A method and system for generating an optical frequency standard that suppresses cavity pulling effects

Abstract

The application discloses a kind of methods and systems for generating optical frequency standard to inhibit cavity pulling effect.The system includes light source and the atom chamber of active atomic clock, wherein the atom chamber is double-layered spherical structure and vacuum is extracted between inner and outer layers;Two windows are left on the inner surface of inner spherical structure without diffuse reflection coating, as light inlet and light outlet, the rest of the inner surface of inner spherical structure is coated with diffuse reflection coating;The laser output by light source is injected into inner spherical structure through light inlet;First lens with a certain reflectivity of light source wavelength is arranged at the position corresponding to light outlet outside the atom chamber;Second lens with a certain reflectivity of light source wavelength is arranged at the position corresponding to light inlet outside the atom chamber, so that the laser signal output by light source interacts with atoms in the atom chamber to form optical feedback, realize bad cavity oscillation, obtain clock laser signal and output from light outlet.The stability index of active atomic clock system is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of optical frequency standards, and in particular to a method and system for generating optical frequency standards based on the principle of diffuse reflection of an integrating sphere to suppress cavity traction effect. Background Technology

[0002] Atomic clocks can be classified into microwave atomic clocks and optical frequency atomic clocks according to their operating frequency. They are instruments used to generate stable and accurate time and frequency standards and are currently widely used in satellite navigation and positioning systems, information network time synchronization, and precision measurement. Based on their working principle, atomic clocks can be divided into passive atomic clocks and active atomic clocks. Passive atomic clocks utilize quantum energy level transitions as a frequency reference, locking the frequency of an external local oscillator to the quantum transition energy level through a servo feedback system. Currently, the best-performing passive atomic clocks have achieved a stability index of 10⁻¹⁰. -18 In terms of magnitude, active atomic clocks are based on the principle of stimulated emission, directly using the coherent stimulated emission signal of multi-atom atoms as an optical frequency standard signal, with the output frequency determined by the atomic transition frequency. Therefore, active optical frequency standards are highly robust to cavity frequency manipulation and, in principle, can be used to realize laser reference sources with narrower linewidths.

[0003] On the other hand, an integrating sphere, also known as a photometric sphere, is a hollow spherical cavity with its inner wall coated with a diffuse reflective coating. Because its inner wall is coated with a highly reflective diffuse reflective coating, and its spherical geometry allows for sufficient diffuse reflection of light incident upon it, ultimately forming a uniform light field. Furthermore, the incident angle and spatial distribution of the incident light do not affect the intensity and uniformity of the output beam. Therefore, the integrating sphere can reduce errors caused by unevenness or beam deviation of the light incident on the detector during measurement. Consequently, integrating spheres are widely used in the field of optical detection.

[0004] To achieve continuous, small-volume active optical frequency standard signal output, an active atomic clock can be realized using a four-level alkali metal atomic structure. To increase the atomic number density and thus obtain higher output power, the atomic gas chamber generally needs to be heated. On the one hand, the temperature control precision requirements are very high, making the operation very difficult. On the other hand, thermal atomic quantum systems have problems such as collision frequency shift, which will affect the performance of the clock laser. Furthermore, due to the Doppler motion causing the gain linewidth to broaden, it will ultimately limit the further improvement of the cavity traction suppression effect. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to propose an optical frequency standard based on the principle of diffuse reflection of an integrating sphere to suppress cavity pulling effect. This invention applies the principle of diffuse reflection of an integrating sphere to the atomic cell design of an active atomic clock, changing the shape and structure of the traditional atomic cell. This eliminates the need for heating the atomic cell, as the atoms inside are cooled by pump light. Because there are no collisions between hot atoms, the gain linewidth broadening caused by Doppler motion is reduced, resulting in a narrower gain linewidth and a correspondingly larger cavity pulling coefficient. This achieves greater suppression of the cavity pulling effect. Furthermore, the use of cold atoms avoids the impact of collision frequency shifts introduced by hot atoms on the long-term frequency stability of the active atomic clock, thus significantly improving the stability index of the active atomic clock system.

