Wide-spectrum light source driven echo wall optical microcavity multimode common detection resonant optical gyroscope

Abstract

The invention discloses an echo wall optical microcavity multimode common detection resonant optical gyroscope driven by a wide-spectrum light source, and belongs to the field of gyroscope light path system design. The whole system is composed of an optical system and a signal detection system, and the optical system comprises a wide-spectrum light source, a push-pull Y waveguide, a circulator, a transmission-type multimode transmission echo wall optical microcavity and a photoelectric detector; the signal detection system comprises a modulation-demodulation module and a low-pass filtering module. According to the invention, the echo wall optical microcavity is connected with the broadband light source by adopting a symmetrical connection method, the multimode transmission characteristic of the echo wall optical microcavity is utilized, and a multimode common detection mechanism is utilized, so that the detection light power is greatly improved, the problem that the detection light power is reduced due to the increase of the quality factor of a single-mode resonant cavity is solved, and the detection precision of the system is improved.

Description

Technical Field

[0001] The invention belongs to the field of gyroscope optical path system design, and in particular relates to a whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope driven by a wide-spectrum light source. Background Art

[0002] The resonant optical gyroscope based on the Sagnac effect uses a high-quality resonant cavity to enhance the Sagnac effect, which can achieve higher precision with a smaller volume and has unique advantages in miniaturization. However, the traditional classical resonant optical gyroscope uses a narrow linewidth laser as the driving light source, which makes the actual precision of the gyroscope seriously restricted by the noise related to the coherence of the light source. The resonant optical gyroscope driven by a wide-spectrum light source proposed in recent years uses a low-coherence wide-spectrum light source, which can greatly reduce the noise related to the coherence of the light source from the source. However, under the drive of the wide-spectrum light source, the high-quality factor resonant cavity is used as a filter. The higher the quality factor, the weaker the light power passing through the resonant cavity. Even if the resonant optical gyroscope with a high-quality factor resonant cavity as the angular velocity sensitive unit is used, the actual detection power is greatly reduced, which directly affects the signal-to-noise ratio of this gyroscope detection system, making the high-precision gyroscope put forward extremely demanding requirements on the detection capability of the detection system. The high-quality factor resonant cavity is the premise for the resonant optical gyroscope to obtain high sensitivity. Therefore, using a wide-spectrum light source as the driving light source urgently needs to solve the contradiction between the gyroscope sensitivity and the signal-to-noise ratio of the detection system. Summary of the invention

[0003] The invention proposes a whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope driven by a wide-spectrum light source.

[0004] The technical solution adopted by the present invention is as follows:

[0005] In the first aspect, the present invention discloses a wide-spectrum light source driven whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope, comprising an optical system and a signal detection system, wherein the optical system comprises a wide-spectrum light source, a push-pull Y-waveguide, a circulator, a transmission-type multi-mode transmission whispering gallery optical microcavity and a photodetector, and the signal detection system comprises a modulation and demodulation module and a low-pass filtering module;

[0006] A wide-spectrum light source, a circulator and a push-pull Y-waveguide are connected in sequence, two output ports of the push-pull Y-waveguide are connected to a pair of transmission ports of a whispering gallery optical microcavity, and the circulator is also connected to a photodetector;

[0007] The photodetector is connected to the modulation and demodulation module, which generates a modulation signal and outputs it to the push-pull Y-waveguide. The modulation and demodulation module demodulates the output of the photodetector and outputs the demodulation signal to the push-pull Y-waveguide and the low-pass filter module. The demodulation signal passes through the low-pass filter module and is output to an external data recorder as the gyro output of the gyroscope.

