Zero-bias stability optimization device and optimization method for interference type optical fiber gyroscope based on optical switch modulation

Abstract

The invention discloses a device and a method for optimizing zero-bias stability of an interference type optical fiber gyroscope based on optical switch modulation. The device comprises an amplified spontaneous emission light source, an optical fiber circulator, a Y waveguide phase modulator, a 2 * 2 type optical switch and an optical fiber ring which are sequentially arranged along an optical path, the optical fiber circulator is also connected with a photoelectric detector; and the photoelectric detector is connected with a data acquisition card. According to the invention, optical paths are periodically switched through the optical switch, so that optical signals are propagated in a complementary path in the optical fiber ring, and zero offset errors caused by nonreciprocal phase shift are dynamically counteracted. The device is simple in structure and convenient to operate, can effectively suppress common-mode noise, remarkably improves the output stability of the interference type optical fiber gyroscope in long-time operation, reduces zero-offset drift, and is suitable for the high-precision measurement fields of inertial navigation, aerospace and the like.

Description

Technical Field

[0001] This invention relates to the field of fiber optic gyroscope and optical measurement technology, and in particular to a zero-bias stability optimization device and method for an interferometric fiber optic gyroscope based on optical switch modulation. Background Technology

[0002] Interferometric fiber optic gyroscopes (IFOGs) are high-precision angular velocity measurement devices based on the Sagnac effect. They offer advantages such as no moving parts, high sensitivity, and high reliability, and are widely used in aerospace, marine navigation, and precision inertial measurement. However, during long-term operation, IFOGs are often affected by factors such as ambient temperature fluctuations, light source power drift, and fiber stress variations, leading to problems such as slowly varying zero-bias drift and scale factor instability in the system output, severely limiting their zero-bias stability and measurement accuracy. To suppress these slowly varying errors, existing technologies typically employ overmodulation methods, dual-frequency light source methods, or polarization control techniques. However, these methods often increase system complexity or introduce additional noise sources, making it difficult to achieve long-term stable operation while simplifying the structure. Especially in single-channel IFOG systems, zero-bias drift caused by environmental non-reciprocal effects is difficult to effectively cancel using traditional differential methods. Therefore, a stability optimization scheme with a simple structure and effective suppression of slowly varying errors is urgently needed. Summary of the Invention

[0003] This invention aims to solve the aforementioned technical problems by periodically switching between two optical path states using an optical switch, enabling light to propagate along a complementary path in the fiber optic ring, thereby canceling the zero-bias error caused by non-reciprocal phase shift. This device achieves dynamic common-mode noise suppression without altering the original optical path structure, significantly improving the system's long-term stability and environmental interference resistance.

[0004] To achieve the above objectives, this invention proposes a device for optimizing the zero-bias stability of an interferometric fiber optic gyroscope based on optical switch modulation, comprising: an amplified spontaneous emission source, a fiber optic circulator, a Y-waveguide phase modulator, a 2×2 type optical switch, and a fiber optic ring arranged sequentially along the optical path; wherein...

[0005] The amplified spontaneous emission light source is used to generate an optical signal with stable output power.

[0006] The fiber optic circulator is used to enable unidirectional transmission of optical signals in a fixed direction in the optical fiber, directing the input light from one port to a specific other port while isolating reverse optical signals; the fiber optic circulator is also connected to a photodetector, which is connected to a data acquisition card.

[0007] The Y-waveguide phase modulator is used to split an input beam into two output beams with a splitting ratio of 50:50 and a relative phase difference.

[0008] The 2×2 type optical switch is used to switch the optical signal between two different paths through external control, thereby controlling the transmission path of the optical signal;

[0009] The optical fiber loop is used to provide a closed propagation path for the optical signal, enabling it to form interference or achieve phase accumulation in the loop, thereby realizing the measurement or sensing of physical quantities; the optical signal emitted from the optical fiber loop is transmitted in reverse along the original path and enters the photodetector.

[0010] The photodetector is used to convert the interference optical signal returned from the fiber optic loop into an analog electrical signal and output it.

[0011] The data acquisition card, as a signal processing unit, is used to convert the analog electrical signals output by the photodetector into digital signals and transmit them to the computer for processing and analysis.

