Dispersion microcavity angular velocity sensing method based on compression light field enhancement

Abstract

The invention discloses a dispersion optical microcavity angular velocity detection structure based on compression light field enhancement. The dispersion optical microcavity angular velocity detection structure is composed of a compression light source, a coherent light source, an optical beam splitter, a straight waveguide, two annular optical resonant cavities and a photoelectric detector. The two annular resonant cavities form a coupled resonant cavity system, the dispersion in the cavities can be regulated to be normal dispersion or abnormal dispersion by regulating the reflection coefficient of the coupler between the two rings, and whether a compressed light field is coupled into the system or not can be regulated by operating the opening and closing of the optical baffle. Light fields emitted by the compression light source and the coherent light source are coupled by the optical beam splitter and then enter the straight waveguide as input light signals, and then enter the coupling resonant cavity through the two couplers to be transmitted, and then output signal light enters the photoelectric detector through the straight waveguide to be detected. The standard quantum limit sensitivity of the system to angular velocity sensing can be remarkably broken through by a method of coupling the compressed light field in the dispersive optical resonant cavity.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical precision measurement, and more specifically, the present invention relates to a method for enhancing the angular velocity sensing characteristics of a dispersion optical microcavity based on a compressed light field. Background Art

[0002] The gyroscope is one of the core components of the inertial navigation system and plays a key role in navigation applications in fighter jets, ships, and civilian drones. The optical gyroscope based on the Sagnac effect is also expanding in military equipment and civilian facilities due to its mature processing technology and high precision. The accuracy of a traditional optical gyroscope is proportional to the area of ​​the optical loop, which means that if the gyroscope has a higher accuracy, its volume must be larger, and vice versa, which makes it difficult for traditional optical gyroscopes to achieve high accuracy and small volume at the same time. The resonant optical gyroscope measures angular velocity by detecting the resonant frequency shift in the resonant cavity. Studies have shown that introducing anomalous dispersion in the resonant cavity can significantly improve the sensitivity of the optical gyroscope. However, current research on the introduction of anomalous dispersion effects to enhance the frequency shift measurement characteristics of resonant cavities is mostly based on classical light. Considering the influence of light field shot noise, the resonant cavity has a standard quantum limit sensitivity, which limits the upper limit of the introduction of anomalous dispersion to enhance the sensitivity of the gyroscope. How to suppress the shot noise of the light field in the dispersive cavity through new methods and structures, thereby further improving the detection limit of the dispersive cavity angular velocity sensing, has become a technical bottleneck problem that needs to be solved urgently. Summary of the invention

[0003] In order to solve the technical problem that it is difficult for an optical gyroscope to have both high precision and small size, the present invention proposes a dispersive optical microcavity structure based on compressed light field enhancement. By suppressing the shot noise of the light field in the dispersive cavity, the standard quantum limit of angular velocity sensing of the dispersive cavity can be broken.

[0004] The solution of the present invention: The present invention is an improvement on the angular velocity sensing dispersive optical resonant cavity, which is a dispersive optical microcavity angular velocity detection structure based on a compressed light field, which is composed of a compressed light source, an optical baffle, an optical beam splitter, a coherent light source, a straight waveguide, two ring resonant cavities, two couplers and a detector (such as Figure 1 ); the relationship between them is: the compressed light emitted by the compressed light source and the coherent light emitted by the coherent light source are coupled on the optical beam splitter to form the input light signal of the system, and then coupled into the straight waveguide, the straight waveguide and the first ring resonant cavity are coupled through a coupler, and the first ring cavity and the second ring cavity are also coupled through a coupler, the incident light in the straight waveguide enters the two ring cavities through two couplers for transmission, and then passes through the coupler as the output signal light, and the output signal light is finally incident on the detector.

[0005] The main body of the straight waveguide and the two annular resonant cavities is silicon dioxide; the effective refractive index of the two annular cavities is neff,R6=neff,R7,=2, the loss coefficient of annular cavity 7 is, the transmission loss of 6 is, and the circumferences of annular cavities 6 and 7 are the same, about 53um.

[0006] The central wavelength of the coherent light source and the compressed light source is 1064 nm.

[0007] The optical beam splitter has a splitting ratio of 50:50, and is used to achieve the coupling of the compressed light field and the coherent light as the input light signal of the system.

[0008] The losses of the two couplers are assumed to be 0, and the coupling strength between the two ring cavities can be changed by adjusting the reflection coefficient r1 of the coupler 8, thereby regulating the dispersion state of the coupled resonant cavity.

[0009] The reflection coefficient of the coupler is calculated by the dispersion condition of the system.

