A low temperature optical fiber coupler and its use method

Abstract

The present application provides a low-temperature optical fiber coupler and a method for using the same, and relates to the technical field of optical coupling devices. The low-temperature optical fiber coupler includes: a body; a substrate, the body is arranged on the substrate, the substrate includes at least two substrate layers, and the materials of the substrate layers include aluminum oxide and aluminum nitride; an inner packaging layer, which is packaged outside the substrate and the body; an outer packaging layer, which is packaged outside the inner packaging layer; the inner packaging layer and the outer packaging layer cooperate to form an optical fiber connection area; an optical fiber module, which is connected to the body through the optical fiber connection area; a temperature compensation module, which is arranged on the body and / or the substrate, and is used to measure the real-time temperature of the body and / or the substrate, and heat the body and / or the substrate according to the real-time temperature, so that the low-temperature optical fiber coupler can work normally in a low-temperature environment. The present application can improve the optical transmission performance, structural stability and service life of the optical fiber coupler in a low-temperature environment, so that it has a wide range of application prospects in the field of low-temperature communications.

Description

Technical Field

[0001] The present application relates to the technical field of optical coupling devices, and in particular to a low-temperature optical fiber coupler and a method for using the same. Background Art

[0002] In extremely low temperature environments, such as superconducting quantum computing, deep space exploration, and low temperature physics experiments, fiber couplers are one of the key optical components. However, existing low temperature fiber couplers have significant challenges in the following aspects:

[0003] 1. Material selection: Commonly used optical fiber materials (such as ordinary quartz optical fiber) have high transmission loss at low temperatures and are sensitive to temperature changes. Although some optical fiber materials with low hydroxyl content have been developed, their application range and reliability are still limited.

[0004] 2. Temperature compensation: Existing temperature compensation mechanisms mostly rely on external heaters or complex temperature control systems, which are ineffective at extremely low temperatures and have high energy consumption.

[0005] 3. Packaging technology: Traditional packaging materials (such as ordinary epoxy resin) easily lose their sealing properties at low temperatures and lack mechanical strength. Although existing multi-layer packaging technology has improved, it still has reliability issues.

[0006] Therefore, there is an urgent need for a low-temperature optical fiber coupler to solve at least one of the above problems. Summary of the invention

[0007] The present application provides a low-temperature optical fiber coupler and a method for using the same, aiming to solve the significant challenges of existing low-temperature optical fiber couplers in terms of material selection, temperature compensation, and packaging technology.

[0008] In a first aspect, the present application provides a low-temperature optical fiber coupler, comprising:

[0009] A body, wherein the body is a multi-mode interference structure;

[0010] A substrate, the body is disposed on the substrate, the substrate comprises at least two substrate layers, and the material of each substrate layer comprises at least one of aluminum oxide and aluminum nitride;

[0011] An inner packaging layer, the inner packaging layer is packaged on the outer sides of the substrate and the body;

[0012] An outer packaging layer, the outer packaging layer is packaged on the outer side of the inner packaging layer; wherein the inner packaging layer and the outer packaging layer cooperate to form an optical fiber connection area;

[0013] An optical fiber module, wherein the optical fiber module is connected to the body via the optical fiber connection area;

[0014] A temperature compensation module is arranged on the body and / or the substrate, and is used to measure the real-time temperature of the body and / or the substrate, and heat the body and / or the substrate according to the real-time temperature, so that the low-temperature optical fiber coupler can work normally in a low-temperature environment.

[0015] The optical fiber coupler provided in the first aspect of the present application can maintain good light wave transmission performance in a low temperature environment by adopting a multimode interference (MMI) structure in the body. The multimode interference structure has strong robustness and low temperature sensitivity, and is suitable for working under extreme low temperature conditions. The substrate includes at least two substrate layers, and the material of each substrate layer includes at least one of aluminum oxide and aluminum nitride. Aluminum oxide and aluminum nitride have excellent thermal stability and mechanical properties, and can maintain structural stability and mechanical strength in a low temperature environment. Using the inner and outer double-layer packaging technology, the inner packaging layer and the outer packaging layer jointly form a fiber connection area to ensure a good connection between the optical fiber and the body. The selection and design of the inner packaging layer and the outer packaging layer can effectively prevent the influence of environmental factors (such as humidity and temperature changes) on the performance of the optical fiber coupler. The temperature compensation module is arranged on the body and / or the substrate, and can measure the temperature of the body and the substrate in real time. According to the measured real-time temperature, the temperature compensation module heats the body and / or the substrate to ensure that the optical fiber coupler can work normally in a low temperature environment.

[0016] The provided optical fiber coupler has the following beneficial effects:

[0017] 1. Improve optical transmission performance: The multi-mode interference structure has excellent optical transmission performance at low temperatures, which can effectively reduce the loss and distortion of optical signals and ensure high reliability of communication. The real-time temperature measurement and heating of the temperature compensation module further stabilizes the optical transmission performance, making it consistent in different temperature environments.

[0018] 2. Enhanced structural stability: The choice of alumina and aluminum nitride materials ensures that the substrate still has good mechanical strength and thermal stability in low-temperature environments, avoiding material deformation and performance degradation caused by temperature changes. The double-layer packaging technology not only improves the sealing of the fiber coupler, but also enhances the overall structural strength, making it more reliable in extreme low-temperature environments.

[0019] 3. Extended service life: Through the optimization of material selection and packaging technology, the service life of the fiber optic coupler in a low-temperature environment is significantly extended, reducing the frequency of maintenance and replacement and reducing the cost of use.

[0020] 4. Improve the working temperature range: The introduction of the temperature compensation module enables the fiber coupler to work in a lower temperature range, broadening its application range. Real-time temperature measurement and heating functions ensure that the fiber coupler can maintain good working conditions under different temperature conditions.

[0021] 5. Enhanced anti-interference ability: The internal and external double-layer packaging technology effectively isolates interference from the external environment, such as humidity, electromagnetic interference, etc., and improves the anti-interference ability of the fiber coupler. The selection of substrate materials also helps to reduce the impact of the external environment on the performance of the fiber coupler.

[0022] 6. Simplified design and manufacturing: The design and manufacturing process of the cryogenic fiber coupler is simplified by combining the multimode interference structure and the temperature compensation module. Compared with the traditional cryogenic fiber coupler, this design reduces the complexity of materials and processes while improving the overall performance.

[0023] In summary, the low-temperature fiber coupler significantly improves its optical transmission performance, structural stability and service life in low-temperature environments through innovative designs such as multi-mode interference structure, optimized material selection, double-layer packaging technology and temperature compensation module. At the same time, it broadens the operating temperature range and enhances anti-interference ability, making it have broad application prospects in the field of low-temperature communications.

[0024] In some embodiments, the outer packaging layer forms a pressure regulating zone; the low-temperature optical fiber coupler also includes: a micro-gas valve module, which is installed in the pressure regulating zone and is used to adjust the pressure of the inner packaging layer, and the response time range of the micro-gas valve module is 5ms to 15ms; wherein, if the external temperature of the low-temperature optical fiber coupler increases, the micro-gas valve module opens to release excess gas so that the air pressure of the inner packaging layer is consistent with the external atmospheric pressure; if the external temperature decreases, the micro-gas valve module is closed to prevent external gas from entering, so that the air pressure of the inner packaging layer is stable; if the external air pressure of the low-temperature optical fiber coupler increases, the micro-gas valve module is closed to prevent external high-pressure gas from entering the interior of the package; if the external air pressure decreases, the micro-gas valve module is opened to allow external low-pressure gas to enter, so that the air pressure of the inner packaging layer is balanced.

[0025] In some embodiments, the material of the inner packaging layer is polyimide, the material of the outer packaging layer is nickel alloy, and the thickness of the inner packaging layer is less than the thickness of the outer packaging layer.

[0026] Exemplarily, the thickness of the substrate is equal to the thickness of the inner packaging layer, and the thickness of the outer packaging layer is twice the thickness of the inner packaging layer.

[0027] In some embodiments, the body and / or substrate include multiple preset measuring points and at least one preset heating point; the temperature compensation module includes: multiple temperature sensors, each of which is installed in one of the preset measuring points, for obtaining the real-time temperature corresponding to the preset measuring point; a thin film heater, which is installed in the preset heating point; a controller, which is used to obtain the real-time temperature measured by each temperature sensor, so as to generate a temperature control signal according to each real-time temperature, the position of the preset measuring point corresponding to the real-time temperature, and the position of the preset heating point, so as to control the thin film heater to heat the body and / or substrate according to the temperature control signal.