[0012] An interferometric fiber optic gyroscope system is constructed from the amplified spontaneous emission source, the fiber optic circulator, the Y-waveguide phase modulator, the 2×2 type optical switch, and the fiber optic ring. It achieves opposite interference signal outputs in two different switching states of the optical switch.

[0013] The photodetector and the data acquisition card complete the measurement and acquisition of interference signal data.

[0014] Preferably, the 2×2 optical switch is driven by an external TTL signal to achieve periodic switching between two different optical path states. The specific period value is determined by the performance of the optical switch device and the experimental environment: the optical switch needs to ensure a good depolarization ratio. When the switching time period of the optical switch is less than the noise change period in the experimental environment, some environmental noise can be suppressed by time difference detection. The specific switching time period is based on the optimal zero-bias stability of the gyroscope.

[0015] Preferably, the Y-waveguide phase modulator is provided with a modulation signal by an arbitrary waveform signal generator, so that the system operates at the optimal phase point ±π / 2.

[0016] Based on the above device, this invention proposes a method for optimizing the zero-bias stability of an interferometric fiber optic gyroscope based on optical switch modulation. This method differentially cancels common-mode noise by analyzing the opposite response signals of the interferometric fiber optic gyroscope under the two switching states of the optical switch, thereby optimizing the zero-bias stability of the interferometric fiber optic gyroscope system. The specific steps include the following:

[0017] Step 1: Build and utilize an amplified spontaneous emission light source, and adjust the parameters to obtain a laser with stable output power.

[0018] Step 2: Using fiber optic flanges, connect the output laser sequentially to the fiber optic circulator, Y-waveguide phase modulator, 2×2 optical switch, fiber optic ring, and photodetector to complete the optical path setup.

[0019] Step 3: Use an arbitrary waveform signal generator to provide a modulation signal for the Y-waveguide phase modulator, so that the two output optical signals have a relative phase difference, ensuring that the interferometric fiber optic gyroscope system operates at the optimal phase point ±π / 2.

[0020] Step 4: Use an arbitrary waveform signal generator to provide a drive TTL signal for the 2×2 optical switch, so that it cycles between two different paths, changing the transmission path of the optical signal within the corresponding period.

[0021] Step 5: Connect the output of the photodetector to the input of the data acquisition card to convert the analog signal into a digital signal, and then connect it to the computer host for data processing and analysis.

[0022] Step 6: Differential processing is performed on the data from the two path states of the 2×2 optical switch to eliminate common-mode noise, thereby optimizing the zero-bias stability of the interferometric fiber optic gyroscope system.

[0023] Steps one and two are used to build the optical path of the interferometric fiber optic gyroscope device.

[0024] Steps three and four are used to realize the optical interference phenomenon and to prepare the switching state of the two different paths of the optical switch.

[0025] Steps five and six are used to acquire system data and process output signals to improve system zero-bias stability.

[0026] The device for optimizing the zero-bias stability of an interferometric fiber optic gyroscope based on optical switch modulation provided by this invention has a simple structure and is easy to operate. On the other hand, it reduces the common-mode noise of the interferometric fiber optic gyroscope system, which can improve the output stability of the system over a long period of time and reduce zero-bias drift. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the device for optimizing the zero-bias stability of an interferometric fiber optic gyroscope based on optical switch modulation, according to the present invention.

[0029] Figure 2This is a schematic diagram of two different path states of the 2×2 type optical switch of the present invention. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the specific embodiments and accompanying drawings. Except for the contents specifically mentioned below, the processes, conditions, and experimental methods for implementing the present invention are all common knowledge and general knowledge in the art, and the present invention does not have any particular limitations.

[0031] Figure 1 In the diagram, 1-Amplified spontaneous emission source, 2-Fiber optic circulator, 3-Y-waveguide phase modulator, 4-2×2 type optical switch, 5-Fiber optic ring, 6-Photodetector, 7-Data acquisition card.

[0032] This invention provides a zero-bias stability optimization device for an interferometric fiber optic gyroscope based on optical switch modulation. It consists of an amplified spontaneous emission light source 1, a fiber optic circulator 2, a Y-waveguide phase modulator 3, a 2×2 type optical switch 4, a fiber optic ring 5, a photodetector 6, and a data acquisition card 7. All optical components are connected via fiber optic flanges.

