Optical integrated device for multi-axis optical fiber gyroscope and multi-axis optical fiber gyroscope

Abstract

The invention relates to an optical integrated device for a multi-axis optical fiber gyroscope and the multi-axis optical fiber gyroscope. The optical integrated device comprises a photoelectric detector, a first optical fiber and a second optical fiber, the optical switch structure is provided with an input port and N output ports, the ith output port in the N output ports is coupled with the ith optical fiber ring in the external N optical fiber rings, and an optical path between the input port and the ith output port is marked as the ith optical path; wherein in the ith time period, only the ith optical path in the optical switch structure is gated, an optical signal emitted by the light source enters the ith optical fiber ring through the ith optical path after entering the input port and is interfered in the ith optical fiber ring, and interference light returned by the ith optical fiber ring enters the ith output port and then enters the photoelectric detector through the ith optical path; wherein N is a positive integer greater than 1, and 1 < = i < = N. According to the scheme provided by the embodiment of the invention, the measurement precision of the multi-axis optical fiber gyroscope is improved, and the packaging difficulty is reduced.

Description

Technical Field

[0001] The present application relates to the field of integrated photonic chips, and in particular to an optical integrated device for a multi-axis fiber optic gyroscope and a multi-axis fiber optic gyroscope. Background Art

[0002] Fiber optic gyroscope is an interferometer type angular velocity measurement device based on the Sagnac effect and composed of fiber optic loops. As a fully solid-state instrument, it has no moving parts and wear parts, and has the characteristics of long life, light weight, small size, large dynamic range, high accuracy, and anti-electromagnetic interference. Fiber optic gyroscopes have gradually replaced traditional electromechanical gyroscopes and expensive laser gyroscopes, becoming the mainstream solution for gyroscope manufacturing, and have important applications in inertial navigation, attitude modulation, and weak rotation signal detection.

[0003] At present, integrated multi-axis fiber optic gyroscopes have been introduced. Integrated multi-axis fiber optic gyroscopes integrate many originally discrete optoelectronic devices into one module, which can realize angular velocity measurement on multiple coordinate axes. However, due to the complex and precise assembly process of integrated fiber optic gyroscopes, their cost is high and production efficiency is low. In addition, the measurement accuracy of integrated multi-axis fiber optic gyroscopes needs to be improved. Summary of the invention

[0004] One of the technical objectives of the embodiments of the present application is to provide an optical integrated device for a multi-axis fiber optic gyroscope, which is beneficial to improving the measurement accuracy in the integrated multi-axis fiber optic gyroscope and reducing the packaging difficulty.

[0005] In a first aspect, an embodiment of the present application provides an optical integrated device for a multi-axis fiber optic gyroscope, comprising: a photodetector; an optical switch structure, having an input port and N output ports, the i-th output port among the N output ports being coupled to the i-th fiber ring among N external fiber rings, and the optical path between the input port and the i-th output port being recorded as the i-th optical path; wherein, in the i-th time period, only the i-th optical path in the optical switch structure is selected, and after an optical signal emitted by a light source enters the input port, it enters the i-th fiber ring via the i-th optical path, and after the optical signal is output from the i-th fiber ring, interference occurs and returns, and after the returned interference light enters the i-th output port, it enters the photodetector via the i-th optical path; wherein N is a positive integer greater than 1, and 1≤i≤N, and i is a positive integer.

[0006] Optionally, the method further includes: N Y waveguides, wherein the i-th output port is coupled to the i-th optical fiber ring via the i-th Y waveguide among the N Y waveguides.

[0007] Optionally, it also includes: a first beam splitter, having a first port, a second port and a third port, wherein the first port is coupled to the input port, the second port is used to couple to the light source, and the third port is coupled to the photodetector; wherein the light signal emitted by the light source is transmitted to the input port via the optical path between the second port and the first port, and the interference light is transmitted to the photodetector via the optical path between the first port and the third port.

[0008] Optionally, it further includes: a polarization beam splitter, wherein the first port is coupled to the input port via the polarization beam splitter; wherein the optical signal output from the polarization beam splitter contains only one polarization state.

[0009] Optionally, it further includes: an end face coupler, and the second port is coupled to the light source via the end face coupler.

[0010] Optionally, the light source is also included.

[0011] Optionally, N=2, or N=3.

[0012] In a second aspect, an embodiment of the present application provides a multi-axis fiber optic gyroscope, including the optical integrated device for the multi-axis fiber optic gyroscope provided in the first aspect.

[0013] Optionally, it also includes: an optical switch control circuit, used to control the switching of the optical path in the optical switch structure.

[0014] Optionally, it also includes: the N optical fiber rings.

[0015] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0016] In the scheme of the embodiment of the present application, the optical integrated device for the multi-axis fiber optic gyroscope includes: a photodetector and an optical switch structure, wherein the optical switch structure has an input port and N output ports, the i-th output port among the N output ports is coupled with the i-th fiber ring among the external N fiber rings, and the optical path between the input port and the i-th output port is recorded as the i-th optical path, wherein N is a positive integer greater than 1, and 1≤i≤N, and i is a positive integer. In the i-th time period, only the i-th optical path in the optical switch structure is selected, and the optical signal emitted by the light source enters the input port and enters the i-th fiber ring via the i-th optical path. After the optical signal is output from the fiber ring, interference occurs, and the returned interference light enters the i-th output port and enters the photodetector via the i-th optical path.

[0017] In the above scheme, by setting up an optical switch structure and controlling the optical path in the optical switch structure, the optical signal emitted by the light source is transmitted to only one optical fiber ring in a time period, and the optical signal interferes and returns after being transmitted in the optical fiber ring, and the returned interference light enters the photodetector. In the above scheme, by setting up an optical switch structure, the optical signal enters N optical fiber rings in turn in time, and the optical signal emitted by the light source is time-division multiplexed.