[0028] Exemplarily, the controller further stores a target temperature corresponding to each preset measuring point, so as to generate a temperature control signal according to each real-time temperature, the position of the preset measuring point corresponding to the real-time temperature, the target temperature corresponding to the preset measuring point and the position of the preset heating point, wherein the temperature control signal includes a power control signal corresponding to the film heater; the expression corresponding to the power control signal includes:

[0029] ;

[0030] Wherein, P(j) is the heating power of the thin film heater corresponding to the preset heating point j, N is the number of the preset measuring points, d(i, j) is the distance between the i-th preset measuring point and the preset heating point j, is the distance attenuation coefficient, which is used to adjust the effect of heat conduction distance on temperature control. is the real-time temperature of the i-th preset measuring point, is the target temperature corresponding to the i-th preset measuring point, is the temperature control coefficient, is the temperature deviation compensation coefficient, is the distance attenuation term, which is used to represent the distance attenuation of heat conduction.

[0031] It should be noted that, in some embodiments, the coefficient range corresponding to the distance attenuation coefficient is 0.1 to 0.5; and / or, the coefficient range corresponding to the temperature control coefficient is 0.1 to 1; and / or, the coefficient range corresponding to the temperature deviation compensation coefficient is 0.01 to 1.

[0032] In some embodiments, the hydroxyl content of the material of the optical fiber module is lower than a preset content; and / or the diameter of the optical fiber module ranges from 100 μm to 150 μm; and / or the numerical aperture of the optical fiber module ranges from 0.1 to 0.15.

[0033] In some embodiments, the low-temperature optical fiber coupler is fixed in a preset low-temperature environment via a low-temperature epoxy resin, and the temperature range corresponding to the low-temperature environment at least includes -200°C to -273°C.

[0034] In a second aspect, the present application provides a method for using a low-temperature optical fiber coupler, the low-temperature optical fiber coupler comprising a body, a substrate, an inner packaging layer, an outer packaging layer, an optical fiber module and a temperature compensation module, the body being a multimode interference structure, the body being arranged on the substrate, the substrate comprising at least two substrate layers, the material of each of the substrate layers comprising at least any one of aluminum oxide and aluminum nitride, the inner packaging layer being packaged on the outside of the substrate and the body, and the outer packaging layer being packaged on the outside of the inner packaging layer; wherein the inner packaging layer and the outer packaging layer cooperate to form an optical fiber connection area, the optical fiber module being connected to the body via the optical fiber connection area, and the temperature compensation module being arranged on the body and / or the substrate; the method comprising:

[0035] Using a fiber optic alignment device to connect the cleaned fiber optic module to the body via the fiber optic connection area;

[0036] Fixing the connected low-temperature optical fiber coupler in a preset low-temperature environment using low-temperature epoxy resin;

[0037] Initialize the temperature compensation module of the fixed low-temperature optical fiber coupler to obtain the real-time temperature of the body and / or substrate measured by the temperature compensation module, and heat the body and / or substrate according to the real-time temperature so that the low-temperature optical fiber coupler can work normally in a low-temperature environment.

[0038] The method for using the low-temperature fiber optic coupler provided in the second aspect ensures the effective operation of the fiber optic coupler in a low-temperature environment through a series of detailed steps. The cleaned fiber optic module is connected to the main body through the fiber optic connection area by using a fiber optic alignment device. Ensure accurate alignment between the fiber optic module and the main body to reduce connection losses and improve light transmission efficiency. The connected low-temperature fiber optic coupler is fixed in a preset low-temperature environment using low-temperature epoxy resin. Low-temperature epoxy resin has good low-temperature performance and mechanical strength, and can ensure the stability and reliability of the fiber optic coupler in a low-temperature environment. Initialize the temperature compensation module of the fixed low-temperature fiber optic coupler. Obtain the real-time temperature of the main body and / or substrate measured by the temperature compensation module. Heat the main body and / or substrate according to the real-time temperature so that the low-temperature fiber optic coupler can work normally in a low-temperature environment.

[0039] The method provided thereby has at least the following beneficial effects:

[0040] 1. Improve connection accuracy: Use fiber alignment equipment to align and connect the fiber optic module, ensuring high-precision connection between the fiber optic module and the body, reducing loss and distortion during optical transmission, and improving the overall communication performance of the system.

[0041] 2. Enhanced fixing effect: The use of low-temperature epoxy resin to fix the optical fiber coupler ensures the mechanical strength and stability of the fixing material in a low-temperature environment, avoids problems such as embrittlement and falling off of the fixing material caused by low temperature, and thus ensures the long-term stable operation of the optical fiber coupler.

[0042] 3. Real-time temperature monitoring and compensation: The initialization of the temperature compensation module and real-time temperature measurement enable the fiber coupler to monitor the temperature changes of the body and substrate in real time in a low-temperature environment. Heating compensation is performed according to temperature changes to ensure the normal operation of the fiber coupler under different low-temperature conditions and improve the reliability and stability of the system.

[0043] 4. Reduced maintenance costs: Through the above method, the performance of the fiber coupler in a low-temperature environment is more stable, reducing failures and maintenance requirements caused by temperature fluctuations, thereby reducing maintenance costs.

[0044] 5. Broaden the scope of application: This method is particularly suitable for extremely low temperature environments, such as deep space exploration, polar scientific research, etc., and broadens the application scope of low-temperature fiber couplers. Through the heating function of the temperature compensation module, the fiber coupler can work normally in a lower temperature range, meeting the requirements of more application scenarios.

[0045] 6. Simplified installation process: The use of fiber alignment equipment and low-temperature epoxy resin fixation simplifies the installation and fixing process, making on-site installation more convenient and efficient. The initialization steps of the temperature compensation module are simple and clear, and users can simplify the operation, which improves the convenience and reliability of installation.

[0046] In summary, the method of using the low-temperature fiber coupler ensures the efficient, stable and reliable operation of the fiber coupler in a low-temperature environment through precise fiber alignment, low-temperature epoxy resin fixation, and real-time monitoring and heating of the temperature compensation module. This method not only improves the optical transmission performance and structural stability, but also reduces maintenance costs, broadens the scope of application, and simplifies the installation process. Therefore, it has important value and broad application prospects in scientific research and engineering applications in low-temperature communications and extreme environments.

[0047] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 is a schematic structural block diagram of a low-temperature optical fiber coupler provided in one embodiment of the present application;

[0050] Figure 2 It is a schematic flow chart of the steps of a method for using a cryogenic optical fiber coupler provided in one embodiment of the present application.

[0051] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0054] It should be understood that, in order to facilitate the clear description of the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, the words "first", "second", etc. are used to distinguish the same items or similar items with substantially the same functions and effects. Those skilled in the art can understand that the words "first", "second", etc. do not limit the quantity and execution order, and the words "first", "second", etc. do not necessarily limit the difference.

[0055] It should be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0056] It should also be understood that the term “and / or” used in the specification and appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0057] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0058] In extremely low temperature environments, such as superconducting quantum computing, deep space exploration, and low temperature physics experiments, fiber couplers are one of the key optical components. However, existing low temperature fiber couplers have significant challenges in the following aspects:

[0059] 1. Material selection: Commonly used optical fiber materials (such as ordinary quartz optical fiber) have high transmission loss at low temperatures and are sensitive to temperature changes. Although some optical fiber materials with low hydroxyl content have been developed, their application range and reliability are still limited.

[0060] 2. Temperature compensation: Existing temperature compensation mechanisms mostly rely on external heaters or complex temperature control systems, which are ineffective at extremely low temperatures and have high energy consumption.

[0061] 3. Packaging technology: Traditional packaging materials (such as ordinary epoxy resin) easily lose their sealing properties at low temperatures and lack mechanical strength. Although existing multi-layer packaging technology has improved, it still has reliability issues.

[0062] Therefore, there is an urgent need for a low-temperature optical fiber coupler to solve at least one of the above problems.

[0063] To solve the above problems, please refer to Figure 1 The low-temperature optical fiber coupler 10 provided in the embodiment of the present application includes a body 11, a substrate 12, an inner packaging layer 13, an outer packaging layer 14, an optical fiber module 15 and a temperature compensation module 16. The body 11 is a multi-mode interference structure. The body 11 is arranged on the substrate 12. The substrate 12 includes at least two substrate 12 layers. The material of each substrate 12 layer includes at least one of aluminum oxide and aluminum nitride. The inner packaging layer 13 is packaged on the outside of the substrate 12 and the body 11, and the outer packaging layer 14 is packaged on the outside of the inner packaging layer 13; wherein the inner packaging layer 13 and the outer packaging layer 14 cooperate to form an optical fiber connection area, and the optical fiber module 15 is connected to the body 11 via the optical fiber connection area. The temperature compensation module 16 is arranged on the body 11 and / or the substrate 12, and is used to measure the real-time temperature of the body 11 and / or the substrate 12, and heat the body 11 and / or the substrate 12 according to the real-time temperature, so that the low-temperature optical fiber coupler 10 can work normally in a low-temperature environment.

