CN117075363A

CN117075363A - Optical signal phase modulation device and gyroscope

Info

Publication number: CN117075363A
Application number: CN202311034225.4A
Authority: CN
Inventors: 许文渊
Original assignee: Chongqing Zizhe Technology Co ltd
Current assignee: Chongqing Zizhe Technology Co ltd
Priority date: 2023-08-16
Filing date: 2023-08-16
Publication date: 2023-11-17

Abstract

The application provides an optical signal phase modulation device and a gyroscope. The optical signal phase modulation device comprises a substrate, an optical waveguide layer, a piezoelectric control unit and an isolation layer. An optical waveguide layer is provided on the substrate, the optical waveguide layer being for transmitting an optical signal. The piezoelectric control unit is arranged on one side of the optical waveguide layer, which is away from the substrate, and can apply pressure to the optical waveguide layer to adjust the refractive index of the optical waveguide layer to the optical signal. The isolation layer is arranged between the piezoelectric control unit and the optical waveguide layer and is used for blocking the diffusion of the piezoelectric material in the piezoelectric control unit to the cladding layer of the optical waveguide layer. The isolation layer is arranged between the piezoelectric control unit and the optical waveguide layer, and can serve as a diffusion barrier layer with low optical absorption so as to ensure the light transmission efficiency in the core layer; the isolation layer also provides a good crystal orientation for the piezoelectric control unit, and improves the yield of the piezoelectric control unit. Therefore, the structure can effectively reduce the power consumption of optical signal transmission and improve the efficiency of phase modulation.

Description

Optical signal phase modulation device and gyroscope

Technical Field

The application belongs to the technical field of integrated optical sensing, and particularly relates to an optical signal phase modulation device and a gyroscope.

Background

In the fields of unmanned, aviation navigation, geographical mapping and the like, the fiber-optic gyroscope plays an important role because it can accurately measure the angular displacement of an object. And compared with the traditional mechanical gyroscope, the optical gyroscope is not influenced by impact and vibration, so that the optical gyroscope has the advantages of convenience in installation and wider application range.

The rapid development of integrated optical technology has indicated the direction of advancement for the miniaturization, low cost and low power consumption of fiber optic gyroscopes (Swac-P, size Weight cost and Power). The adoption of monolithic integration schemes to fully chip the individual optical components of the fiber optic gyroscope (light source, detector, beam splitter, modulator and interference ring) is the initial concept of integrated optical gyroscopes. The optical gyro of the chip type not only can greatly reduce the system volume, but also can be like an integrated circuit, and the chip cost is continuously reduced through mass production along with the increase of the shipment volume. The chip production flow which is fully automatic can further replace the complex optical fiber device fusion and debugging process of the optical fiber gyro, and further improves the batch and standardized production capacity of the gyro. Researchers have quickly found that there are a number of material compatibility and process manufacturing challenges associated with the current desire to achieve light "output", "detection", "modulation" and "low loss transmission" functions on a single chip, subject to limitations in the development of integrated optical material processes.

For an interference type optical gyroscope, stable phase modulation is an important guarantee for realizing high-sensitivity and high-accuracy extraction of Sagnac phase difference signals in a system, so that the phase shifter is required to have higher performance characteristics such as modulation responsivity, modulation linearity, large modulation bandwidth and the like. The integrated phase shifter widely applied in the fiber-optic gyroscope system at present is mainly realized based on the electro-optic effect in the bulk lithium niobate waveguide, is used for realizing closed-loop feedback of the interference phase in the fiber-optic gyroscope under different precision, so as to reduce the influence of device drift, and has higher precision. However, in the process of chip formation of the integrated optical gyroscope, the problem of modulation by using the lithium niobate thin film is also more remarkable: (1) The low cost dry etching problem of lithium niobate materials is difficult to solve. Dry etching is the first choice for integrated photonics, but unlike most other integrated photonics platforms (e.g., si and SiNx), lithium niobate does not have an appropriate reactive ion etching recipe. Fluorine-based Reactive Ion Etching (RIE) can be effective in removing lithium by forming volatile niobium fluoride (Nb). However, it also forms non-volatile lithium fluoride (LiF) and causes serious redeposition problems. LiF generated by the redeposition problem in thin film lithium niobate waveguides can exhibit extremely high resistance to further etching, thereby increasing sidewall roughness and scattering losses. (2) The lithium niobate material and the silicon light material need an interlayer coupling structure to realize the transmission of light among different materials, wherein the interlayer coupling structure has higher alignment precision requirement, and multimode is easy to excite under the non-alignment condition. While a portion of the energy coupled into the base film by the multimode modulation may cause non-reciprocal errors that are difficult to eliminate by the system