[0018] By adopting the above scheme, on the one hand, only one axis of optical signal and electrical signal can always exist in the optical integrated device, which can completely avoid the problem of signal crosstalk on different axes, thereby improving the measurement accuracy of the fiber optic gyroscope. On the other hand, the above scheme only does not need to set up devices for each axis, and realizes the function of the multi-axis fiber optic gyroscope through a single-axis structure, which significantly reduces the number of on-chip devices and the size of the optical integrated device, which is conducive to reducing the difficulty of packaging and facilitating mass production.

[0019] Furthermore, in the solution of the embodiment of the present application, the optical integrated device further includes N Y waveguides, and the i-th output port is coupled to the i-th optical fiber ring via the i-th Y waveguide among the N Y waveguides. The above solution also integrates the Y waveguide into the optical integrated device, which is beneficial to improving the integration of the fiber optic gyroscope and reducing the size of the fiber optic gyroscope.

[0020] Furthermore, in the solution of the embodiment of the present application, the optical integrated device may further include: a polarization beam splitter, and the first port may be coupled to the input port via the polarization beam splitter. In the above solution, by providing the polarization beam splitter, it is beneficial to improve the polarization extinction ratio of the fiber optic gyroscope, thereby improving the measurement accuracy of the fiber optic gyroscope. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of a multi-axis fiber optic gyroscope;

[0022] Figure 2 It is a structural schematic diagram of a dual-axis fiber optic gyroscope in an embodiment of the present application;

[0023] Figure 3 yes Figure 2 A schematic structural diagram of the optical switch structure 214;

[0024] Figure 4 It is a schematic structural diagram of another dual-axis optical gyroscope in an embodiment of the present application;

[0025] Figure 5 It is a structural schematic diagram of a three-axis fiber optic gyroscope in an embodiment of the present application;

[0026] Figure 6 yes Figure 5 A schematic structural diagram of the optical switch structure 514;

[0027] Figure 7 It is a structural schematic diagram of another three-axis fiber optic gyroscope in an embodiment of the present application. DETAILED DESCRIPTION

[0028] As described in the background art, integrated multi-axis fiber optic gyroscopes are prone to problems such as low precision and high packaging difficulty.

[0029] Reference Figure 1 , Figure 1 This is a schematic diagram of the structure of a three-axis fiber optic gyroscope. Specifically, Figure 1 The three-axis fiber optic gyroscope 1 shown can be used to measure angular velocity on three coordinate axes. For ease of description, the three coordinate axes are denoted as x-axis, y-axis and z-axis. Figure 1 As shown, the three-axis fiber optic gyroscope 1 may include: a light source 10, a silicon photonic chip 11, a fiber array 12, and three fiber rings, which are fiber ring 131, fiber ring 132, and fiber ring 133.

[0030] Specifically, the silicon photonic chip 11 integrates a 1×3 beam splitter 111, three photodetectors, three 3dB beam splitters and three polarization beam splitters. The three photodetectors are photodetector 1121, photodetector 1122 and photodetector 1123. The three 3dB beam splitters are 3dB beam splitter 1131, 3dB beam splitter 1132 and 3dB beam splitter 1133. The three polarization beam splitters are polarization beam splitter 1141, polarization beam splitter 1142 and polarization beam splitter 1143.

[0031] Among them, the photodetector 1121, the 3dB beam splitter 1131, the polarization beam splitter 1141 and the optical fiber ring 131 are used to measure the angular velocity on the x-axis; the photodetector 1122, the 3dB beam splitter 1132, the polarization beam splitter 1142 and the optical fiber ring 132 are used to measure the angular velocity on the y-axis; the photodetector 1123, the 3dB beam splitter 1133, the polarization beam splitter 1143 and the optical fiber ring 133 are used to measure the angular velocity on the z-axis.

[0032] In a specific implementation, the optical signal emitted by the light source 10 is transmitted to the input end of the 1×3 beam splitter 111, and the 1×3 beam splitter 111 splits the input optical signal into three optical signals, which are transmitted to 3dB beam splitters 1131, 3dB beam splitters 1132, and 3dB beam splitters 1133 respectively.

[0033] Specifically, the first optical signal is transmitted to the polarization beam splitter 1141 via the 3dB beam splitter 1131, and after being output from the polarization beam splitter 1141, the first optical signal is transmitted to the optical fiber ring 131 via the optical fiber array 12. Further, the first interference light returns, and the first interference light is transmitted to the polarization beam splitter 1141 via the optical fiber array 12, and after being output from the polarization beam splitter 1141, the first interference light is transmitted to the photodetector 1121 via the 3dB beam splitter 1131. The photodetector 1121 converts the first interference light into an electrical signal, and the electrical signal is processed by an external circuit to obtain the angular velocity on the x-axis.

[0034] The second optical signal is transmitted to the polarization beam splitter 1142 via the 3dB beam splitter 1132. After the second optical signal is output from the polarization beam splitter 1142, it is transmitted to the optical fiber ring 132 via the optical fiber array 12. Further, the second interference light returns, and the second interference light is transmitted to the polarization beam splitter 1142 via the optical fiber array 12. After the second interference light is output from the polarization beam splitter 1142, it is transmitted to the photodetector 1122 via the 3dB beam splitter 1132. The photodetector 1122 converts the second interference light into an electrical signal, and the electrical signal is processed by an external circuit to obtain the angular velocity on the y-axis.

[0035] The third optical signal is transmitted to the polarization beam splitter 1143 via the 3dB beam splitter 1133. After the third optical signal is output from the polarization beam splitter 1143, it is transmitted to the optical fiber ring 133 via the optical fiber array 12. Further, the third interference light returns, and the third interference light is transmitted to the polarization beam splitter 1143 via the optical fiber array 12. After the third interference light is output from the polarization beam splitter 1143, it is transmitted to the photodetector 11323 via the 3dB beam splitter 1133. The photodetector 1123 converts the third interference light into an electrical signal, and the electrical signal is processed by an external circuit to obtain the angular velocity on the z-axis.

