All-normal dispersion super-continuum spectrum driven resonant optical gyroscope and working method thereof

Abstract

The invention discloses an all-normal dispersion super-continuum spectrum driven resonant optical gyroscope and a working method thereof, and belongs to the field of optical gyroscopes. The input end of the mode-locked laser ML is connected to a left port of the full-normal dispersion photonic crystal fiber ANDi-PCF, input ports of the full-normal dispersion photonic crystal fiber ANDi-PCF and the photoelectric detector PD are connected to two left ports of the circulator CIR respectively, and a right port of the circulator CIR is connected with a left port of the multifunctional integrated optical chip MIOC. And two ports on the right side of the multifunctional integrated optical chip MIOC are respectively connected with two ports of the waveguide ring resonator WRR. Based on the resonance mode of the full-normal dispersion super-continuum spectrum excitation waveguide ring resonator, the influence of relative intensity noise and shot noise on the gyroscope performance is further reduced by using the broadband and smooth light source spectrum pattern, and finally the angle random walk of the gyroscope is promoted.

Description

Technical Field

[0001] This invention belongs to the field of optical gyroscopes; specifically, it relates to a resonant optical gyroscope driven by a fully normal dispersive supercontinuum spectrum and its working method. Background Technology

[0002] As a high-precision inertial navigation instrument, fiber optic gyroscopes are used to measure the angular velocity of an object's rotation. In recent years, with the development of integrated optics, there has been an urgent need for optical gyroscopes with high precision and integration potential.

[0003] In existing mature interferometric fiber optic gyroscopes, angular velocity causes a phase difference between the clockwise and counterclockwise optical paths, and this phase difference is proportional to the length of the fiber optic ring resonator. While this method offers high precision, the length of the fiber optic ring resonator needs to reach the km level, hindering device miniaturization and integration. In contrast, resonant fiber optic gyroscopes detect angular velocity by utilizing the resonant frequency difference between the clockwise and counterclockwise optical paths. High-Q optical microcavities can replace multi-turn wound fiber optic rings, overcoming the disadvantage of large size and demonstrating potential for integration. Furthermore, with the development of resonant fiber optic gyroscopes driven by broadband light sources, the requirements for high-precision light source linewidth and complex laser frequency locking technology have been significantly reduced.

[0004] The angular random walk of existing broadband light source-driven resonant fiber optic gyroscopes is limited by both relative intensity noise and shot noise, with the former contributing far more than the latter, which hinders further improvement in gyroscope performance. Summary of the Invention

[0005] This invention provides a fully normal dispersive supercontinuum driven resonant optical gyroscope and its working method. By using a smooth and broadband supercontinuum light source to excite more resonant modes of a transmission waveguide ring resonator, the angular random walk limited by relative intensity noise and shot noise is significantly improved, and a resonant optical gyroscope with a lower noise level is realized.

[0006] This invention is achieved through the following technical solution: A fully normal dispersion supercontinuum driven resonant optical gyroscope, the gyroscope comprising a mode-locked laser ML, a fully normal dispersion photonic crystal fiber ANDi-PCF, a photodetector PD, a circulator CIR, an integrated optical chip MIOC, and a waveguide ring resonator WRR; The input terminal of the mode-locked laser ML is connected to the left port of the fully normal dispersion photonic crystal fiber ANDi-PCF. The input ports of the fully normal dispersion photonic crystal fiber ANDi-PCF and the input ports of the photodetector PD are both connected to the left port of the circulator CIR. The right port of the circulator CIR is connected to the left port of the integrated optical chip MIOC. The two right ports of the integrated optical chip MIOC are respectively connected to the two ports of the waveguide ring resonator WRR.