In recent years, cladding stress management of waveguides in integrated platforms such as silicon-on-insulator (SOI) has been studied. The strain is generated by changing the stress applied to the waveguide by the inverse piezoelectric effect of the piezoelectric material, and the equivalent refractive index of the optical transmission mode is changed by the elasto-optic effect. In this way, the photoelastic effect may produce a relatively strong birefringence compared to other effects used to change the refractive index of the optical medium (e.g., thermo-optic effects or injected carrier dispersion effects).

Therefore, in addition to the solution based on lithium niobate material, the elasto-optic phase shifter based on piezoelectric thin film material will provide a powerful solution for the key active control device-phase shifter in the optical gyro integrated driving chip. The manufacturing difficulty of the piezoelectric modulator at present is the compatibility problem of the piezoelectric material layer manufacturing process and the silicon light manufacturing process. Accordingly, improvements to the above-described problems are needed.

Disclosure of Invention

The embodiment of the application provides an optical signal phase modulation device and a gyroscope, which can reduce the diffusion of piezoelectric materials to a core layer, reduce the transmission loss of optical signals and improve the adjustment efficiency.

In a first aspect, the present application provides an optical signal phase modulation device, including a substrate, an optical waveguide layer, a piezoelectric control unit, and an isolation layer. An optical waveguide layer is provided on the substrate, and is used for transmitting optical signals. The piezoelectric control unit is arranged on one side of the optical waveguide layer, which is away from the substrate, and can apply pressure to the optical waveguide layer so as to adjust the refractive index of the optical waveguide layer for optical signals. The isolation layer is arranged between the piezoelectric control unit and the optical waveguide layer and is used for blocking the diffusion of the piezoelectric material in the piezoelectric control unit to the optical waveguide layer.

In some embodiments, the barrier material comprises at least one of strontium titanate, silica, a lanthanide, a nitrate compound of an ytterbium element.

In some embodiments, the optical waveguide layer includes a first cladding layer, a second cladding layer, and a core layer. The first cladding layer is arranged on the substrate. The second cladding layer is arranged on one side of the first cladding layer, which is away from the substrate. The core layer is arranged between the first cladding layer and the second cladding layer, the refractive index of the core layer is larger than that of the first cladding layer, and the refractive index of the core layer is larger than that of the second cladding layer.

In some embodiments, the isolation layer is disposed on a side of the second cladding layer facing away from the first cladding layer, the isolation layer comprising an isolation material having a greater uniformity of crystal orientation than the second cladding layer.

In some embodiments, the optical waveguide layer further comprises a detection unit capable of acquiring an optical signal in the core layer and converting the optical signal into an electrical signal.

In some embodiments, the surface of the second cladding layer facing away from the first cladding layer protrudes to form a protrusion, the orthographic projection of the protrusion onto the substrate at least partially coinciding with the orthographic projection of the core layer onto the substrate.

In some embodiments, the surface of the substrate facing the optical waveguide layer is concave to form a recess for receiving at least a portion of the optical waveguide layer.

In some embodiments, the orthographic projection of the core layer onto the substrate at least partially coincides with the groove.

In some embodiments, the piezoelectric control unit includes a first electrode, a second electrode, and a layer of piezoelectric material, the first electrode being disposed on a side of the optical waveguide layer facing away from the substrate. The second electrode is arranged on one side of the first electrode, which is away from the substrate. And the piezoelectric material layer is arranged between the first electrode and the second electrode. The first electrode and the second electrode can apply voltage to the piezoelectric material layer to deform the piezoelectric material layer.

In some embodiments, the number of piezoelectric control units is two, and the two piezoelectric control units are disposed at intervals along a first direction on a side of the optical waveguide layer facing away from the substrate, the first direction intersecting a direction in which the optical signal in the core layer propagates.