[0036] also, Figure 1 The fiber optic gyroscope 1 shown may also include a first end coupler 15 and three second end couplers, wherein the three second end couplers are respectively a second end coupler 161, a second end coupler 162, and a third end coupler 163. Specifically, the light source 10 is coupled to the 1×3 beam splitter 111 via the first end coupler 15, the polarization beam splitter 1141 is coupled to the fiber array 12 via the second end coupler 161, the polarization beam splitter 1142 is coupled to the fiber array 12 via the second end coupler 162, and the polarization beam splitter 1143 is coupled to the fiber array 12 via the second end coupler 163. Among them, the first end coupler 15 is a light source end coupler, and the second end coupler is a fiber end coupler.

[0037] From the above, adopt Figure 1The fiber optic gyroscope shown can measure angular velocity on three coordinate axes.

[0038] However, in practical applications, due to Figure 1 The silicon photonic chip includes the devices required for the three axes, and the optical signals on each axis have crosstalk between the devices on the chip. For example, the first interference light received by the photodetector 1121 will affect the second interference light input to the photodetector 1122. For another example, the second interference light input to the 3dB beam splitter 1132 will affect the first interference light input to the 3dB beam splitter 1131.

[0039] In addition, the output ends of the photodetector 1121, the photodetector 1122, and the photodetector 1123 are connected to the external circuit through wires. Since the layout of the integrated multi-axis fiber optic gyroscope is very dense, this will cause crosstalk in space between the three electrical signals transmitted in the wires.

[0040] The crosstalk between the above optical signals and the crosstalk between the electrical signals will affect the measurement accuracy of the fiber optic gyroscope. In addition, in the above scheme, the devices required for each axis (photodetector, 3dB beam splitter, polarization beam splitter) are respectively set on the silicon photonic chip 11, resulting in a large number of on-chip devices, making the size of the silicon photonic chip 20 larger and increasing the difficulty of packaging.

[0041] In view of this, an embodiment of the present application provides an optical integrated device for a multi-axis fiber optic gyroscope. In the scheme of the embodiment of the present application, the optical integrated device for a multi-axis fiber optic gyroscope includes: a photodetector and an optical switch structure, wherein the optical switch structure has an input port and N output ports, the i-th output port among the N output ports is coupled with the i-th fiber ring among the external N fiber rings, and the optical path between the input port and the i-th output port is recorded as the i-th optical path, wherein N is a positive integer greater than 1, and 1≤i≤N, and i is a positive integer. In the i-th time period, only the i-th optical path in the optical switch structure is selected, and after the optical signal emitted by the light source enters the input port, it enters the i-th fiber ring via the i-th optical path, and the optical signal interferes after being output from the fiber ring. After the returned interference light enters the i-th output port, it enters the photodetector via the i-th optical path.

[0042] In the above scheme, by setting up an optical switch structure and controlling the optical path in the optical switch structure, the optical signal emitted by the light source is transmitted to only one optical fiber ring in a time period, and the optical signal interferes and returns after being transmitted in the optical fiber ring, and the returned interference light enters the photodetector. In the above scheme, by setting up an optical switch structure, the optical signal enters N optical fiber rings in turn in time, and the optical signal emitted by the light source is time-division multiplexed.

[0043] By adopting the above scheme, on the one hand, only one axis of optical signal and electrical signal can always exist in the optical integrated device, which can completely avoid the problem of signal crosstalk on different axes, thereby improving the measurement accuracy of the fiber optic gyroscope. On the other hand, the above scheme only does not need to set up devices for each axis, and realizes the function of the multi-axis fiber optic gyroscope through a single-axis structure, which significantly reduces the number of on-chip devices and the size of the optical integrated device, which is conducive to reducing the difficulty of packaging and facilitating mass production.

[0044] In order to make the above-mentioned purposes, features and beneficial effects of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0045] It should be noted that this article mainly uses a dual-axis fiber optic gyroscope and a three-axis fiber optic gyroscope as examples for specific description.

[0046] Embodiment 1

[0047] Reference Figure 2 , Figure 2 It is a structural schematic diagram of a dual-axis fiber optic gyroscope in an embodiment of the present application. Figure 2 The fiber optic gyroscope 2 shown can measure angular velocity on two coordinate axes, wherein the two coordinate axes are respectively represented as an x-axis and a y-axis, and the x-axis and the y-axis may be orthogonal.

[0048] Specifically, Figure 2 The fiber optic gyroscope 2 shown may include: a light source 20, an optical integrated device 21, and two fiber optic rings.

[0049] The light source 20 may be any light source capable of providing an optical signal. For example, the light source in this article may be a super luminescent diode (SLD) light source chip, but is not limited thereto.

[0050] In a specific implementation, the light source 20 may be a device independent of the optical integrated device 21. Alternatively, the light source 20 may also be integrated on the optical integrated device 21. It should be noted that the optical integrated device in this article may be a silicon photonic chip, but is not limited thereto.

[0051] Among them, the two fiber optic rings are the first fiber optic ring 241 and the second fiber optic ring 242. It should be noted that this article does not limit the order of the two fiber optic rings. In a specific implementation, the first fiber optic ring 241 can correspond to the x-axis, that is, the first fiber optic ring 241 can be used to measure the angular velocity on the x-axis, and the second fiber optic ring 242 can correspond to the y-axis, that is, the second fiber optic ring 242 is used to measure the angular velocity on the y-axis. Alternatively, the first fiber optic ring 241 can correspond to the y-axis, and the second fiber optic ring 242 can correspond to the x-axis. This article mainly describes the example that the first fiber optic ring 241 corresponds to the x-axis and the second fiber optic ring 242 corresponds to the y-axis.

[0052] It should be noted that the specific structure of the optical fiber ring is not limited in this article, and it can be various optical fiber rings that can be applied to the optical fiber gyroscope.

[0053] Further, Figure 2 The optical integrated device 21 may include: a photodetector 211 and an optical switch structure 214 .

[0054] The photodetector 211 may have an optical signal input terminal and an electrical signal output terminal. The photodetector 211 may convert the optical signal input from the optical signal input terminal into an electrical signal, and output the electrical signal to an external circuit via the electrical signal output terminal. The external circuit processes the electrical signal to obtain the angular velocity.

