CN114199222B - Active resonance optical fiber gyroscope - Google Patents

Abstract

The invention discloses an active resonant fiber optic gyroscope, comprising a laser light source, a phase modulator, a circulator, a first coupler, a gas-filled photonic crystal fiber resonator cavity, a second coupler, a third coupler, an FPGA module and Signal processing system. The invention uses gas-filled photonic crystal fiber as a resonant cavity to increase the gain, unidirectional pump light input to solve the problem of poor stability caused by uneven laser beam splitting, and uses a reverse output cascaded Brillouin laser Sensing angular velocity can solve the latching effect in the original solution.

Description

An Active Resonant Fiber Optic Gyroscope

technical field

The invention belongs to the technical field of fiber optic gyroscopes, in particular to a gas-filled active resonant fiber optic gyroscope.

Background technique

Fiber optic gyroscope (FOG) is a new type of inertial device based on the Sagnac effect in optical fiber to sense the rotational angular velocity. The Sagnac effect is a phenomenon in which the angular rate of external rotation affects the interference of light: in a closed optical loop, two beams of light waves that propagate in opposite directions from any point in a closed optical loop return to this point after traveling for a week , the phase of the two light waves will change with the rotation of the relative inertial space, which is the theoretical basis of all optical gyroscopes.

So far, it has experienced three generations of development: interferometric (I-FOG), resonant (R-FOG) and Brillouin (BFOG). Among them, the interferometric fiber optic gyroscope has been successfully commercialized and applied in various fields. The resonant fiber optic gyroscope is in the stage of transition from laboratory research to practical application, and the stimulated Brillouin fiber optic gyroscope is basically still in the stage of principle research.

BFOG is an active fiber optic resonator gyroscope. When the light intensity incident on the optical fiber exceeds the Brillouin threshold of the optical fiber, due to the electrostrictive effect, moving acoustic waves will be generated in the optical fiber, and the existence of this moving acoustic wave leads to the generation of stimulated Brillouin scattering. When two beams of pump light are incident into the ring resonant cavity in opposite directions at the same time, two beams of Brillouin light in the opposite direction to the pump light will be generated. If the ring resonator is stationary, the frequencies of the two beams of Brillouin light are the same; When the ring resonator rotates at an angular velocity along a certain direction, there will be a frequency difference proportional to the angular velocity between the two beams of Brillouin light generated. Combine two beams of Brillouin light to generate a beat frequency, and measure the size of the beat frequency to obtain the rotation rate of the fiber resonator. This type of fiber optic gyroscope has a simple structure and can achieve accurate measurement without complex peripheral circuits. It is an ideal development direction for gyroscopes in the future.

However, the gain in the resonant cavity of the current active resonant gyro scheme is low, and the light source needs to have the characteristics of narrow linewidth, high power, and high stability of wavelength and power to generate stable laser light in a short fiber ring cavity. At the same time, it also has the same latch-up problem as the traditional laser gyro. The light amplification in the hollow-core photonic crystal fiber can be realized by using the gas Brillouin effect, and its gain coefficient can be much larger than that of the traditional standard single-mode fiber.

Contents of the invention

In order to solve the deficiencies in the prior art above, the present invention proposes a gas-filled active resonant fiber optic gyroscope, which has the advantages of high gain of the resonant cavity, low power of the light source, no latch-up effect, and high reliability. Concrete technical scheme of the present invention is as follows:

An active resonant fiber optic gyro, including a laser light source, a phase modulator, a circulator, a first coupler, a gas-filled hollow-core photonic crystal fiber resonator, a second coupler, a third coupler, an FPGA module and signal processing system, where

The pump light emitted by the laser light source enters the circulator after passing through the phase modulator driven by a signal generator, and then enters the gas-filled hollow-core photonic crystal fiber resonator via the second coupler;

The pump light resonates in the gas-filled hollow-core photonic crystal fiber resonator, and the reverse first-order Stokes light is excited after the power reaches the first-order stimulated Brillouin scattering threshold;

The pump light and the first-order Stokes light are output from the gas-filled hollow-core photonic crystal fiber resonator, and after passing through the second coupler, the first-order Stokes light passes through the circulator and the The first coupler, part of the pump light passes through the third coupler, and the two beams are combined and then output to the signal processing system through the first coupler for signal processing and output signals; part of the pump light passes through the The output of the third coupler enters the FPGA module for processing, and is fed back to the phase modulator for stabilizing the frequency of the laser light source.