[0006] Compared to current technical solutions, this invention patent has the following advantages: Firstly, by applying the unique geometric structure of the integrating sphere and the principle of diffuse reflection to the atomic chamber design of the active atomic clock, atomic cooling is achieved. Therefore, the system does not introduce Doppler broadening due to collisions caused by atomic thermal motion, further narrowing the gain linewidth and better suppressing the cavity traction effect, thereby greatly improving the system stability of the active atomic clock. Secondly, through the unique double-layer vacuum atomic chamber structure, atomic cooling is achieved while also possessing excellent thermal insulation performance, enhancing the active atomic clock system, especially the immunity of atoms within the atomic chamber to external environmental fluctuations, resulting in significantly improved temperature control accuracy.

[0007] The technical solution of this invention is:

[0008] An optical frequency standard based on the principle of diffuse reflection of an integrating sphere to suppress cavity traction effect is proposed. The unique geometry of the integrating sphere and the principle of diffuse reflection are applied to the design of the atomic gas cell in an active atomic clock. The atomic gas cell is designed as a double-layered spherical structure, with a vacuum between the inner and outer layers. Due to the excellent thermal insulation effect of the vacuum structure, the atomic gas cell effectively suppresses changes in ambient temperature. The inner layer is coated with a highly reflective diffuse reflection paint, leaving two windows uncoated as the light inlet and outlet apertures of the atomic gas cell. This design leverages the principle of diffuse reflection of the integrating sphere, allowing the pump light to undergo sufficient diffuse reflection within the atomic gas cell, forming a uniform light field. After the pump laser emits a laser signal, it undergoes precise frequency stabilization through a modulation transfer spectrum stabilization system. The resulting pump light enters the atomic gas chamber, where the atoms are slowed down and cooled due to the pump light. A portion of the pump light exits from the exit aperture of the atomic gas chamber. The external optical path of the exit aperture uses a lens with high reflectivity, so a large portion of the light is reflected back into the atomic gas chamber. After diffuse reflection, it exits from the entrance aperture. An external optical path structure is also set outside the entrance aperture to reflect most of the light back to the integrating sphere cavity. In this way, the laser signal is continuously reflected between the two lenses and the atomic gas chamber, and after fully interacting with the atoms in the gas chamber, optical feedback is formed, realizing cavity lasing and obtaining the clock laser signal required by the system. This achieves an optical frequency standard based on the principle of diffuse reflection of the integrating sphere to suppress the cavity traction effect.

[0009] The method for implementing an optical frequency standard based on the principle of diffuse reflection of an integrating sphere to suppress cavity traction effect includes the following steps:

[0010] 1) Laser 1 emits a laser signal, which passes through isolator 2 and first half-wave plate 3 and then is directed to polarization beam splitter 4. The polarization beam splitter 4 splits the signal into two paths. One path is used for frequency stabilization control of the laser signal by modulation transfer spectrum stabilization system 5, and the other path is directed to first plano-concave mirror 6 and then enters atomic gas cell 7 based on the principle of diffuse reflection of integrating sphere.

[0011] 2) The laser signal directed towards the modulation transfer spectrum frequency stabilization system 5 passes through the second half-wave plate 501 and then towards the second polarization beam splitter 502. The second polarization beam splitter 502 splits the signal into two beams. One beam is directed towards the atomic gas cell 503 for frequency stabilization, and the other beam serves as the pump light for the frequency stabilization system. After passing through the total reflection mirror and the third half-wave plate 505, the signal is directed towards the Glan Taylor prism 506. After passing through the Glan Taylor prism 506, the signal is directed towards the high-speed electro-optic modulator 507 for modulation to obtain the pump light for frequency stabilization. The frequency-stabilized pump light passes through the fourth half-wave plate 508 and the third polarization beam splitter 504 and then coincides with the frequency-stabilized laser signal in the opposite direction. The signal interacts with the atoms in the atomic gas cell 503. The resulting laser signal is then directed towards the high-speed photodetector 509 via the third polarization beam splitter 504.