[0033] In implementation, all optical components are first placed on an optical experimental platform to reduce vibration and interference, achieving a highly stable effect. The amplified spontaneous emission source 1 provides a laser source with stable output power, and its output center wavelength is 1550 nm. The output fiber of the amplified spontaneous emission source 1 is connected to the fiber input port of the fiber optic circulator 2 via a fiber optic flange. Based on the unidirectional transmission principle, one of the output fiber ends of the fiber optic circulator 2 is connected to the input fiber end of the Y-waveguide phase modulator 3. Based on this, the optical signal is transmitted unidirectionally to the Y-waveguide phase modulator 3, which is driven by an arbitrary waveform signal generator. The output square wave is used for phase modulation to generate two optical signals with a fixed phase difference. The voltage amplitude of the modulated square wave is set to the half-wave voltage value of the Y-waveguide phase modulator 3, and the frequency of the modulated square wave... Satisfying the relation ,in The speed at which light travels in a vacuum; is the refractive index of the optical fiber medium; The total length of fiber optic ring 5 is given. After setting the parameters, the two output fiber ends of the Y-waveguide phase modulator 3 are connected to the two input fiber ends of the 2×2 optical switch 4. The 2×2 optical switch 4 receives a TTL signal with a high level of +5V and a low level of 0V output from an arbitrary waveform signal generator. A suitable TTL signal frequency is selected to enable the 2×2 optical switch 4 to periodically switch optical paths. Based on this, the two output fiber ends of the 2×2 optical switch 4 are connected to the two fiber ports of the fiber optic ring 5, allowing the two output optical signals of the 2×2 optical switch 4 to propagate along different clockwise and counterclockwise paths in the fiber optic ring 5, forming interference and achieving phase accumulation, which is then used for angular velocity measurement. The optical signal returning from the original path is converted into an electrical signal by the photodetector 6. A program is designed using LabVIEW software to communicate with the data acquisition card 7 and save the acquired signals to the computer. By differentially processing the output data of the 2×2 optical switch 4 in both states, common-mode noise can be effectively eliminated, thereby improving the zero-bias stability and measurement accuracy of the system.

[0034] The amplified spontaneous emission light source 1 is used to generate an optical signal with stable output power.

[0035] The fiber optic circulator 2 is used to realize the unidirectional transmission of optical signals in a fixed direction in the optical fiber, directing the input light from one port to a specific other port, while isolating the reverse optical signal.

[0036] The Y-waveguide phase modulator 3 is used to split an input beam into two output beams with a splitting ratio of 50:50 and a relative phase difference.

[0037] The 2×2 type optical switch 4 is used to switch the optical signal between two different paths through external control, thereby controlling the transmission path of the optical signal.

[0038] The fiber optic loop 5 is used to provide a closed propagation path for optical signals, enabling them to form interference or achieve phase accumulation in the loop, thereby realizing physical quantity measurement or sensing.

[0039] The photodetector 6 is used to convert the input optical signal into an analog electrical signal and output it.

[0040] The data acquisition card 7 is used to convert the analog electrical signal output by the photodetector into a digital signal and transmit it to the computer for processing and analysis.

[0041] This invention provides a zero-bias stability optimization device for interferometric fiber optic gyroscopes based on optical switch modulation. The entire system has a simple structure and is easy to operate, and can maintain the stability of the system output over a long period of time. It provides a new approach to optimizing the zero-bias stability of interferometric fiber optic gyroscope systems, making them better applicable to inertial navigation systems.

[0042] This invention uses an optical switch to periodically switch the optical path, enabling the optical signal to propagate along complementary paths within the fiber optic ring, dynamically canceling out the zero-bias error caused by non-reciprocal phase shift. The device has a simple structure, is easy to operate, effectively suppresses common-mode noise, significantly improves the output stability of interferometric fiber optic gyroscopes during long-term operation, and reduces zero-bias drift. It is suitable for high-precision measurement fields such as inertial navigation and aerospace.

[0043] The specific embodiments of the present invention have been described in detail above, but they are merely examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of the present invention should be covered within the scope of the present invention.