[0064] Specifically, a multimode interference coupler (MMI) is a fiber coupler based on the principle of multimode interference, which can achieve high-efficiency optical signal transmission in a wide wavelength range. This structure is particularly suitable for applications in low-temperature environments because the MMI structure is less sensitive to external temperature changes and can maintain stable performance in environments with large temperature changes. The present application can use a 3x3 MMI structure.

[0065] The substrate 12 is composed of at least two substrate 12 layers, and the material of each substrate 12 layer includes at least one of aluminum oxide and aluminum nitride. Aluminum oxide and aluminum nitride have excellent thermal stability and mechanical strength at low temperatures, and can effectively reduce the impact of temperature changes on coupler performance. In addition, these materials also have a low thermal expansion coefficient, which helps to maintain the stability of the structure and reduce thermal stress.

[0066] The inner encapsulation layer 13 is encapsulated on the outside of the substrate 12 and the body 11, and uses materials with stable performance at low temperatures, such as low-temperature epoxy resin or other organic materials designed for low-temperature environments. These materials can still maintain good sealing and mechanical strength at low temperatures. The outer encapsulation layer 14 is further encapsulated on the outside of the inner encapsulation layer 13, and uses materials that are more resistant to low temperatures, such as polyimide or low-temperature metal alloys. The role of the outer encapsulation layer 14 is to further enhance the sealing and mechanical strength to ensure the long-term reliability of the coupler at extreme low temperatures.

[0067] The inner packaging layer 13 and the outer packaging layer 14 together form an optical fiber connection area, through which the optical fiber module 15 is connected to the body 11. This design ensures a stable connection between the optical fiber and the coupler body 11 and reduces transmission loss.

[0068] By setting the temperature compensation module 16 on the body 11 and / or the substrate 12, the temperature of the body 11 and the substrate 12 can be measured in real time. According to the real-time temperature measurement results, the temperature compensation module 16 can heat the body 11 and / or the substrate 12 to maintain them working within a suitable temperature range. This heating mechanism can use a micro-heating wire or a micro-heater, which has low energy consumption and high efficiency.

[0069] Furthermore, by selecting materials with stable performance at low temperatures (such as optical fiber materials with low hydroxyl content, aluminum oxide and aluminum nitride), the transmission loss of the coupler at extremely low temperatures is effectively reduced, thereby improving the transmission efficiency and reliability of optical signals.

[0070] The combination of the multi-layer substrate 12 and the temperature compensation module 16 enables the coupler to maintain stable performance in an environment with large temperature changes. The real-time heating function of the temperature compensation module 16 can accurately control the operating temperature of the coupler and reduce performance fluctuations caused by temperature changes.

[0071] The use of low-temperature packaging materials, such as low-temperature epoxy resin and polyimide, ensures that the coupler still has good mechanical strength and sealing at extremely low temperatures, reduces the interference of the external environment on the internal optical components, and improves the overall reliability.

[0072] The heating mechanism of the temperature compensation module 16 adopts a low-power micro-heating wire or a micro-heater, which can reduce energy consumption while maintaining the normal operation of the coupler. It is suitable for application scenarios with high energy consumption requirements, such as deep space exploration.

[0073] The following are some examples of application scenarios of the provided fiber couplers:

[0074] 1. Application in superconducting quantum computing

[0075] Superconducting quantum computing usually needs to be performed in an environment close to absolute zero (-273°C). At such extremely low temperatures, transmission loss and instability of traditional optical fiber couplers are major problems.

[0076] By using the provided low-temperature optical fiber coupler 10, the multi-mode interference structure ensures high-efficiency transmission of optical signals, the selection of substrate 12 materials (aluminum oxide and aluminum nitride) improves temperature stability, the double-layer packaging technology enhances mechanical strength and sealing, and the real-time heating function of the temperature compensation module 16 ensures that the coupler can still work normally at near absolute zero, thereby meeting the requirements of superconducting quantum computing.

[0077] 2. Application in deep space exploration

[0078] Deep space probes experience extreme temperature changes in space, ranging from tens of degrees below zero to hundreds of degrees above zero. Traditional fiber couplers have difficulty maintaining stable operation in such extreme environments.

[0079] By using the provided low-temperature optical fiber coupler 10, the multi-mode interference structure reduces the impact of temperature changes on optical signal transmission, the selection of substrate 12 materials (aluminum oxide and aluminum nitride) improves temperature stability, the double-layer packaging technology ensures the sealing and mechanical strength in the low-temperature environment of outer space, and the low-power heating function of the temperature compensation module 16 maintains the operating temperature of the coupler, greatly improving the performance and reliability of deep space probes.

[0080] 3. Application in low temperature physics experiments

[0081] Low-temperature physics experiments usually need to be conducted at liquid nitrogen (-196°C) or liquid helium (-269°C). The experiments require extremely high transmission efficiency and stability of the optical fiber coupler.

[0082] By using the provided low-temperature optical fiber coupler 10, the multimode interference structure ensures the high-efficiency transmission of optical signals, the substrate 12 material (aluminum oxide and aluminum nitride) improves the temperature stability, the double-layer packaging technology enhances the mechanical strength and sealing, and the real-time heating function of the temperature compensation module 16 ensures the normal operation of the coupler in a low-temperature environment, making the experimental results more accurate and reliable.

[0083] Through the above technical content and specific examples, it can be seen that the provided cryogenic fiber optic coupler 10 has significant advantages in extreme low temperature environments, can effectively solve the problems existing in traditional fiber optic couplers, and improve the performance and reliability of the application system.

[0084] In some embodiments, the outer packaging layer 14 forms a pressure adjustment zone; the low-temperature optical fiber coupler 10 also includes: a micro-valve module, which is installed in the pressure adjustment zone and is used to adjust the pressure of the inner packaging layer 13, and the response time range of the micro-valve module is 5ms to 15ms; wherein, if the external temperature of the low-temperature optical fiber coupler 10 increases, the micro-valve module opens to release excess gas so that the air pressure of the inner packaging layer 13 is consistent with the external atmospheric pressure; if the external temperature decreases, the micro-valve module is closed to prevent external gas from entering, so that the air pressure of the inner packaging layer 13 is stable; if the external air pressure of the low-temperature optical fiber coupler 10 increases, the micro-valve module is closed to prevent external high-pressure gas from entering the interior of the package; if the external air pressure decreases, the micro-valve module is opened to allow external low-pressure gas to enter so that the air pressure of the inner packaging layer 13 is balanced.

[0085] The outer packaging layer 14 not only plays a role in physical protection and mechanical strength enhancement, but also forms a pressure adjustment area. This area is used to install a micro-valve module to adjust the pressure of the inner packaging layer 13. The micro-valve module is installed in the pressure adjustment area to adjust the pressure of the inner packaging layer 13. The response time of the micro-valve module ranges from 5ms to 15ms, ensuring fast and accurate pressure adjustment.

[0086] When the external temperature rises, the volume of gas in the inner packaging layer 13 will expand, resulting in an increase in air pressure. The micro-valve module will open to release excess gas, so that the air pressure of the inner packaging layer 13 is consistent with the external atmospheric pressure, thereby avoiding structural damage or performance degradation caused by excessive internal pressure. When the external temperature decreases, the volume of gas in the inner packaging layer 13 will shrink, resulting in a decrease in air pressure. The micro-valve module will close to prevent external gas from entering, so that the air pressure of the inner packaging layer 13 remains stable, thereby avoiding pollution or other adverse effects caused by gas entry. When the external air pressure increases, the micro-valve module will close to prevent external high-pressure gas from entering the package, thereby protecting the internal optical components from damage by high-pressure gas. When the external air pressure decreases, the micro-valve module will open to allow external low-pressure gas to enter, so that the air pressure of the inner packaging layer 13 is consistent with the external air pressure, thereby avoiding structural problems caused by excessive internal pressure.

[0087] Through the dynamic adjustment of the micro-valve module, the pressure of the inner packaging layer 13 is always kept within an appropriate range, effectively preventing sealing problems caused by changes in external temperature and air pressure. This pressure adjustment mechanism improves the stability and reliability of the coupler in extreme environments and reduces the stress and deformation of the packaging material caused by pressure changes.

