Atomic oscillator and frequency signal generating system

Abstract

To provide an atomic oscillator which has a light quantity correction function and outputs a stable frequency, and a frequency signal generation system.SOLUTION: An atomic oscillator 1 comprises: a light-emitting element 10; an atom cell 31 into which light L from the light-emitting element 10 is input and which accommodates alkali metal atoms; a first light detection element 32 which outputs a first light quantity signal L1 by detecting the light L after being output from the light-emitting element 10 and before being input into the atom cell, or by detecting the light L output from the light-emitting element 10 and transmitted through the atom cell 31; a second light detection element 33 which outputs a second light quantity signal L2 by detecting the light L transmitted through the atom cell 31; a temperature detection element 34 which detects a temperature of the atom cell 31; a bias current control circuit 47 which controls a bias current output to the light-emitting element 10 according to the first light quantity signal L1 and a temperature signal T that is output from the temperature detection element 34; and a temperature control circuit 45 which controls a temperature of the light-emitting element 10 according to a wave detection signal S of the second light quantity signal L2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an atomic oscillator and a frequency signal generating system. [Background technology]

[0002] Atomic oscillators that oscillate based on the energy transition of alkali metal atoms such as rubidium and cesium are known as oscillators that have high-precision oscillation characteristics over a long period of time. For example, in Patent Document 1, in order to control the wavelength of the light source in an atomic oscillator, the temperature of the light source is controlled based on the light amount of the light source to output a stable oscillation frequency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-25166 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the atomic oscillator described in Patent Document 1 cannot control the amount of light from the light source. Therefore, when the amount of light from the light source or the amount of light changes due to a change in temperature of the atomic cell containing the alkali metal atoms, the amount of light incident on the atomic cell changes, causing a change in frequency called the Stark shift, and thus making it impossible to output a stable oscillation frequency. [Means for solving the problem]

[0005] The atomic oscillator includes a light-emitting element, an atomic cell into which light from the light-emitting element is incident and in which alkali metal atoms are accommodated, a first photodetection element that detects light emitted from the light-emitting element before it enters the atomic cell, or detects light emitted from the light-emitting element and transmitted through the atomic cell, and thereby outputs a first light amount signal, a second photodetection element that detects the light that has transmitted through the atomic cell, and thereby outputs a second light amount signal, a temperature detection element that detects the temperature of the atomic cell, a bias current control circuit that controls a bias current to be output to the light-emitting element in response to the first light amount signal and a temperature signal output from the temperature detection element, an oscillator that outputs an oscillation signal and a modulation signal that modulates the bias current, a detection circuit that detects the second light amount signal using the oscillation signal and outputs a detection signal, and a temperature control circuit that controls the temperature of the light-emitting element in response to the detection signal.

[0006] The frequency signal generating system includes an atomic oscillator and a processing unit that processes a frequency signal from the atomic oscillator. The atomic oscillator includes a light-emitting element, an atomic cell into which light from the light-emitting element is incident and in which alkali metal atoms are accommodated, a first light detection element that detects light emitted from the light-emitting element before it is incident on the atomic cell, or detects light emitted from the light-emitting element and transmitted through the atomic cell, and thereby outputs a first light amount signal, a second light detection element that detects the light that has transmitted through the atomic cell, and thereby outputs a second light amount signal, a temperature detection element that detects the temperature of the atomic cell, a bias current control circuit that controls a bias current to be output to the light-emitting element in response to the first light amount signal and a temperature signal output from the temperature detection element, an oscillator that outputs an oscillation signal and a modulation signal that modulates the bias current, a detection circuit that detects the second light amount signal using the oscillation signal and outputs a detection signal, and a temperature control circuit that controls the temperature of the light-emitting element in response to the detection signal. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram showing an atomic oscillator according to a first embodiment. [Diagram 2] FIG. 13 is a graph showing the temperature characteristics of light amount. [Diagram 3] FIG. 4 is a diagram showing a schematic diagram of a temperature characteristic correction table for light quantity. [Figure 4] FIG. 4 is a diagram for explaining a method for generating a temperature characteristic correction table for light amount. [Diagram 5] 5A and 5B are diagrams for explaining a method for calculating a temperature characteristic correction light amount value. [Figure 6] 5A and 5B are diagrams for explaining a method of calculating a light amount estimation value. [Figure 7] FIG. 11 is a schematic configuration diagram showing an atomic oscillator according to a second embodiment. [Figure 8] FIG. 11 is a schematic configuration diagram showing an atomic oscillator according to a third embodiment. [Figure 9] FIG. 13 is a schematic configuration diagram showing a frequency signal generating system according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 1. First embodiment First, an atomic oscillator 1 according to the first embodiment will be described with reference to FIG.