[0012] 3) The detector 509 converts the measured optical signal into an electrical signal and transmits it to the laser phase detection and high-speed servo feedback control circuit 510. The laser phase detection and high-speed servo feedback control circuit 510 controls the power control system 511 of the laser through the generated servo signal, thereby realizing the frequency stabilization control of the laser output.

[0013] 4) After the modulation and transfer spectrum stabilization operation, the pump light signal used to realize the bad cavity lasing is injected into the atomic gas cell 7 based on the principle of diffuse reflection of the integrating sphere through the first plano-concave mirror 6. After multiple diffuse reflections in the atomic gas cell 7, a uniform light field is formed. The atoms in the gas cell are slowed down by the light field formed by the diffuse reflection of the pump light until they cool down. Part of the pump light is emitted from the light exit hole. The second plano-concave mirror 8 is coated with a film with a certain reflectivity. Part of the pump light is reflected back and injected into the atomic gas cell 7 based on diffuse reflection of the integrating sphere. After multiple reflections, it is emitted from the light entrance hole and reflected back by the first plano-concave mirror 6 and injected back into the atomic gas cell 7 based on diffuse reflection of the integrating sphere. In this way, the pump light is continuously reflected between the two plano-concave mirrors and the atomic gas cell, forming optical feedback, realizing bad cavity lasing, and obtaining the clock laser signal required by the system, thereby realizing the optical frequency standard based on the principle of diffuse reflection of the integrating sphere to suppress the cavity pulling effect.

[0014] 5) In step 4), the first and second plano-concave mirrors have undergone coating treatment and are not 100% transmittance. This operation is to allow some light to pass through the plano-concave mirrors and reflect the rest of the light back, so that the laser signal is continuously reflected between the resonant cavities, thereby realizing cavity lasing.

[0015] In specific implementation, the present invention provides an optical frequency standard generation system based on the principle of diffuse reflection of an integrating sphere to suppress cavity traction effect, comprising: a semiconductor laser, an isolator, a first half-wave plate, a first polarizing beam splitter prism, a modulation transfer spectrum stabilization system, a first plano-concave mirror, an atomic gas cell based on the principle of diffuse reflection of an integrating sphere, and a second plano-concave mirror. The modulation transfer spectrum stabilization system comprises: a second half-wave plate, a second polarizing beam splitter prism, a third half-wave plate, a GlanTeller prism, a high-speed electro-optic modulator, a fourth half-wave plate, a third polarizing beam splitter prism, a high-speed photodetector, a laser phase detection and high-speed servo feedback control circuit, and a power control system.

[0016] The overall process of the system to suppress cavity pulling effect based on the principle of diffuse reflection of the integrating sphere is as follows: The laser signal emitted by the semiconductor laser passes through an isolator and a first half-wave plate, and then is directed to a first polarizing beam splitter. The first polarizing beam splitter splits the signal into two paths. One path is used for frequency stabilization control of the modulation transfer spectrum stabilization system, while the other path is directed to a first plano-concave mirror and then into an atomic gas cell based on the principle of diffuse reflection of the integrating sphere. The laser signal directed to the modulation transfer spectrum stabilization system passes through a second half-wave plate and then is directed to a second polarizing beam splitter. The second polarizing beam splitter splits the signal into two paths. The laser beam is split into two beams. One beam is directed towards the atomic gas cell used for frequency stabilization, while the other serves as the pump light for the frequency stabilization system. After passing through a total reflection mirror and a third half-wave plate, the pump light is directed towards a Glan Taylor prism. From there, it is modulated by a high-speed electro-optic modulator to obtain the pump light used for frequency stabilization. This pump light then passes through a fourth half-wave plate and a third polarization beam splitter before entering the atomic gas cell again, where it overlaps with the frequency-stabilized laser signal in the opposite direction. Within the atomic gas cell, the laser light interacts with the atoms. The resulting laser signal is then directed towards a high-speed photodetector via the third polarization beam splitter. The detector converts the measured optical signal into an electrical signal, which is then transmitted to the laser phase detection and high-speed servo feedback control circuit. The laser phase detection and high-speed servo feedback control circuit controls the laser's power system through the generated servo signal, thereby achieving frequency stabilization control of the laser output. On the other hand, the laser signal directed towards the atomic gas cell based on the principle of diffuse reflection of an integrating sphere serves as the pump light for achieving cavity lasing. After multiple diffuse reflections within the atomic gas cell, a uniform optical field is formed. The atoms within the gas cell are slowed down by the optical field formed by the diffuse reflection of the pump light until they cool down. A portion of the pump light exits from the exit aperture. The second plano-concave mirror is coated with a high-reflectivity film, and the pump light is reflected back and re-enters the atomic gas cell based on diffuse reflection of an integrating sphere. Similarly, after multiple reflections, it exits from the entrance aperture, is reflected back by the first plano-concave mirror, and re-enters the atomic gas cell based on diffuse reflection of an integrating sphere. Thus, the pump light continuously reflects between the two plano-concave mirrors and the atomic gas cell, forming optical feedback, achieving cavity lasing, and obtaining the desired clock laser signal, thereby realizing an optical frequency standard based on the principle of diffuse reflection of an integrating sphere to suppress the cavity pulling effect.