Further, the gas-filled hollow-core photonic crystal fiber resonator is coupled with the ordinary optical fiber through a space coupling and alignment device, and a sealed inflatable gas chamber and a gas valve are arranged on the space coupling and alignment device for coupling the air The core photonic crystal fiber is evacuated and filled with gas.

An active resonant fiber optic gyro is characterized in that it includes a laser light source, a circulator, a first coupler, a gas-filled hollow-core photonic crystal fiber resonator, a second coupler, a third coupler, an FPGA module, and a signal processing system and piezoelectric ceramics, where,

The gas-filled hollow-core photonic crystal fiber resonator is wound on the piezoelectric ceramic, and the piezoelectric ceramic is controlled by the feedback signal of the FPGA module to cause deformation, thereby fine-tuning the gas-filled hollow core The length of the photonic crystal fiber resonant cavity is used to maintain resonance;

The pump light emitted by the laser light source enters the circulator, and then enters the gas-filled hollow-core photonic crystal fiber resonator via the second coupler;

The pump light resonates in the gas-filled hollow-core photonic crystal fiber resonator, and the reverse first-order Stokes light is excited after the power reaches the first-order stimulated Brillouin scattering threshold;

The pumping light and the first-order Stokes light are output from the gas-filled hollow-core photonic crystal fiber resonator, and after passing through the second coupler, the first-order Stokes light passes through the circulator and the The first coupler, part of the pump light passes through the third coupler, and the two beams are combined and then output to the signal processing system through the first coupler for signal processing and output signals; part of the pump light passes through the The output of the third coupler enters the FPGA module for processing, and is fed back to the piezoelectric ceramic for fine-tuning the length of the gas-filled hollow-core photonic crystal fiber resonator to maintain resonance.

Further, the gas-filled hollow-core photonic crystal fiber resonator is coupled with the ordinary optical fiber through a space coupling alignment device, and an inflatable air chamber and a gas valve are arranged on the space coupling alignment device for the hollow-core photonic crystal fiber The crystal fiber is filled with gas after being evacuated.

Further, the first coupler is a diaphragm fiber coupler with a splitting ratio of 50/50, and the second coupler is 98/2, 99/1, 99.5/0.5, 97/3 or 96/4 The membrane-type optical fiber coupler, the third coupler is a 98/2, 99/1, 99.5/0.5, 97/3 or 96/4 membrane-type optical fiber coupler.

The beneficial effects of the present invention are:

1. Compared with the traditional active resonant fiber optic gyroscope, the present invention uses a gas-filled photonic crystal fiber resonator cavity to increase the gain coefficient and compensate for loss.

2. Compared with the traditional passive resonant fiber optic gyroscope, the present invention changes the resonant cavity into an active resonant cavity, which can improve the signal-to-noise ratio of the fiber optic gyroscope.

3. Solve the blocking problem in the traditional Brillouin fiber optic gyroscope.

4. The present invention adopts unidirectional pumping light, reduces the difficulty of implementation, and solves the problem of poor power stability caused by the difficulty of 100% equal sharing of the pumping light by the front coupler.

5. The active resonant fiber optic gyroscope proposed by the present invention has fewer components and a simple structure, which is conducive to realizing the miniaturization of the fiber optic gyroscope, and has strong feasibility and practicability.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the embodiments, and the features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings , the accompanying drawings are schematic and should not be construed as limiting the present invention in any way. For those skilled in the art, other drawings can be obtained according to these drawings without creative work. in:

Fig. 1 is a schematic structural diagram of an active resonant fiber optic gyro according to an embodiment of the present invention;

Fig. 2 is the schematic structural diagram of the active resonant fiber optic gyroscope of the second embodiment of the present invention;

Figure 3 shows the coupling mode of the optical fiber.