[0010] The present invention is a dispersive optical microcavity angular velocity detection structure based on a compressed light field. The incident compressed light and coherent light are respectively reflected and transmitted by an optical splitter and then coupled into a straight waveguide as input optical signals. A part of the incident light enters the annular cavity 6 through a coupler 9 and is transmitted counterclockwise. When passing through the coupler 8, part of the light enters the annular cavity 7 and is also transmitted counterclockwise. By changing the value of the reflection coefficient r1 of the coupler 8, the intracavity dispersion of the coupled resonant cavity system can be regulated to make it work in an anomalous dispersion or normal dispersion state. By controlling the opening or closing of the optical baffle, the compressed light injection system can be controlled or blocked. The light transmitted in the coupled resonant cavity is coupled into the straight waveguide as an output optical signal and then transmitted to a photodetector. By detecting the change of the electrical signal on the detector, information on the angular velocity change can be obtained.

[0011] Advantages of the present invention: The advantages of the angular velocity sensing method based on compressed light field enhanced dispersion optical microcavity of the present invention are: (1) The compressed light field enhancement method described in the present invention can suppress the shot noise of the light field in the micro-ring coupled resonant cavity, thereby enabling the angular velocity measurement sensitivity of the system to break through the standard quantum limit, thereby achieving a significant improvement. (2) The compressed light field enhancement method described in the present invention adopts a dual-ring resonant cavity structure with vertical spatial coupling, which avoids the mutual cancellation of Sagnac phase shifts caused by the two ring cavities being arranged side by side on a plane. The phase shifts accumulated in the dual rings can be superimposed on each other, thereby increasing the measurement sensitivity of the system and reducing the front projection area of ​​the system, thereby effectively reducing the overall size. (3) The compressed light field enhancement method described in the present invention adopts the method of coupling the compressed light field from the input end of the system. Compared with the reverse coupling from the output end of the system, the positive feedback brought by the anomalous dispersion and the compressed light field enhancement can be superimposed, thereby greatly improving the measurement sensitivity of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the structure of the dispersive optical microcavity angular velocity detection based on compressed light field enhancement according to the present invention; in the figure, 1-compressed light field 2-optical baffle 3-coherent light 4-optical beam splitter 5-straight waveguide 6-annular optical resonant cavity 7-annular optical resonant cavity 8-coupler 9-coupler 10-photodetector; Figure 2 The dispersion diagram of the dual-ring coupled resonant cavity system; Figure (a) is normal dispersion, and Figure (b) is anomalous dispersion Figure 3 Figure 1 shows the sensitivity of the dual-ring coupled resonant cavity system under different working conditions. Figures (a)-(c) show the sensitivity curves when the resonant cavity is under normal dispersion conditions; Figures (d)-(f) show the sensitivity curves when the system is under anomalous dispersion conditions. DETAILED DESCRIPTION

[0013] Example:

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. A dispersive optical microcavity angular velocity detection structure based on compressed light field enhancement, such as Figure 1 As shown, it includes a compressed light field 1, an optical baffle 2, coherent light 3, an optical beam splitter 4, a straight waveguide 5, a coupled resonant cavity composed of ring resonators 6 and 7, couplers 8 and 9, and a photodetector 10; the relationship between them is that the compressed light 1 and the coherent light 3 enter the straight waveguide 5 as the input light signal of the system after being coupled by the optical beam splitter 4, the incident light propagates in the resonant cavity through the couplers 8 and 9, and the output light signal enters the straight waveguide 5 through the coupler 9 and is finally transmitted to the photodetector 10.

[0015] The main body of the ring resonator 6 and 7 is silicon dioxide; the effective refractive index is neff,R6=neff,R7,=2, the loss coefficient of the ring cavity 7 is, the transmission loss of the ring cavity 6 is, the circumference of 6 and 7 is the same, about 53um, the central wavelength of the coherent light 3 and the compressed light 1 is 1064nm, and the splitting ratio of the optical beam splitter 4 is 50:50.

[0016] like Figure 1As shown, after the compressed light 1 and the coherent light 3 are coupled by the beam splitter 4, they enter the straight waveguide 5 as input optical signals (whether the compressed light is injected into the system can be regulated by controlling the opening or closing of the optical baffle 2). When passing through the coupler 9, a part of the incident light is coupled into the ring cavity 6 and transmitted in the counterclockwise direction therein. When passing through the coupler 8, a part of the light is coupled into the ring cavity 7 and also transmitted in the counterclockwise direction. After a circle of propagation, it passes through the couplers 8, 9 and the straight waveguide 5 in turn and enters the photodetector 10. In the present invention, it is assumed that the couplers 8, 9 and the straight waveguide 5 have no loss, and the reflection coefficients of 8 and 9 are r1 and r2 respectively. The coupling strength between the ring cavities 6 and 7 can be adjusted by changing r1. By setting different r1 values, the dispersion state of the coupled resonant cavity can be regulated according to demand. When r1=0.93999, the coupled resonant cavity is in a normal dispersion state. When r1=0.99809, the system is in an abnormal dispersion state (such as Figure 2 shown).