In some embodiments, the piezoelectric control unit includes a piezoelectric material layer, a first electrode, and a second electrode, where the piezoelectric material layer is disposed on a side of the piezoelectric material layer away from the substrate, and the first electrode and the second electrode are disposed on a side of the piezoelectric material layer away from the substrate.

In some embodiments, the orthographic projection of the piezoelectric material layer on the substrate has an extension width W1 along a first direction, and the orthographic projection of the core layer on the substrate has an extension width W2 along the first direction, the first direction intersecting a direction in which the optical signal propagates in the core layer. Wherein, W1 and W2 satisfy the relation: W1/W2 is more than or equal to 13 and less than or equal to 20.

In some embodiments, the piezoelectric material layer has an extension length H1 in the thickness direction of the substrate, and the first electrode layer has an extension length H2 in the thickness direction of the substrate. Wherein, H1 and H2 satisfy the relation: H1/H2 is more than or equal to 5 and less than or equal to 15.

In a second aspect, an embodiment of the present application provides a gyroscope, including an optical signal phase modulation device in any one of the foregoing embodiments.

According to the optical signal phase modulation device and the gyroscope, the optical signal is transmitted through the optical waveguide layer, and the piezoelectric control unit can change the refractive index of the optical waveguide layer so as to control the phase of optical transmission in the optical waveguide layer. And, locate the isolation layer between optical waveguide layer and the piezoelectric control unit: first, the isolation layer can act as a diffusion barrier layer with low optical absorption, ensuring the light transmission efficiency in the core layer; second, the isolation layer provides a good crystal orientation for the piezoelectric control unit, and improves the manufacturing efficiency of the piezoelectric control unit. Therefore, the structure can effectively reduce the power consumption of optical signal transmission and improve the efficiency of phase modulation.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic cross-sectional structure of an optical signal phase modulation device according to an embodiment of the present application;

fig. 2 is a schematic diagram illustrating a cross-sectional structure of a detection unit of an optical signal phase modulation device according to an embodiment of the present application;

FIG. 3 is a schematic cross-sectional view of a protruding portion of an optical signal phase modulation device according to an embodiment of the present application;

FIG. 4 is a schematic diagram illustrating a cross-sectional structure of a groove of an optical signal phase modulation device according to an embodiment of the present application;

fig. 5 is a schematic cross-sectional structure of an optical signal phase modulation device according to another embodiment of the present application;

fig. 6 is a schematic cross-sectional structure of an optical signal phase modulation device according to another embodiment of the present application;

fig. 7 is a schematic cross-sectional structure of an optical signal phase modulation device according to still another embodiment of the present application;

fig. 8 is a schematic diagram illustrating the dimensions of an optical signal phase modulation device according to an embodiment of the present application.

In the drawings, the drawings are not necessarily to scale.

Reference numerals in the specific embodiments are as follows:

1. an optical signal phase modulation device; x, a first direction; y, second direction; 10. a substrate; 101. a groove; 20. an optical waveguide layer; 201. a first cladding layer; 202. a second cladding layer; 203. a core layer; 204. a detection unit; 205. a boss; 30. a piezoelectric control unit; 301. a first electrode; 302. a second electrode; 303. a piezoelectric material layer; 304. a first wire; 305. a second wire; 306. a first control unit; 307. a second control unit; 308. a third electrode; 309. a fourth electrode; 310. a second piezoelectric material; 311. a fifth electrode; 312. a sixth electrode; 313. a third piezoelectric material; 314. a third wire; 315. a fourth wire; 316. a fifth wire; 317. a sixth wire; 40. an isolation layer.

Detailed Description

Features and exemplary embodiments of various aspects of the present application will be described in detail below, and in order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail below with reference to the accompanying drawings and the detailed embodiments. It should be understood that the particular embodiments described herein are meant to be illustrative of the application only and not limiting. It will be apparent to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the application by showing examples of the application.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element.

It should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of description, and do not indicate or imply that the apparatus or element to be referred to must have a specific direction, be configured and operated in a specific direction, and thus should not be construed as limiting the patent.

It should also be noted that unless explicitly stated or limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.

