CN203289410U - Cpt atomic frequency standard - Google Patents
Cpt atomic frequency standard Download PDFInfo
- Publication number
- CN203289410U CN203289410U CN2013203636306U CN201320363630U CN203289410U CN 203289410 U CN203289410 U CN 203289410U CN 2013203636306 U CN2013203636306 U CN 2013203636306U CN 201320363630 U CN201320363630 U CN 201320363630U CN 203289410 U CN203289410 U CN 203289410U
- Authority
- CN
- China
- Prior art keywords
- laser
- optical fiber
- servo circuit
- frequency standard
- air chamber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
Abstract
The utility model discloses a CPT atomic frequency standard, consisting of an electronics system and a physical package. The physical package mainly consists of a laser, a conversion light path, 1/4 wave plate, an alkali atom bubble air chamber and a photodetector in sequence along a light path transmission direction. The CPT atomic frequency standard is characterized in that the conversion light path comprises a connecting optical fiber and a self-focusing lens, the connecting optical fiber connects an output end of the laser and the self-focusing lens, and parallel light output by the self-focusing lens enters the 1/4 wave plate. According to the CPT atomic frequency standard, the laser with tail fibers and the self-focusing lens with tail fibers are connected, thereby enabling the laser to be away from the alkali atom bubble air chamber, and reducing influence of temperature and a magnetic field on the laser; use of the optical fiber can reduce loss of light; and in addition, the self-focusing lens can generate a parallel beam, and circularly polarized light is easily obtained after the parallel beam passes through the 1/4 wave plate.
Description
Technical field
The utility model relates to a kind of atomic clock device, is specifically related to a kind of CPT atomic frequency standard.
Background technology
Along with the develop rapidly of electronic technology and control technology, for the research of atomic clock mainly aspect two: be to explore development accuracy and the higher atomic clock of stability on the one hand.In recent years, many different types of possess the more New type atom clock of high accuracy and stability, such as Cold atomic fountain clock, ion trap clock, light clock etc. have successfully been developed; The approach that realizes high-precision mini engineering atomic clock of actively finding on the other hand, to meet various engineering development needs.Traditional atomic clocks such as hydrogen clock, caesium clock and rubidium clock are bigger than normal due to volume, power consumption, and its application form is specific installation or the parts that are built in equipment, and range of application also is confined to high-end devices or system basically.And do not need the CPT(CPT in traditional microwave chamber, Coherent Population Trapping, Coherent Population Trapping imprison) atomic clock, because its volume, power consumption can reduce 2-3 the order of magnitude by more traditional atomic clock, making the portability of atomic clock apply becomes possibility.
The CPT atomic clock is the microminiaturized atomic clock that utilizes the development of Coherent Population Trapping imprison principle.The Coherent Population Trapping imprison is a kind of quantum interference phenomenon that atom and coherent light interaction produce.Utilizing the good coherence of laser, prepare Coherent Population Trapping imprison state in atom system, can realize the New type atom clock of chip-scale, is the cutting edge technology of current atomic clock field and navigation field.Its advantage is: on the one hand, do not need microwave cavity, can obviously reduce volume; On the other hand, adopt the relevant bi-coloured light of laser preparation that is subjected to the microwave frequency modulation, can reduce optical frequency shift.Although the CPT atomic clock proposed so far time and soon from 1998, its development rapidly, has demonstrated superior performance, and also has larger room for improvement.