[0055] The optical switch structure 214 may have an input port 2140 and two output ports, wherein the two output ports are respectively a first output port 2141 and a second output port 2142. The input port 2140 of the optical switch structure 214 is used to couple with the light source 20, the first output port 2141 of the optical switch structure 214 is used to couple with the first optical fiber ring 241, and the second output port 2142 is used to couple with the second optical fiber ring 242.

[0056] There are two optical paths in the optical switch structure 214, wherein the optical path between the input port 2140 and the first output port 2141 is recorded as the first optical path, and the optical path between the input port 2140 and the second output port 2142 is recorded as the second optical path. In the scheme of the embodiment of the present application, the fiber optic gyroscope 2 may also include: an optical switch control circuit (not shown), which can control the switching of the optical paths in the optical switch structure 214. The optical switch control circuit can control the first optical path to be enabled and the second optical path to be interrupted. That is, all the optical signals input from the input port 2140 are output from the first output port 2141. Alternatively, the optical switch control circuit can control the second optical path to be enabled and the first optical path to be interrupted. That is, all the optical signals input from the input port 2140 are output from the second output port 2142.

[0057] Exemplarily, the optical switch structure 214 may include a 1×2 optical switch. Figure 3 , Figure 3 yes Figure 2 A schematic diagram of a structure of an optical switch structure 214. Figure 3 As shown, the optical switch structure 214 may include an input port 2140 , a first output port 2141 , a second output port 2142 , two 2×2 beam splitters, and two phase shifters.

[0058] Specifically, the two 2×2 beam splitters are 2×2 beam splitter 2144 and 2×2 beam splitter 2145 , and the two phase shifters are phase shifter 2146 and phase shifter 2147 .

[0059] Each 2×2 beam splitter has two input ports and two output ports. One input port of the 2×2 beam splitter 2144 can be used as the input port 2140 of the optical switch structure 214, and the other input port of the 2×2 beam splitter 2144 is not coupled with other devices on the optical integrated device 21. Further, one output port of the 2×2 beam splitter 2144 is coupled to one input port of the 2×2 beam splitter 2145 via a phase shifter 2146, and the other output port of the 2×2 beam splitter 2144 is coupled to another input port of the 2×2 beam splitter 2145 via a phase shifter 2147. One output port of the 2×2 beam splitter 2145 serves as the first output port 2141 of the optical switch structure 214, and the other output port of the 2×2 beam splitter 2145 serves as the second output port 2142 of the optical switch structure 214.

[0060] In a specific implementation, by changing the voltage applied to the phase shifter 2146 and the phase shifter 2147, the amount of the optical signal output from the first output port 2141 can be changed, and the amount of the optical signal output from the second output port 2142 can be changed, thereby achieving switching of the optical path in the optical switch result.

[0061] It should be noted that Figure 3 What is shown is only one optical switch structure applicable to the embodiment of the present application, but it is not limited thereto.

[0062] Continue to refer to Figure 2 In a specific implementation, the measurement cycle of the fiber optic gyroscope 2 can be divided into two time periods. In each time period, only one optical path in the optical switch structure 214 is enabled, and all other optical paths other than the optical path are interrupted. In other words, in each time period, the input port 2140 of the optical switch structure 214 is coupled to only one output port.

[0063] In a specific implementation, the fiber optic gyroscope 2 may further include: two Y waveguides, the two Y waveguides are respectively a first Y waveguide 231 and a second Y waveguide 232. The first output port 2141 of the optical switch structure 214 is coupled to the first optical fiber ring 241 via the first Y waveguide 231. The second output port 2142 of the optical switch structure 214 is coupled to the second optical fiber ring 242 via the second Y waveguide 232.

[0064] Among them, the Y waveguide can split and phase modulate the input optical signal. Specifically, the Y waveguide has 1 input end and 2 output ends. In the scheme of the embodiment of the present application, the input end of the Y waveguide is coupled with the output port of the optical switch structure, and the output end of the Y waveguide is coupled with the optical fiber ring. More specifically, the Y waveguide can divide the input optical signal into 2 optical signals, and the 2 optical signals are respectively input into the optical fiber ring via the 2 output ends, and the 2 optical signals are transmitted in opposite directions in the optical fiber ring. Furthermore, the 2 optical signals transmitted in opposite directions are further returned to the Y waveguide, and interfere at the input end of the Y waveguide to obtain interference light, and the interference light is further transmitted to the input port of the optical switch structure. It should be noted that this article does not limit the structure of the Y waveguide, and it can be various existing Y waveguides.

[0065] In a possible implementation, in the first time period, the first optical path in the optical switch structure 214 is enabled, and the second optical path is interrupted. After the optical signal emitted by the light source 20 enters the output port 2140, it is output from the first output port 2141 through the first optical path, and the output optical signal is transmitted to the first Y-waveguide 231. The first Y-waveguide 231 divides the input optical signal into two optical signals, and the two optical signals are transmitted in opposite directions in the first optical fiber ring 241. Further, the two optical signals transmitted in opposite directions return to the first Y-waveguide 231, and interfere at the input end of the first Y-waveguide 231 to obtain interference light, which is further transmitted to the first output port 2141 of the optical switch structure 214. Further, the interference light is output from the input port 2140 through the first optical path. After being output from the input port 2140, the interference light is transmitted to the photodetector 211. Thus, the photodetector 211 can convert the received interference light into an electrical signal and output it to an external circuit, and the external circuit processes it to obtain the angular velocity on the x-axis.

[0066] In the second time period, the second optical path in the optical switch structure 214 is selected, and the first optical path is interrupted. After the optical signal emitted by the light source 20 enters the input port 2140, it is output from the second output port 2142 through the second optical path, and the output optical signal is transmitted to the second Y waveguide 232. The second Y waveguide 232 divides the input optical signal into two optical signals, and the two optical signals are transmitted in opposite directions in the second optical fiber ring 242. The two optical signals transmitted in opposite directions return to the second Y waveguide 232, and interfere at the input end of the second Y waveguide 232 to obtain interference light, which is further transmitted to the second output port 2142 of the optical switch structure 214. Further, the interference light is output from the input port 2140 through the second optical path. After being output from the input port 2140, the interference light is transmitted to the photodetector 211. Thus, the photodetector 211 can convert the received interference light into an electrical signal and output it to an external circuit, and the external circuit processes it to obtain the angular velocity on the y-axis.

