A Fast Scanning Method for the Optimal Operating Point of a CPT Atomic Clock and the CPT Atomic Clock

Abstract

This invention belongs to the field of gyroscope technology and discloses a rapid scanning method for the optimal operating state of a CPT atomic clock and the CPT atomic clock itself. The method involves setting the radio frequency (RF) to 0 and the temperature of the TEC heating element to the minimum operating temperature via a CPT control circuit. A DC scan is performed to check for absorption peaks in the light signal received by the phototube. The operating temperature of the TEC heating element is increased by ΔT, the number of absorption peaks is detected, ΔT is halved, and the operating temperature of the TEC heating element is increased again by the current ΔT value. A DC scan is then performed again, increasing the operating temperature of the TEC heating element by the current ΔT value. The DC value at the center of the double absorption peaks is checked to see if it falls within a preset range around the median of the DC scan range. The DC value is then set to the median of the DC scan range. An RF scan is performed via the CPT control circuit to determine the frequency domain image of the light signal received by the phototube. The RF is then set to the absorption peak of the frequency domain image of the light signal, thereby achieving the optimal operating state of the CPT atomic clock.

Description

Technical Field

[0001] This invention belongs to the field of gyroscope technology, and particularly relates to a method for rapid scanning of the optimal operating state point of a CPT atomic clock and the CPT atomic clock itself. Background Technology

[0002] The core sensing component of the CPT atomic clock is its physical part, in which the main control sensor is the VCSEL laser. The operating state of the VCSEL laser is affected by three parameters: DC, RF, and temperature. The DC and RF are provided by the CPT atomic clock control circuit, while the temperature is controlled by the TEC heating element. For the CPT atomic clock to reach its optimal operating state, all three parameters of the VCSEL laser—DC, RF, and TEC temperature control—must reach their optimal points. Among these three parameters, the TEC temperature control has the greatest impact on the operating state of the CPT atomic clock. For rapid scanning of the optimal state of the CPT atomic clock, the key is to find the optimal TEC temperature control point, DC, and RF values. Since it is necessary to determine the status of multiple parameters, and the VCSEL laser generally operates in the range of 25℃~65℃ with many temperature points, if DC and RF are performed at each temperature point, the scanning time will be extremely long. If the state of the CPT atomic clock is unknown when it is first started, it will take a lot of time to determine its optimal operating state. Therefore, a method is needed to achieve rapid scanning of the operating state of the CPT atomic clock. Summary of the Invention

[0003] To address the issues of long operating point determination time and slow initial startup of traditional CPT atomic clocks, this invention proposes a rapid scanning method for the optimal operating point of a CPT atomic clock and a CPT atomic clock itself.

[0004] The technical solution of the present invention:

[0005] In a first aspect, the present invention provides a rapid scanning method for the optimal operating point of a CPT atomic clock. Determining the operating point of a CPT atomic clock requires determining three parameters: DC, RF, and TEC heating element temperature. The method includes:

[0006] Step 1: Set the radio frequency to 0 and the temperature of the TEC heating element to the minimum operating temperature using the CPT control circuit;

[0007] Step 2: Perform a DC scan to check if there is an absorption peak in the light signal received by the phototube. If there is an absorption peak, proceed to Step 3; otherwise, increase the operating temperature of the TEC heating element by ΔT and repeat Step 2.

[0008] Step 3: Detect the number of absorption peaks. If there is only a single absorption peak, proceed to Step 4; if there are double absorption peaks, proceed to Step 5.

[0009] Step 4: Halve ΔT, raise the operating temperature of the TEC heating element to the current ΔT value, and perform DC scanning again. If there is only a single absorption peak, repeat step 4.

[0010] Step 5: Increase the operating temperature of the TEC heating element to the current ΔT value, perform a DC scan, and check whether the DC value at the center of the double absorption peak is within the preset range around the midpoint of the DC scan range. If not, halve the absolute value of ΔT and repeat Step 5. If yes, proceed to Step 6.

[0011] Step 6: Set the DC value to the median of the DC scanning range, and perform RF scanning through the CPT control circuit to determine the frequency domain image of the optical signal received by the phototube;

[0012] Step 7: Set the radio frequency to the absorption peak of the frequency domain image of the optical signal to achieve the optimal working state of the CPT atomic clock.