Explanation of reference numbers:

1-laser source, 2-phase modulator, 3-circulator, 4-first coupler, 5-gas-filled hollow-core photonic crystal fiber resonator, 6-second coupler, 7-third coupler, 8-FPGA module, 9-signal processing system, 10-space coupling alignment device, 11-piezoelectric ceramics, 12-inflatable air chamber.

Detailed ways

In order to understand the above-mentioned purpose, features and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described here. Therefore, the protection scope of the present invention is not limited by the specific details disclosed below. EXAMPLE LIMITATIONS.

In the traditional active resonant fiber optic gyro scheme, the resonant cavity is an ordinary optical fiber. This scheme is a gas-filled photonic crystal fiber. On the premise of ensuring the advantages of low magnetic sensitivity and radiation resistance of the photonic crystal fiber, its gain is improved. In order to add a coupler in front of the resonator, the pump light is divided into two counter-propagating beams to respectively stimulate the stimulated Brillouin scattering laser with the same frequency clockwise and counterclockwise, so there are poor laser output stability and blocking phenomenon. The invention adopts unidirectional pump light input to solve the problem of poor stability caused by uneven laser beam splitting, and uses reverse output high-order light for angular velocity sensitivity to solve the blocking effect in the traditional solution.

As shown in Figure 1, an active resonant fiber optic gyroscope includes a laser light source 1, a phase modulator 2, a circulator 3, a first coupler 4, a gas-filled hollow-core photonic crystal fiber resonator 5, and a second coupler 6. The third coupler 7, the FPGA module 8 and the signal processing system 9, wherein,

The pump light emitted by the laser light source 1 enters the circulator 3 after passing through the phase modulator 2 driven by the signal generator, and then enters the gas-filled hollow-core photonic crystal fiber resonator 5 through the second coupler 6;

The pump light resonates in the gas-filled hollow-core photonic crystal fiber resonator 5, and the reverse first-order Stokes light is excited after the power reaches the first-order stimulated Brillouin scattering threshold;

The pump light and the first-order Stokes light are output from the gas-filled hollow-core photonic crystal fiber resonator 5, and after passing through the second coupler 6, the first-order Stokes light passes through the circulator 3 and the first coupler 4 , part of the pump light passes through the third coupler 7, and after the two beams are combined, they are output through the first coupler 4 and enter the signal processing system 9 for signal processing and output signals; part of the pump light is output through the third coupler 7 and enters the FPGA module 8 processing, fed back to the phase modulator 2 for stabilizing the frequency of the laser light source 1.

The gas-filled hollow-core photonic crystal fiber resonator 5 is filled with gas in the hollow-core photonic crystal fiber to form a gas-filled hollow-core photonic crystal fiber resonator. The gas filled is CO ₂ /CH ₄ to generate gain gas.

The gas-filled hollow-core photonic crystal fiber resonator 5 is coupled with an ordinary optical fiber through a space coupling alignment device 10, and a sealed air-filled gas chamber 12 and a gas valve are arranged on the space coupling alignment device 10 for aligning the hollow-core photonic crystal The fiber is filled with gas after being evacuated.

The first coupler 3 is a patch fiber coupler with a splitting ratio of 50/50, and the second coupler 6 is a patch fiber of 98/2, 99/1, 99.5/0.5, 97/3 or 96/4 As for the coupler, the third coupler 7 is a 98/2, 99/1, 99.5/0.5, 97/3 or 96/4 membrane fiber coupler.

Taking the second coupler 6 as a 98/2 diaphragm type fiber coupler and the third coupler 7 as a 99/1 diaphragm type fiber coupler as an example, the light transmission process in FIG. 1 of the present invention is described.