[0007] Furthermore, the mode-locked laser ML is used to provide femtosecond-level laser pulses; The fully normal dispersion photonic crystal fiber ANDi-PCF is used to generate smooth and broadband supercontinuum. The photodetector PD is used to detect laser interference signals transmitted through a circulator, a multifunctional integrated optical chip, and a waveguide ring resonator. The circulator CIR is used to split the supercontinuum light source beam and combine the laser beam after passing through the waveguide ring resonator. The multifunctional integrated optical chip MIOC is used to modulate the signals of two laser beams propagating clockwise and counterclockwise in the waveguide ring resonator WRR. The waveguide ring resonator (WRR) is used for multi-turn cyclic propagation of the laser to enhance the rotational angular velocity signal.

[0008] Furthermore, the operating wavelength ranges of the mode-locked laser ML, the fully normal dispersion photonic crystal fiber ANDi-PCF, the photodetector PD, the circulator CIR, the multifunctional integrated optical chip MIOC, and the waveguide ring resonator WRR are matched.

[0009] Furthermore, the waveguide ring resonator (WRR) has a transmission resonant cavity structure.

[0010] A working method for a fully normal dispersion supercontinuum driven resonant optical gyroscope, wherein the working method uses a fully normal dispersion supercontinuum driven resonant optical gyroscope as described above, wherein the working method specifically involves pumping a fully normal dispersion photonic crystal fiber ANDi-PCF with a femtosecond pulse laser output from a mode-locked laser ML, and the supercontinuum is split into two laser beams by a multifunctional integrated optical chip MIOC after passing through a circulator CIR. A modulation signal is applied to one end of the multifunctional integrated optical chip MIOC, and two laser beams are incident on the waveguide ring resonator WRR, and the two beams propagate in the resonant cavity in clockwise and counterclockwise directions, respectively. After multiple loops of propagation inside the waveguide ring resonator (WRR), the unmodulated laser returns to the modulation port of the multifunctional integrated optical chip (MIOC), while the modulated laser returns to the unmodulated port. After passing through the circulator CIR, the interference signal of the two laser beams is detected by the photodetector PD.

[0011] Furthermore, the transmittance function of the waveguide ring resonator (WRR): (1) (2) (3) in, and ; It is the detuning amount of the laser angular frequency; and These are the intrinsic loss and coupling loss of the waveguide ring resonator (WRR), respectively. It is the free spectral range of the waveguide ring resonator (WRR).

[0012] Furthermore, the light intensity detected by the photodetector PD for a beam of light propagating in clockwise and counterclockwise directions without signal modulation: (4) in, This represents the power spectral density function of the light source.

[0013] Furthermore, after applying a sinusoidal modulation signal, the light intensity of the beam propagating in clockwise and counterclockwise directions is detected by the photodetector PD: (5) in, It is a Bessel function of the first kind, nth order. Represents the modulation coefficient. Indicates the modulation frequency.

[0014] Furthermore, RIN noise can be expressed as: (11) in, It is optical power.

[0015] Furthermore, for a resonant optical gyroscope driven by a fully normal dispersive supercontinuum, under the constraints of relative intensity noise and shot noise, the angular random walk can be expressed as: (12) in, This represents the perimeter of the waveguide ring resonator WRR. This indicates the diameter of the waveguide ring resonator (WRR). This indicates the fineness of the waveguide ring resonator (WRR). It is shot noise.

[0016] A fully normal dispersive supercontinuum driven resonant optical gyroscope, as described above, can be applied to the field of attitude control for microsatellites or autonomous navigation for unmanned aerial vehicles.

[0017] The beneficial effects of this invention are: This invention employs a smooth and broadband supercontinuum light source to excite a greater number of resonant modes in a transmission waveguide ring resonator, significantly reducing the relative intensity noise of the laser interference signal and thus substantially improving angular random walk. The optical path structure of this invention is simple and reciprocal, requiring no laser frequency locking technology or feedback control loop, and offers advantages such as high precision and integrability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Figure 2 This is a comparison of the spectra of the supercontinuum spectrum and the amplified spontaneous emission ASE source used in this invention, where (a) is the spectrum of the supercontinuum spectrum used in this invention, and (b) is the spectrum of the amplified spontaneous emission ASE source.

[0020] Figure 3 This is the theoretical relative intensity noise spectrum of the laser interference signal after the supercontinuum is adopted in this invention.