[0017] By controlling the opening or closing of the optical baffle 2, the compressed light field 1 can be coupled into the system or blocked. By adjusting the value of r1, the system can be operated in three different states, namely, the case of no dispersion and no compressed light field coupling; the case of dispersion but no compressed light coupling; the case of dispersion and compressed light field coupling. The relationship between the sensitivity of the system and the frequency detuning in these three cases is shown as follows: Figure 3 As shown, if there is no compressed light injection, when the system works under normal dispersion conditions, its sensitivity is lower than the value under no dispersion conditions; when the system works under anomalous dispersion conditions, its sensitivity is higher than the corresponding value under no dispersion conditions; if the compressed light field is coupled into the system, its sensitivity is higher than the case without dispersion even under normal dispersion conditions. When the system is under anomalous dispersion conditions, the sensitivity of the system is significantly improved compared to the case without dispersion and no compressed light.

[0018] The present invention can significantly improve the detection sensitivity of angular velocity sensing of a dispersive optical resonant cavity through a method of compressed light field enhancement, breaking through the corresponding standard quantum limit. Compared with a resonant cavity of the same size without dispersion and without compressed light field injection, the present invention can adjust the coupling strength of the two ring cavities by adjusting the reflection coefficient of the coupler 8, so that the system works in a normal dispersion or anomalous dispersion state. The compressed light 1 can be injected into the system or blocked by controlling the optical baffle 2 to be opened or closed. Adjust r1=0.99809 to make the intracavity dispersion of the system anomalous dispersion. At this time, the anomalous dispersion effect has a significant enhancement effect on the intracavity resonant frequency shift. Open the optical baffle 2 to couple the compressed light field 1 into the system. Under the action of the compressed light field 1, the shot noise of the intracavity light field is effectively suppressed. At this time, the enhancement effect of the anomalous dispersion and the compressed light field on the detection angular velocity of the coupled resonant cavity is superimposed. The system can effectively break through the corresponding standard quantum limit sensitivity of angular velocity measurement, which is 5 orders of magnitude higher than the minimum detectable angular velocity of the system when there is no dispersion and no compressed light injection (such as Figure 3 shown).

Claims

1. A dispersive optical microcavity angular velocity detection structure based on compressed light field enhancement, characterized in that: The system consists of a compressed light source, a coherent light source, an optical baffle, an optical beam splitter, a straight waveguide, two annular optical resonators, two couplers and a photodetector; the two annular resonators form a coupled resonant cavity through a coupler, and the compressed light and the coherent light are coupled into the straight waveguide through the optical beam splitter, and then enter the coupled resonant cavity for transmission as input signal light.

2. The dispersive optical microcavity angular velocity detection structure based on compressed light field enhancement according to claim 1, characterized in that: The main bodies of the straight waveguide and the ring resonant cavity are made of silicon dioxide.

3. The dispersive optical microcavity angular velocity detection structure based on compressed light field enhancement according to claim 1, characterized in that: The central wavelength of the compressed light and the coherent light input into the coupling resonant cavity is λ=1064 nm, and the circumference of the two ring cavities is about 53 um.

4. The dispersive optical microcavity angular velocity detection structure based on compressed light field enhancement according to claim 1, characterized in that: The two annular cavities are coupled by vertically stacking them in space and opening them at a small angle.

5. The dispersive optical microcavity angular velocity detection structure based on compressed light field enhancement according to claim 1, characterized in that: The reflection coefficient of the coupler between the two ring cavities is calculated from the input-output relationship of the system.

6. The dispersive optical microcavity angular velocity detection structure based on compressed light field enhancement according to claim 1, characterized in that: The compressed light field is coupled into the system from the input port of the coupled resonant cavity, and can also be coupled into the system from the output port (not shown in the figure).

7. The dispersive optical microcavity angular velocity detection structure based on compressed light field enhancement according to claim 1, characterized in that: By changing the parameters of the coupler between the two ring cavities to control the intra-cavity dispersion, the system can operate in normal dispersion or anomalous dispersion state according to requirements.

8. A method for detecting using the coupled resonant cavity structure according to claims 1 to 7, characterized in that: By controlling the optical baffle to be in the open state, the compressed light emitted from the compressed light source and the coherent light emitted from the coherent light source are coupled by the optical beam splitter and enter the straight waveguide as the signal input light, and then enter the coupled resonant cavity through the coupler and transmit in the counterclockwise direction. The light transmitted in the coupled resonant cavity then passes through the coupler as the output signal light and enters the straight waveguide and finally incident on the photodetector. By changing the reflection coefficient of the coupler between the two ring resonators, the dispersion in the cavity can be adjusted to normal dispersion or anomalous dispersion according to demand. When the system works in the anomalous dispersion state, the anomalous dispersion effect and the enhanced effect of the compressed light field on the resonant frequency shift detection are superimposed, thereby significantly improving the system's sensitivity to angular velocity detection. By detecting the change in the photodetector signal, the information on the angular velocity change can be obtained.

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