In the optical waveguide technology, active control of waveguide material stress can be achieved by depositing a piezoelectric thin film material on top of the waveguide structure. The piezoelectric material is deformed by applying a driving voltage, so that the optical waveguide is strained, and the refractive index of the material is changed by the wave guided missile light effect, thereby realizing the function of phase modulation. However, in the process of chip formation of integrated optical gyroscopes, there are still some problems to achieve phase modulation on silicon optical platforms using lead zirconate titanate. For example, the waveguide structure is disposed adjacent to the lead zirconate titanate piezoelectric material, and metal elements in the piezoelectric material (lead zirconate titanate) may diffuse into the waveguide cladding material during the preparation process, resulting in a decrease in purity of the waveguide cladding material and absorption of an optical signal, resulting in a greatly reduced optical signal transmission capability and improved optical transmission loss.

In some related technologies, a metal electrode layer is further disposed between the piezoelectric material and the waveguide structure, where the metal electrode layer is usually a platinum electrode layer or a gold electrode layer, and the metal electrode layer can play a role in blocking diffusion of lead zirconate titanate metal elements, but generally has a strong absorption effect on light. In order to reduce the optical absorption losses, the minimum distance between the metal electrode layer and the waveguide structure can only be further enlarged. The stress generated by the piezoelectric material decreases with increasing distance, which makes it difficult for the waveguide structure to fully utilize the strain effect generated by the piezoelectric material, resulting in an increase in the modulation power consumption of the modulator.

Based on the above, embodiments of the present application provide an optical signal phase modulation apparatus. As shown in fig. 1 and 2, an optical signal phase modulation device 1 according to an embodiment of the present application includes a substrate 10, an optical waveguide layer 20, a piezoelectric control unit 30, and an isolation layer 40. An optical waveguide layer 20 is provided on the substrate 10, the optical waveguide layer 20 being for transmitting optical signals. The piezoelectric control unit 30 is provided on a side of the optical waveguide layer 20 facing away from the substrate 10, and the piezoelectric control unit 30 is capable of applying pressure to the optical waveguide layer 20 to adjust the refractive index of the optical waveguide layer 20 for optical signals. The isolation layer 40 is disposed between the piezoelectric control unit 30 and the optical waveguide layer 20, and the isolation layer 40 is used to block diffusion of the piezoelectric material in the piezoelectric control unit 30 to the optical waveguide layer 20.

Illustratively, the substrate 10 may be a silicon substrate 10. The isolation layer 40 is provided on the substrate 10, i.e., the isolation layer 40 is in close contact with the substrate 10. Isolation layer 40 may be deposited, grown on substrate 10. Specifically, the spacer layer 40 film forming step may include: at least one method of Chemical Vapor Deposition (CVD), atomic Layer Deposition (ALD), plasma Enhanced Chemical Vapor Deposition (PECVD), plasma Enhanced Atomic Layer Deposition (PEALD), pulsed Chemical Vapor Deposition (PCVD), low Pressure Chemical Vapor Deposition (LPCVD), subatmospheric chemical vapor deposition (SACVD), atmospheric Pressure Chemical Vapor Deposition (APCVD), spatial ALD, radical assisted film formation, supercritical fluid film formation. The method described above may be selected according to the actual needs, and likewise, the isolation layer 40 may be prepared by other techniques known in the art, without limitation.

In the above-described embodiment, the provision of the substrate 10 provides the optical waveguide layer 20 with a good growth crystal orientation, facilitating the growth of the optical waveguide layer 20. The optical waveguide layer 20 has low light absorption characteristics, and improves light transmission efficiency. The piezoelectric control unit 30 is capable of deforming under voltage control, and the deformation of the piezoelectric control unit 30 generates strain on the optical waveguide layer 20, so that the elasto-optical effect of the optical waveguide layer 20 changes the refractive index thereof, and further modulation of the optical phase is realized.

Further, the isolation layer 40 is arranged in the modulation device, so that the diffusion of the piezoelectric material of the piezoelectric control unit 30 into the optical waveguide layer 20 is reduced, and the absorption of the optical waveguide layer 20 to the light energy is reduced; in addition, by providing the isolation layer 40, the distance between the piezoelectric control unit 30 and the optical waveguide layer 20 can be further reduced, the sensitivity of piezoelectric control is improved, the transmission efficiency of the optical waveguide layer 20 is improved, and the modulation loss is reduced. Further, the isolation layer 40 can also be deformed under the action of the piezoelectric control unit 30, so that the above structure can still realize the control of the optical waveguide layer 20 by the piezoelectric control unit 30.