[0017] Furthermore, the diffuse reflection treatment of the inner surface of the atomic gas cell based on the principle of diffuse reflection of the integrating sphere proposed in this invention can be coated with white water-based barium sulfate reflective material, but it is not limited to this. It can also be other diffuse reflective materials with high diffraction efficiency, or it can be silver-plated on its inner surface, etc.

[0018] Furthermore, in the atomic gas chamber based on the principle of diffuse reflection of the integrating sphere, the gas filled can be alkali metal atom gas such as potassium atoms, rubidium atoms, and cesium atoms.

[0019] Furthermore, the atomic gas chamber based on the principle of diffuse reflection of the integrating sphere has a double-layer glass structure with a vacuum structure between the inner and outer layers. This is done to better insulate the atomic gas chamber, so that the atomic gas chamber has a better suppression effect on changes in the external environment temperature, thereby ensuring that the atomic temperature inside the gas chamber remains constant.

[0020] Furthermore, the plano-concave mirrors used in the system are coated plano-concave mirrors. This operation is to allow part of the light to pass through the plano-concave mirrors and the other part of the light to be reflected back, so that the laser signal is continuously reflected between the two plano-concave mirrors and the atomic gas cell, thereby realizing cavity lasing and obtaining the clock laser signal to be output by the system.

[0021] Furthermore, the positions of the light inlet and outlet apertures of the atomic gas cell based on the principle of diffuse reflection of the integrating sphere are not limited to the angles shown in the accompanying drawings of this patent. This patent is merely an illustration, and the apertures can be set in different positions according to the specific project requirements. Some optical frequency standards have specific requirements for the direction of incident and outgoing light due to the design of the optical path. Using the atomic gas cell proposed in this invention, even if the apertures are set in different positions, the cooling of atoms and cavity lasing can still be achieved, thereby obtaining the required clock laser signal.

[0022] Furthermore, in addition to the optical path system mentioned above, the modulation transfer spectrum stabilization system also includes a radio frequency signal source, which generates a modulation signal to phase-modulate the pump light passing through the electro-optic modulator, and simultaneously generates a demodulation signal, which is used to mix with the detection signal measured by the high-speed photodetector to obtain an error signal.

[0023] Furthermore, in the modulation transfer spectrum frequency stabilization system, the electro-optic phase modulator will have a certain residual amplitude modulation during the phase modulation process. In this invention, a Glan Taylor prism is used in front of the electro-optic phase modulator, and a third half-wave plate is used to adjust the polarization direction of the pump light, thereby reducing the impact of residual amplitude modulation.

[0024] Furthermore, in the atomic gas cell of the modulation transfer spectrum frequency stabilization system, alkali metal atoms such as rubidium atoms, lithium atoms, sodium atoms, potassium atoms, and cesium atoms can be used. The appropriate alkali metal atoms can be selected according to the different wavelengths of the laser signal.

