Miniaturized rubidium atomic clock

Abstract

The invention relates to the technical field of atomic frequency standards, in particular to a miniaturized rubidium atomic clock, which comprises a light source module, a microwave cavity module, a microwave coupling module and a control module, and is characterized in that the light source module, the microwave cavity module and the microwave coupling module are sequentially arranged along a light path; parallel light output by the light source module passes through the microwave cavity module and then is received by the microwave coupling module; the microwave coupling module and the microwave cavity module are fixedly mounted through a supporting structure; the control module is electrically connected with the light source module, the microwave cavity module and the microwave coupling module. The miniature laser is used as a light source to replace a traditional spectral lamp, so that the size and power consumption of the light source are reduced; the manufacturing of the microwave cavity and microwave feed-in are directly realized by adopting a circuit board process, the size of a physical system is further reduced, and the miniature rubidium atomic clock has the advantages of low cost, short production period and capability of realizing batch production, and is expected to realize mass production of commercial products of miniature rubidium atomic clocks.

Description

Technical Field

[0001] This application relates to the field of atomic frequency standard technology, and more specifically, to a miniaturized rubidium atomic clock. Background Technology

[0002] Rubidium atomic clocks are currently the most widely used atomic clocks, with extensive applications in navigation and positioning, communication networks, and power systems. As electronic technology continues to advance, the integration of various electronic systems is becoming increasingly sophisticated, leading to smaller and smaller requirements for commercial atomic clocks.

[0003] Traditional rubidium atomic clocks use electrodeless discharge lamps as their light source. These lamps require significant radio frequency excitation power to start, resulting in high power consumption and significant challenges in miniaturization. Additionally, the microwave cavity provides the microwave magnetic field necessary for the atomic clock's magnetic resonance transitions, making it another core component of the rubidium atomic clock. Traditional rubidium atomic clocks use microwave resonant cavities made of metal; however, after years of optimization and development, their size has now reached several centimeters. 3 However, further miniaturization is difficult, which is the most important challenge restricting the miniaturization and chip design of rubidium atomic clocks. Moreover, the long machining cycle and high cost are not conducive to large-scale production.

[0004] Therefore, although commercial rubidium atomic clocks have achieved miniaturization, further increasing their integration level remains a significant challenge, hindering their further development. How to further reduce the size of rubidium atomic clocks and achieve miniaturized or even chip-level commercial products is a major challenge facing the field. Summary of the Invention

[0005] This application provides a miniaturized rubidium atomic clock that uses a miniature laser as a light source to replace the traditional spectral lamp, and is small in size and low in cost.

[0006] To achieve the above objectives, this application provides a miniaturized rubidium atomic clock, comprising a light source module, a microwave cavity module, a microwave coupling module, and a control module, wherein: the light source module, microwave cavity module, and microwave coupling module are arranged sequentially along the optical path; parallel light output from the light source module passes through the microwave cavity module and is received by the microwave coupling module; the microwave coupling module and the microwave cavity module are fixedly installed by a support structure, with the microwave coupling module located on one side of the microwave cavity module, and the two are spaced apart and arranged parallel to each other; the control module is electrically connected to the light source module, microwave cavity module, and microwave coupling module respectively, and is used to provide drive, control, and signal processing.

[0007] Furthermore, the light source module includes a microlaser, a beam expander, and a collimator, wherein: the microlaser is a micro vertical cavity surface-emitting laser; the output light of the microlaser is paralleled after passing through the beam expander and collimator.

[0008] Furthermore, the microwave cavity module includes a microwave resonant cavity, an atomic gas chamber, a magnetic field coil, and a temperature control component, wherein: the microwave resonant cavity is made of a printed circuit board; the atomic gas chamber is located at the center of the microwave resonant cavity; the magnetic field coil is set on the top and bottom layers of the microwave resonant cavity circuit board to form a Helmholtz coil; and the temperature control component includes a thermistor and a heater.

[0009] Furthermore, the microwave resonant cavity consists of an outer cavity, a dielectric layer, and an electrode structure from the outside in. The outer cavity is made of printed circuit board vias. The dielectric layer is made of printed circuit board material with a dielectric constant determined according to the resonant frequency and structural dimensions. The electrode structure is a mesh structure formed by interconnecting and laminating multiple layers of circular conductors through circuit board technology.