The pumping light is emitted by the laser 1, passes through the phase modulator 2 and the circulator 3, and then reaches the second coupler 6, where 98% of the pumping light is coupled into the gas-filled hollow-core photonic crystal fiber resonator 5, and is excited in the cavity Reverse first-order stimulated Brillouin scattered laser light, after a cycle, 2% of the pump light and 2% of the first-order stimulated Brillouin scattered laser light in the fiber resonator 5 exit through the second coupler 6, and 98% of the pump light The pump light and 98% of the first-order stimulated Brillouin scattered laser light continue to circulate in the gas-filled hollow-core photonic crystal fiber resonator 5 sensitive to angular velocity. The outgoing first-order stimulated Brillouin scattered laser light passes through the circulator 3 and reaches the first coupler 4; when the outgoing pump light passes through the third coupler 7, 1% of the pump light reaches the FPGA module 8 for frequency stabilization, 99 % of the pump light reaches the first coupler 4. After the two beams of light are merged, they are sent to the signal processing system 8 for signal detection to obtain an angular velocity output.

As shown in Figure 2, an active resonant fiber optic gyroscope includes a laser light source 1, a circulator 3, a first coupler 4, a gas-filled hollow-core photonic crystal fiber resonator 5, a second coupler 6, a third coupling device 7, FPGA module 8, signal processing system 9 and piezoelectric ceramics 11, wherein,

The gas-filled hollow-core photonic crystal fiber resonator 5 is wound on the piezoelectric ceramic 10, and the piezoelectric ceramic 11 is controlled by the feedback signal of the FPGA module 8 to cause deformation, thereby fine-tuning the gas-filled hollow-core photonic crystal fiber resonator 5 length, to maintain the resonance effect;

The pump light emitted by the laser light source 1 enters the circulator 3, and then enters the gas-filled hollow-core photonic crystal fiber resonator 5 via the second coupler 6;

The pump light resonates in the gas-filled hollow-core photonic crystal fiber resonator 5, and the reverse first-order Stokes light is excited after the power reaches the first-order stimulated Brillouin scattering threshold;

The pump light and the first-order Stokes light are output from the fiber resonator 5, and after passing through the second coupler 6, the first-order Stokes light passes through the circulator 3 and the first coupler 4, and part of the pump light passes through the second coupler 6. Three couplers 7, after the two beams of light are combined, output through the first coupler 4 and enter the signal processing system 9 for signal processing and output signals; part of the pump light is output through the third coupler 7 and enters the FPGA module 8 for processing, and is fed back to the piezoelectric The ceramic 11 is used to stabilize the frequency of the laser light source 1 .

Preferably, the fiber resonator 5 is a doped medium or an undoped ordinary fiber, and the fibers are coupled by fusion splicing.

The gas-filled hollow-core photonic crystal fiber resonator 5 is filled with gas in the hollow-core photonic crystal fiber to form a gas-filled hollow-core photonic crystal fiber resonator. The gas filled is CO ₂ /CH ₄ to generate gain gas.

The gas-filled hollow-core photonic crystal fiber resonant cavity 5 is coupled with the ordinary optical fiber through a space coupling alignment device 10, and an inflatable air chamber 12 and a gas valve are arranged on the space coupling alignment device 10 for pumping the hollow-core photonic crystal fiber Filled with gas after vacuum.

The first coupler 3 is a patch fiber coupler with a splitting ratio of 50/50, and the second coupler 6 is a patch fiber of 98/2, 99/1, 99.5/0.5, 97/3 or 96/4 As for the coupler, the third coupler 7 is a 98/2, 99/1, 99.5/0.5, 97/3 or 96/4 membrane fiber coupler.