[0088] Since the pressure of the inner packaging layer 13 is effectively regulated, the optical elements inside the coupler will not be damaged by pressure fluctuations, thereby extending the service life of the coupler. Traditional temperature and air pressure regulation methods usually rely on complex external control systems, which are expensive and complex to maintain. The use of micro-valve modules simplifies the pressure regulation process and reduces the cost and maintenance difficulty of the overall system. The cryogenic fiber optic coupler 10 is not only suitable for a single extreme low temperature environment, but can also work normally in an environment with large changes in temperature and air pressure, and has a wide range of adaptability.

[0089] Exemplarily, a cavity or gap with a certain volume is designed inside the outer packaging layer 14 as a pressure regulating area. This area can be realized by precision machining or mold forming. The pressure regulating area needs to maintain a certain degree of sealing with the external environment to prevent the external environment from directly interfering with the air pressure of the inner packaging layer 13. Sealing can be achieved by using materials such as sealing rings and sealants. The micro-valve module is installed in the pressure regulating area of ​​the outer packaging layer 14, usually in the area between the outer packaging layer 14 and the inner packaging layer 13. The micro-valve module is fixed in the pressure regulating area of ​​the outer packaging layer 14 by low-temperature epoxy resin or other low-temperature resistant fixing materials to ensure that it does not loosen or fall off in an extremely low temperature environment. The micro-valve module is connected to the inner packaging layer 13 and the external environment through tiny gas channels, which need to be designed very finely to ensure efficient regulation of the airflow.

[0090] A temperature sensor is installed on the outer packaging layer 14 to monitor the external temperature changes in real time. The temperature sensor is connected to the micro-valve module through a control system. When the temperature rises, the control system will quickly instruct the micro-valve module to open and release excess gas; when the temperature drops, the control system will instruct the micro-valve module to close to prevent external gas from entering.

[0091] At the same time, an air pressure sensor is installed on the outer packaging layer 14 to monitor the external air pressure changes in real time. The air pressure sensor is connected to the micro air valve module through a control system. When the external air pressure is detected to increase, the control system will quickly instruct the micro air valve module to close to prevent high-pressure gas from entering; when the external air pressure is detected to decrease, the control system will instruct the micro air valve module to open to allow low-pressure gas to enter.

[0092] The micro air valve module can effectively adjust the air pressure of the inner packaging layer 13 through the quick response of the micro air valve module to keep it stable when the temperature rises or falls. When the external air pressure changes, the micro air valve module can quickly adjust the air pressure of the inner packaging layer 13 to ensure that it is balanced with the external environment.

[0093] In some embodiments, the material of the inner packaging layer 13 is polyimide, the material of the outer packaging layer 14 is nickel alloy, and the thickness of the inner packaging layer 13 is less than the thickness of the outer packaging layer 14 .

[0094] The material of the inner packaging layer 13 is polyimide. Polyimide is a polymer material with excellent high-temperature and low-temperature properties, and can maintain good mechanical strength and sealing properties at extremely low temperatures.

[0095] The material of the outer packaging layer 14 is nickel alloy. Nickel alloy has high mechanical strength and good corrosion resistance at extremely low temperatures, and can provide additional protection and support. The thickness of the inner packaging layer 13 is less than that of the outer packaging layer 14. This design enables the inner packaging layer 13 to better adapt to stress changes in low temperature environments, while the outer packaging layer 14 can provide additional mechanical protection.

[0096] At extremely low temperatures, polyimide can still maintain good mechanical strength and sealing, reducing performance fluctuations caused by temperature changes. At extremely low temperatures, the mechanical strength and corrosion resistance of nickel alloys are superior to traditional metal materials, providing reliable protection.

[0097] Since the inner packaging layer 13 is relatively thin, it can more flexibly adapt to stress changes in a low temperature environment and avoid brittle cracking or deformation caused by excessive thickness. The outer packaging layer 14 is relatively thick, providing additional mechanical protection to ensure the overall structural stability of the coupler. The selection of polyimide and nickel alloy not only has superior performance, but also relatively reasonable cost, making the low-temperature fiber coupler 10 more cost-effective in practical applications. Polyimide and nickel alloy have good durability at extremely low temperatures, which prolongs the service life of the coupler and reduces the frequency of maintenance and replacement.

[0098] Exemplarily, the thickness of the substrate 12 is equal to the thickness of the inner packaging layer 13 , and the thickness of the outer packaging layer 14 is twice the thickness of the inner packaging layer 13 .

[0099] The thickness of the substrate 12 and the inner packaging layer 13 is equal, such as 0.1 mm, so that the stress distribution of the two in a low temperature environment is more uniform, reducing the internal stress concentration point and improving the overall mechanical stability. The thickness of the outer packaging layer 14 is twice that of the inner packaging layer 13, providing stronger mechanical protection, which can effectively resist the impact and pressure changes of the external environment and ensure the long-term reliability of the coupler under extreme conditions.

[0100] The thinner polyimide inner packaging layer 13 can fit more closely to the substrate 12 and the body 11, forming a good sealing effect and reducing the infiltration of gas and pollutants. The thicker nickel alloy outer packaging layer 14 not only enhances physical protection, but also improves the overall performance of the package, ensuring sealing and mechanical strength under different temperature and pressure conditions.

[0101] In some embodiments, the main body 11 and / or the substrate 12 include multiple preset measuring points and at least one preset heating point; the temperature compensation module 16 includes: multiple temperature sensors, each temperature sensor is installed in a preset measuring point, and is used to obtain the real-time temperature corresponding to the preset measuring point; a thin film heater, the thin film heater is installed in the preset heating point; a controller, the controller is used to obtain the real-time temperature measured by each temperature sensor, so as to generate a temperature control signal according to each real-time temperature, the position of the preset measuring point corresponding to the real-time temperature, and the position of the preset heating point, so as to control the thin film heater to heat the main body 11 and / or the substrate 12 according to the temperature control signal.

[0102] By setting a plurality of preset measuring points and at least one preset heating point on the body 11 and / or the substrate 12. The preset measuring points are used to install temperature sensors to monitor the temperature changes of the body 11 and / or the substrate 12 in real time. The preset heating points are used to install thin film heaters, and the body 11 and / or the substrate 12 can be locally heated when necessary.

[0103] A temperature sensor is installed at each measuring point to obtain the real-time temperature corresponding to the measuring point. These temperature sensors can be thermocouples, thermal resistors or other high-precision temperature sensors, which have the characteristics of fast response and high accuracy. The thin film heater is installed in the preset heating point. The thin film heater is usually made of conductive material and has the characteristics of low energy consumption, rapid heating and uniform heating. The controller is responsible for obtaining the real-time temperature measured by each temperature sensor and generating a temperature control signal based on these temperatures, the position of the measuring point and the position of the heating point. The controller can dynamically adjust the heating power through an algorithm to ensure that the body 11 and the substrate 12 operate within an appropriate temperature range.

[0104] By setting multiple measuring points on the body 11 and the substrate 12, comprehensive and accurate temperature monitoring can be achieved to ensure that temperature changes in various parts can be captured in a timely manner. The controller can dynamically generate a temperature control signal based on real-time temperature data and accurately control the thin film heater, so that the body 11 and the substrate 12 can maintain the best working state under different temperature conditions.

[0105] The thin film heater can perform local heating, avoiding the energy consumption and thermal stress problems caused by overall heating, and improving the reliability of the system. The use of multi-layer packaging materials (inner packaging layer 13 and outer packaging layer 14) further enhances the mechanical strength and sealing of the coupler, ensuring long-term reliability at extremely low temperatures.

[0106] At the same time, the thin film heater has the characteristics of low energy consumption, which can reduce energy consumption while maintaining the normal operation of the coupler, and is suitable for application scenarios with high energy consumption requirements, such as deep space exploration and superconducting quantum computing. The design of multi-point temperature monitoring and local heating enables the coupler to adapt to a variety of different environmental conditions, improving its application range and flexibility.

[0107] Through the detailed technical contents and specific examples of the above embodiments, it can be seen that the cryogenic optical fiber coupler 10 has significant advantages in applications under extremely low temperatures and changing environments:

[0108] 1. Accurate temperature control: The design of multi-point temperature monitoring and local heating ensures the stability and reliability of the coupler under different temperature conditions.

[0109] 2. Improve reliability: Local heating avoids the thermal stress problem caused by overall heating and improves the reliability of the system.