[0021] Figure 4 This is a diagram illustrating the theoretical improvement effect of using supercontinuum on angular random walks in this invention. Detailed Implementation

[0022] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0023] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0024] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0025] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0027] Implementation Method 1 This embodiment provides a fully normal dispersion supercontinuum driven resonant optical gyroscope, the gyroscope comprising a mode-locked laser ML, a fully normal dispersion photonic crystal fiber ANDi-PCF, a photodetector PD, a circulator CIR, a waveguide ring resonator WRR, and a multifunctional integrated optical chip MIOC composed of a polarizer, a beam splitter, and a phase modulator. The input terminal of the mode-locked laser ML is connected to the left port of the fully normal dispersion photonic crystal fiber ANDi-PCF. The input ports of the fully normal dispersion photonic crystal fiber ANDi-PCF and the input ports of the photodetector PD are both connected to the left port of the circulator CIR. The right port of the circulator CIR is connected to the left port of the multifunctional integrated optical chip MIOC. The two right ports of the multifunctional integrated optical chip MIOC are respectively connected to the two ports of the waveguide ring resonator WRR.

[0028] Furthermore, the mode-locked laser ML is used to provide femtosecond-level laser pulses; The fully normal dispersion photonic crystal fiber ANDi-PCF is used to generate a smooth and broadband supercontinuum, which is an extremely broadband light source. The photodetector PD is used to detect laser interference signals transmitted through a circulator, a multifunctional integrated optical chip, and a waveguide ring resonator. The circulator CIR is used to split the supercontinuum light source beam and combine the laser beam after passing through the waveguide ring resonator. The multifunctional integrated optical chip MIOC is used to modulate the signals of two laser beams propagating clockwise and counterclockwise in the waveguide ring resonator WRR. The waveguide ring resonator (WRR) is used for multi-turn cyclic propagation of the laser to enhance the rotational angular velocity signal.

[0029] Furthermore, the operating wavelength ranges of the mode-locked laser ML, the fully normal dispersion photonic crystal fiber ANDi-PCF, the photodetector PD, the circulator CIR, the multifunctional integrated optical chip MIOC, and the waveguide ring resonator WRR are matched.

[0030] Specifically, the wavelength range matching refers to ensuring that the operating wavelength ranges of these optical devices have sufficient overlap to guarantee optimal performance of the supercontinuum source driving the optical gyroscope. The operating wavelength ranges of the optical devices, such as circulators, multifunctional integrated optical chips, and photodetectors, are matched with the wavelength range of the supercontinuum source. The supercontinuum source of this invention has a bandwidth of 146.82 nm.

[0031] Furthermore, the waveguide ring resonator (WRR) has a transmission resonant cavity structure.

[0032] Furthermore, the supercontinuum generated by the mode-locked laser ML pumping the fully normal dispersion photonic crystal fiber ANDi-PCF has a spectral linewidth of approximately 146.82 nm; the transmission waveguide ring resonator (WRR) has a diameter of 6 mm and a quality factor of 10. 6 .

[0033] Implementation Method 2 This embodiment provides a working method for a fully normal dispersion supercontinuum driven resonant optical gyroscope. The working method uses a fully normal dispersion supercontinuum driven resonant optical gyroscope as described in Embodiment 1. Specifically, the working method involves pumping a fully normal dispersion photonic crystal fiber ANDi-PCF with a femtosecond pulse laser output from a mode-locked laser ML, and splitting the supercontinuum into two laser beams by a multifunctional integrated optical chip MIOC after passing through a circulator CIR. A modulation signal is applied to one end of the multifunctional integrated optical chip MIOC, and two laser beams are incident on the waveguide ring resonator WRR, and the two beams propagate in the resonant cavity in clockwise and counterclockwise directions, respectively. After multiple loops of propagation inside the waveguide ring resonator (WRR), the unmodulated laser returns to the modulation port of the multifunctional integrated optical chip (MIOC), while the modulated laser returns to the unmodulated port. After passing through the circulator CIR, the interference signal of the two laser beams is detected by the photodetector PD.