In prior art, the CPT atomic clock comprises, laser servo circuit, physical package, radio frequency servo circuit and micro-control circuit.After the output signal of physical package is extracted, is processed by micro-control circuit 400, feed back to respectively laser servo circuit and radio frequency servo circuit, the error signal that produces is input optical maser wavelength and the microwave signal of correcting physics encapsulation respectively, forms atomic frequency standard laser servo loop and radio frequency servo loop.Physical package wherein, usually formed by laser, conversion light path, quarter wave plate, alkaline atom bubble air chamber and photodetector, the laser that laser sends becomes directional light by the conversion light path converting, enter alkaline atom bubble air chamber after quarter wave plate forms the entelechy polarised light, received by photoconductive detector finally.Wherein, the conversion light path is generally set of lenses, can produce loss in the light beam transmittance process; Alkalescence atom bubble air chamber is provided with bias magnetic field, and remains under the working temperature of 70 ℃-90 ℃.Close together due to laser and alkaline atom bubble air chamber, can be subject to the impact of its temperature and bias magnetic field, in addition, the electric current of photodetector work output also can produce magnetic field, operating frequency to laser exerts an influence, therefore, need to improve the structure of CPT atomic frequency standard, to reduce above-mentioned impact.
Summary of the invention
Goal of the invention of the present utility model is to provide that a kind of light beam loss is less, temperature is floated phenomenon and influence of magnetic field is less, stability and the higher CPT atomic frequency standard of accuracy.
To achieve the above object of the invention, the technical solution adopted in the utility model is: a kind of CPT atomic frequency standard, formed by electronic system and physical package, described physical package mainly is comprised of laser, conversion light path, quarter wave plate, alkaline atom bubble air chamber and photodetector successively along the light path direction of transfer, described conversion light path comprises connection optical fiber and GRIN Lens, output and the GRIN Lens of described connection optical fiber connecting laser, the directional light of GRIN Lens output enters quarter wave plate.
Further technical scheme, described connection optical fiber is connected and composed with the tail optical fiber that is connected GRIN Lens by the tail optical fiber of connecting laser.
In technique scheme, described electronic system comprises laser servo circuit, radio frequency servo circuit and micro-control circuit, the output signal end of the photodetector in described physical package is connected to the input of micro-control circuit, the output of micro-control circuit is connected to respectively laser servo circuit and radio frequency servo circuit, and the output of laser servo circuit and radio frequency servo circuit is connected to the control end of laser.
Described radio frequency servo circuit comprises programmable frequency synthesizer, loop filter, voltage controlled oscillator and temperature compensating crystal oscillator.
In technique scheme, described CPT atomic frequency standard is utilized atomic coberent Population Trapping principle and is realized, is also can realize microminiaturized atomic frequency standard at present on principle.It is the absworption peak of ground state to excitation state that the laser servo loop is used for the locking reference signal; In physical package, the light of laser emission is by GRIN Lens outgoing collimated light beam, and this collimated light beam passes through quarter wave plate again, obtains circularly polarized light, and this circularly polarized light enters alkaline atom bubble air chamber again, finally by photodetector, is absorbed; The radio frequency servo loop provides CPT resonance required microwave signal, feeds back to micro-control circuit again and regulate after physical package, so that radio frequency servo loop locking reference signal is the CPT resonance signal; After micro-control circuit is used for photo detector signal is carried out extraction process, form error correction signal to laser servo circuit and radio frequency servo circuit.
Preferred technical scheme, described laser is placed in different package casings from described alkaline atom bubble air chamber.Optic path between them realizes by optical fiber, and the length of optical fiber can be determined according to application demand.
Because technique scheme is used, the utility model compared with prior art has following advantages:
1, the utility model will be connected with the GRIN Lens with tail optical fiber with the laser of tail optical fiber, can be so that laser, away from alkaline atom bubble air chamber, reduces the impact on it of temperature and magnetic field; The use of optical fiber, can reduce the loss of light; And GRIN Lens can produce collimated light beam, and this light beam is easy to obtain circularly polarized light after quarter wave plate.
2, connect owing to being provided with tail optical fiber, as required, laser can be placed in different package casings with alkaline atom bubble air chamber, thereby avoid alkaline atom to steep the interference to laser of the temperature of air chamber and magnetic field.