[0110] 3. Low energy consumption: The low energy consumption characteristics of the film heater are suitable for a variety of application scenarios with high energy consumption requirements.

[0111] 4. Strong adaptability: Multi-point monitoring and adjustment mechanism enables the coupler to adapt to a variety of environmental conditions, improving its application range and flexibility.

[0112] These design and technical features not only improve the performance of the coupler, but also extend its service life and reduce maintenance costs, making it suitable for optical applications in a variety of extreme environments.

[0113] Exemplarily, the controller also stores the target temperature corresponding to each preset measuring point, so as to generate a temperature control signal according to each real-time temperature, the position of the preset measuring point corresponding to the real-time temperature, the target temperature corresponding to the preset measuring point and the position of the preset heating point, wherein the temperature control signal includes a power control signal corresponding to the film heater; the expression corresponding to the power control signal includes:

[0114] ;

[0115] Wherein, P(j) is the heating power of the thin film heater corresponding to the preset heating point j, N is the number of the preset measuring points, d(i, j) is the distance between the i-th preset measuring point and the preset heating point j, is the distance attenuation coefficient, which is used to adjust the effect of heat conduction distance on temperature control. is the real-time temperature of the i-th preset measuring point, is the target temperature corresponding to the i-th preset measuring point, is the temperature control coefficient, is the temperature deviation compensation coefficient, is the distance attenuation term, which is used to represent the distance attenuation of heat conduction.

[0116] The controller stores the target temperature corresponding to each preset measuring point. These target temperatures are preset to ensure that the temperatures of the body 11 and the base 12 can be maintained within an ideal range under different environmental conditions. The controller is based on the real-time temperature of each preset measuring point. , the position of the measuring point corresponding to the real-time temperature, the target temperature of the preset measuring point and the position of the heating point generate a temperature control signal. The temperature control signal includes a power control signal P(j) corresponding to the thin film heater.

[0117] Multiple temperature sensors are used to monitor the temperature of multiple preset measuring points in real time to ensure the comprehensiveness and accuracy of temperature control. The controller stores the target temperature of each preset measuring point and can dynamically adjust the heating power as needed to quickly reach and maintain the temperature of each measuring point within the set target temperature range.

[0118] Distance decay term Ensure the reasonable distribution of heat by adjusting the distance attenuation coefficient , the distance and efficiency of heat conduction can be accurately controlled to avoid excessive concentration or dispersion of heat.

[0119] Temperature deviation compensation item The square term used to compensate for temperature deviation further improves the accuracy and response speed of temperature control.

[0120] Through local heating, the thermal stress problem caused by overall heating is avoided, and the mechanical stability and reliability of the coupler are improved. The controller can dynamically adjust the heating power according to the real-time temperature data to ensure stable operation under different environmental conditions. The low energy consumption characteristics of the thin film heater, combined with the precise temperature control algorithm, can reduce energy consumption while maintaining the normal operation of the coupler, and is suitable for application scenarios with high energy consumption requirements.

[0121] Through the detailed technical content and specific examples of this example, it can be seen that the cryogenic fiber coupler 10 has significant advantages in applications under extreme low temperatures and changing environments:

[0122] 1. Accurate temperature control: Multi-point temperature monitoring and target temperature storage, combined with complex power control signal expressions, ensure accurate control of the coupler under different temperature conditions.

[0123] 2. Optimized energy distribution: Through distance attenuation terms and temperature deviation compensation terms, heating energy is reasonably distributed to avoid excessive concentration or dispersion.

[0124] 3. Improved reliability: Local heating and real-time adjustment mechanism improve the mechanical stability and reliability of the coupler.

[0125] 4. Low energy consumption: The low energy consumption characteristics of the thin film heater combined with the precise control algorithm reduce energy consumption and are suitable for a variety of application scenarios with high energy consumption requirements.

[0126] These design and technical features not only improve the performance of the coupler, but also extend its service life and reduce maintenance costs, making it suitable for optical applications in a variety of extreme environments.

[0127] It should be noted that, in some embodiments, the coefficient range corresponding to the distance attenuation coefficient is 0.1 to 0.5; and / or, the coefficient range corresponding to the temperature control coefficient is 0.1 to 1; and / or, the coefficient range corresponding to the temperature deviation compensation coefficient is 0.01 to 1.

[0128] By selecting a distance attenuation coefficient value between 0.1 and 0.5, the heat conduction distance can be more accurately controlled to ensure that the temperature of each measuring point reaches the target value quickly and evenly.

[0129] By selecting the value of the temperature control coefficient between 0.1 and 1, the influence of the temperature difference on the heating power can be adjusted more flexibly, making the heating more sensitive and accurate.

[0130] By selecting the value of the temperature deviation compensation coefficient between 0.01 and 1, the square term of the temperature deviation can be compensated, further improving the accuracy and response speed of temperature control.

[0131] By adjusting the values ​​of the distance attenuation coefficient, the temperature control coefficient and the temperature deviation compensation coefficient, the coupler can work better in different application scenarios and environmental conditions, thereby improving the adaptability of the system.

[0132] In some embodiments, the hydroxyl content of the material of the optical fiber module 15 is lower than a preset content; and / or the diameter of the optical fiber module 15 ranges from 100 μm to 150 μm; and / or the numerical aperture of the optical fiber module 15 ranges from 0.1 to 0.15.

[0133] The hydroxyl content of the material of the optical fiber module 15 is lower than a preset content, such as lower than 100 ppm, which can significantly reduce the absorption of light signals by water molecules, reduce losses during transmission, and improve the transmission efficiency and stability of light signals.

[0134] Selecting a fiber diameter of 100μm to 150μm can optimize the transmission efficiency of optical signals while maintaining good mechanical strength and anti-interference capabilities.

[0135] The numerical aperture ranges from 0.1 to 0.15, which can ensure the effective coupling of optical signals, reduce scattering and loss, and improve transmission quality.

[0136] Materials with low hydroxyl content can reduce the impact of environmental factors on the optical fiber module 15 and improve its reliability under extreme conditions. Appropriate optical fiber diameter and numerical aperture can improve the mechanical stability and anti-interference ability of the optical fiber module 15 and reduce performance fluctuations caused by changes in the external environment. By comprehensively optimizing the hydroxyl content, diameter and numerical aperture, the coupler can work better in a variety of different application scenarios and improve its adaptability.

[0137] In some embodiments, the low-temperature optical fiber coupler 10 is fixed in a preset low-temperature environment by low-temperature epoxy resin, and the temperature range corresponding to the low-temperature environment at least includes -200°C to -273°C.

[0138] Low-temperature epoxy resin can still maintain good adhesion and mechanical strength in the temperature range of -200°C to -273°C, ensuring the stability and reliability of the coupler at extremely low temperatures. Fixing with low-temperature epoxy resin can reduce the impact of external vibration and mechanical stress on the coupler and improve its mechanical stability in extreme environments. The use of low-temperature epoxy resin can ensure uniform heat conduction between the various components of the coupler and reduce thermal stress problems caused by local temperature gradients. The low-temperature resistance of low-temperature epoxy resin allows the coupler to operate in a wider low-temperature range, from -200°C to -273°C, improving the applicability of the equipment.

[0139] At the same time, the fixation of low-temperature epoxy resin makes the connection between components such as temperature sensors and thin-film heaters and the coupler body more reliable, improving the accuracy and response speed of temperature control. Due to the thermal stability of the material, low-temperature epoxy resin can reduce the impact of temperature fluctuations on the performance of the coupler and ensure the stability of temperature control. It also enables the coupler to work stably for a long time in an extremely low-temperature environment, improving the reliability and service life of the equipment and reducing maintenance and replacement costs.

[0140] Low temperature epoxy resin, such as Epotek 302-3 or Master Bond EP21TDC-3. Apply low temperature epoxy resin evenly to the connection between the body 11 and the base 12, ensuring that the epoxy resin completely fills all gaps, and then fix the fiber coupler on a bracket or platform in a low temperature environment. According to the manufacturer's instructions of the epoxy resin, perform appropriate curing treatment, which usually needs to be cured in a low temperature environment to ensure that the cured resin has good mechanical strength and sealing at low temperatures.

[0141] Exemplarily, Epotek 302-3 low temperature epoxy resin is used, which has good performance in the temperature range of -65°C to 200°C. Epotek 302-3 is evenly applied to the connection between the base 12 and the body 11 of the optical fiber coupler, ensuring that all gaps are filled. The optical fiber coupler is then fixed on a metal bracket in a low temperature environment. According to the instructions of Epotek 302-3, it is cured in a low temperature environment of -50°C for 24 hours.