[0034] Furthermore, the transmittance function of the waveguide ring resonator (WRR): (1) (2) (3) in, and ; It is the detuning amount of the laser angular frequency; and These are the intrinsic loss and coupling loss of the waveguide ring resonator (WRR), respectively. It is the free spectral range of the waveguide ring resonator (WRR).

[0035] Furthermore, the light intensity detected by the photodetector PD for a beam of light propagating in clockwise and counterclockwise directions without signal modulation: (4) in, This represents the power spectral density function of the light source.

[0036] Furthermore, after applying a sinusoidal modulation signal, the light intensity of the beam propagating in clockwise and counterclockwise directions is detected by the photodetector PD: (5) in, It is a Bessel function of the first kind, nth order. Represents the modulation coefficient. Indicates the modulation frequency.

[0037] Furthermore, RIN noise can be expressed as: (11) in, It is optical power.

[0038] Furthermore, for a resonant optical gyroscope driven by a fully normal dispersive supercontinuum, under the constraints of relative intensity noise and shot noise, the angular random walk can be expressed as: (12) in, This represents the perimeter of the waveguide ring resonator WRR. This indicates the diameter of the waveguide ring resonator (WRR). This indicates the fineness of the waveguide ring resonator (WRR). It is shot noise.

[0039] Based on equations (6) to (11), the RIN spectra of the supercontinuum and the ASE source are compared as follows: Figure 3 As shown, the use of supercontinuum significantly reduces RIN noise; after calculation using equation (12), the angle random walk and its improvement are as follows. Figure 4 As shown. In summary, compared with ASE sources, supercontinuum-driven resonant optical gyroscopes have lower RIN noise, thus significantly improving angular random walk.

[0040] Figure 1This scheme uses an all-optical approach to realize a low-noise, fully normal-dispersion supercontinuum driven resonant optical gyroscope. The optical path structure is simple and reciprocal, and it does not require laser frequency locking technology or feedback control loops. It has the advantages of high precision and integrability.

[0041] Figure 2 A smooth and broadband supercontinuum was generated by pumping a fully normal dispersion photonic crystal fiber (ANDi-PCF) with a femtosecond pulsed laser output from a mode-locked laser (ML), as shown in Figure (a). Compared to an amplified spontaneous emission (ASE) source, as shown in Figure (b), it has a wider range of source linewidths and can excite a greater number of resonant modes in a waveguide ring resonator (WRR).

[0042] Figure 3 Compared to ASE sources, supercontinuum-driven resonant optical gyroscopes exhibit a lower RIN spectrum, significantly reduced by approximately 10 dB / Hz at the lowest point. Therefore, under the same signal modulation technique, the relative intensity noise of the laser interference signal is further reduced using this scheme.

[0043] Figure 4 The random walk angle (ARW) of optical gyroscopes under different modulation frequencies and its improvement: After adopting this scheme, it can be seen that the ARW is significantly reduced under all modulation signal parameters, and the improvement effect of ARW is 5.6 dB at the optimal point of the two schemes.

[0044] Implementation Method 3 This embodiment provides a fully normal dispersion supercontinuum driven resonant optical gyroscope as described in Embodiment 1. The gyroscope is applied in the field of microsatellite attitude control or UAV autonomous navigation.

Claims

1. A fully normal dispersive supercontinuum driven resonant optical gyroscope, characterized in that, The gyroscope includes a mode-locked laser ML, a fully normal dispersion photonic crystal fiber ANDi-PCF, a photodetector PD, a circulator CIR, a multifunctional integrated optical chip MIOC, and a waveguide ring resonator WRR. The input terminal of the mode-locked laser ML is connected to the left port of the fully normal dispersion photonic crystal fiber ANDi-PCF. The input ports of the fully normal dispersion photonic crystal fiber ANDi-PCF and the input ports of the photodetector PD are both connected to the left port of the circulator CIR. The right port of the circulator CIR is connected to the left port of the multifunctional integrated optical chip MIOC. The two right ports of the multifunctional integrated optical chip MIOC are respectively connected to the two ports of the waveguide ring resonator WRR.