[0013] Furthermore,

[0014] In step five, when the absolute value of ΔT is halved, the sign of ΔT is determined by the positions of the two absorption peaks and the position of the midpoint of the DC scan range. ΔT is negative when the center of the two absorption peaks is to the left of the midpoint of the DC scan range, and positive when the center of the two absorption peaks is to the right of the midpoint of the DC scan range.

[0015] Furthermore,

[0016] In step two, the operating temperature of the TEC heating element is increased by ΔT, where ΔT = 3℃.

[0017] In a second aspect, the present invention also provides a CPT atomic clock, wherein the optimal operating point of the CPT atomic clock is determined by the method described in the first aspect, and the physical components of the CPT atomic clock include:

[0018] TEC heating element, temperature sensor, VCSEL laser, C-field coil, alkali metal gas chamber, phototube, heating resistance network;

[0019] The VCSEL laser 3 is attached to the TEC heating plate 1, and the temperature sensor 2 is placed next to the VCSEL laser 3; the alkali metal gas chamber 5 is surrounded by a C-field coil 4, and the lower part of the alkali metal gas chamber 5 is heated by a heating resistor network 7.

[0020] The laser emitted by the VCSEL laser 3 passes through the alkali metal gas chamber 5 and then irradiates the phototube 10.

[0021] The electrical parameters of the physical components of the CPT atomic clock are controlled by the CPT control circuit. The phototube feedback signal is also transmitted to the CPT control circuit. These electrical parameters include at least the DC, radio frequency, and TEC heating element temperatures.

[0022] Furthermore,

[0023] The TEC heating element is used to heat or cool the VCSEL laser and maintain the temperature of the laser chamber. Its heating or cooling efficiency is determined by the direction and magnitude of the current passing through the TEC heating element.

[0024] Furthermore,

[0025] The VCSEL laser is used to generate coherent dual-color light, with an operating temperature range of 31℃~65℃, so that the rubidium atoms in the alkali metal gas chamber are in a CPT coherent population trapping state, thus producing the CPT phenomenon.

[0026] Furthermore,

[0027] The alkali metal gas cell is the core sensor of the CPT atomic clock, which produces the CPT phenomenon when irradiated with dual-color light of a specific wavelength.

[0028] The phototube is used to receive the light signal emitted by the VCSEL laser that passes through the standard gas cell assembly, convert it into an electrical signal, and then transmit it to the CPT control circuit.

[0029] Furthermore,

[0030] The temperature sensor is used to provide feedback on the temperature of the VCSEL laser.

[0031] The C-field coil is used to provide a stable magnetic field for the alkali metal gas chamber;

[0032] The heating resistor network is used to heat the alkali metal gas chamber.

[0033] The beneficial effects of the technical solution of this invention:

[0034] Traditional scanning methods perform DC and RF scanning at each temperature point. While VCSEL lasers have a wide operating range (25℃~65℃), CPT correlation only occurs within approximately ±3℃ of the effective operating point. Therefore, traditional methods waste the majority of time scanning in the ineffective temperature range. The scanning method described in this invention utilizes the characteristic of a double absorption peak in the DC scanning curve when there is no RF signal. By increasing the temperature by 3℃, the effective temperature range (optimal temperature ±3℃) is quickly found. Within this range, the temperature approaches the optimal operating point, which is considered to be when the center of the double absorption peak coincides with the center of the DC scanning range. Compared to traditional methods, the scanning method described in this invention saves scanning time in the ineffective temperature range, significantly reducing the overall scanning time. Attached Figure Description

[0035] Figure 1This is a schematic diagram of the physical structure of the CPT atomic clock.

[0036] Among them, 1-TEC, 2-temperature sensor, 3-VCSEL laser, 4-C field coil, 5-alkali metal gas chamber, 6-phototube, 7-heating resistance network;

[0037] Figure 2 The DC absorption peak scan at the optimal temperature point (RF is 0);

[0038] Figure 3 RF scan absorption peak diagram after setting DC and temperature points;

[0039] Figure 4 DC scanning absorption peak diagram of the CPT atomic clock in its optimal operating state;

[0040] Figure 5 This is a flowchart of the method for implementing the present invention;

[0041] Figure 6 This is a DC scanning diagram. Detailed Implementation

[0042] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0043] like Figure 1 As shown, the physical components of the CPT atomic clock mentioned in this invention include a TEC heating element, a temperature sensor, a VCSEL laser, a C-field coil, an alkali metal gas chamber, a phototube, and a heating resistor network.

[0044] In the CPT atomic clock physics section of this invention, the TEC mentioned refers to a TEC heating element, which is used for heating or cooling the VCSEL laser and maintaining the temperature of the laser chamber. Its heating or cooling efficiency is determined by the direction and magnitude of the current passing through the TEC.