[0010] Furthermore, the microwave coupling module includes a microwave coupling coil, a photodetector, and a microwave coupling port. The microwave coupling coil adopts a 50-ohm transmission line design, with one end connected to the microwave signal input and the other end grounded through a capacitor. The photodetector is located at the center of the microwave coupling coil and is used to receive the light signal transmitted through the atomic gas cell. The microwave coupling port is made of miniature radio frequency terminals and is used to connect to an external microwave signal source.

[0011] Furthermore, the microwave coupling coil and the electrode structure are aligned concentrically during assembly, and the photodetector is located directly behind the atomic gas cell in the optical path.

[0012] Furthermore, the control module includes a laser driving circuit, a microwave frequency synthesis circuit, a temperature control circuit, a magnetic field control circuit, and a servo circuit.

[0013] The miniaturized rubidium atomic clock provided in this application has the following beneficial effects: This application uses a miniature laser as the light source to replace the traditional spectral lamp, reducing the size and power consumption of the light source; it uses circuit board technology to directly realize the fabrication of the microwave cavity and microwave feeding, further reducing the size of the physical system, and has the advantages of low cost, short production cycle and mass production capability, which is expected to realize the commercial production of miniaturized rubidium atomic clock products. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This is a schematic diagram of a miniaturized rubidium atomic clock module according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a microwave cavity module according to an embodiment of this application; Figure 3This is a schematic diagram of the structure of a microwave coupling module provided according to an embodiment of this application; In the diagram: 1-Light source module, 2-Microwave cavity module, 21-Outer cavity, 22-Dielectric layer, 23-Electrode structure, 24-Atomic gas chamber, 25-Magnetic field coil, 26-Thermistor, 27-Heater, 3-Microwave coupling module, 31-Microwave coupling coil, 32-Photodetector, 33-Microwave coupling port, 4-Control module. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0016] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0017] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0018] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0019] In addition, the term "multiple" should mean two or more.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figure 1 As shown, this application provides a miniaturized rubidium atomic clock, including a light source module 1, a microwave cavity module 2, a microwave coupling module 3, and a control module 4, wherein: the light source module 1, the microwave cavity module 2, and the microwave coupling module 3 are arranged sequentially along the optical path; the parallel light output by the light source module 1 passes through the microwave cavity module 2 and is received by the microwave coupling module 3; the microwave coupling module 3 and the microwave cavity module 2 are fixedly installed by a support structure, with the microwave coupling module 3 located on one side of the microwave cavity module 2, and the two are spaced apart and arranged in parallel; the control module 4 is electrically connected to the light source module 1, the microwave cavity module 2, and the microwave coupling module 3 respectively, and is used to provide drive, control, and signal processing.

[0022] Specifically, the miniaturized rubidium atomic clock provided in this application includes a light source module 1, a microwave cavity module 2, a microwave coupling module 3, and a control module 4. The light source module 1 uses a miniature laser, coupled with beam expander and collimator optical elements, to output parallel light matched to the atomic gas cell 24. The microwave cavity module 2 uses a multilayer PCB process to fabricate a microwave resonant cavity, integrating the atomic gas cell 24, magnetic field coil 25, and temperature control components to provide microwave and static magnetic fields and to house the atomic gas cell 24. The microwave coupling module 3 integrates a microwave coupling coil 31 and a photodetector 32 to realize microwave signal input and optical signal reception. All modules are precisely assembled through a support structure, and the control module 4 realizes system driving, frequency synthesis, and closed-loop locking.

[0023] Furthermore, the light source module 1 includes a miniature laser, a beam expander, and a collimator, wherein the miniature laser is a miniature vertical-cavity surface-emitting laser (VCSEL); the output light of the miniature laser is parallelized after passing through the beam expander and collimator. The light source module 1 is preferably a miniature VCSEL, but other miniature lasers can also be used. The laser emits a single wavelength, eliminating the need for filtering and removing the filtering components of traditional rubidium atomic clocks. After passing through the beam expander and collimator, the laser becomes parallelized, and the spot size matches the inner diameter of the atomic gas cell 24, maximizing the effective interaction between light and atoms within the allowable size constraints. Simultaneously, the light source module 1 is located at the beginning of the optical path and is electrically connected to the control module 4, receiving current drive and temperature control.