[0142] In some embodiments, humidity sensors are installed inside the outer packaging layer 14 and the inner packaging layer 13 to monitor the humidity of the packaging layer in real time. The accuracy of the humidity sensor is ±3%. The outer packaging layer 14 and the inner packaging layer 13 also include a dryer, such as a porous alumina desiccant, which is replaced or supplemented when necessary by regularly checking the inside of the package. For example, an inspection is performed every 3 months. Ensure that the humidity of the low-temperature optical fiber coupler 10 is always in a controllable state.

[0143] The installation of humidity sensors and high-precision monitoring (±3%) ensures real-time controllability of humidity in the package layer, preventing the impact of excessive humidity on coupler performance. Humidity can be adjusted in time to maintain it within the optimal range through regular inspection and replacement or replenishment of desiccant when necessary. The use of desiccators can significantly reduce the humidity in the package layer, reduce the absorption of light signals by water molecules, and thus reduce the loss during transmission. A low humidity environment helps to improve the transmission efficiency and quality of optical signals, ensuring the stability and reliability of data transmission.

[0144] At the same time, the low humidity environment can effectively prevent the corrosion of the optical fiber module 15 and related components, and extend the service life of the equipment. The desiccant can absorb excess moisture, reduce temperature fluctuations caused by humidity changes, and improve the temperature control accuracy and stability of the system. Through regular inspection and maintenance, problems can be discovered and solved in a timely manner to avoid equipment failures caused by humidity out of control. Due to proper humidity control, the corrosion and performance degradation of the equipment are reduced, its service life is extended, and the cost of frequent replacement and maintenance is reduced.

[0145] Next, the parameters of the low-temperature fiber coupler 10 provided by the present application are given with a specific embodiment, which uses a quartz fiber with a low hydroxyl (OH-) content and has extremely low temperature dependence. The diameter of the optical fiber is 125μm and the numerical aperture (NA) is 0.12. Multilayer composite ceramic materials, including aluminum oxide (Al2O3) and aluminum nitride (AlN), are used to ensure both mechanical strength and good thermal conductivity. The thickness of the substrate 12 is 1mm. A double-layer packaging material is selected, with the inner layer being polyimide (PI) and the outer layer being nickel alloy (Inconel 625) to improve air tightness and corrosion resistance. The thickness of the inner packaging layer 13 is 0.1mm, and the thickness of the outer packaging layer 14 is 0.2mm. A thin film platinum resistor is used as a heater with high precision and low thermal inertia. The thickness of the thin film heater is 0.01mm and the power is 100mW. The body 11 is designed as a 3x3 MMI coupler, using a quartz waveguide with a low hydroxyl content. The waveguide has a width of 10 μm, a length of 500 μm, and a thickness of 5 μm. The waveguide material is low-hydroxy quartz, which has a refractive index of 1.444 and a loss coefficient of 0.2 dB / km. Multiple high-precision thermocouples (type K) are integrated for temperature monitoring and installed at different positions to ensure uniform temperature distribution. The accuracy of the thermocouple is ±0.1°C. A closed-loop control system is designed, using a thin-film platinum resistor heater and a microcontroller (such as STM32) for temperature regulation. The microcontroller controls the power of the heater through a PID algorithm. Multilayer thermal insulation materials are used, including polyimide and aerogel. The thickness of polyimide is 0.1 mm, and the thickness of aerogel is 2 mm, with extremely low thermal conductivity (0.016 W / (m·K)). The inner encapsulation layer 13 is made of polyimide with a thickness of 0.1 mm; the outer encapsulation layer 14 is made of nickel alloy (Inconel 625) with a thickness of 0.2 mm. A micro pneumatic valve, such as a microvalve, is added to the package structure to adjust the internal pressure. The response time of the microvalve is 10ms and the accuracy is ±0.5%. A porous alumina desiccant is added inside the package to effectively absorb moisture and keep the inside dry. The adsorption capacity of the desiccant is 0.5g / g.

[0146] The provided optical fiber coupler has the following beneficial effects:

[0147] 1. Improve optical transmission performance: The multi-mode interference structure has excellent optical transmission performance at low temperatures, which can effectively reduce the loss and distortion of optical signals and ensure high reliability of communication. The real-time temperature measurement and heating of the temperature compensation module further stabilizes the optical transmission performance, making it consistent in different temperature environments.

[0148] 2. Enhanced structural stability: The choice of alumina and aluminum nitride materials ensures that the substrate still has good mechanical strength and thermal stability in low-temperature environments, avoiding material deformation and performance degradation caused by temperature changes. The double-layer packaging technology not only improves the sealing of the fiber coupler, but also enhances the overall structural strength, making it more reliable in extreme low-temperature environments.

[0149] 3. Extended service life: Through the optimization of material selection and packaging technology, the service life of the fiber optic coupler in a low-temperature environment is significantly extended, reducing the frequency of maintenance and replacement and reducing the cost of use.

[0150] 4. Improve the working temperature range: The introduction of the temperature compensation module enables the fiber coupler to work in a lower temperature range, broadening its application range. Real-time temperature measurement and heating functions ensure that the fiber coupler can maintain good working conditions under different temperature conditions.

[0151] 5. Enhanced anti-interference ability: The internal and external double-layer packaging technology effectively isolates interference from the external environment, such as humidity, electromagnetic interference, etc., and improves the anti-interference ability of the fiber coupler. The selection of substrate materials also helps to reduce the impact of the external environment on the performance of the fiber coupler.

[0152] 6. Simplified design and manufacturing: The design and manufacturing process of the cryogenic fiber coupler is simplified by combining the multimode interference structure and the temperature compensation module. Compared with the traditional cryogenic fiber coupler, this design reduces the complexity of materials and processes while improving the overall performance.

[0153] In summary, the low-temperature fiber coupler significantly improves its optical transmission performance, structural stability and service life in low-temperature environments through innovative designs such as multi-mode interference structure, optimized material selection, double-layer packaging technology and temperature compensation module. At the same time, it broadens the operating temperature range and enhances anti-interference ability, making it have broad application prospects in the field of low-temperature communications.

[0154] Please refer to Figure 2 , Figure 2 1 is a schematic flow chart of the steps of the method for using the cryogenic optical fiber coupler provided in the embodiment of the present application. The provided method is used to use the cryogenic optical fiber coupler provided in any embodiment of the present application. Figure 2 As shown, the method includes steps S101 to S103. The details are as follows:

[0155] Step S101: Use a fiber optic alignment device to connect the cleaned fiber optic module to the body via the fiber optic connection area.

[0156] Specifically, before connection, the end face of the fiber optic module needs to be thoroughly cleaned with alcohol or other special cleaning agents to ensure that there are no contaminants such as dust and grease. Use high-precision fiber optic alignment equipment to accurately align the fiber optic module with the body of the cryogenic fiber optic coupler. The alignment equipment usually includes a microscope, a laser alignment system, and a precision mechanical device. The fiber optic module is aligned and connected to the body through the fiber optic connection area. The fiber optic connection area is usually designed as a special mechanical structure to ensure good contact between the fiber optic module and the body and reduce connection losses.

[0157] High-precision alignment equipment can significantly reduce the loss during the connection process and improve the efficiency of optical transmission. Cleaning and precise alignment can ensure the stability of the connection between the fiber module and the body, avoiding performance degradation caused by contamination or inaccurate alignment. Reliable connection technology can ensure the long-term stable operation of the fiber coupler in extreme low temperature environments.

[0158] For example, use ultrasonic cleaning equipment and high-purity alcohol to clean the end face of the fiber module for 10 minutes, and then blow it dry with nitrogen. Use a fiber alignment device with automatic alignment function, such as the OptiCentric alignment system, to ensure that the alignment accuracy reaches the sub-micron level. Through the special design of the fiber connection area, such as the use of a V-groove structure, the alignment and connection between the fiber module and the body are ensured.

[0159] Step S102: Fix the connected low-temperature optical fiber coupler in a preset low-temperature environment using low-temperature epoxy resin.

[0160] Specifically, by selecting a low-temperature epoxy resin that can maintain good performance at extremely low temperatures, such as Epotek302-3 or Master Bond EP21TDC-3. Apply the low-temperature epoxy resin evenly to the connection between the body and the substrate, ensuring that the epoxy resin completely fills all gaps, and then fix the fiber coupler on a bracket or platform in a low-temperature environment. According to the manufacturer's instructions for the epoxy resin, perform appropriate curing treatment, which usually requires curing in a low-temperature environment to ensure that the cured resin has good mechanical strength and sealing at low temperatures.