[0044] The scope of protection of this invention is not limited to the above embodiments. Any variations and advantages that can be conceived by those skilled in the art without departing from the spirit and scope of this invention are included in this invention and are protected by the appended claims.

Claims

1. A zero-bias stability optimization device for an interferometric fiber optic gyroscope based on optical switch modulation, characterized in that, The device comprises: an amplified spontaneous emission source (1), an optical fiber circulator (2), a Y-waveguide phase modulator (3), an optical switch (4), and an optical fiber ring (5) arranged sequentially along the optical path; wherein... The amplified spontaneous emission light source (1) is used to generate an optical signal with stable output power. The fiber optic circulator (2) is used to realize the unidirectional transmission of optical signals in a fixed direction in the optical fiber, directing the input light from one port to a specific other port, while isolating the reverse optical signal; the fiber optic circulator (2) is also connected to a photodetector (6), which is connected to a data acquisition card (7). The Y-waveguide phase modulator (3) is used to split an input beam into two output beams with a splitting ratio of 50:50 and a relative phase difference. The optical switch (4) is optically connected to the Y-waveguide phase modulator and is used to respond to external driving signals. It is used to switch the optical signal between two different paths through external control, thereby controlling the transmission path of the optical signal. The optical fiber loop (5) is used to provide a closed propagation path for the optical signal, so that it can form interference or achieve phase accumulation in the loop, and realize physical quantity measurement or sensing; the optical signal emitted from the optical fiber loop (5) is transmitted in reverse along the original path and enters the photodetector (6). The photodetector (6) is used to receive the interference optical signal returned from the fiber optic loop (5) and convert it into an analog electrical signal and output it. The data acquisition card (7) is used to acquire and process the analog electrical signal, and to suppress common-mode noise by performing differential processing on the signals acquired under different switching states of the optical switch.

2. The apparatus according to claim 1, characterized in that, The optical switch (4) is a 2×2 type optical switch.

3. The apparatus according to claim 2, characterized in that, The 2×2 type optical switch achieves periodic switching between two different optical path states through external TTL signal driving.

4. The apparatus according to claim 1, characterized in that, The Y-waveguide phase modulator (3) is provided with a modulation signal by an arbitrary waveform signal generator, so that the system operates at the optimal phase point ±π / 2.

5. A method for optimizing the zero-bias stability of an interferometric fiber optic gyroscope based on optical switch modulation, characterized in that, Includes the following steps: Step 1: Build and utilize an amplified spontaneous emission source (1), and adjust the parameters to obtain a laser with stable output power; Step 2: Connect the output laser to the fiber optic circulator (2), Y-waveguide phase modulator (3), 2×2 type optical switch (4), fiber optic ring (5) and photodetector (6) via fiber optic flange to complete the optical path construction; Step 3: Use an arbitrary waveform signal generator to provide a modulation signal for the Y-waveguide phase modulator, so that the two output optical signals have a relative phase difference, ensuring that the interferometric fiber optic gyroscope system works at the optimal phase point; Step 4: Use an arbitrary waveform signal generator to provide a drive TTL signal for the 2×2 type optical switch (4), so that it cycles between two different paths and changes the transmission path of the optical signal within the corresponding period; Step 5: Connect the output of the photodetector (6) to the input of the data acquisition card (7) to convert the analog signal of photoelectric conversion into a digital signal and connect it to the computer host for data processing and analysis; Step 6: Differential processing is performed on the data of the two path states of the 2×2 type optical switch (4) to eliminate common mode noise and thus optimize the zero bias stability of the interferometric fiber optic gyroscope system.

6. The method according to claim 5, characterized in that, The optimal phase point is at ±π / 2.

7. The method according to claim 5, characterized in that, The voltage amplitude of the modulated square wave is set to the half-wave voltage value of the Y-waveguide phase modulator 3, and the frequency of the modulated square wave is... Satisfying the relation: ， in, The speed at which light travels in a vacuum; is the refractive index of the optical fiber medium; is the total length of the fiber optic ring (5).

8. The method according to claim 5, characterized in that, The device described in any one of claims 1-4 is an interferometric fiber optic gyroscope zero-bias stability optimization device.

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