[0024] Furthermore, such as Figure 2As shown, the microwave cavity module 2 includes a microwave resonant cavity, an atomic gas chamber 24, a magnetic field coil 25, and a temperature control component. The microwave resonant cavity is made of a printed circuit board. The atomic gas chamber 24 is located at the center of the microwave resonant cavity. The magnetic field coil 25 is set on the top and bottom layers of the microwave resonant cavity circuit board to form a Helmholtz coil. The temperature control component includes a thermistor 26 and a heater 27.

[0025] Furthermore, the microwave resonant cavity consists of an outer cavity 21, a dielectric layer 22, and an electrode structure 23 from the outside to the inside. The outer cavity 21 is made by through-holes in a printed circuit board. The dielectric layer 22 is made of a printed circuit board material with a dielectric constant determined according to the resonant frequency and structural dimensions. The electrode structure 23 is a mesh structure formed by interconnecting and laminating multiple layers of circular conductors through circuit board technology.

[0026] Specifically, the microwave cavity module 2 is fabricated using a PCB circuit board, and the entire microwave resonant cavity is fabricated using printed circuit board technology. The microwave resonant cavity consists of an outer cavity body 21, a dielectric layer 22, and an electrode structure 23 from the outside to the inside. The outer cavity body 21 is composed of an array of through holes in the printed circuit board. The dielectric layer 22 is made of a printed circuit board material with a corresponding dielectric constant, taking into account the resonant frequency and structural dimensions. The electrode structure 23 adopts a multi-layer circular conductor design, which is interconnected and laminated using circuit board technology. After the multi-layer circular conductors are interconnected, a mesh-like electrode structure 23 is formed, achieving the effect of traditional solid metal electrodes.

[0027] More specifically, circular wires are used to design Helmholtz magnetic field coils 25 on the top and bottom layers of the microwave cavity module 2 circuit board to ensure that the magnetic field at the center of the microwave resonant cavity is uniform and has good parallelism. The design of the Helmholtz coil takes into account both the thickness of the microwave cavity and the size of the circuit board. A thermistor 26 is also installed on the microwave cavity module 2 circuit board, and a heater 27 is installed on the outermost layer. The heater 27 uses a bidirectional wound heating element or a power transistor to avoid significant changes in the magnetic field caused by changes in heating current. The heating components achieve temperature stability of the microwave resonant cavity and its internal atomic gas chamber 24 under the control of the control module 4.

[0028] Furthermore, such as Figure 3 As shown, the microwave coupling module 3 includes a microwave coupling coil 31, a photodetector 32, and a microwave coupling port 33. The microwave coupling coil 31 is designed with a 50-ohm transmission line, with one end connected to the microwave signal input and the other end grounded through a capacitor. The photodetector 32 is located at the center of the microwave coupling coil 31 and is used to receive the light signal transmitted through the atomic gas cell 24. The microwave coupling port 33 is made of a miniature radio frequency terminal and is used to connect to an external microwave signal source.

[0029] Specifically, the microwave coupling module 3 is implemented using a circuit board, and the microwave coupling port 33 is fabricated using a miniature RF terminal. The microwave coupling coil 31 adopts a 50-ohm transmission line design, with its input end connected to the microwave coupling port 33 and the other end grounded through a capacitor; the diameter and position of the microwave coupling coil 31 match the dimensions of the electrode structure 23. A photodetector 32 is installed in the middle of the microwave coupling coil 31, and its dimensions match the inner diameter of the atomic gas chamber 24. The circuit boards of the microwave cavity module 2 and the microwave coupling module 3 are mounted together by a support structure, ensuring that the positions of the photodetector 32, the microwave coupling coil 31, the electrode structure 23, and the atomic gas chamber 24 are matched. The height of the support structure matches the height of the photodetector 32, preventing direct contact between the photodetector 32 and the atomic gas chamber 24 or the microwave resonant cavity.

[0030] Furthermore, the microwave coupling coil 31 and the electrode structure 23 are aligned concentrically during assembly, and the photodetector 32 is located directly behind the atomic gas cell 24 in the optical path.

[0031] Furthermore, the control module 4 includes a laser driving circuit, a microwave frequency synthesis circuit, a temperature control circuit, a magnetic field control circuit, and a servo circuit. The microwave frequency synthesis circuit can be integrated on the circuit board of the microwave coupling module 3 and directly connected to the microwave coupling coil 31 via a transmission line. The control module 4 provides driving and temperature control signals through an electrical connection with the light source module 1; it is connected to the microwave cavity module 2 to provide magnetic field control and heating control signals; and it is connected to the microwave coupling module 3 to receive photoelectric detection signals and output microwave excitation signals.