[0045] The temperature sensor mentioned in the CPT atomic clock physics section of this invention provides feedback on the temperature of the VCSEL laser.

[0046] The VCSEL laser mentioned in the CPT atomic clock physics section of this invention is used to generate coherent two-color light, with an operating temperature range of 31℃~65℃, so that rubidium atoms in the alkali metal gas chamber are in a CPT coherent population trapping state, thus producing the CPT phenomenon.

[0047] The C-field coil mentioned in the CPT atomic clock physics section of this invention is used to provide a stable magnetic field for the gas chamber.

[0048] The alkali metal gas cell mentioned in the physical part of the CPT atomic clock in this invention is the core sensor device of the CPT atomic clock, which produces the CPT phenomenon after being irradiated with bicolor light of a specific wavelength.

[0049] In the physical part of the CPT atomic clock in this invention, the phototube is used to receive the light signal emitted by the VCSEL laser that passes through the standard gas cell assembly, convert it into an electrical signal and transmit it to the CPT control circuit.

[0050] The heating resistor network mentioned in the CPT atomic clock physics section of this invention is used to heat the gas chamber.

[0051] According to the appendix Figure 1 The physical components of the CPT atomic clock designed in this invention will be described as follows:

[0052] The VCSEL laser 3 is attached to the TEC1, and the temperature sensor 2 is placed next to the VCSEL laser 3. The alkali metal gas chamber 5 is surrounded by a C-field coil 4, and the lower part is heated by a heating resistor network 7. The laser emitted by the VCSEL laser 3 passes through the alkali metal gas chamber 5 and then shines on the phototube 10. The control of the electrical parameters of the entire physical part (including at least the DC, RF and TEC heating element temperatures) is performed by the CPT control circuit, and the phototube feedback signal is also transmitted to the CPT control circuit.

[0053] Combined with appendix Figure 5 The implementation steps of this invention are explained as follows:

[0054] Step 1: Set the RF radio frequency to 0 and the TEC temperature to the minimum operating temperature T = T0 using the CPT control circuit;

[0055] Step 2: Perform DC scanning. See [link to scanning method] for details. Figure 6 Check if there is an absorption peak in the light signal received by phototube 10. If there is an absorption peak, proceed to step three. Otherwise, increase the operating temperature by ΔT (the initial value of ΔT is 3℃) and repeat step two.

[0056] Step 3: Detect the number of absorption peaks. If there is only a single absorption peak, proceed to Step 4; if there are two absorption peaks, proceed to Step 5.

[0057] Step 4: Halve ΔT, increase the operating temperature by ΔT, and perform DC scanning again. If only a single absorption peak is found, repeat Step 4.

[0058] Step 5: Increase the TEC operating temperature by ΔT and perform a DC scan. Check if the DC value at the center of the two absorption peaks is around the midpoint of the DC scan range. If not, halve the absolute value of ΔT (the sign of ΔT is determined by the position of the two absorption peaks relative to the midpoint of the DC scan range; ΔT is negative if the center of the two absorption peaks is to the left of the midpoint, and positive if the center of the two absorption peaks is to the right of the midpoint). Repeat Step 5. If (e.g.) Figure 2 (As shown), then proceed to step six.

[0059] Step 6: Set the DC to the median value of the DC scanning range, and perform RF scanning through the CPT control circuit to determine the frequency domain image of the light signal received by the phototube.

[0060] Step 7: Set RF to the absorption peak of the frequency domain image of the optical signal (e.g., Figure 3 As shown in the figure, this means that the CPT atomic clock has reached its optimal working state.

[0061] After reaching the optimal operating temperature and RF frequency, the DC scanning image is as follows: Figure 4 As shown.

[0062] The beneficial effects of the technical solution of this invention:

[0063] Traditional scanning methods perform DC and RF scanning at each temperature point. While VCSEL lasers have a wide operating range (25℃~65℃), CPT correlation only occurs within approximately ±3℃ of the effective operating point. Therefore, traditional methods waste the majority of time scanning in the ineffective temperature range. The scanning method described in this invention utilizes the characteristic of a double absorption peak in the DC scanning curve when there is no RF signal. By increasing the temperature by 3℃, the effective temperature range (optimal temperature ±3℃) is quickly found. Within this range, the temperature approaches the optimal operating point, which is considered to be when the center of the double absorption peak coincides with the center of the DC scanning range. Compared to traditional methods, the scanning method described in this invention saves scanning time in the ineffective temperature range, significantly reducing the overall scanning time.