[0025] The technological innovation of this invention compared with the prior art is as follows:

[0026] 1. This invention provides an optical frequency standard and its implementation method based on the principle of diffuse reflection of an integrating sphere to suppress cavity traction effect. By applying the unique geometric structure of the integrating sphere and the principle of diffuse reflection to the atomic cell design of an active atomic clock, atomic cooling is achieved. Therefore, the system will not introduce Doppler broadening due to collisions caused by atomic thermal motion, which further narrows the gain linewidth and has a better suppression effect on cavity traction effect, thereby greatly improving the system stability index of the active atomic clock.

[0027] 2. This invention achieves atomic cooling through a unique double-layer vacuum atomic chamber structure, which greatly improves the heat preservation performance of the active atomic clock and makes the system more resistant to changes in ambient temperature.

[0028] 3. The optical frequency standard based on the principle of diffuse reflection of the integrating sphere to suppress cavity traction effect implemented in this invention not only makes the existing active atomic clock more immune to cavity traction effect and greatly improves the system stability index, but also provides new ideas and directions for the future development of active atomic clocks. Attached Figure Description

[0029] Figure 1 This is the optical path diagram of the optical frequency standard for suppressing cavity traction effect based on the principle of diffuse reflection of the integrating sphere in this invention;

[0030] Wherein: 1—semiconductor laser, 2—isolator, 3—first half-wave plate, 4—first polarization beam splitter, 5—modulation transfer spectrum frequency stabilization system, 6—first plano-concave mirror, 7—atomic gas cell based on the principle of diffuse reflection of integrating sphere, 8—second plano-concave mirror.

[0031] Figure 2 This is the optical path diagram of the modulation transfer spectrum frequency stabilization system in the system;

[0032] Among them: 501—second half-wave plate, 502—second polarizing beam splitter, 503—atomic gas cell for frequency stabilization system, 504—third polarizing beam splitter, 505—third half-wave plate, 506—Glan Taylor prism, 507—high-speed electro-optic modulator, 508—fourth half-wave plate, 509—high-speed photodetector, 510—laser phase detection and high-speed servo feedback control circuit, 511—power control system. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 1As shown, the optical frequency standard for suppressing cavity pulling effect based on the principle of diffuse reflection of the integrating sphere includes: a semiconductor laser 1, an isolator 2, a first half-wave plate 3, a first polarizing beam splitter prism 4, a modulation transfer spectrum stabilization system 5, a first plano-concave mirror 6, an atomic gas cell based on the principle of diffuse reflection of the integrating sphere 7, and a second plano-concave mirror 8. The optical path of the modulation transfer spectrum stabilization system 5 is as follows: Figure 2 As shown, it includes: a second half-wave plate 501, a second polarizing beam splitter 502, an atomic gas cell 503 for a frequency stabilization system, a third polarizing beam splitter 504, a third half-wave plate 505, a Glan Taylor prism 506, a high-speed electro-optic modulator 507, a fourth half-wave plate 508, a high-speed photodetector 509, a laser phase detection and high-speed servo feedback control circuit 510, and a power control system 511.