[0008] In a second aspect, the present invention discloses a method for detecting a whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope of the gyroscope, comprising the following steps:

[0009] The broadband light source outputs broadband light to the first port of the circulator, and the broadband light is then output to the push-pull Y waveguide through the second port of the circulator. The push-pull Y waveguide divides the broadband light into two paths of light and couples them into the interior of the whispering gallery optical microcavity through a pair of transmission ports, respectively. The two paths of light are transmitted in the whispering gallery optical microcavity in multiple optical modes, and then the two paths of light transmitted through each optical mode are respectively coupled to the corresponding transmission ports in the whispering gallery optical microcavity. The two paths of light after multi-mode transmission are respectively output to the push-pull Y waveguide through the corresponding transmission ports. The push-pull Y waveguide combines the two received paths of light into one beam of light, and outputs the combined beam of light to the photodetector through the circulator for photoelectric conversion, and the photodetector outputs an electrical signal to the modulation and demodulation module;

[0010] The modulation and demodulation module demodulates the electrical signal output by the photodetector to obtain a demodulated signal, and outputs the demodulated signal to the low-pass filtering module; the modulation and demodulation module generates a modulation signal and outputs it to the push-pull Y waveguide, and the push-pull Y waveguide performs phase modulation on the light passing through it according to the modulation signal; the low-pass filtering module performs low-pass filtering on the demodulated signal, and the filtered demodulated signal is output to an external data recorder as the gyroscope output of the gyroscope.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] The present invention uses a transmission-type whispering gallery optical microcavity that supports multi-mode transmission to greatly improve the power utilization rate of the wide-spectrum light source, increase the detection light power at the transmission end of the microcavity, and ultimately improve the signal-to-noise ratio of the detection system of the resonant optical gyroscope, which is beneficial to improving the actual detection accuracy of the gyroscope.

[0013] The present invention uses a whispering gallery optical microcavity with transmissive multimode transmission to solve the problem that a single-mode resonant cavity cannot be used due to too low transmittance, thereby improving the signal-to-noise ratio of the detection system.

[0014] The present invention utilizes a wide-spectrum light source to effectively reduce optical parasitic effects in the system, thereby greatly improving the stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1It is a schematic diagram of the structure of a whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope driven by a wide-spectrum light source;

[0016] Figure 2 It is a schematic diagram of a specific implementation case of a whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope driven by a wide-spectrum light source;

[0017] Figure 3 is the transmission spectrum of the whispering gallery optical microcavity supporting multimode transmission;

[0018] Figure 4 is the transmission spectrum of an ordinary single-mode resonant cavity.

[0019] In the figure: 1. Broad-spectrum light source; 2. circulator; 3. push-pull Y-waveguide; 4. photodetector; 5. whispering gallery optical microcavity; 6. modulation and demodulation module; 7. low-pass filter module; 8. data recorder. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0022] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0023] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0025] The purpose of the present invention is to provide a resonant optical gyroscope for multi-mode co-detection of a whispering gallery optical microcavity driven by a wide-spectrum light source, using a whispering gallery optical microcavity with a high quality factor and supporting multi-mode transmission as an angular velocity sensitive unit. The high quality factor of the microcavity ensures that the resonant optical gyroscope has high sensitivity, and the characteristic of supporting multi-mode transmission is conducive to improving the output light power at the transmission end of the microcavity.

[0026] According to different fiber coupling methods, whispering gallery optical microcavities can be divided into two basic structural types: reflective structures based on single-sided fiber coupling and transmissive structures based on double-sided fiber coupling. In this field, the design structure usually adopted is a reflective structure whispering gallery optical microcavity based on single-sided fiber coupling. This is mainly because compared with the transmissive structure whispering gallery optical microcavity, the reflective structure whispering gallery optical microcavity has only one coupling zone, so it can achieve a higher Q (quality factor) value and have a higher response sensitivity. Reflective whispering gallery optical microcavities have a wide range of applications in the research fields of theoretical physics and nonlinear optics, such as the preparation of single photons and entangled light sources or quantum optical frequency conversion by means of the strong interaction between light and matter in the microcavity; and the optical frequency comb generated by the nonlinear effect inside the microcavity plays an important role in the field of time measurement and optical fiber communication. Transmissive structure whispering gallery mode microcavities can also be used to generate optical frequency combs, and are also used in the fields of biological and chemical sensing and as high-precision optical filters in the field of optical communication. In the above applications, both the reflective structure of the whispering gallery optical microcavity and the transmissive structure of the whispering gallery optical microcavity generally realize their basic functions based on one or several specific eigenmodes in the cavity. In the present invention, all the excited modes in the whispering gallery optical microcavity are utilized, and the microcavity transmissive structure is also utilized to improve the comprehensive signal-to-noise ratio of the system.