Claims

1. A method for rapid scanning of the optimal operating state point of a CPT atomic clock, characterized in that, Determining the operating point of a CPT atomic clock requires determining three parameters: DC, RF, and TEC heating element temperature. The method includes: Step 1: Set the radio frequency to 0 and the temperature of the TEC heating element to the minimum operating temperature using the CPT control circuit; Step 2: Perform a DC scan to check if there is an absorption peak in the light signal received by the phototube. If there is an absorption peak, proceed to Step 3; otherwise, increase the operating temperature of the TEC heating element by ΔT and repeat Step 2. Step 3: Detect the number of absorption peaks. If there is only a single absorption peak, proceed to Step 4; if there are double absorption peaks, proceed to Step 5. Step 4: Halve ΔT, raise the operating temperature of the TEC heating element to the current ΔT value, and perform DC scanning again. If there is only a single absorption peak, repeat step 4. Step 5: Increase the operating temperature of the TEC heating element to the current ΔT value, perform a DC scan, and check whether the DC value at the center of the double absorption peak is within the preset range around the midpoint of the DC scan range. If not, halve the absolute value of ΔT and repeat Step 5. If yes, proceed to Step 6. Step 6: Set the DC value to the median of the DC scanning range, and perform RF scanning through the CPT control circuit to determine the frequency domain image of the optical signal received by the phototube; Step 7: Set the radio frequency to the absorption peak of the frequency domain image of the optical signal to achieve the optimal working state of the CPT atomic clock.

2. The method for rapid scanning of the optimal operating state point of a CPT atomic clock according to claim 1, characterized in that, In step five, when the absolute value of ΔT is halved, the sign of ΔT is determined by the positions of the two absorption peaks and the position of the midpoint of the DC scan range. ΔT is negative when the center of the two absorption peaks is to the left of the midpoint of the DC scan range, and positive when the center of the two absorption peaks is to the right of the midpoint of the DC scan range.

3. The method for rapid scanning of the optimal operating state point of a CPT atomic clock according to claim 1, characterized in that, In step two, the operating temperature of the TEC heating element is increased by ΔT, where ΔT = 3℃.

4. A CPT atomic clock, characterized in that, The optimal operating point of the CPT atomic clock is determined using the method described in any one of claims 1-3, wherein the physical components of the CPT atomic clock include: TEC heating element, temperature sensor, VCSEL laser, C-field coil, alkali metal gas chamber, phototube, heating resistance network; The VCSEL laser (3) is attached to the TEC heating plate (1), and the temperature sensor (2) is placed next to the VCSEL laser (3); the alkali metal gas chamber (5) is surrounded by a C-field coil (4), and the lower part of the alkali metal gas chamber (5) is heated by a heating resistor network (7); The laser emitted by the VCSEL laser (3) passes through the alkali metal gas chamber (5) and then irradiates the phototube (10); The electrical parameters of the physical components of the CPT atomic clock are controlled by the CPT control circuit, and the phototube feedback signal is also transmitted to the CPT control circuit. The electrical parameters include at least the DC, radio frequency, and TEC heating element temperatures.

5. A CPT atomic clock according to claim 4, characterized in that, The TEC heating element is used to heat or cool the VCSEL laser and maintain the temperature of the laser chamber. Its heating or cooling efficiency is determined by the direction and magnitude of the current passing through the TEC heating element.

6. A CPT atomic clock according to claim 4, characterized in that, The VCSEL laser is used to generate coherent two-color light, with an operating temperature range of 31℃~65℃, which puts rubidium atoms in the alkali metal gas chamber into a CPT coherent population trapping state, thus producing the CPT phenomenon.

7. A CPT atomic clock according to claim 4, characterized in that, The alkali metal gas cell is the core sensor of the CPT atomic clock, which produces the CPT phenomenon when irradiated with dual-color light of a specific wavelength. The phototube is used to receive the light signal emitted by the VCSEL laser that passes through the standard gas cell assembly, convert it into an electrical signal, and then transmit it to the CPT control circuit.

8. A CPT atomic clock according to claim 4, characterized in that, The temperature sensor is used to provide feedback on the temperature of the VCSEL laser. The C-field coil is used to provide a stable magnetic field for the alkali metal gas chamber; The heating resistor network is used to heat the alkali metal gas chamber.

Images