In some embodiments of the present application, isolation layer 40 comprises an isolation material having a greater crystal orientation uniformity than that of optical waveguide layer 20. In the above technical solution, the higher the crystal orientation consistency is, the higher the compactness of the material is, and the higher the crystal orientation consistency is, the higher the control efficiency of the piezoelectric control unit 30 can be improved. The piezoelectric efficiency of the piezoelectric control unit 30 depends greatly on the crystal orientation and the degree of densification of the material of the isolation layer 40, and when the isolation material is higher in crystal orientation uniformity and higher in degree of densification, the piezoelectric effect is more excellent, and the modulation power consumption of the piezoelectric control unit 30 is lower.

In some embodiments of the application, the barrier material comprises at least one of strontium titanate, silica, a nitrate compound of a lanthanide, ytterbium element. The above materials all have the characteristic of high crystal orientation uniformity, and most of them can perform good growth on the optical waveguide layer 20, and are excellent materials for the isolation layer 40.

In some embodiments of the present application, the optical waveguide layer 20 includes a first cladding layer 201, a second cladding layer 202, and a core layer 203. The first cladding layer 201 is disposed on the substrate 10, the second cladding layer 202 is disposed on a side of the first cladding layer 201 facing away from the substrate 10, and the core layer 203 is disposed between the first cladding layer 201 and the second cladding layer 202. Wherein the refractive index of the core layer 203 is greater than the refractive index of the first cladding layer 201, and the refractive index of the core layer 203 is greater than the refractive index of the second cladding layer 202.

Illustratively, the first cladding 201 and the second cladding 202 may be fabricated from a silicon dioxide material. The core layer 203 may be fabricated from at least one of silicon nitride or a silicon material. Alternatively, the first cladding 201 and the second cladding 202 are made of the same material by integral molding. The first cladding 201 and the second cladding 202 surround the core 203. In the above-described embodiment, the refractive index of the core layer 203 in the optical waveguide layer 20 is high, and the optical signal is restricted to propagate in the core layer 203, so that the transmission loss of the optical waveguide layer 20 can be effectively reduced.

As shown in fig. 2, in some embodiments of the present application, the optical waveguide layer 20 further includes a detection unit 204, and the detection unit 204 is capable of acquiring an optical signal in the core layer 203 and converting the optical signal into an electrical signal.

Illustratively, the detection unit 204 may be implemented using silicon material to fabricate a silicon germanium detector, and the detection unit 204 may include: the silicon nitride layer is arranged on one side of the first cladding 201, which is away from the substrate 10, the detection layer is arranged on one side of the silicon carbide layer, which is away from the first cladding 201, the cathode and the anode. The detection layer comprises a silicon germanium detection material and can acquire an optical signal in the core layer 203. The cathode is electrically connected with the silicon nitride layer, and the anode is connected with the detection layer. Wherein the detection layer is connected to the core layer 203, and the optical signal in the core layer 203 can be obtained. After the anode applies voltage to the detection layer, when the optical signal acts on the silicon germanium detection material, the silicon germanium detection material can convert the optical signal into an electric signal and output the electric signal to realize real-time detection of the optical signal. The above structure can also be replaced by a micro silicon germanium detection circuit in the prior art, and details are not described here.

In the above-described configuration, the micro detector is integrated in the optical waveguide layer 20, and the optical signal in the core layer 203 is detected, so that the optical signal can be converted into an electrical signal, thereby realizing miniaturization of the optical signal detection, and further improving the integration level of the optical signal phase modulation device 1.

As shown in fig. 3, in some embodiments of the application, the surface of the second cladding layer 202 facing away from the first cladding layer 201 protrudes to form a protrusion 205, the orthographic projection of the protrusion 205 onto the substrate 10 at least partially coinciding with the orthographic projection of the core layer 203 onto the substrate 10. Illustratively, a portion of the boss 205 protrudes toward the piezoelectric control unit 30, and presses the isolation layer 40, the piezoelectric control unit 30 to form an upward boss. In the above technical solution, the protruding portion 205 is disposed above the core layer 203, and the protruding portion 205 can improve the sensitivity of the piezoelectric control unit 30 to control, so as to improve the response of the piezoelectric control unit 30 to the strain of the core layer 203 and improve the efficiency of phase modulation.