[0161] Low-temperature epoxy resin can maintain good sealing at low temperatures to prevent the external environment from affecting the fiber coupler. Low-temperature epoxy resin has high mechanical strength at low temperatures and can effectively fix the fiber coupler to prevent mechanical damage caused by temperature changes. Curing treatment at low temperatures can ensure the long-term stability of epoxy resin in extreme low-temperature environments and improve the reliability of fiber couplers.

[0162] Exemplarily, Epotek 302-3 low temperature epoxy resin is used, which has good performance in the temperature range of -65°C to 200°C. Epotek 302-3 is evenly applied to the connection between the base and the body of the fiber coupler, ensuring that all gaps are filled. The fiber coupler is then fixed to a metal bracket in a low temperature environment. According to the instructions of Epotek 302-3, it is cured at a low temperature environment of -50°C for 24 hours.

[0163] Step S103. Initialize the temperature compensation module of the fixed low-temperature optical fiber coupler to obtain the real-time temperature of the body and / or substrate measured by the temperature compensation module, and heat the body and / or substrate according to the real-time temperature so that the low-temperature optical fiber coupler can work normally in a low-temperature environment.

[0164] Specifically, the temperature compensation module is a temperature sensor installed on the body and / or substrate, such as a thermocouple or a resistance thermometer, for real-time monitoring of temperature changes. According to the feedback from the temperature sensor, a heating resistor or other heating element is used to heat the body and / or substrate to compensate for the temperature change in a low temperature environment. A microcontroller or a dedicated temperature control circuit is used to read the data of the temperature sensor and perform heating control according to a preset temperature threshold.

[0165] The temperature compensation module can monitor the temperature changes of the body and substrate in real time to ensure that the temperature is within the set range. Through the precise control of the heating element, the temperature changes can be effectively compensated to maintain the optical performance of the fiber coupler stable. The automated temperature compensation system can reduce the frequency of manual adjustments and improve the overall work efficiency and reliability of the system.

[0166] Exemplarily, a PT100 resistance thermometer is used, which has high accuracy and stability in the temperature range of -200°C to 650°C. A thin sheet-shaped heating resistor, such as a 50Ω, 1W heating resistor, is installed on the body and the substrate, and connected to the control system through a wire. Using a microcontroller such as an Arduino, a temperature control program is written to read the data of the PT100 resistance thermometer and control the operation of the heating resistor according to a preset temperature threshold (for example, set to -270°C). A PID control algorithm can be set in the program to achieve more accurate temperature control.

[0167] The above steps ensure the reliable connection between the optical fiber module and the body through cleaning and high-precision alignment technology, use low-temperature epoxy resin to fix it to improve the sealing and mechanical strength, and finally achieve precise temperature control through temperature compensation module and heating element. It comprehensively solves the challenges of material selection, temperature compensation and packaging technology, so that the low-temperature optical fiber coupler can work stably and efficiently in extreme low temperature environments.

[0168] Next, a specific embodiment is used to illustrate the provided usage method:

[0169] Ensure that all fiber end faces are clean and dust-free. Use a fiber cleaner (such as IPA) to clean them. Use a microscope to inspect the end faces to ensure that there are no scratches or contamination. Insert the optical fiber into the input and output ports of the coupler. Use a fiber alignment tool (such as a fiber coupler) to ensure that the optical fibers are aligned and tightly connected. It is recommended to use FC / PC type fiber connectors to ensure good contact. Fix the coupler in a proper position in a low-temperature environment and fix it with a low-temperature epoxy (such as 3M Scotchweld DP190) to ensure that it is not affected by external forces.

[0170] Connect the coupler to the control system and initialize the temperature sensors and heating system. Make sure all sensors and heaters are working properly. Use the integrated multiple thermocouples to monitor the temperature of the coupler in real time and set the temperature monitoring frequency to 1Hz. Transfer the temperature data to the microcontroller through a data acquisition card (such as NI USB-6009).

[0171] The microcontroller controls the power of the heater through a PID algorithm to ensure that the coupler temperature is within a set range (e.g. -200°C). The PID parameters can be pre-set or optimized through experiments. The heater power is fine-tuned based on the feedback from the temperature sensor. The maximum power of the heater is 100mW, the minimum power is 1mW, and the accuracy is ±1mW.

[0172] Use an optical power meter (such as Thorlabs PM100D) to measure the optical power at the input and output ends and calculate the transmission loss. Use an optical spectrum analyzer (such as Agilent 86140B) to measure the coupling efficiency and ensure that the coupling efficiency is stable at low temperatures. Perform performance tests at different temperatures (such as -200°C, -230°C, -250°C, -273°C), record data and analyze. Regulate the internal pressure through a micro pneumatic valve to ensure airtightness at low temperatures. A pressure sensor (such as a MEMS pressure sensor) is used to monitor the internal pressure in real time, and the valve controller adjusts the valve opening through feedback.

[0173] Install a humidity sensor (such as Honeywell HIH-4030) inside the package to monitor humidity in real time. The humidity sensor has an accuracy of ±3%. Regularly check the porous alumina desiccant inside the package and replace or replenish it if necessary. It is recommended to check it every 3 months.

[0174] Transmission loss is reduced by selecting quartz waveguides with low hydroxyl content. Waveguide size optimization is performed using simulation software to ensure transmission efficiency and coupling efficiency at low temperatures.

[0175] The multi-layer composite ceramic substrate is used to improve thermal conductivity and mechanical strength. The temperature of the coupler is kept constant by integrating multiple high-precision temperature sensors and a closed-loop heating system. The internal pressure is regulated by a micro pneumatic valve to maintain airtightness.

[0176] Micro-nano processing technology (such as electron beam lithography) is used to achieve miniaturized design of waveguides and heaters. The temperature sensor, heater, pressure sensor and humidity sensor are integrated into a small module to reduce volume and weight.

[0177] At the same time, the heating system can be optimized to reduce energy consumption. Low-power microcontrollers and efficient heating elements are used. The heater power is automatically adjusted through intelligent algorithms to extend the service life.

[0178] Combining the performance of aluminum oxide and aluminum nitride, the stability and mechanical strength of the coupler at low temperatures are improved. By integrating multiple high-precision temperature sensors, pressure sensors, and humidity sensors, all-round environmental monitoring and control are achieved. Micro-nano processing technology is used to achieve miniaturization of waveguides and heaters to improve the performance and reliability of the coupler. Precise temperature control is achieved through PID algorithms and microcontrollers to ensure that the coupler works properly at extremely low temperatures.

[0179] It should be noted that the coupler needs to be able to adapt to extreme low temperature and high vacuum environments, and all external interfaces need to be cryogenically sealed. In low temperature environments, the mechanical properties of materials will decrease, so the mechanical strength and structural stability of the coupler need to be ensured. Ensure the compatibility and reliability of all sensors and controllers to avoid failures in low temperature environments.

[0180] The provided method has at least the following beneficial effects:

[0181] 1. Improve connection accuracy: Use fiber alignment equipment to align and connect the fiber optic module, ensuring high-precision connection between the fiber optic module and the body, reducing loss and distortion during optical transmission, and improving the overall communication performance of the system.

[0182] 2. Enhanced fixing effect: The use of low-temperature epoxy resin to fix the optical fiber coupler ensures the mechanical strength and stability of the fixing material in a low-temperature environment, avoids problems such as embrittlement and falling off of the fixing material caused by low temperature, and thus ensures the long-term stable operation of the optical fiber coupler.

[0183] 3. Real-time temperature monitoring and compensation: The initialization of the temperature compensation module and real-time temperature measurement enable the fiber coupler to monitor the temperature changes of the body and substrate in real time in a low-temperature environment. Heating compensation is performed according to temperature changes to ensure the normal operation of the fiber coupler under different low-temperature conditions and improve the reliability and stability of the system.

[0184] 4. Reduced maintenance costs: Through the above method, the performance of the fiber coupler in a low-temperature environment is more stable, reducing failures and maintenance requirements caused by temperature fluctuations, thereby reducing maintenance costs.

[0185] 5. Broaden the scope of application: This method is particularly suitable for extremely low temperature environments, such as deep space exploration, polar scientific research, etc., and broadens the application scope of low-temperature fiber couplers. Through the heating function of the temperature compensation module, the fiber coupler can work normally in a lower temperature range, meeting the requirements of more application scenarios.

[0186] 6. Simplified installation process: The use of fiber alignment equipment and low-temperature epoxy resin fixation simplifies the installation and fixing process, making on-site installation more convenient and efficient. The initialization steps of the temperature compensation module are simple and clear, and users can simplify the operation, which improves the convenience and reliability of installation.