[0027] like Figure 1As shown, the present invention provides a wide-spectrum light source driven whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope, which includes an optical system consisting of a wide-spectrum light source, a push-pull Y-waveguide, a circulator, a transmission-type multi-mode transmission whispering gallery optical microcavity (transmission-type whispering gallery optical microcavity) and a photodetector, and a signal detection system consisting of a modulation and demodulation module and a low-pass filtering module.

[0028] The output end of the wide-spectrum light source is connected to the first port of the circulator; the second port of the circulator is connected to the input port of the push-pull Y branch; the two output ports of the push-pull Y waveguide are connected to a pair of transmission ports of the transmissive multimode transmission whispering gallery optical microcavity, and the other pair of transmission ports of the transmissive multimode transmission whispering gallery optical microcavity is vacant; the third port of the circulator is connected to the photodetector. The output signal of the photodetector enters the signal detection system, is processed by the modulation and demodulation module and the low-pass filter module, and is finally input to the external data recorder; the modulation and demodulation module is also connected to the push-pull Y waveguide.

[0029] The higher the quality factor, the lower the light transmittance of the single-mode transmission resonant cavity. Too low a light transmittance makes it impractical. Transmission-type whispering gallery optical microcavities often allow multiple modes to propagate, and each propagation mode is equivalent to a single-mode resonant cavity with a high quality factor. The optical power received by the photoelectric detection location is the sum of the optical powers transmitted by each mode, such as Figure 3 and Figure 4 As shown in the figure, the transmission power of the whispering gallery optical microcavity is much greater than that of the single-mode resonant cavity. Therefore, the use of the whispering gallery optical microcavity enables the microcavity with a high quality factor to be applied to the resonant optical gyroscope driven by a wide-spectrum light source, greatly improving the detection light power. In addition, the whispering gallery optical microcavity can achieve up to 10 8 The above quality factors further improve the detection sensitivity of the resonant optical gyroscope.

[0030] In the present invention, the structure of the transmissive multimode transmission whispering gallery optical microcavity is a double-side coupled microcavity, and the processing method of the whispering gallery optical microcavity is micro-nano processing, and the specific process includes dry etching and wet etching.

[0031] The high-quality factor whispering gallery optical microcavity in this scheme is a transmissive structure, and adopts a transmissive symmetrical connection method in which the clockwise and counterclockwise optical signals share the same input and output ports, which is extremely beneficial to improving the signal-to-noise ratio of the gyroscope output.

[0032] like Figure 2 As shown, it is a schematic diagram of a specific implementation case of a whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope driven by a wide-spectrum light source.

[0033] The present invention also discloses a method for detecting a whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope of the gyroscope, comprising the following steps:

[0034] The broadband light source 1 outputs broadband light to the first port of the circulator, and the broadband light is then output to the push-pull Y waveguide 3 through the second port of the circulator 2. The push-pull Y waveguide 3 divides the broadband light into two paths of light and couples them into the interior of the whispering gallery optical microcavity 5 through a pair of transmission ports, respectively. The two paths of light are transmitted in the whispering gallery optical microcavity 5 in multiple optical modes, and then the two paths of light transmitted through each optical mode are respectively coupled to the corresponding transmission ports in the whispering gallery optical microcavity 5. The two paths of light after multi-mode transmission are respectively output to the push-pull Y waveguide 3 through the corresponding transmission ports. The push-pull Y waveguide 3 combines the two received paths of light into one beam of light, and outputs the combined beam of light to the photodetector 4 through the circulator 2. The photodetector 4 performs photoelectric conversion on the received light and outputs an electrical signal to the modulation and demodulation module 6;

[0035] The modulation and demodulation module 6 generates a modulation signal and outputs it to the push-pull Y waveguide 3. The push-pull Y waveguide 3 performs phase modulation on the light passing through it according to the modulation signal. The modulation and demodulation module 6 demodulates the electrical signal output by the photodetector 4 to obtain a demodulation signal, and outputs the demodulation signal to the low-pass filter module 7. The low-pass filter module 7 performs low-pass filtering on the demodulation signal. The filtered demodulation signal is output to an external data recorder as the gyroscope output of the gyroscope.