Description of drawings
Fig. 1 is the system schematic of the utility model embodiment;
Fig. 2 is the schematic diagram of embodiment;
Fig. 3 is embodiment neutral and alkali atom rubidium hyperfine levels transition figure;
Fig. 4 is embodiment neutral and alkali atom caesium hyperfine levels transition figure;
Fig. 5 is embodiment neutral and alkali atom bubble air chamber schematic diagram;
Fig. 6 is that in embodiment, pitch is 1/4 o'clock, GRIN Lens light path schematic diagram.
Embodiment
Below in conjunction with drawings and Examples, the utility model is further described:
Embodiment 1:
Shown in accompanying drawing 1, a kind of CPT atomic frequency standard comprises four parts: first is laser servo circuit 100, enters the laser dc offset voltage of laser 210 in order to adjusting; Second portion is physical package 200, comprise laser 210, the GRIN Lens 230 with tail optical fiber 220, quarter wave plate 240, alkaline atom bubble air chamber 250 and photodetector 260 with tail optical fiber 220, described laser beam is by the GRIN Lens 230 with tail optical fiber 220 and the rear output circularly polarized light of quarter wave plate 240, and this circularly polarized light arrives photodetector 260 through parlkaline atom bubble air chamber 250 again; Third part is radio frequency servo circuit 300, mainly comprises voltage controlled oscillator 310, loop filter 320, programmable frequency synthesizer 330 and temperature compensating crystal oscillator 340, and being used for provides laser 210 required microwave signal; The 4th part is micro-control circuit 400, micro-control circuit 400 with the photo detector signal extraction process after, form error correction signal and feed back to laser servo circuit 100 and radio frequency servo circuit 300.
Wherein, referring to accompanying drawing 2, laser servo circuit 100 comprises attenuator 110 etc.The output signal of physical package 200 is controlled attenuator 110 by micro-control circuit 400 extractions, processing Hou，Yi road and is adjusted the microwave power that enters laser 210, to obtain CPT resonance peak preferably; Optical maser wavelength is regulated by direct current biasing in another road.
The groundwork principle of the present embodiment is: at first radiofrequency signal is modulated on laser 210, produces incident laser; This light signal forms collimated light beam by GRIN Lens 230 outgoing with tail optical fiber 220; This collimated light beam passes through quarter wave plate again, obtains circularly polarized light; This circularly polarized light enters alkaline atom bubble air chamber 250 again, and in alkaline atom bubble air chamber 250, alkaline atom is heated to certain temperature and forms steam, and with this circularly polarized light, has an effect.Around alkaline atom bubble air chamber 250, a little bias magnetic field is used to isolate the atomic state of the m=0 that wants, so that hyperfine energy level splitting occurs alkaline atom, and with the coherent laser beam of incident, produces CPT resonance; Last alkaline atom bubble air chamber 250 light beam is out surveyed by photodetector 260.
Described laser 210 can be based on vertical-cavity-face emitting semiconductor laser (VCSEL, vertical-cavity surface-emitting lasers).Drive this VCSEL, the DC threshold current need be set.Caesium atom bubble air chamber externally encourage and magnetic fields under, the hyperfine energy level splitting of caesium atom obtains required frequency, consults Fig. 4.In order to obtain the hyperfine energy level that two energy level differences are 9.2GHz, a kind of method of most convenient is exactly to be modulated on laser on the microwave signal source of 4.6GHz, thereby obtains a FM modulation signal take ± 4.6 GHz as sideband.
Be connected with the GRIN Lens 230 with tail optical fiber 220 with the laser 210 of tail optical fiber 220, not only can reduce light loss, and can be so that laser 210 steeps the impact of air chamber 250 temperature and bias magnetic field away from alkaline atom.
GRIN Lens 230 is by GRIN Lens 230 realizations with tail optical fiber 220, and GRIN Lens 230 is the lens that use the radial gradual refraction materials to make, and its refraction index profile is the column optical lens of radially gradual change.Consult shown in Figure 6: when length of lens is got 1/4 pitch,, with the outgoing collimated light beam, utilize these characteristics can design with GRIN Lens 230 collimater of collimated light beam.
