such as low loss, high integration density, and low cost.

[0047] In addition, if Figure 3 As shown, in this embodiment, in order to reduce the bending loss of the optical signal, the silicon waveguide 1 adopts a ridge waveguide structure. Here, the so-called "ridge waveguide structure" refers to the cross-section of the silicon waveguide having a shape with low sides and high middle. Figure 3 In the example, the silicon waveguide 1 is formed as a thin flat plate on both sides, with a raised center section forming a thicker optical confinement region. In a ridge waveguide structure, light waves undergo total internal reflection at the ridge, thus reducing bending losses in the optical signal. Of course, the silicon waveguide of the present invention is not limited to this shape; for example, a "strip waveguide structure" with a uniform thickness can also be employed.

[0048] On the silicon waveguide 1, specifically around the light confinement region therein, there is covered with a covering layer 6. The covering layer 6 is made of, for example, silicon oxide material and is a light-impermeable material that is used to prevent the light signal from passing from the silicon waveguide 1 to the outside of the Demux device. Under the influence of the sidewall roughness of the silicon waveguide 1, the light wave will be scattered on the sidewall of the silicon waveguide, causing part of the light field distribution to diffuse to the outside of the silicon waveguide, resulting in transmission loss. In this embodiment, in order to reduce transmission loss, the silicon waveguide 1 adopts a high-contrast grating structure to limit the propagation direction of the light wave. Specifically, the difference between the refractive index of the silicon waveguide 1 and the refractive index of the covering layer 3 is set to 1.5 to 2.5, preferably to 2. In this way, the confinement ability of the light wave in the silicon waveguide can be improved.

[0049] The temperature control structure 6 is disposed on top of the silicon waveguide 1, and its thickness can be adjusted based on the actual device requirements and spatial parameters. In this embodiment, the temperature control structure 6 is made of materials such as tungsten and titanium oxide, and therefore has the following advantages: 1. High melting point and high-temperature stability (specifically, tungsten and titanium nitride both have high melting points and excellent high-temperature stability, can maintain stable physical and chemical properties in high-temperature environments, and can achieve precise temperature control in high-temperature environments); 2. Good thermal conductivity (specifically, tungsten and titanium nitride are both excellent thermal conductors that can quickly transfer and diffuse heat, thereby reducing temperature gradients and improving the uniformity and stability of temperature control); 3. High strength and high hardness (specifically, tungsten and titanium nitride both have high strength and hardness, can withstand the stress caused by temperature changes while maintaining structural integrity, thereby helping to reduce the impact of temperature changes on structural stability and improve the reliability and lifespan of the temperature control structure); 4. Good oxidation resistance and corrosion resistance (specifically, tungsten and titanium nitride both have good oxidation resistance and corrosion resistance, can maintain stable performance in complex environments, and have a wider range of applications and a longer service life). Of course, other materials can also be selected as the material of the temperature control structure according to the actual needs of temperature control.

[0050] Regarding the specific shape of the temperature control structure 6, Figure 2 As shown, its width varies arithmetically with the position of grating 2. This allows for proportional phase adjustment by varying the temperature, improving temperature compensation efficiency. Furthermore, the greater the rate of change of the temperature-control structure with grating position, the higher the temperature compensation efficiency achieved during temperature control.

[0051] In a specific embodiment in which the width of the temperature-control structure 3 varies arbitrarily with the position of the grating 2, the width of the temperature-control structure 3 can be set to increase as the optical path difference (OPD) on the grating 2 increases. Since gratings create dispersion effects through OPD, the "OPD" of a grating refers to the difference in optical path lengths traveled by light of different diffraction orders after passing through the grating. Specifically, when light passes through the grating, light of different diffraction orders is diffracted at different angles and propagates in different directions. Due to the different propagation paths, the distances traveled by light of each diffraction order also differ, resulting in an OPD. The magnitude of the OPD depends on the grating constant, the wavelength of the incident light, and the angle of incidence. When the OPD is an integer multiple of the wavelength, light of each diffraction order reinforces each other, producing bright diffracted light. Conversely, when the OPD is not an integer multiple of the wavelength, light of each diffraction order cancels each other out, producing dark diffracted light. Therefore, the bright and dark fringes in grating diffraction are caused by the OPD of the grating. Therefore, in this embodiment, the arithmetic variation of the temperature control structure 3 is reflected in that the width of the temperature control structure 3 corresponding to the position with a larger optical path difference on the grating 2 is larger, and the width of the temperature control structure 3 corresponding to the position with a smaller optical path difference on the grating 2 is smaller.

[0052] Furthermore, when the wavelengths of the light signals incident on the grating are equal, the optical path difference can also be reflected as a phase difference in the light signals. Therefore, in this embodiment, the rate of change of the temperature-control structure with the grating position can also be considered the rate of change of the phase difference with the grating position. That is, the greater the rate of change of the phase difference with the grating position, the wider the temperature-control structure 3.

[0053] Furthermore, in this embodiment, the width of the temperature control structure 3 can be set to vary linearly with the optical path difference on the grating 2. This allows for proportional temperature adjustment, and thus proportional phase adjustment, improving the efficiency of temperature compensation. However, the present invention is not limited to this embodiment; the width of the temperature control structure can also be set to vary nonlinearly with the optical path difference.

[0054] Below, Figure 4 As an example, a structural example of a multiplexer temperature control system for controlling the temperature of the multiplexer as described above will be described.

[0055] Figure 4 Schematic diagram showing the structure of the multiplexer temperature control system involved in this embodiment. Figure 4 In the figure, as a multiplexer, only the temperature control structure 3 is schematically shown, and other structures such as the silicon waveguide 1 and the grating 2 are omitted.