As shown in fig. 3 and 4, in some embodiments of the present application, the surface of the substrate 10 facing the optical waveguide layer 20 is concave to form a groove 101, the groove 101 being configured to receive at least a portion of the optical waveguide layer 20. In the above technical solution, the grooves 101 can accommodate the optical waveguide layer 20 that presses the substrate 10 due to deformation, and increase the movable space of the optical waveguide layer 20, so as to increase the equivalent mode refractive index difference of the optical waveguide layer 20 under the same stress, and improve the phase modulation efficiency of the piezoelectric control unit 30.

In some embodiments of the application, the orthographic projection of the core layer 203 onto the substrate 10 coincides at least partially with the groove 101. Alternatively, the orthographic projection of the core layer 203 onto the substrate 10 is completely coincident with the groove 101. In the above technical solution, the grooves 101 are disposed corresponding to the core layer 203, so that the sensitivity of the core layer 203 in the optical waveguide layer 20 to strain can be improved, and the accuracy of the phase modulation of the piezoelectric control unit 30 can be further improved.

As shown in fig. 5, in some embodiments of the present application, the optical signal phase modulation device 1 includes a substrate 10, an optical waveguide layer 20, a piezoelectric control unit 30, and an isolation layer 40. An optical waveguide layer 20 is provided on the substrate 10, the optical waveguide layer 20 being for transmitting optical signals. The piezoelectric control unit 30 is provided on a side of the optical waveguide layer 20 facing away from the substrate 10, and the piezoelectric control unit 30 is capable of applying pressure to the optical waveguide layer 20 to adjust the refractive index of the optical waveguide layer 20 for optical signals. The isolation layer 40 is disposed between the piezoelectric control unit 30 and the optical waveguide layer 20, and the isolation layer 40 is used to block diffusion of the piezoelectric material in the piezoelectric control unit 30 to the optical waveguide layer 20.

The optical waveguide layer 20 further comprises a detection unit 204, the detection unit 204 being capable of acquiring an optical signal in the core layer 203 and converting the optical signal into an electrical signal. The surface of the substrate 10 facing the optical waveguide layer 20 is concave to form a recess 101, the recess 101 being adapted to receive at least part of the optical waveguide layer 20. The orthographic projection of the core layer 203 onto the substrate 10 coincides at least partially with the groove 101. Alternatively, the orthographic projection of the core layer 203 onto the substrate 10 is completely coincident with the groove 101.

In the above embodiment, the isolation layer 40 is disposed in the modulation device, which reduces the buckle diffusion of the piezoelectric material of the piezoelectric control unit 30 into the optical waveguide layer 20, reduces the absorption of the optical waveguide layer 20 to the optical energy, improves the transmission efficiency of the optical waveguide layer 20, and reduces the modulation loss. The micro detector is integrated in the optical waveguide layer 20 to detect the optical signal, and can convert the optical signal into an electrical signal, thereby realizing the miniaturization of the optical signal detection and further improving the integration level of the optical signal phase modulation device 1. Further, the grooves 101 can accommodate the optical waveguide layer 20 pressed against the substrate 10 by deformation, and can improve the sensitivity of the optical waveguide layer 20 to strain, and improve the efficiency and accuracy of the phase modulation of the piezoelectric control unit 30. The grooves 101 are provided corresponding to the core layer 203, so that the sensitivity of the core layer 203 in the optical waveguide layer 20 to strain can be improved, and the accuracy of the phase modulation of the piezoelectric control unit 30 can be further improved.

As shown in fig. 1 to 5, in some embodiments of the present application, the piezoelectric control unit 30 includes a first electrode 301, a second electrode 302, and a piezoelectric material layer 303. The first electrode 301 is provided on a side of the optical waveguide layer 20 facing away from the substrate 10. The second electrode 302 is provided on a side of the first electrode 301 facing away from the substrate 10. The piezoelectric material layer 303 is disposed between the first electrode 301 and the second electrode 302. Wherein the first electrode 301 and the second electrode 302 are capable of applying a voltage to the piezoelectric material layer 303 to deform the piezoelectric material layer 303.