[0067] It should be noted that, in other embodiments, the first time period can be used to detect the angular velocity on the y-axis, and the second time period can be used to detect the angular velocity on the x-axis. That is, in the first time period, the second optical path in the optical switch structure 214 is enabled, and the first optical path is interrupted. In the second time period, the first optical path in the optical switch structure 214 is enabled, and the second optical path is interrupted.

[0068] like Figure 2 As shown, the fiber optic gyroscope 2 may further include: a fiber array 22, and the output port of the optical switch structure 214 is coupled to the Y-waveguide via the fiber array 22. Specifically, the first output port 2141 of the optical switch structure 214 is coupled to the input end of the first Y-waveguide 231 via the fiber array 22, and the second output port 2142 of the optical switch structure 214 is coupled to the input end of the second Y-waveguide 232 via the fiber array 22.

[0069] In a possible implementation, the optical integrated device 21 may further include a beam splitter 212. Exemplarily, the beam splitter 212 may be a 3dB beam splitter, but is not limited thereto.

[0070] Specifically, the beam splitter 212 may have a first port 2121, a second port 2122, and a third port 2123. The first port 2121 is coupled to the input port 2140, the second port 2122 is used to couple with the light source 20, and the third port 2123 is coupled to the photodetector 211. Specifically, the third port 2123 is coupled to the optical signal input end of the photodetector 211.

[0071] In a specific implementation, the optical signal emitted by the light source 20 is input to the beam splitter 212 via the second port 2122 and output from the first port 2121. The optical signal output from the first port 2121 is further transmitted to the input port 2140. In addition, after the interference light is output from the input port 2140, it is transmitted to the beam splitter 212 via the first port 2121 and output to the photodetector 211 via the third port 2123.

[0072] In a possible implementation, the optical integrated device 21 may further include: a polarization beam splitter 213. The optical signal output from the polarization beam splitter 213 contains only one polarization state. Specifically, the optical signal input to the polarization beam splitter 213 may contain multiple polarization states, and the optical signal output from the polarization beam splitter contains only one polarization state. That is, the polarization beam splitter 213 may be used to retain an optical signal of a specific polarization state and filter optical signals of other polarization states except the specific polarization state.

[0073] In the solution of the embodiment of the present application, the first port 2120 can be coupled to the input port 2140 via the polarization beam splitter 213. Specifically, the input end of the polarization beam splitter 213 is coupled to the first port 2121 of the beam splitter 212, and the output end of the polarization beam splitter 213 is coupled to the input port 2140 of the optical switch structure 214, and the optical signal output from the first port 2121 of the beam splitter 212 passes through the polarization beam splitter 213 before being transmitted to the input port 2140.

[0074] By providing the polarization beam splitter 213 , it is helpful to improve the polarization extinction ratio of the fiber optic gyroscope, thereby helping to improve the measurement accuracy of the fiber optic gyroscope.

[0075] It should be noted that the specific type or structure of the polarization beam splitter 213 is not limited herein, and it can be any existing polarization beam splitter 213 .

[0076] In a possible implementation, the optical integrated device 21 may further include: a first end face coupler 25, and the second port 2122 of the beam splitter 212 may be coupled to the light source 20 via the first end face coupler 25. Specifically, the optical signal emitted by the light source 20 is first transmitted to the input end of the first end face coupler 25, and then output from the output end of the first end face coupler 25 and transmitted to the second port 2122 of the beam splitter 212. Exemplarily, the first end face coupler 25 may be a light source end face coupler.

[0077] In a possible implementation, the optical integrated device 21 may further include: a second end face coupler 261 and a second end face coupler 262. The first output port 2141 of the optical switch structure 214 is coupled to the optical fiber array 22 via the second end face coupler 261, and the second output port 2142 of the optical switch structure 214 is coupled to the optical fiber array 22 via the second end face coupler 262. Exemplarily, the second end face coupler herein may be an optical fiber end face coupler.

[0078] Reference Figure 4 , Figure 4 FIG. 1 is a schematic diagram of the structure of another dual-axis fiber optic gyroscope in the embodiment of the present application. Figure 2 The fiber optic gyroscope 2 shown, Figure 4 In the fiber optic gyroscope 4 shown, the Y-waveguide is integrated into an optical integrated device 41 .

[0079] Specifically, Figure 4 As shown, the optical integrated device 41 further includes: two Y waveguides, the two Y waveguides are respectively a first Y waveguide 231 and a second Y waveguide 232. The first output port 2141 of the optical switch structure 214 is coupled to the first optical fiber ring 241 via the first Y waveguide 231. The second output port 2142 of the optical switch structure 214 is coupled to the second optical fiber ring 232 via the second Y waveguide 232.

[0080] Further, Figure 4 In the illustrated solution, the output end of the Y-waveguide can be coupled to the optical fiber ring via the optical fiber array 22 .

[0081] In a possible implementation, the optical integrated device 41 may further include: a second end coupler 261 and a second end coupler 262. The first Y-waveguide 231 is coupled to the optical fiber array 22 via the second end coupler 261, and the second optical fiber ring 232 is coupled to the optical fiber array 22 via the second end coupler 262.

[0082] about Figure 4 For more details of the optical integrated device 41 shown, reference may be made to the above detailed description of the optical integrated device 21. Figure 4 For more details of the fiber optic gyroscope 4 shown, reference may be made to the above detailed description of the fiber optic gyroscope 2 .

[0083] As can be seen from the above, in the scheme of embodiment 1, a 1×2 optical switch structure is set on the optical integrated device, and the measurement cycle is divided into two time periods, so that the optical signal enters the two optical fiber rings in turn in time, so that the angular velocities on the two axes are obtained in the two time periods respectively, and the function of the dual-axis fiber optic gyroscope can be realized by using a single-axis device structure.