2. The gyroscope according to claim 1, characterized in that, The mode-locked laser ML is used to provide femtosecond-level laser pulses; The fully normal dispersion photonic crystal fiber ANDi-PCF is used to generate smooth and broadband supercontinuum. The photodetector PD is used to detect laser interference signals transmitted through a circulator, a multifunctional integrated optical chip, and a waveguide ring resonator. The circulator CIR is used to split the supercontinuum light source beam and combine the laser beam after passing through the waveguide ring resonator. The multifunctional integrated optical chip MIOC is used to modulate the signals of two laser beams propagating clockwise and counterclockwise in the waveguide ring resonator WRR. The waveguide ring resonator (WRR) is used for multi-turn cyclic propagation of the laser to enhance the rotational angular velocity signal.

3. The gyroscope according to claim 1, characterized in that, The operating wavelength ranges of the mode-locked laser ML, the fully normal dispersion photonic crystal fiber ANDi-PCF, the photodetector PD, the circulator CIR, the multifunctional integrated optical chip MIOC, and the waveguide ring resonator WRR are matched.

4. The gyroscope according to claim 1, characterized in that, The waveguide ring resonator (WRR) has a transmission-type resonant cavity structure.

5. A method for operating a fully normal dispersive supercontinuum driven resonant optical gyroscope, characterized in that, The working method uses a fully normal dispersion supercontinuum driven resonant optical gyroscope as described in any one of claims 1-4. Specifically, the working method is as follows: the femtosecond pulse laser output from the mode-locked laser ML pumps the fully normal dispersion photonic crystal fiber ANDi-PCF, and the supercontinuum is split into two laser beams by the multifunctional integrated optical chip MIOC after passing through the circulator CIR. A modulation signal is applied to one end of the multifunctional integrated optical chip MIOC, and two laser beams are incident on the waveguide ring resonator WRR, and the two beams propagate in the resonant cavity in clockwise and counterclockwise directions, respectively. After multiple loops of propagation inside the waveguide ring resonator (WRR), the unmodulated laser returns to the modulation port of the multifunctional integrated optical chip (MIOC), while the modulated laser returns to the unmodulated port. After passing through the circulator CIR, the interference signal of the two laser beams is detected by the photodetector PD.

6. The working method according to claim 5, characterized in that, Transmittance function of waveguide ring resonator (WRR): (1) (2) (3) in, and ; It is the detuning amount of the laser angular frequency; and These are the intrinsic loss and coupling loss of the waveguide ring resonator (WRR), respectively. It is the free spectral range of the waveguide ring resonator (WRR).

7. The working method according to claim 6, characterized in that, The light intensity detected by the photodetector PD for a beam of light propagating in clockwise and counterclockwise directions without signal modulation: (4) in, This represents the power spectral density function of the light source.

8. The working method according to claim 7, characterized in that, After a sinusoidal modulation signal is applied, the light intensity of the beam propagating in clockwise and counterclockwise directions is detected by a photodetector (PD): (5) in, It is a Bessel function of the first kind, nth order. Represents the modulation coefficient. Indicates the modulation frequency; RIN noise is represented as: (11) in, It is optical power.

9. The working method according to claim 8, characterized in that, For a resonant optical gyroscope driven by a fully normal dispersive supercontinuum spectrum, under the constraints of relative intensity noise and shot noise, the angular random walk can be expressed as: (12) in, This represents the perimeter of the waveguide ring resonator WRR. This indicates the diameter of the waveguide ring resonator (WRR). This indicates the fineness of the waveguide ring resonator (WRR). It is shot noise.

10. A fully normal dispersive supercontinuum driven resonant optical gyroscope as described in any one of claims 1-4, characterized in that, The gyroscope is used in the field of attitude control for microsatellites or autonomous navigation for unmanned aerial vehicles.

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