[0009] The atomic oscillator 1 according to this embodiment is an atomic oscillator that utilizes the quantum interference effect (CPT: Coherent Population Trapping), which is a phenomenon that occurs when two resonant lights of specific different wavelengths are simultaneously irradiated to an alkali metal atom, and the two resonant lights are transmitted through the alkali metal atom without being absorbed. Note that this phenomenon caused by the quantum interference effect is also called the electromagnetically induced transparency (EIT) phenomenon. The atomic oscillator 1 according to this embodiment may also be an atomic oscillator that utilizes the double resonance phenomenon caused by light and microwaves.

[0010] As shown in FIG. 1, the atomic oscillator 1 includes a light-emitting element 10, an optical system unit 20, an atomic cell unit 30, a detection circuit 42, a temperature control circuit 45, an oscillator 46, and a bias current control circuit 47.

[0011] The light emitting element 10 emits linearly polarized light L containing two types of light with different frequencies. The light emitting element 10 is a Vertical Cavity Surface Emitting Laser (VCSEL) or the like.

[0012] The optical system unit 20 is disposed between the light emitting element 10 and the atom cell unit 30. The optical system unit 20 includes a neutral density filter 21, a lens 22, and a quarter-wave plate .

[0013] The neutral density filter 21 reduces the intensity of the light L emitted from the light emitting element 10. The lens 22 adjusts the radiation angle of the light L. Specifically, the lens 22 collimates the light L. The quarter-wave plate 23 converts two types of light with different frequencies contained in the light L from linearly polarized light to circularly polarized light.

[0014] The atom cell unit 30 includes an atom cell 31, a first photodetection element 32, a second photodetection element 33, and a temperature detection element .

[0015] The atomic cell 31 transmits the light L emitted from the light-emitting element 10. The atomic cell 31 accommodates an alkali metal atom. The alkali metal atom has a three-level energy level system consisting of two mutually different ground levels and an excited level. The light L emitted from the light-emitting element 10 enters the atomic cell 31 via the neutral density filter 21, the lens 22, and the quarter-wave plate 23.

[0016] The first light detection element 32 receives the light L emitted from the light emitting element 10 before entering the atomic cell 31, and outputs a first light amount signal L1. The first light detection element 32 is, for example, a photodiode.

[0017] The second light detection element 33 receives the light L transmitted through the atomic cell 31 and outputs a second light amount signal L2. The second light detection element 33 is, for example, a photodiode.

[0018] The temperature detection element 34 detects the temperature of the atom cell 31 and outputs a temperature signal T. The temperature detection element 34 is, for example, a thermistor or a thermocouple. The temperature detection element 34 is disposed in the vicinity of the atom cell 31 so that the time constant for the temperature change of the atom cell 31 is small.

[0019] Incidentally, a coil (not shown) is provided outside the atomic cell 31. The coil applies a magnetic field in a predetermined direction to the alkali metal atoms contained in the atomic cell 31, thereby Zeeman-splitting the energy levels of the alkali metal atoms.

[0020] When an alkali metal atom is irradiated with a circularly polarized resonant light pair in a state where the alkali metal atom is Zeeman split, the number of alkali metal atoms at a desired energy level among a plurality of levels of the alkali metal atom Zeeman split becomes relatively larger than the number of alkali metal atoms at other energy levels. Therefore, the number of atoms exhibiting the desired EIT phenomenon increases, and the desired EIT signal becomes larger. As a result, the oscillation characteristics of the atomic oscillator 1 can be improved.

[0021] The detection circuit detects the second light amount signal L2 output from the second light detection element 33 via the amplifier circuit 41 by using the oscillation signal F output by the oscillator .

[0022] The temperature control circuit 45 controls the temperature of the light-emitting element 10 in response to the detection signal S output from the detection circuit 42 via the integrating amplifier 43 and the loop filter 44. More specifically, the temperature control circuit 45 controls the temperature of the light-emitting element 10, thereby controlling the wavelength of the light L emitted from the light-emitting element 10.