In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection , or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In the present invention, unless otherwise clearly specified and limited, a first feature being "on" or "under" a second feature may include direct contact between the first and second features, and may also include the first and second features Not in direct contact but through another characteristic contact between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "under" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

In the present invention, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance. The term "plurality" means two or more, unless otherwise clearly defined.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (3)

1. An active resonant fiber optic gyroscope, characterized in that, comprises a laser light source (1), a phase modulator (2), a circulator (3), a first coupler (4), a gas-filled hollow-core photonic crystal fiber Resonant cavity (5), second coupler (6), third coupler (7), FPGA module (8) and signal processing system (9), wherein, The pump light emitted by the laser light source (1) enters the circulator (3) after passing through the phase modulator (2) driven by a signal generator, and then enters the In a gas-filled hollow-core photonic crystal fiber resonator (5); The pump light resonates in the gas-filled hollow-core photonic crystal fiber resonator (5), and the reverse first-order Stokes light is excited after the power reaches the first-order stimulated Brillouin scattering threshold; The pumping light and the first-order Stokes light are output from the gas-filled hollow-core photonic crystal fiber resonator (5), and after passing through the second coupler (6), the first-order Stokes light passes through the The circulator (3) and the first coupler (4), part of the pump light passes through the third coupler (7), and the two beams are combined and then output through the first coupler (4) and enter the The signal processing system (9) performs signal processing and outputs a signal; part of the pumping light enters the FPGA module (8) through the output of the third coupler (7) for processing, and feeds back to the phase modulator (2) Used to stabilize the frequency of the laser light source (1); The gas-filled hollow-core photonic crystal fiber resonator (5) is coupled with an ordinary optical fiber through a space coupling alignment device (10), and a sealed gas-filled air chamber (12) is arranged on the space coupling alignment device (10). ) and a gas valve, which are used to vacuumize the hollow-core photonic crystal fiber and fill it with gas. 2. An active resonant fiber optic gyroscope is characterized in that it comprises a laser light source (1), a circulator (3), the first coupler (4), a gas-filled hollow-core photonic crystal fiber resonator (5), the first Second coupler (6), third coupler (7), FPGA module (8), signal processing system (9) and piezoelectric ceramics (11), wherein, The gas-filled hollow-core photonic crystal fiber resonator (5) is wound on the piezoelectric ceramic (11), and the piezoelectric ceramic (11) is controlled by the feedback signal of the FPGA module (8), so that it Generating deformation, and then fine-tuning the length of the hollow-core photonic crystal fiber resonator (5) filled with the gas, so as to maintain the resonance effect; The pump light emitted by the laser light source (1) enters the circulator (3), and then enters the gas-filled hollow-core photonic crystal fiber resonator (5) via the second coupler (6); The pump light resonates in the gas-filled hollow-core photonic crystal fiber resonator (5), and the reverse first-order Stokes light is excited after the power reaches the first-order stimulated Brillouin scattering threshold; Pumping light and first-order Stokes light are output from the gas-filled hollow-core photonic crystal fiber resonator (5), and after passing through the second coupler (6), the first-order Stokes light passes through the The circulator (3) and the first coupler (4), part of the pump light passes through the third coupler (7), and the two beams are combined and then output through the first coupler (4) and enter the The signal processing system (9) performs signal processing and outputs a signal; part of the pump light is output into the FPGA module (8) through the third coupler (7) for processing, and fed back to the piezoelectric ceramic (11) It is used to fine-tune the length of the gas-filled hollow-core photonic crystal fiber resonator (5) to maintain resonance; The gas-filled hollow-core photonic crystal fiber resonator (5) is coupled with an ordinary optical fiber through a space coupling alignment device (10), and an air-filled air chamber (12) and The gas valve is used to vacuumize the hollow-core photonic crystal fiber and fill it with gas. 3. The active resonant fiber optic gyroscope according to claim 1 or 2, characterized in that, the first coupler (3) is a diaphragm fiber coupler with a splitting ratio of 50/50, and the second coupling The device (6) is a diaphragm type optical fiber coupler of 98/2, 99/1, 99.5/0.5, 97/3 or 96/4, and the third coupler (7) is 98/2, 99/1, 99.5/0.5, 97/3 or 96/4 membrane fiber optic coupler.

Images