[0032] Specifically, when the miniaturized rubidium atomic clock provided in this application embodiment is working, the control module 4 first controls the temperature of the miniature laser and microwave cavity module 2 to reach the set value, and sets parameters such as magnetic field current; the control module 4 scans the current of the miniature laser to realize laser wavelength scanning, and the photodetector 32 converts the light intensity of the laser after passing through the atomic gas chamber 24 into an electrical signal and sends it to the control module 4; the servo circuit in the control module 4 determines the rubidium atom absorption spectrum line according to the photoelectric conversion signal and locks the laser wavelength to the 5S of 87Rb atom. 1 / 2 Up to 5P 1 / 2 The Doppler broadening spectral line; the microwave frequency synthesis circuit adopts a digital phase-locked loop circuit to achieve microwave frequency doubling from 10MHz crystal oscillator to about 6.8GHz, and feeds the microwave signal into microwave cavity module 2 through microwave excitation, and control module 4 controls the 10MHz output frequency to achieve 6.8GHz microwave frequency scanning; the servo circuit judges the magnetic resonance transition spectral line of the hyperfine energy level of the 87Rb atom ground state according to the photoelectric conversion signal, and locks the microwave frequency to the transition to achieve atomic clock closed-loop locking.

[0033] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A miniaturized rubidium atomic clock, characterized in that, It includes a light source module, a microwave cavity module, a microwave coupling module, and a control module, among which: The light source module, microwave cavity module, and microwave coupling module are arranged sequentially along the optical path; The parallel light output by the light source module passes through the microwave cavity module and is received by the microwave coupling module; The microwave coupling module and the microwave cavity module are fixedly installed by a support structure. The microwave coupling module is located on one side of the microwave cavity module, and the two are spaced apart and arranged in parallel. The control module is electrically connected to the light source module, the microwave cavity module, and the microwave coupling module, respectively, and is used to provide drive, control, and signal processing.

2. The miniaturized rubidium atomic clock according to claim 1, characterized in that, The light source module includes a miniature laser, a beam expander, and a collimating lens, wherein: The microlaser is a micro vertical-cavity surface-emitting laser; The output light from the microlaser is parallelized after passing through the beam expander and the collimator.

3. The miniaturized rubidium atomic clock according to claim 2, characterized in that, The microwave cavity module includes a microwave resonant cavity, an atomic gas chamber, a magnetic field coil, and a temperature control component, wherein: The microwave resonant cavity is made of a printed circuit board; The atomic gas chamber is located at the center of the microwave resonant cavity; The magnetic field coils are disposed on the top and bottom layers of the microwave resonant cavity circuit board to form Helmholtz coils; The temperature control component includes a thermistor and a heater.

4. The miniaturized rubidium atomic clock according to claim 3, characterized in that, The microwave resonant cavity consists of an outer cavity, a dielectric layer, and an electrode structure from the outside in, wherein: The outer cavity is made of through holes in a printed circuit board; The dielectric layer is made of printed circuit board material with a corresponding dielectric constant based on the resonant frequency and structural dimensions. The electrode structure is a mesh structure formed by interconnecting and pressing together multiple layers of circular wires using circuit board technology.

5. The miniaturized rubidium atomic clock according to claim 4, characterized in that, The microwave coupling module includes a microwave coupling coil, a photodetector, and a microwave coupling port, wherein: The microwave coupling coil adopts a 50-ohm transmission line design, with one end connected to the microwave signal input and the other end grounded through a capacitor; The photodetector is located at the center of the microwave coupling coil and is used to receive the light signal transmitted through the atomic gas cell; The microwave coupling port is made of miniature radio frequency terminals and is used to connect to an external microwave signal source.

6. The miniaturized rubidium atomic clock according to claim 5, characterized in that, The microwave coupling coil and the electrode structure are concentrically aligned during assembly, and the photodetector is located directly behind the atomic gas cell in the optical path.

7. The miniaturized rubidium atomic clock according to claim 6, characterized in that, The control module includes a laser driving circuit, a microwave frequency synthesis circuit, a temperature control circuit, a magnetic field control circuit, and a servo circuit.

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