[0023] The oscillator 46 outputs an oscillation signal F for detecting the second light amount signal L2 output from the second photodetection element 33, and a modulation signal M for modulating a bias current for controlling the amount of light L emitted from the light-emitting element 10.

[0024] The bias current control circuit 47 calculates a temperature characteristic corrected light amount value L3 by performing temperature characteristic correction on the first light amount signal L1 or the second light amount signal L2 according to the temperature signal T output from the temperature detection element 34, calculates a light amount estimate value L4 by linear approximation to estimate a change over time in the temperature characteristic corrected light amount value L3, obtains a light amount difference between the temperature characteristic corrected light amount value L3 and the light amount estimate value L4, and controls a bias current to be output to the light emitting element 10 based on the light amount difference when the light amount difference exceeds a threshold value. More specifically, the bias current control circuit 47 controls the amount of light L emitted from the light emitting element 10 by controlling the bias current based on a current control signal V that is the light amount difference between the generated light amount estimate value L4 and the temperature characteristic corrected light amount value L3 in the voltage generation unit 50 so that the current control signal V becomes zero.

[0025] In this embodiment, the signal selection unit 51 selects one of the first light intensity signal L1 output from the first light detection element 32 and the second light intensity signal L2 output from the second light detection element 33, and the comparison judgment unit 54 compares the calculated light intensity estimate value L4 with the temperature characteristic corrected light intensity value L3 to calculate the light intensity difference between the light intensity estimate value L4 and the temperature characteristic corrected light intensity value L3.

[0026] In addition, in order to estimate the change over time of the temperature characteristic corrected light amount value L3 calculated by the temperature characteristic correction unit 52, the light amount estimation unit 53 calculates a light amount estimation value L4 using an approximate straight line calculated by the least squares method, and the comparison judgment unit 54 compares the calculated light amount estimation value L4 with the temperature characteristic corrected light amount value L3.If it is determined that the light amount difference between the light amount estimation value L4 and the temperature characteristic corrected light amount value L3 exceeds a threshold value, the light amount difference is output as a current control signal V.

[0027] In this embodiment, the plurality of temperature characteristic corrected light amount values ​​L3 for calculating the approximation line for calculating the light amount estimated value L4 uses the average value of the plurality of temperature characteristic corrected light amount values ​​L3 calculated at a predetermined time.

[0028] Next, a method for controlling the wavelength and amount of light L emitted from the light emitting element 10 will be described in detail with reference to FIGS. The wavelength and light quantity of the light L emitted from the light emitting element 10 can be controlled by controlling the temperature of the light emitting element 10 and the bias current applied to the light emitting element 10. With regard to the light quantity sensitivity of the temperature and the bias current, the light quantity sensitivity per wavelength of the bias current is several tens of times higher than that of the temperature. Therefore, a bias current with high light quantity sensitivity is suitable for correcting light quantity jumps, and a temperature with low light quantity sensitivity is suitable for controlling the wavelength.

[0029] In addition, the amount of light L has a temperature characteristic in which the amount of light converted into voltage increases with an increase in temperature, as shown in Figure 2. Therefore, since there is a possibility that the change in the amount of light due to a change in temperature may be regarded as a jump in the amount of light, it is necessary to perform a temperature characteristic correction for the amount of light. Note that the higher the voltage value of the amount of light, the darker the light L becomes.

[0030] First, the amount of light required for the temperature characteristic correction of the amount of light is calculated based on the temperature characteristic correction table of the amount of light shown in FIG. 3, and the light amount value for the temperature signal T, which is the measured temperature, is calculated. The first light quantity signal L1 or the second light quantity signal L2 is temperature-corrected according to the temperature signal T. The temperature characteristic correction table in Fig. 3 is calculated as a temperature characteristic corrected light amount value L3. The values ​​in the temperature characteristic correction table in Fig. 3 are values ​​obtained by AD converting the temperature signal T output as a voltage and the temperature characteristic corrected light amount value L3. As shown in Fig. 4, the temperature characteristic of the light amount of light L has a hysteresis with different characteristics when the temperature rises and when the temperature falls, so the temperature characteristic correction table for the light amount is generated using the center value of the hysteresis when the temperature rises and when the temperature falls. The smaller the value obtained by AD converting the light amount value, the dimmer the light L becomes.