[0084] Embodiment 2

[0085] Reference Figure 5 , Figure 5 It is a structural schematic diagram of a three-axis fiber optic gyroscope in an embodiment of the present application. Figure 5 The fiber optic gyroscope 5 shown can measure angular velocity on three coordinate axes, wherein the three coordinate axes are respectively represented as an x-axis, a y-axis and a z-axis, wherein any two of the three coordinate axes can be orthogonal.

[0086] Specifically, Figure 5 The fiber optic gyroscope 5 shown may include: a light source 20, an optical integrated device 51 and three fiber optic rings.

[0087] Among them, the three fiber optic rings are the first fiber optic ring 541, the second fiber optic ring 542, and the third fiber optic ring 543. It should be noted that the order of the three fiber optic rings is not limited in this article. In a specific implementation, the first fiber optic ring 541 can correspond to the x-axis, that is, the first fiber optic ring 541 can be used to measure the angular velocity on the x-axis, the second fiber optic ring 542 can correspond to the y-axis, that is, the second fiber optic ring 542 is used to measure the angular velocity on the y-axis, and the third fiber optic ring 543 can correspond to the z-axis, that is, the third fiber optic ring 543 is used to measure the angular velocity on the z-axis. Alternatively, the first fiber optic ring 541 can correspond to the y-axis, the second fiber optic ring 542 can correspond to the z-axis, and the third fiber optic ring 543 can correspond to the x-axis. But it is not limited to this.

[0088] This embodiment is mainly described by taking the example that the first optical fiber ring 541 corresponds to the x-axis, the second optical fiber ring 542 corresponds to the y-axis, and the third optical fiber ring 543 corresponds to the z-axis.

[0089] Further, the optical integrated device 51 may include: a photodetector 211, and an optical switch structure 514. The optical switch structure 514 may have an input port 5140 and three input ports, and the three output ports are respectively a first output port 5141, a second output port 5142, and a third output port 5143. The input port 5140 of the optical switch structure 514 is used to couple with the light source 20, the first output port 5141 of the optical switch structure 514 is used to couple with the first optical fiber ring 541, the second output port 5142 is used to couple with the second optical fiber ring 542, and the third output port 5143 is used to couple with the third optical fiber ring 543.

[0090] There are three optical paths in the optical switch structure 514, wherein the optical path between the input port 5140 and the first output port 5141 is recorded as the first optical path, the optical path between the input port 5140 and the second output port 5142 is recorded as the second optical path, and the optical path between the input port 5140 and the third output port 5143 is recorded as the third optical path.

[0091] The fiber optic gyroscope 5 may also include: an optical switch control circuit (not shown), which can control the switching of the optical paths in the optical switch structure 514. Specifically, the optical switch control circuit can control the first optical path to be enabled and the second optical path and the third optical path to be interrupted. That is, all the optical signals input from the input port 5140 are output from the first output port 5141. Alternatively, the optical switch control circuit can control the second optical path to be enabled and the first optical path and the third optical path to be interrupted. That is, all the optical signals input from the input port 5140 are output from the second output port 5142. Alternatively, the optical switch control circuit can control the third optical path to be enabled and the first optical path and the second optical path to be interrupted. That is, all the optical signals input from the input port 5140 are output from the third output port 5143.

[0092] For example, the optical switch structure 514 may be a 1×3 optical switch. Figure 6 , Figure 6 yes Figure 5 A schematic diagram of a structure of an optical switch structure 514. Figure 6 As shown, the optical switch structure 514 may include three 1×2 optical switches, and the three 1×2 optical switches are a 1×2 optical switch 60 , a 1×2 optical switch 61 , and a 1×2 optical switch 62 .

[0093] Each 1×2 optical switch may have one input end and two output ends. The input end of the 1×2 optical switch 60 may be used as the input port 5140 of the optical switch structure 514, and the two output ends of the 1×2 optical switch 60 are respectively coupled with the input ends of the 1×2 optical switch 61 and the 1×2 optical switch 62. The two output ends of the 1×2 optical switch 61 may be used as the first output port 5141 and the second output port 5142 of the optical switch structure 514, respectively, one output end of the 1×2 optical switch 62 may be used as the third output port 5143 of the optical switch structure 514, and the other output end of the 1×2 optical switch 62 may be used as the monitoring port 5144. The monitoring port 5144 may be used to calibrate the optical switch voltage of the optical switch structure 514.

[0094] It should be noted that Figure 6 The illustrated example is only one optical switch structure applicable to this embodiment, and the structure of the optical switch structure 514 is not limited thereto.

[0095] Continue to refer to Figure 5 In a specific implementation, the measurement cycle of the fiber optic gyroscope 5 can be divided into three time periods. In each time period, only one optical path in the optical switch structure 514 is enabled, and all other optical paths other than the optical path are interrupted. In other words, in each time period, the input port 5140 of the optical switch structure 514 is coupled to only one output port.

[0096] In a specific implementation, the fiber optic gyroscope 5 may further include: three Y waveguides, the three Y waveguides are respectively the first Y waveguide 531, the second Y waveguide 532 and the third Y waveguide 533. Among them, the first output port 5141 of the optical switch structure 514 is coupled to the first fiber ring 541 via the first Y waveguide 531. The second output port 5142 of the optical switch structure 514 is coupled to the second fiber ring 542 via the second Y waveguide 532. The third output port 5143 of the optical switch structure 514 is coupled to the third fiber ring 543 via the third Y waveguide 533.