[0187] In summary, the method of using the low-temperature fiber coupler ensures the efficient, stable and reliable operation of the fiber coupler in a low-temperature environment through precise fiber alignment, low-temperature epoxy resin fixation, and real-time monitoring and heating of the temperature compensation module. This method not only improves the optical transmission performance and structural stability, but also reduces maintenance costs, broadens the scope of application, and simplifies the installation process. Therefore, it has important value and broad application prospects in scientific research and engineering applications in low-temperature communications and extreme environments.

[0188] It should be noted that those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the above method can refer to the corresponding process in each embodiment of the low-temperature optical fiber coupler described in the above embodiments, and will not be repeated here.

[0189] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A low temperature optical fiber coupler, characterized in that: include: A body, wherein the body is a multi-mode interference structure; A substrate, the body is disposed on the substrate, the substrate comprises at least two substrate layers, and the material of each substrate layer comprises at least one of aluminum oxide and aluminum nitride; An inner packaging layer, the inner packaging layer is packaged on the outer sides of the substrate and the body; An outer packaging layer, the outer packaging layer is packaged on the outer side of the inner packaging layer; wherein the inner packaging layer and the outer packaging layer cooperate to form an optical fiber connection area; An optical fiber module, wherein the optical fiber module is connected to the body via the optical fiber connection area; A temperature compensation module, the temperature compensation module is arranged on the body and / or the substrate, and is used to measure the real-time temperature of the body and / or the substrate, and heat the body and / or the substrate according to the real-time temperature, so that the low-temperature optical fiber coupler can work normally in a low-temperature environment; the body and / or the substrate include a plurality of preset measuring points and at least one preset heating point; the temperature compensation module includes: a plurality of temperature sensors, each temperature sensor is installed in a preset measuring point, and is used to obtain the real-time temperature corresponding to the preset measuring point; a film heater, the film heater is installed in the preset heating point; a controller, the controller is used to obtain the real-time temperature measured by each temperature sensor, and generate a temperature control signal according to each real-time temperature, the position of the preset measuring point corresponding to the real-time temperature, and the position of the preset heating point, so as to control the film heater to heat the body and / or the substrate according to the temperature control signal; the controller also stores the target temperature corresponding to each preset measuring point, and generates the temperature control signal according to each real-time temperature, the position of the preset measuring point corresponding to the real-time temperature, the target temperature corresponding to the preset measuring point, and the position of the preset heating point, and the temperature control signal includes a power control signal corresponding to the film heater; the expression corresponding to the power control signal includes: ; in, Preset heating point The corresponding heating power of the thin film heater, is the number of preset measuring points, For the Preset measuring points and preset heating points The distance is the distance attenuation coefficient, which is used to adjust the effect of heat conduction distance on temperature control. It is Real-time temperature of preset measuring points, It is The target temperature corresponding to the preset measuring point, is the temperature control coefficient, is the temperature deviation compensation coefficient, The distance attenuation term is used to represent the distance attenuation of heat conduction. The distance attenuation term ensures the reasonable distribution of heat by adjusting the distance attenuation coefficient. , can control the distance and efficiency of heat conduction to avoid excessive concentration or dispersion of heat; temperature deviation compensation item Used to compensate the square term of temperature deviation to improve the accuracy and response speed of temperature control.

2. The cryogenic optical fiber coupler according to claim 1, characterized in that: The outer packaging layer forms a pressure regulating area; the low-temperature optical fiber coupler also includes: A micro-valve module, which is installed in the pressure regulating area and is used to regulate the pressure of the inner packaging layer. The response time of the micro-valve module ranges from 5 ms to 15 ms. Wherein, if the external temperature of the low-temperature optical fiber coupler rises, the micro-gas valve module opens to release excess gas so that the air pressure of the inner packaging layer is consistent with the external atmospheric pressure; if the external temperature decreases, the micro-gas valve module closes to prevent external gas from entering, so that the air pressure of the inner packaging layer is stable; If the external air pressure of the low-temperature optical fiber coupler increases, the micro-valve module is closed to prevent external high-pressure gas from entering the interior of the package; if the external air pressure decreases, the micro-valve module is opened to allow external low-pressure gas to enter, so as to balance the air pressure of the inner packaging layer.

3. The cryogenic optical fiber coupler according to claim 1, characterized in that: The material of the inner packaging layer is polyimide, the material of the outer packaging layer is nickel alloy, and the thickness of the inner packaging layer is less than the thickness of the outer packaging layer.

4. The cryogenic optical fiber coupler according to claim 3, characterized in that: The thickness of the substrate is equal to the thickness of the inner packaging layer, and the thickness of the outer packaging layer is twice the thickness of the inner packaging layer.

5. The cryogenic optical fiber coupler according to claim 1, characterized in that: The coefficient range corresponding to the distance attenuation coefficient is 0.1 to 0.5; and / or, The coefficient range corresponding to the temperature control coefficient is 0.1 to 1; and / or, The temperature deviation compensation coefficient corresponds to a coefficient range of 0.01 to 1.

6. The cryogenic optical fiber coupler according to claim 1, characterized in that: The hydroxyl content of the material of the optical fiber module is lower than a preset content; and / or, The diameter of the optical fiber module ranges from 100 μm to 150 μm; and / or, The numerical aperture of the optical fiber module ranges from 0.1 to 0.

15.

7. The cryogenic optical fiber coupler according to claim 1, characterized in that: The low-temperature optical fiber coupler is fixed in a preset low-temperature environment by means of low-temperature epoxy resin, and the temperature range corresponding to the low-temperature environment at least includes -200°C to -273°C.

8. A method for using a cryogenic optical fiber coupler, characterized in that: The low-temperature optical fiber coupler comprises a body, a substrate, an inner packaging layer, an outer packaging layer, an optical fiber module and a temperature compensation module. The body is a multi-mode interference structure. The body is arranged on the substrate. The substrate comprises at least two substrate layers. The material of each substrate layer comprises at least one of aluminum oxide and aluminum nitride. The inner packaging layer is packaged on the outside of the substrate and the body, and the outer packaging layer is packaged on the outside of the inner packaging layer. The inner packaging layer and the outer packaging layer cooperate to form an optical fiber connection area. The optical fiber module is connected to the body via the optical fiber connection area. The temperature compensation module is arranged on the body and / or the substrate. The body and / or the substrate comprise a plurality of preset measuring points and at least one preset heating point. The temperature compensation module comprises: a plurality of temperature sensors, each temperature sensor A temperature sensor is installed in a preset measuring point, and is used to obtain the real-time temperature corresponding to the preset measuring point; a film heater, the film heater is installed in the preset heating point; a controller, the controller is used to obtain the real-time temperature measured by each temperature sensor, so as to generate a temperature control signal according to each real-time temperature, the position of the preset measuring point corresponding to the real-time temperature, and the position of the preset heating point, so as to control the film heater to heat the body and / or the substrate according to the temperature control signal; the controller also stores the target temperature corresponding to each preset measuring point, so as to generate a temperature control signal according to each real-time temperature, the position of the preset measuring point corresponding to the real-time temperature, the target temperature corresponding to the preset measuring point, and the position of the preset heating point, the temperature control signal includes a power control signal corresponding to the film heater; the expression corresponding to the power control signal includes: ; in, Preset heating point The corresponding heating power of the thin film heater, is the number of preset measuring points, For the Preset measuring points and preset heating points The distance is the distance attenuation coefficient, which is used to adjust the effect of heat conduction distance on temperature control. It is Real-time temperature of preset measuring points, It is The target temperature corresponding to the preset measuring point, is the temperature control coefficient, is the temperature deviation compensation coefficient, The distance attenuation term is used to represent the distance attenuation of heat conduction. The distance attenuation term ensures the reasonable distribution of heat by adjusting the distance attenuation coefficient. , can control the distance and efficiency of heat conduction to avoid excessive concentration or dispersion of heat; temperature deviation compensation item The method is used to compensate for the square term of temperature deviation and improve the accuracy and response speed of temperature control; the method comprises: Using a fiber optic alignment device to connect the cleaned fiber optic module to the body via the fiber optic connection area; Fixing the connected low-temperature optical fiber coupler in a preset low-temperature environment using low-temperature epoxy resin; Initialize the temperature compensation module of the fixed low-temperature optical fiber coupler to obtain the real-time temperature of the body and / or substrate measured by the temperature compensation module, and heat the body and / or substrate according to the real-time temperature so that the low-temperature optical fiber coupler can work normally in a low-temperature environment.

Images