[0056] In this embodiment, the demultiplexer temperature control system includes not only the demultiplexer described above, but also a temperature sensing unit 7 and a control circuit 8 .

[0057] The temperature sensing unit 7 detects the on-chip temperature information of the grating 2. A specific example of the temperature sensing unit 7 may be a thermal element such as a thermistor, or a sensor element such as a temperature sensor. The temperature sensing unit 7 may be integrated into the silicon substrate on which the demultiplexer is mounted, or may be disposed in an area separate from the demultiplexer. When the temperature sensing unit 7 is integrated into the silicon substrate, the temperature sensing unit 7 may be integrated into the demultiplexer or may be electrically connected to the demultiplexer as an external component.

[0058] The control circuit 8 obtains the on-chip temperature information detected by the temperature sensing unit 7, and adjusts the temperature of the temperature control structure 3 based on the on-chip temperature information. Specifically, the control circuit 8 can determine the corresponding adjustment scheme based on the received temperature information, and adjust the voltage or current applied to the temperature control structure 3 according to the determined adjustment scheme, thereby achieving the adjustment of different temperatures of the temperature control structure 3. The control circuit 8 can be integrated on a silicon substrate on which a multiplexer is installed, or it can be set in other areas different from the multiplexer. In the case of integrating the control circuit 8 on the silicon substrate, the control circuit 8 can be integrated into the multiplexer, or the control circuit 8 can be electrically connected to the multiplexer as an external component.

[0059] According to the structure of the multiplexer temperature control system of this embodiment, the voltage or current value on the temperature control structure can be adjusted according to the actual temperature of the device chip, so as to achieve precise temperature adjustment of the multiplexer.

[0060] The above describes the specific implementation of the present invention. According to the multiplexer and multiplexer temperature control system involved in the present invention, there is no need to set up additional energy sources, heat dissipation devices and other temperature control elements to perform temperature control on the devices, thereby reducing costs.

[0061] In addition, according to the multiplexer and multiplexer temperature control system involved in the present invention, temperature control structures of different shapes can be set according to the actual situation of the grating to perform effective temperature control. Therefore, the accuracy and range of temperature control can be improved to meet various temperature control requirements.

[0062] Furthermore, according to the multiplexer and the multiplexer temperature control system of the present invention, there is no need to integrate complex temperature control elements into the device, thereby reducing the difficulty of manufacturing the device.

[0063] All aspects of the embodiments disclosed herein are intended to be illustrative only and not restrictive. The scope of the present invention is indicated by the claims, not by the embodiments described above, and includes all modifications and variations within the meaning and scope of the claims.

[0064] Industrial applicability

[0065] As described above, the demultiplexer and the demultiplexer temperature control system according to the present invention are useful for stabilizing the performance of Demux devices integrated on a silicon substrate.

[0066] Description of labels

[0067] 1Silicon waveguide

[0068] 2 gratings

[0069] 3 Temperature control structure

[0070] 4SOI substrate

[0071] 5 buried layer

[0072] 6 covering layers

[0073] 7 Temperature sensing unit

[0074] 8 control circuit.

Claims

1. A demultiplexer integrated on a silicon substrate, characterized in that: include: an input free propagation region, wherein the input free propagation region is configured with an input-side silicon waveguide; an output free propagation region, wherein the output free propagation region is provided with an output-side silicon waveguide; a phase difference structure, the phase difference structure forming a grating, and arranged between the input free propagation region and the output free propagation region; and A temperature control structure is configured at the top of the input side silicon waveguide and the top of the output side silicon waveguide, and the width of the temperature control structure is in an arithmetically varying relationship with the position of the grating.

2. The demultiplexer according to claim 1, wherein: The width of the temperature control structure increases as the optical path difference on the grating increases.

3. The demultiplexer according to claim 2, wherein: The width of the temperature control structure is linearly related to the optical path difference.

4. The demultiplexer according to claim 2, wherein: The width of the temperature control structure is in a nonlinear relationship with the optical path difference.

5. The demultiplexer according to any one of claims 1 to 4, characterized in that The temperature control structure is made of tungsten or titanium nitride.

6. The demultiplexer according to any one of claims 1 to 4, characterized in that A difference between a refractive index of the input-side silicon waveguide and the output-side silicon waveguide and a refractive index of a cover layer covering the input-side silicon waveguide and the output-side silicon waveguide is 1.5 to 2.

5.

7. The demultiplexer according to any one of claims 1 to 4, characterized in that The input-side silicon waveguide and the output-side silicon waveguide respectively adopt a ridge waveguide structure.

8. The demultiplexer according to any one of claims 1 to 4, characterized in that The input side silicon waveguide and the output side silicon waveguide are respectively arranged on the top of the silicon substrate, The silicon substrate is an SOI substrate.

9. A multiplexer temperature control system, characterized in that: include: The demultiplexer according to any one of claims 1 to 8; a temperature sensing unit, which detects on-chip temperature information of the grating; as well as A control circuit is configured to obtain the on-chip temperature information from the temperature sensing unit and to adjust the temperature of the temperature control structure based on the on-chip temperature information.

10. The multiplexer temperature control system according to claim 9, wherein: The control circuit adjusts the temperature of the temperature control structure by adjusting the voltage or current applied to the temperature control structure.

11. The multiplexer temperature control system according to claim 9 or 10, characterized in that: The temperature sensing unit and the control circuit are integrated into the multiplexer.

12. The multiplexer temperature control system according to claim 9 or 10, characterized in that: The temperature sensing unit and the control circuit are electrically connected to the demultiplexer as external components.

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