[0097] In a possible implementation, in the first time period, the first optical path in the optical switch structure 514 is selected, and the second optical path and the third optical path are interrupted. After the optical signal emitted by the light source 20 enters the input port 5140, it is output from the first output port 5141 through the first optical path, and the output optical signal is transmitted to the first Y-waveguide 531. The first Y-waveguide 531 divides the input optical signal into two optical signals, and the two optical signals are transmitted in opposite directions in the first optical fiber ring 541. Further, the two optical signals transmitted in opposite directions return to the first Y-waveguide 531, and interfere at the input end of the first Y-waveguide 531 to obtain interference light, and the interference light is further transmitted to the first output end 5141 of the optical switch structure 514. Further, the interference light is output from the input port 5140 through the first optical path. After being output from the input port 5140, the interference light is transmitted to the photodetector 211. Thus, the photodetector 211 can convert the received interference light into an electrical signal and output it to an external circuit, and the external circuit processes it to obtain the angular velocity on the x-axis.

[0098] In the second time period, the second optical path in the optical switch structure 514 is selected, and the first optical path and the third optical path are interrupted. After the optical signal emitted by the light source 20 enters the output port 5140, it is output from the second output port 5142 through the second optical path, and the output optical signal is transmitted to the second Y waveguide 532. The second Y waveguide 532 divides the input optical signal into two optical signals, and the two optical signals are transmitted in opposite directions in the second optical fiber ring 542. The two optical signals transmitted in opposite directions are further input to the second Y waveguide 532, and interfere at the input end of the second Y waveguide 532 to obtain interference light, which is further transmitted to the second output end 5142 of the optical switch structure 514. Further, the interference light is output from the input port 5140 through the second optical path. After being output from the input port 5140, the interference light is transmitted to the photodetector 211. Thus, the photodetector 211 can convert the received interference light into an electrical signal and output it to an external circuit, and the external circuit processes it to obtain the angular velocity on the y-axis.

[0099] In the third time period, the third optical path in the optical switch structure 514 is selected, and the first optical path and the second optical path are interrupted. After the optical signal emitted by the light source 20 enters the output port 5140, it is output from the third output port 5143 through the third optical path, and the output optical signal is transmitted to the third Y-waveguide 533. The third Y-waveguide 533 divides the input optical signal into two optical signals, and the two optical signals are transmitted in opposite directions in the third optical fiber ring 543. The two optical signals transmitted in opposite directions are further input to the third Y-waveguide 533, and interfere at the input end of the third Y-waveguide 533 to obtain interference light, which is further transmitted to the third output end 5143 of the optical switch structure 514. Further, the interference light is output from the input port 5140 through the third optical path. After being output from the input port 5140, the interference light is transmitted to the photodetector 211. Thus, the photodetector 211 can convert the received interference light into an electrical signal and output it to an external circuit, and the external circuit processes it to obtain the angular velocity on the z-axis.

[0100] It should be noted that this article does not limit the order of detecting the angular velocities on each axis.

[0101] like Figure 5 As shown, the fiber optic gyroscope 5 may further include: a fiber array 52, and the output port of the optical switch structure 514 may be coupled to the Y-waveguide via the fiber array 52. ​​Specifically, the first output port 5141 of the optical switch structure 514 is coupled to the input end of the first Y-waveguide 531 via the fiber array 52, the second output port 5142 of the optical switch structure 514 is coupled to the input end of the second Y-waveguide 532 via the fiber array 52, and the third output port 5143 of the optical switch structure 514 is coupled to the input end of the third Y-waveguide 533 via the fiber array 52.

[0102] In a possible implementation, the optical integrated device 51 may further include a beam splitter 212 .

[0103] Specifically, the beam splitter 212 may have a first port 2121 , a second port 2122 and a third port 2123 , wherein the first port 2121 is coupled to the input port 5140 , the second port 2122 is used to couple to the light source 20 , and the third port 2123 is coupled to the photodetector 211 .

[0104] In a possible implementation, the optical integrated device 21 may further include a polarization beam splitter 213 . In the solution of this embodiment, the first port 2120 may be coupled to the input port 5140 via the polarization beam splitter 213 .

[0105] In a possible implementation, the optical integrated device 51 may further include: a first end face coupler 25 .

[0106] For the specific contents of the beam splitter 212 , the polarization beam splitter 213 and the first end face coupler 25 , reference may be made to the related description in the first embodiment, which will not be repeated here.

[0107] In a possible implementation, the optical integrated device 51 may further include: a second end face coupler 561, a second end face coupler 562, and a second end face coupler 563. The first output port 5141 of the optical switch structure 514 is coupled to the optical fiber array 52 via the second end face coupler 561, the second output port 5142 of the optical switch structure 514 is coupled to the optical fiber array 52 via the second end face coupler 562, and the third output port 5143 of the optical switch structure 514 is coupled to the optical fiber array 52 via the second end face coupler 563. Exemplarily, the second end face coupler herein may be an optical fiber end face coupler.

[0108] Reference Figure 7 , Figure 7 Schematic diagram of another three-axis fiber optic gyroscope in the embodiment of the present application. Figure 5 The fiber optic gyroscope 5 shown, Figure 7 In the fiber optic gyroscope 7 shown, the Y-waveguide is integrated into an optical integrated device 51 .

[0109] Specifically, Figure 7As shown, the optical integrated device 71 further includes: three Y waveguides, which are the first Y waveguide 531, the second Y waveguide 532 and the third Y waveguide 533. The first output port 5141 of the optical switch structure 514 is coupled to the first optical fiber ring 541 via the first Y waveguide 531. The second output port 5142 of the optical switch structure 514 is coupled to the second optical fiber ring 542 via the second Y waveguide 532. The third output port 5143 of the optical switch structure 514 is coupled to the third optical fiber ring 543 via the third Y waveguide 533.

[0110] Further, Figure 7 In the illustrated solution, the output end of the Y-waveguide can be coupled to the fiber ring via the fiber array 52 .

[0111] In a possible implementation, the optical integrated device 71 may further include: a second end face coupler 561, a second end face coupler 562, and a second end face coupler 563. The first Y-waveguide 531 is coupled to the optical fiber array 52 via the second end face coupler 561, the second Y-waveguide 532 is coupled to the optical fiber array 52 via the second end face coupler 562, and the third Y-waveguide 533 is coupled to the optical fiber array 52 via the second end face coupler 563.