Illustratively, a first electrode metal material, a piezoelectric thin film material, and a second electrode metal material are sequentially deposited on top of the optical waveguide layer 20 to obtain the piezoelectric control unit 30 described above, so as to realize active control of stress of the optical waveguide layer 20. By energizing the first electrode 301 and the second electrode 302, the piezoelectric material layer 303 is deformed by applying a driving voltage, so that the optical waveguide layer 20 is strained, and the refractive index of the material of the core layer 203 is changed by the wave guided missile light effect, thereby realizing the function of phase modulation of the optical signal. The piezoelectric film material includes: at least one of barium titanate (BaTiO), lead zirconate titanate (PZT), zinc oxide (ZnO), aluminum nitride (AlN) or scandium-doped aluminum nitride (sc_aln). The core of the material is characterized by a compound or doped mixture material with an inverse piezoelectric effect. The preparation method of the piezoelectric material layer 303 may include at least one of magnetron sputtering, a sol gel method, and pulsed laser deposition.

In the above technical solution, the voltage applied to the piezoelectric material layer 303 by the two electrodes deforms, so as to convert the electrical signal into the pressing force on the optical waveguide layer 20. The structure has the characteristics of high modulation efficiency and low optical transmission loss.

In some alternative embodiments, the piezoelectric control unit 30 further includes a first wire 304 and a second wire 305. Wherein, the first wire 304 is electrically connected to the first electrode 301, and the second wire 305 is electrically connected to the second electrode 302. By providing the first wire 304 and the second wire 305, the first electrode 301 and the second electrode 302 can be connected to an external power source, and a voltage can be applied to the piezoelectric material layer 303, thereby realizing active control of stress of the core layer 203.

As shown in fig. 6, in some embodiments of the present application, the number of piezoelectric control units 30 is two, and two piezoelectric control units 30 are disposed at intervals along a first direction X on a side of the optical waveguide layer 20 facing away from the substrate 10, the first direction X intersecting a direction in which an optical signal propagates in the core layer 203. Illustratively, the first direction X is perpendicular to the direction of optical signal propagation in the core layer 203.

The piezoelectric control unit 30 includes, for example, a first control unit 306 and a second control unit 307. The first control unit 306 and the second control unit 307 are disposed at intervals on both sides of the optical waveguide layer 20 in the first direction X. The propagation of the optical signal in the optical waveguide layer 20 is along the axial direction of the core layer 203, and the first direction X may be the radial direction of the core layer 203. The first control unit 306 and the second control unit 307 are arranged along the radial direction of the core layer 203, so that the space on the upper side of the optical waveguide layer 20 can be better utilized, the distance between the first control unit 306 and the second control unit 307 is ensured to be large enough, the electrical bandwidth of the piezoelectric control unit 30 is increased, and the modulation efficiency is improved.

Specifically, the first control unit 306 includes a third electrode 308, a fourth electrode 309, and a second piezoelectric material 310. The third electrode 308 is disposed on the isolation layer 40, the fourth electrode 309 is disposed on a side of the third electrode facing away from the isolation layer 40, and the second piezoelectric material 310 is disposed between the third electrode 308 and the fourth electrode 309. The first control unit 306 further includes a third wire 314 and a fourth wire 315. The third wire 314 is electrically connected to the third electrode 308, and the fourth wire 315 is electrically connected to the fourth electrode 309.

The second control unit 307 includes a fifth electrode 311, a sixth electrode 312, and a third layer of piezoelectric material 313 303. The fifth electrode 311 is disposed on the isolation layer 40, the sixth electrode 312 is disposed on a side of the fifth electrode 311 facing away from the isolation layer 40, and the third piezoelectric material 313 layer 303 is disposed between the fifth electrode 311 and the sixth electrode 312, and the second control unit 307 further includes a fifth conductive line 316 and a sixth conductive line 317. The fifth wire 316 is electrically connected to the fifth electrode 311, and the sixth wire 317 is electrically connected to the sixth electrode 312.