[0031] 5, for example, when the temperature signal T is between 48° C. and 50° C., an approximation line is obtained between the values ​​of 48° C. and 50° C., and the temperature characteristic corrected light amount value L3 is calculated. Note that the difference between the value of 25° C. and the value of 48° C. is set to Δ1, the difference between the value of 48° C. and the calculated temperature characteristic corrected light amount value L3 is set to Δ2, and Δ1+Δ2 may be set as the temperature characteristic corrected light amount value based on the value of 25° C.

[0032] Next, the light quantity estimated value L4 required for the temperature characteristic correction of the light quantity is calculated using an approximate straight line obtained by the least square method from the average values ​​P0 to P31 of a plurality of temperature characteristic corrected light quantity values ​​L3 calculated at a predetermined time, for example, every six hours, as shown in Fig. 6. More specifically, the data for calculating the approximate straight line is set to 32 data as one set, and five slopes are calculated for this one set: the slope of the approximate straight line calculated from the first four data (P0 to P3), the slope of the approximate straight line calculated from the first eight data (P0 to P7), the slope of the approximate straight line calculated from the first twelve data (P0 to P11), the slope of the approximate straight line calculated from the first 16 data (P0 to P15), and the slope of the approximate straight line calculated from all 32 data (P0 to P31). Among these five slopes, the smallest slope is regarded as the amount of change in a state where no jump in the light quantity occurs. However, until the acquisition of 32 data points is completed, the smallest slope among the slopes that have been acquired is used as the amount of change without any light intensity jumps. Therefore, the light intensity estimation value L4 is calculated using the approximation line with the smallest slope.

[0033] Then, the calculated light amount estimation value L4 and the selected first light amount signal L1 or second light amount signal L2 are Temperature characteristic corrected light intensity value L3 and compare it with the estimated light intensity L4. Temperature compensation light intensity L3 When it is determined that the difference in the amount of light between the atomic cell 31 and the current control signal V exceeds the threshold, the current control signal V is generated from the difference in the amount of light. By controlling the bias current using the current control signal V, it is possible to correct the change in the amount of light caused by the change in the temperature around the atomic cell 31.

[0034] Incidentally, the wavelength change caused by the bias current change is absorbed by a temperature wavelength control loop that has low sensitivity to the amount of light.

[0035] As described above, the atomic oscillator 1 of this embodiment calculates the temperature characteristic corrected light amount value L3 according to the temperature signal T that detects the temperature of the atomic cell 31, obtains the light amount difference between the temperature characteristic corrected light amount value L3 and the light amount estimated value L4 calculated from a plurality of temperature characteristic corrected light amount values ​​L3, and controls the bias current output to the light emitting element 10 based on the light amount difference when the light amount difference exceeds a threshold value, so that it is possible to control the amount of light L emitted by the light emitting element 10. Therefore, it is possible to make it difficult for a frequency change due to a jump in the light amount of the light L associated with a temperature change of the atomic cell 31 to occur, and it is possible to output a stable oscillation frequency.

[0036] 2. Second embodiment Next, an atomic oscillator 1a according to a second embodiment will be described with reference to FIG.

[0037] The atomic oscillator 1a of this embodiment is similar to the atomic oscillator 1 of the first embodiment, except that the light intensity correction function is performed by the first light intensity signal L1 and the temperature signal T. The following description will focus on the differences from the first embodiment, and similar items are denoted by the same reference numerals and their description will be omitted.

[0038] 7, the atomic oscillator 1a controls the bias current output to the light emitting element 10 in response to the first light amount signal L1 output from the first light detection element 32 and the temperature signal T output from the temperature detection element 34, thereby controlling the amount of light L emitted from the light emitting element 10. More specifically, the bias current control circuit 47 calculates a light amount estimation value L4 in the voltage generation unit 50a in response to the temperature signal T, and when it is determined that the light amount difference between the light amount estimation value L4 and the temperature characteristic corrected light amount value L3 exceeds a threshold value, controls the bias current based on the current control signal V generated from the light amount difference so that the current control signal V becomes zero.

[0039] With this configuration, it is possible to obtain the same effects as the atomic oscillator 1 of the first embodiment.

[0040] 3. Third embodiment Next, an atomic oscillator 1b according to a third embodiment will be described with reference to FIG.

[0041] The atomic oscillator 1b of this embodiment is similar to the atomic oscillator 1 of the first embodiment, except that the light intensity correction function is performed by the light intensity signal L5 and the temperature signal T. The following description will focus on the differences from the first embodiment, and similar items are denoted by the same reference numerals and their description will be omitted.