[0112] about Figure 7 For more details of the optical integrated device 71 shown, reference may be made to the above detailed description of the optical integrated device 51. Figure 7 For more details of the fiber optic gyroscope 7 shown, reference may be made to the above detailed description of the fiber optic gyroscope 5 .

[0113] As can be seen from the above, in the solution of the second embodiment, a 1×3 optical switch structure is set on the optical integrated device, and the measurement cycle is divided into three time periods, so that the optical signal enters the three optical fiber rings in turn in time, so that the angular velocities on the three axes are obtained in the three time periods respectively, and the function of the three-axis fiber optic gyroscope can be realized by using a single-axis device structure.

[0114] Embodiment 3

[0115] The embodiment of the present application provides a multi-axis fiber optic gyroscope, which may include an optical integrated device and N fiber optic rings, wherein one fiber optic ring corresponds to one axis, and different fiber optic rings correspond to different axes. In other words, one fiber optic ring is used to measure the angular velocity on the axis corresponding to the fiber optic ring.

[0116] Further, the optical integrated device includes: a photodetector, an optical switch structure, wherein the optical switch structure has an input port and N output ports, that is, the optical switch structure can be a 1×N optical switch. N is a positive integer greater than 1. Each of the N output ports is coupled to a fiber ring, and different output ports are coupled to different fiber rings. More specifically, the i-th output port of the N output ports is coupled to the i-th fiber ring of the N fiber rings. 1≤i≤N, i is a positive integer.

[0117] Furthermore, the multi-axis fiber optic gyroscope may also include: N Y waveguides, the i-th output port is coupled to the i-th fiber ring via the i-th Y waveguide, wherein the Y waveguide may be a device independent of the optical integrated device, or the Y waveguide may be integrated into the optical integrated device.

[0118] It should be noted that the order of the N output ports, the order of the N Y-waveguides, and the order of the N optical fiber rings are not limited in this document.

[0119] Furthermore, the multi-axis fiber optic gyroscope may also include: an optical switch control circuit, which can be used to control the switching of the optical path in the optical switch structure. Specifically, the measurement cycle of the fiber optic gyroscope may include N time periods, and the optical switch control circuit is used so that the optical signals input from the input port to the optical switch structure in each time period are all output from one of the N output ports. That is, in a time period, the input port is only coupled to one output port. More specifically, in the i-th time period among the N time periods, the optical path between the input port and the i-th output port (that is, the i-th optical path) is enabled, and the optical path between the input port and the other output ports is interrupted. That is, in the i-th time period, only the i-th optical path is enabled.

[0120] Therefore, by controlling only one optical path in the optical switch structure to be selected in each time period, it can be ensured that there is only an optical signal on one axis on the integrated optical device. In the i-th time period, the optical signal emitted by the light source can be transmitted to the input port and output to the i-th Y-waveguide and the i-th optical fiber ring via the i-th optical path. The optical signal returned by the i-th optical fiber ring interferes at the input end of the i-th Y-waveguide, and the interference light is further transmitted to the input port of the optical switch structure through the i-th optical path, and further transmitted to the photodetector, thereby obtaining the angular velocity on the coordinate axis corresponding to the i-th optical fiber ring.

[0121] For more details about the optical integrated device and the multi-axis fiber optic gyroscope in the third embodiment, reference may be made to the descriptions in the first and second embodiments above, which will not be repeated here.

[0122] It should be understood that the term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article indicates that the associated objects before and after are in an "or" relationship.

[0123] The "plurality" appearing in the embodiments of the present application refers to two or more.

[0124] The first, second, etc. descriptions appearing in the embodiments of the present application are only used for illustration and distinction of the description objects. There is no order, nor do they indicate any special limitation on the number of devices in the embodiments of the present application, and cannot constitute any limitation on the embodiments of the present application.

[0125] Although the present application is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. An optical integrated device for a multi-axis fiber optic gyroscope, characterized in that: include: Photodetectors; An optical switch structure, comprising an input port and N output ports, wherein an i-th output port among the N output ports is coupled to an i-th optical fiber ring among the external N optical fiber rings, and an optical path between the input port and the i-th output port is recorded as an i-th optical path; In the i-th time period, only the i-th optical path in the optical switch structure is selected, and the optical signal emitted by the light source enters the i-th optical fiber ring through the i-th optical path after entering the input port, and the optical signal interferes and returns after being output from the i-th optical fiber ring, and the returned interference light enters the i-th output port and enters the photoelectric detector through the i-th optical path; Wherein, N is a positive integer greater than 1, and 1≤i≤N, i is a positive integer.

2. The optical integrated device according to claim 1, characterized in that: Also includes: N Y-waveguides, wherein the i-th output port is coupled to the i-th optical fiber ring via the i-th Y-waveguide among the N Y-waveguides.

3. The optical integrated device according to claim 1, characterized in that: Also includes: A beam splitter having a first port, a second port and a third port, wherein the first port is coupled to the input port, the second port is used to couple to the light source, and the third port is coupled to the photodetector; The optical signal emitted by the light source is transmitted to the input port via the optical path between the second port and the first port, and the interference light is transmitted to the photodetector via the optical path between the first port and the third port.

4. The optical integrated device according to claim 3, characterized in that: Also includes: a polarization beam splitter, wherein the first port is coupled to the input port via the polarization beam splitter; Wherein, the optical signal output from the polarization beam splitter contains only one polarization state.

5. The optical integrated device according to claim 3, characterized in that: Also includes: An end face coupler, wherein the second port is coupled to the light source via the end face coupler.

6. The optical integrated device according to claim 1, characterized in that: Also included is the light source.

7. The optical integrated device according to any one of claims 1 to 6, characterized in that: N=2, or, N=3.

8. A multi-axis fiber optic gyroscope, characterized in that: include: An optical integrated device as claimed in any one of claims 1 to 7.

9. The multi-axis fiber optic gyroscope according to claim 8, characterized in that: Also includes: The optical switch control circuit is used to control the switching of the optical path in the optical switch structure.

10. The multi-axis fiber optic gyroscope according to claim 8, characterized in that: Also includes: The N optical fiber rings.

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