The light beam of laser 210 outgoing, by after GRIN Lens 230, changes collimated light beam into and enters described quarter wave plate 240 again.This quarter wave plate can produce λ/4 additional optical path differences, and making the light that appears wave plate is circularly polarized light.
Described alkaline atom bubble air chamber 250 can be caesium atom bubble air chamber or rubidium atom bubble air chamber.
When alkalescence atom bubble air chamber 250 is selected caesium atom bubble air chamber, shown in accompanying drawing 5: caesium atom bubble air chamber adopts MEMS technique and in conjunction with the anode linkage method, makes, and its volume is only 1mm
3, its technological process is: the first step, first with KOH or deep reaction ion etching method, etch the square groove of 1mm size on silicon chip, and be used for holding the caesium atomic sample; Second step, make the size dimension Pyrex wave plate the same with silicon chip, with the anode linkage method, the semi-enclosed absorption of formation that is close together of sheet glass and silicon chip steeped; In the 3rd step,, at vacuum environment buffer release atmosphere, inject sample atoms or adopt BaN toward absorbing in bubble simultaneously
6The method that chemical reaction occurs in bubble chamber with CsCl produces sample atoms, realizes that caesium atom bubble air chamber fills system.In the 4th step, the Pyrex slide that size is identical covers tightly caesium atom bubble air chamber opening surface, and recycling anode linkage method is close to both, thereby complete caesium atom bubble air chamber, makes.
When alkalescence atom bubble air chamber 250 was selected rubidium atom bubble air chamber, as shown in Figure 3, other manufacturing process were the same for the hyperfine energy level splitting energy level of rubidium atom schematic diagram.
The enforcement of described second portion physical package 200 utilizes the making of wafer level and assemble method to complete, each layer of system is made array on disk, by the bonding mode, each layer is assembled into together successively, then to whole, carry out scribing and obtain the atomic frequency standard physical system.The enforcement of outside magnetic shielding device can use the permalloy of processing through annealing, demagnetization to make, and makes alkaline atom bubble air chamber obtain the effect of magnetic screen, to reduce the impact for alkaline atomic transition frequency of space stray magnetic field and earth magnetic field.
Described radio frequency servo circuit 300, as shown in Figure 2: comprise voltage controlled oscillator 310, loop filter 320, programmable frequency synthesizer 330 and temperature compensating crystal oscillator 340.Temperature compensating crystal oscillator 340 provides the reference signal of 10M frequency, and 400 pairs of programmable frequency synthesizer 330 initialization of micro-control circuit make radio frequency servo loop 300 lock onto on the CPT resonance frequency, so that the microwave signal that enters laser 210 to be provided.
Described micro-control circuit 400, as shown in Figure 2: after this circuit is used for photo detector signal is carried out extraction process, form error correction signal to laser servo circuit 100 and radio frequency servo circuit 300.
The enforcement of described first and third part: laser servo circuit 100 and radio frequency servo circuit 300 are the regulating circuit of photodetector 260 output signals after micro-control circuit 400 extracts.According to this feedback information, micro-control circuit 400 is with excitation of suitable adjusting laser 210 etc., so that atom frequency standard locking.
Claims (5)
1. CPT atomic frequency standard, formed by electronic system and physical package, described physical package mainly is comprised of laser, conversion light path, quarter wave plate, alkaline atom bubble air chamber and photodetector successively along the light path direction of transfer, it is characterized in that: described conversion light path comprises connection optical fiber and GRIN Lens, output and the GRIN Lens of described connection optical fiber connecting laser, the directional light of GRIN Lens output enters quarter wave plate.
2. CPT atomic frequency standard according to claim 1, it is characterized in that: described connection optical fiber is connected and composed with the tail optical fiber that is connected GRIN Lens by the tail optical fiber of connecting laser.