[0042] 8, the atomic oscillator 1b detects the light L emitted from the light-emitting element 10 and transmitted through the atomic cell 31, and controls the bias current output to the light-emitting element 10 according to the light amount signal L5 output from the light detection element 33b and the temperature signal T output from the temperature detection element 34, thereby controlling the amount of light L emitted from the light-emitting element 10. More specifically, the bias current control circuit 47 calculates the light amount estimation value L4 according to the temperature signal T in the voltage generation unit 50b, and when it is determined that the light amount difference between the light amount estimation value L4 and the temperature characteristic corrected light amount value L3 exceeds a threshold value, controls the bias current based on the current control signal V generated from the light amount difference so that the current control signal V becomes zero. Incidentally, the photodetection element 33b in this embodiment is configured by combining the first photodetection element 32 and the second photodetection element 33 in the first embodiment into one photodetection element.

[0043] With this configuration, it is possible to obtain the same effects as the atomic oscillator 1 of the first embodiment.

[0044] 4. Fourth embodiment Next, a clock transmission system (timing server) 90 will be taken as an example of a frequency signal generating system according to a fourth embodiment and described with reference to FIG.

[0045] The clock transmission system 90 includes atomic oscillators 1 to 1b according to this embodiment. In the following, the clock transmission system 90 including the atomic oscillator 1 will be described as an example.

[0046] The clock transmission system 90 synchronizes the clocks of the various devices in a time division multiplexing network, and is a system having a redundant configuration of an N (Normal) system and an E (Emergency) system.

[0047] As shown in Fig. 9, the clock transmission system 90 includes an N-system clock supply device 901 and an SDH (Synchronous Digital Hierarchy) device 902 that are higher-level devices in the A station, an E-system clock supply device 903 and an SDH device 904 that are higher-level devices in the B station, and a lower-level clock supply device 905 and SDH devices 906 and 907 that are lower-level devices in the C station. The clock supply device 901 has an atomic oscillator 1 and generates an N-system clock signal. The atomic oscillator 1 in the clock supply device 901 generates a clock signal in synchronization with a more accurate clock signal from master clocks 908 and 909 that include atomic oscillators using cesium. The clock supply devices 901 and 903 correspond to processing units that process the frequency signal from the atomic oscillator 1.

[0048] The SDH device 902 transmits and receives a main signal based on the clock signal from the clock supply device 901, and also superimposes an N-system clock signal on the main signal and transmits it to a lower-level clock supply device 905. The clock supply device 903 has an atomic oscillator 1 and generates an E-system clock signal. The atomic oscillator 1 in the clock supply device 903 generates a clock signal in synchronization with a more accurate clock signal from master clocks 908 and 909, which include atomic oscillators using cesium.

[0049] The SDH device 904 transmits and receives a main signal based on the clock signal from the clock supply device 903, and also superimposes the E-system clock signal on the main signal and transmits it to the downstream clock supply device 905. The clock supply device 905 receives the clock signals from the clock supply devices 901 and 903, and generates a clock signal in synchronization with the received clock signal.

[0050] Clock supply device 905 normally generates a clock signal in synchronization with the N system clock signal from clock supply device 901. If an abnormality occurs in the N system, clock supply device 905 generates a clock signal in synchronization with the E system clock signal from clock supply device 903. By switching from the N system to the E system in this way, stable clock supply is ensured and the reliability of the clock path network can be improved. SDH device 906 transmits and receives main signals based on the clock signal from clock supply device 905. Similarly, SDH device 907 transmits and receives main signals based on the clock signal from clock supply device 905. This allows the equipment at station C to be synchronized with the equipment at station A or B.

[0051] The frequency signal generation system according to the present embodiment is not limited to the clock transmission system 90. The frequency signal generation system includes various devices equipped with the atomic oscillator 1 and utilizing the frequency signal of the atomic oscillator 1, and a system composed of a plurality of devices.