[0035] The laser signal emitted by semiconductor laser 1 passes through isolator 2 and first half-wave plate 3, and then is directed to first polarizing beam splitter 4. First polarizing beam splitter 4 splits the optical path into two paths: one path is used for frequency stabilization control of the laser signal by modulation transfer spectrum stabilization system 5; the other path is directed to first plano-concave mirror 6 and then into atomic gas cell 7 based on the principle of diffuse reflection from an integrating sphere. The laser signal directed to modulation transfer spectrum stabilization system 5 passes through second half-wave plate 501 and then to second polarizing beam splitter 502. Second polarizing beam splitter 502 splits the laser signal into two beams, one of which is directed to atomic gas cell 503 used for frequency stabilization system. Another pump beam, serving as the frequency stabilization system, passes through a total reflection mirror and a third half-wave plate 505 before being directed to a Glan Taylor prism 506. After passing through the Glan Taylor prism, it is modulated by a high-speed electro-optic modulator 507 to obtain the pump beam used for frequency stabilization. This stabilized pump beam then passes through a fourth half-wave plate 508 and a third polarization beam splitter 504 before entering the frequency-stabilized atomic gas cell, where it coincides with the frequency-stabilized laser signal in the opposite direction. Within the atomic gas cell 503 of the frequency stabilization system, it interacts with atoms. The resulting laser signal is then directed through the third polarization beam splitter 504 to a high-speed photodetector 509. The high-speed photodetector 509 converts the measured optical signal into an electrical signal, which is then transmitted to the laser phase detection and high-speed servo feedback control circuit 510. The laser phase detection and high-speed servo feedback control circuit 510 controls the power supply system 511 of the laser through the generated servo signal, thereby achieving frequency stabilization control of the output laser of the semiconductor laser 1. On the other hand, the laser signal directed towards the atomic gas cell 7 based on the principle of diffuse reflection of the integrating sphere serves as the pump light for achieving cavity lasing. After multiple diffuse reflections within the atomic gas cell, a uniform light field is formed. The atoms within the gas cell, due to the diffuse reflection of the pump light, form... The light field is slowed down until it cools down. A portion of the pump light is emitted from the exit aperture. The second plano-concave mirror 8 is coated with a high-reflectivity film. The pump light is reflected and re-emitted into the atomic gas cell 7 based on the diffuse reflection of the integrating sphere. After multiple diffuse reflections, it is emitted from the entrance aperture and reflected back by the first plano-concave mirror 6 and re-emitted into the atomic gas cell 7 based on the diffuse reflection of the integrating sphere. In this way, the pump light is continuously reflected between the two plano-concave mirrors and the atomic gas cell, forming optical feedback, realizing cavity lasing, and obtaining the clock laser signal required by the system. Thus, the optical frequency standard based on the principle of diffuse reflection of the integrating sphere suppresses the cavity traction effect is realized.

[0036] Finally, it should be noted that the purpose of disclosing the embodiments is to help further understand the present invention. However, those skilled in the art will understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. These substitutions include replacing different lasers, replacing the diffuse reflection material used in the inner wall of the atomic gas chamber, replacing different alkali metal atoms in the atomic gas chamber, and replacing the position and angle of the light inlet and outlet apertures of the atomic gas chamber. Any position required by different systems and different optical frequency standards is possible. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the scope of protection of the present invention is defined by the scope of the claims.

Claims

1. A system for generating optical frequency standards to suppress cavity traction effects, characterized in that, The atomic gas cell includes a light source and an active atomic clock; among which The active atomic clock has a double-layered spherical structure in its atomic chamber, with a vacuum formed between the inner and outer layers. The inner spherical structure of the active atomic clock has two windows on its inner surface that are not coated with diffuse reflection paint, serving as light inlet and light outlet. The remaining part of the inner surface of the inner spherical structure is coated with diffuse reflection paint. The light source includes a pump laser and a modulation transfer spectrum stabilization system. The laser output from the pump laser is split into two beams in sequence through an isolator, a first half-wave plate, and a first polarizing beam splitter. One beam is incident into the inner spherical structure through a second lens and an entrance aperture to decelerate the atoms in the atomic chamber of the active atomic clock. The other beam is fed back to the pump laser through the modulation transfer spectrum stabilization system to stabilize the laser signal output by the pump laser. The active atomic clock has a pair of first lenses with a certain reflectivity at the position corresponding to the light exit hole on the outside of the atomic gas cell. These lenses are used to partially reflect the light beam emitted from the light exit hole back into the atomic gas cell of the active atomic clock. Similarly, the active atomic clock has a pair of second lenses with a certain reflectivity at the position corresponding to the light inlet hole on the outside of the atomic gas cell. These second lenses are used to reflect the light beam emitted from the light inlet hole back into the atomic gas cell of the active atomic clock. This allows the laser signal output from the light source to interact with the atoms in the atomic gas cell of the active atomic clock, forming optical feedback, achieving cavity lasing, obtaining a clock laser signal, and outputting it from the light exit hole.

2. The frequency standard generation system as described in claim 1, characterized in that, The first lens is a plano-concave mirror, and the second lens is a plano-concave mirror.