[0036] In a specific embodiment, the present invention uses a mode number of 67 and a Q value of 2×10 8 The wide-spectrum light source emits a wide-spectrum light with a power of 20 mW. After a series of transmissions of the wide-spectrum light in the whispering gallery optical microcavity of the present invention, the power of the light received by the photodetector is about 10 μW, and the data recorder measures the gyro random walk to be 0.8° / h. 1 / 2 ; Then, a single-mode resonant cavity with the same Q value is used to replace the whispering gallery optical microcavity of the transmission-type multimode transmission of the present invention. The broadband light source also emits broadband light of the same power. After a series of transmissions of the broadband light in the single-mode cavity, it is tested that the light received by the photodetector is less than 0.15 μW. Because the light power at this time is too small, the gyroscope signal is submerged in the noise and cannot be detected. Therefore, the use of the whispering gallery optical microcavity of the transmission-type multimode transmission of the present invention greatly improves the power utilization rate of the broadband light source, increases the detection light power at the transmission end of the microcavity, and ultimately improves the signal-to-noise ratio of the detection system of the resonant optical gyroscope, which is beneficial to improving the actual detection accuracy of the gyroscope. It also solves the problem that the single-mode resonant cavity cannot be used due to too low transmittance, thereby improving the signal-to-noise ratio of the detection system.

[0037] The above-mentioned embodiments only express several implementation modes of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. For those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope driven by a wide-spectrum light source, characterized in that: The invention comprises an optical system and a signal detection system. The optical system comprises a wide-spectrum light source, a push-pull Y-waveguide, a circulator, a transmission-type multi-mode transmission whispering gallery optical microcavity and a photodetector. The signal detection system consists of a modulation and demodulation module and a low-pass filter module. The wide-spectrum light source, the circulator and the push-pull Y-waveguide are connected in sequence. Two output ports of the push-pull Y-waveguide are connected to a pair of transmission ports of the whispering gallery optical microcavity. The circulator is also connected to the photodetector. The photodetector is connected to a modulation and demodulation module, which generates a modulation signal and outputs it to a push-pull Y-waveguide. The modulation and demodulation module demodulates the output of the photodetector and outputs the demodulation signal to a low-pass filter module. The demodulation signal passes through the low-pass filter module and is output to an external data recorder as a gyro output of the gyroscope.

2. The whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope driven by a wide-spectrum light source according to claim 1, characterized in that: The broadband light source is connected to a first port of the circulator, a second port of the circulator is connected to an input end of a push-pull Y-waveguide, and a third port of the circulator is connected to an input end of a photodetector.

3. The whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope driven by a wide-spectrum light source according to claim 1, characterized in that: The whispering gallery optical microcavity adopts a transmission-type symmetrical connection method in which the optical signals in the clockwise and counterclockwise directions share the input and output ports.

4. A method for detecting a whispering gallery optical microcavity multi-mode co-detection resonant optical gyroscope based on the gyroscope of claim 1, characterized in that: The following steps are involved: The broadband light source outputs broadband light to the first port of the circulator, and the broadband light is then output to the push-pull Y waveguide through the second port of the circulator. The push-pull Y waveguide divides the broadband light into two paths of light and couples them into the interior of the whispering gallery optical microcavity through a pair of transmission ports, respectively. Both paths of light are transmitted in the whispering gallery optical microcavity in multiple optical modes, and then the two paths of light transmitted through each optical mode are respectively coupled to the corresponding transmission ports in the whispering gallery optical microcavity. The two paths of light after multi-mode transmission are respectively output to the push-pull Y waveguide through the corresponding transmission ports. The push-pull Y waveguide combines the two received paths of light into one beam of light, and outputs the combined beam of light to the photodetector through the circulator for photoelectric conversion, and the photodetector outputs an electrical signal to the modulation and demodulation module; The modulation and demodulation module demodulates the electrical signal output by the photodetector to obtain a demodulated signal, and outputs the demodulated signal to the low-pass filtering module; the modulation and demodulation module generates a modulation signal and outputs it to the push-pull Y waveguide, and the push-pull Y waveguide performs phase modulation on the light passing through it according to the modulation signal; the low-pass filtering module performs low-pass filtering on the demodulated signal, and the filtered demodulated signal is output to an external data recorder as the gyroscope output of the gyroscope.

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