[0052] The frequency signal generating system according to this embodiment may be, for example, a smartphone, a tablet terminal, a watch, a mobile phone, a digital still camera, a liquid ejection device (e.g., an inkjet printer), a personal computer, a television, a video camera, a video tape recorder, a car navigation device, a pager, an electronic organizer, an electronic dictionary, a calculator, an electronic game device, a word processor, a workstation, a videophone, a security television monitor, electronic binoculars, a POS (point of sales) terminal, medical equipment (e.g., electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic equipment, electronic endoscopes, magnetocardiographs), a fish finder, a GNSS (Global Navigation Satellite System) frequency standard, various measuring instruments, instruments (e.g., instruments in automobiles, aircraft, and ships), a flight simulator, a terrestrial digital broadcasting system, a mobile phone base station, or a moving object (automobiles, aircraft, ships, etc.). [Explanation of symbols]

[0053] 1, 1a, 1b... atomic oscillator, 10... light emitting element, 20... optical system unit, 21... neutral density filter, 22... lens, 23... quarter-wave plate, 30... atomic cell unit, 31... atomic cell, 32... first photodetector, 33... second photodetector, 34... temperature detector, 41... amplifier circuit, 42... detector circuit, 43... integral amplifier, 44... loop filter, 45... temperature control circuit, 46... oscillator, 47... bipolar transistor As current control circuit, 50...voltage generation unit, 51...signal selection unit, 52...temperature characteristic correction unit, 53...light amount estimation unit, 54...comparison and judgment unit, 90...clock transmission system as frequency signal generation system, F...oscillation signal, M...modulation signal, L...light, L1...first light amount signal, L2...second light amount signal, L3...temperature characteristic corrected light amount value, L4...light amount estimation value, L5...light amount signal, S...detection signal, T...temperature signal, V...current control signal.

Claims

1. A light-emitting element; an atomic cell that receives light from the light-emitting element and contains alkali metal atoms; a first light detection element that detects light emitted from the light emitting element before entering the atom cell, or detects light emitted from the light emitting element and transmitted through the atom cell, thereby outputting a first light amount signal; a second light detection element that detects light transmitted through the atomic cell and outputs a second light amount signal; a temperature detection element for detecting a temperature of the atomic cell; a bias current control circuit that controls a bias current to be output to the light emitting element in response to the first light amount signal and a temperature signal output by the temperature detection element; an oscillator that outputs an oscillation signal and a modulation signal that modulates the bias current; a detection circuit that detects the second light amount signal by using the oscillation signal and outputs a detection signal; a temperature control circuit for controlling a temperature of the light-emitting element in response to the detection signal; An atomic oscillator comprising:

2. The atomic oscillator according to claim 1 , wherein the first light detection element detects light emitted from the light emitting element and before entering the atomic cell.

3. the first light detection element detects light emitted from the light emitting element and transmitted through the atomic cell; The atomic oscillator according to claim 1 , wherein the first photodetection element and the second photodetection element are configured as one photodetection element.

4. 4. The atomic oscillator according to claim 1, wherein the bias current control circuit calculates a temperature characteristic corrected light intensity value by temperature-correcting the first light intensity signal in response to the temperature signal, determines a light intensity difference between a light intensity estimate value calculated from a plurality of the temperature characteristic corrected light intensity values ​​and the temperature characteristic corrected light intensity value, and controls the bias current based on the light intensity difference when the light intensity difference exceeds a threshold value.

5. 5. The atomic oscillator according to claim 4, wherein the light intensity estimation value is calculated by finding an approximation line from a plurality of the temperature characteristic corrected light intensity values ​​and using the approximation line.

6. 6. The atomic oscillator according to claim 4, wherein the plurality of temperature characteristic compensation light intensity values ​​are an average value of the plurality of temperature characteristic compensation light intensity values ​​calculated at a predetermined time.

7. The atomic oscillator according to claim 5 , wherein the approximation line is calculated by a least squares method.

8. An atomic oscillator; A processing unit that processes a frequency signal from the atomic oscillator; Including, The atomic oscillator comprises: A light-emitting element; an atomic cell that receives light from the light-emitting element and contains alkali metal atoms; a first light detection element that detects light emitted from the light emitting element before entering the atom cell, or detects light emitted from the light emitting element and transmitted through the atom cell, thereby outputting a first light amount signal; a second light detection element that detects light transmitted through the atomic cell and outputs a second light amount signal; a temperature detection element for detecting a temperature of the atomic cell; a bias current control circuit that controls a bias current to be output to the light emitting element in response to the first light amount signal and a temperature signal output by the temperature detection element; an oscillator that outputs an oscillation signal and a modulation signal that modulates the bias current; a detection circuit that detects the second light amount signal by using the oscillation signal and outputs a detection signal; a temperature control circuit for controlling a temperature of the light-emitting element in response to the detection signal; A frequency signal generating system comprising:

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