3. The frequency standard generation system as described in claim 1, characterized in that, The modulation transfer spectrum frequency stabilization system includes a second half-wave plate, a second polarization beam splitter, a third half-wave plate, a Glan Taylor prism, a high-speed electro-optic modulator, a fourth half-wave plate, a third polarization beam splitter, a high-speed photodetector, a laser phase detection and high-speed servo feedback control circuit, and a power control system. The beam split by the first polarization beam splitter is then directed by the second half-wave plate and split into two beams by the second polarization beam splitter. One beam is directed towards the atomic gas cell used for frequency stabilization, and the other beam passes sequentially through a total reflection mirror and the third half-wave plate before reaching the Glan Taylor prism. The light is then modulated by a high-speed electro-optic modulator to obtain pump light for frequency stabilization. The frequency-stabilized pump light passes through a fourth half-wave plate and a third polarization beam splitter before being directed to the frequency-stabilized atomic gas cell. The laser signal output from the frequency-stabilized atomic gas cell is then directed to a high-speed photodetector via the third polarization beam splitter. The high-speed photodetector converts the received optical signal into an electrical signal and transmits it to the laser phase detection and high-speed servo feedback control circuit, generating a servo signal to control the power control system of the pump laser, thereby achieving frequency stabilization of the laser signal output by the pump laser.

4. A method for generating an optical frequency standard to suppress cavity traction effect, comprising the following steps: 1) The laser output from the light source enters the atomic gas chamber of the active atomic clock through the light inlet to decelerate the atoms in the active atomic clock; wherein the atomic gas chamber of the active atomic clock is a double-layer spherical structure with a vacuum between the inner and outer layers; the inner surface of the inner spherical structure of the active atomic clock has two windows that are not coated with diffuse reflection paint, serving as the light inlet and light outlet, while the remaining part of the inner surface of the inner spherical structure is coated with diffuse reflection paint; 2) A pair of first lenses with a certain reflectivity of the light source wavelength are provided on the outside of the atomic gas cell of the active atomic clock, corresponding to the position of the light outlet. The first lenses reflect part of the light beam emitted from the light outlet back to the atomic gas cell of the active atomic clock. A pair of second lenses with a certain reflectivity of the light source wavelength are provided on the outside of the atomic gas cell of the active atomic clock, corresponding to the position of the light inlet. The second lenses reflect the light beam emitted from the light inlet back to the atomic gas cell of the active atomic clock. This allows the laser signal output by the light source to interact with the atoms in the atomic gas cell of the active atomic clock to form optical feedback, realize cavity lasing, obtain a clock laser signal, and output it from the light outlet. The light source includes a pump laser and a modulation transfer spectrum stabilization system. The modulation transfer spectrum stabilization system is used to stabilize the frequency of the laser signal output by the pump laser. The laser output by the pump laser is split into two beams in sequence through an isolator, a first half-wave plate, and a first polarizing beam splitter. One beam is incident into the inner spherical structure through a second lens and an entrance aperture, and the other beam is fed back to the pump laser by the modulation transfer spectrum stabilization system.

5. The method as described in claim 4, characterized in that, The modulation transfer spectrum frequency stabilization system includes a second half-wave plate, a second polarization beam splitter, a third half-wave plate, a Glan Taylor prism, a high-speed electro-optic modulator, a fourth half-wave plate, a third polarization beam splitter, a high-speed photodetector, a laser phase detection and high-speed servo feedback control circuit, and a power control system. The beam split by the first polarization beam splitter is then directed by the second half-wave plate and split into two beams by the second polarization beam splitter. One beam is directed towards the atomic gas cell used for frequency stabilization, and the other beam passes sequentially through a total reflection mirror and the third half-wave plate before reaching the Glan Taylor prism. The light is then modulated by a high-speed electro-optic modulator to obtain pump light for frequency stabilization. The frequency-stabilized pump light passes through a fourth half-wave plate and a third polarization beam splitter before being directed to the frequency-stabilized atomic gas cell. The laser signal output from the frequency-stabilized atomic gas cell is then directed to a high-speed photodetector via the third polarization beam splitter. The high-speed photodetector converts the received optical signal into an electrical signal and transmits it to the laser phase detection and high-speed servo feedback control circuit, generating a servo signal to control the power control system of the pump laser, thereby achieving frequency stabilization of the laser signal output by the pump laser.

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