3. CPT atomic frequency standard according to claim 1, it is characterized in that: described electronic system comprises laser servo circuit, radio frequency servo circuit and micro-control circuit, the output signal end of the photodetector in described physical package is connected to the input of micro-control circuit, the output of micro-control circuit is connected to respectively laser servo circuit and radio frequency servo circuit, and the output of laser servo circuit and radio frequency servo circuit is connected to the control end of laser.
4. CPT atomic frequency standard according to claim 3, it is characterized in that: described radio frequency servo circuit comprises programmable frequency synthesizer, loop filter, voltage controlled oscillator and temperature compensating crystal oscillator.
5. CPT atomic frequency standard according to claim 1 and 2 is characterized in that: described laser is placed in different package casings from described alkaline atom bubble air chamber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013203636306U CN203289410U (en) | 2013-06-24 | 2013-06-24 | Cpt atomic frequency standard |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013203636306U CN203289410U (en) | 2013-06-24 | 2013-06-24 | Cpt atomic frequency standard |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203289410U true CN203289410U (en) | 2013-11-13 |
Family
ID=49545752
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2013203636306U Expired - Fee Related CN203289410U (en) | 2013-06-24 | 2013-06-24 | Cpt atomic frequency standard |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203289410U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103281079A (en) * | 2013-06-24 | 2013-09-04 | 苏州大学 | Cpt atomic frequency standard |
| CN114609888A (en) * | 2022-03-07 | 2022-06-10 | 电子科技大学 | Atomic clock-cavity optical mechanical system interlocking type photo-generated microwave source |
-
2013
- 2013-06-24 CN CN2013203636306U patent/CN203289410U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103281079A (en) * | 2013-06-24 | 2013-09-04 | 苏州大学 | Cpt atomic frequency standard |
| CN114609888A (en) * | 2022-03-07 | 2022-06-10 | 电子科技大学 | Atomic clock-cavity optical mechanical system interlocking type photo-generated microwave source |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103454902B (en) | A kind of atomic clock | |
| US10763966B1 (en) | Data communications system using an optical antenna | |
| CN110535005B (en) | Light and small photoelectric oscillator based on electromagnetic induction transparency principle and low-phase-noise microwave signal generation method | |
| CN103825184B (en) | A kind of ultra-narrow band excited state faraday anomalous dispersion atomic light filter of communication band | |
| EP1493212A2 (en) | Atomic clock based on an opto-electronic oscillator | |
| CN104659637A (en) | Photoelectric oscillator based on optical resonant cavity | |
| JP2009212494A (en) | Light-microwave oscillator and pulse generator | |
| WO2013120334A1 (en) | Physical system device for chip cpt atomic clock | |
| CN103441410B (en) | Optical loop device and photoelectric oscillator based on optical loop energy storage and filtering | |
| CN104767119A (en) | Center frequency tunable semiconductor laser unit frequency stabilizing device and method | |
| CN108598856B (en) | Femtosecond laser | |
| CN203289410U (en) | Cpt atomic frequency standard | |
| Heidel et al. | A review of electronic-photonic heterogeneous integration at DARPA | |
| CN103281079A (en) | Cpt atomic frequency standard | |
| CN101794952B (en) | Accurately-tunable optical fiber laser microwave source with low phase noise and narrow line width | |
| CN102736510A (en) | Wristwatch with atomic oscillator | |
| CN112362175A (en) | Laser frequency measuring device based on microcavity optical frequency synthesizer | |
| Liu et al. | Design of a phase sensor applied in the optical phase-locked loop based on a high-speed coherent laser communication system | |
| CN110750044A (en) | Integrated CPT atomic clock physical system device | |
| CN203455615U (en) | Atomic clock | |
| CN114243435B (en) | Plasma photonic crystal shock wave device | |
| CN113310480B (en) | Optical gyroscope system based on silicon nitride waveguide resonant cavity | |
| WO2018103104A1 (en) | Device and method for tracking light wavelength | |
| CN103929175A (en) | Quantum system device for CPT atomic frequency maker | |
| CN108923259B (en) | Method for manufacturing THz pumping source of double-mode laser |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20131113 Termination date: 20160624 |