The above-described structure changes the electric field application manner of the piezoelectric control unit 30. The structural electric field in this embodiment is applied along the first direction X on both sides and the cell in the embodiment of fig. 1 is applied along the second direction Y. Compared to the embodiment of fig. 1, the distance between the first control unit 306 and the second control unit 307 is increased, which can effectively increase the electrical bandwidth of the piezoelectric control unit 30 and improve the modulation efficiency.

As shown in fig. 7, in some embodiments of the present application, the piezoelectric control unit 30 includes a piezoelectric material layer 303, a first electrode 301, and a second electrode 302, where the piezoelectric material layer 303 is disposed on a side of the piezoelectric material layer 303 away from the substrate 10, and the first electrode 301 and the second electrode 302 are disposed on a side of the piezoelectric material layer 303 away from the substrate 10. Illustratively, the first electrode 301 and the second electrode 302 are disposed on both sides of the piezoelectric material layer 303 at intervals along the first direction X. The propagation of the optical signal in the optical waveguide layer 20 is along the axial direction of the core layer 203, and the first direction X may be the radial direction of the core layer 203. The first electrode 301 and the second electrode 302 are arranged along the radial direction of the core layer 203, so that the space on the upper side of the optical waveguide layer 20 can be better utilized, the electric field application mode of the piezoelectric control unit 30 is changed, the distance between the first electrode 301 and the second electrode 302 is ensured to be large, the electrical bandwidth of the piezoelectric control unit 30 is increased, and the modulation efficiency is improved.

As shown in fig. 8, in some embodiments of the present application, the front projection of the piezoelectric material layer 303 on the substrate 10 has an extension width W1 along the first direction X, and the front projection of the core layer 203 on the substrate 10 has an extension width W2 along the first direction X, which intersects the direction in which the optical signal propagates in the core layer 203. Wherein, W1 and W2 satisfy the relation: W1/W2 is more than or equal to 13 and less than or equal to 20. Under the value range, the half-wave voltage of the waveguide layer is minimum, and the modulation efficiency is high.

Referring to table one, when the ratio of the width W1 of the piezoelectric material layer 303 to the width W2 of the core layer 203 is different, the half-wave voltage value of the optical signal phase modulation device 1 is measured.

List one

Typically, the half-wave voltage value of the optical signal phase modulation device 1 is less than or equal to 6.5v.cm to be an acceptable range. As can be seen from Table one, in comparative example one, W1/W2 was 10, the half-wave voltage reached 9.1V.cm, and the half-wave voltage exceeded the standard value. In the second comparative example, W1/W2 was 23, and the half-wave voltage reached 7.3V.cm. The half-wave voltages of the optical signal phase modulation devices 1 of the first and second comparative examples exceed the standard value, and thus the modulation loss is large and the modulation efficiency is low.

In the first, second and third embodiments, the half-wave voltage is less than 6.5v.cm, the modulation loss is low, and the manufacturing efficiency is high.

Specifically, when the ratio W1/W2 of the width W1 of the piezoelectric material layer 303 to the width W2 of the core layer 203 is in the range of 13 to 20, the probability of alignment between the piezoelectric material layer 303 and the core layer 203 is high, and manufacturing is facilitated. Illustratively, when W1/W2 is smaller than 13, the width of the piezoelectric material layer 303 is smaller, the probability of occurrence of staggering between the piezoelectric material layer 303 and the core layer 203 is increased, the range of influence of deformation of the piezoelectric material layer 303 on the core layer 203 is reduced, and thus the modulation efficiency thereof is reduced, and the half-wave voltage is increased. When W1/W2 is greater than 20, the width of the core layer 203 is too small, the deformation of the piezoelectric material layer 303 will cause too large deformation of the core layer 203, so that the control accuracy requirement of the deformation of the piezoelectric material layer 303 is improved by the above structure, and the efficiency of production and manufacture is reduced. In summary, controlling the ratio W1/W2 of the width W1 of the piezoelectric material layer 303 to the width W2 of the core layer 203 within the range of 13-20 can ensure the modulation efficiency of the piezoelectric control unit 30, and at the same time, ensure the production efficiency.

With continued reference to fig. 8, in some embodiments of the present application, the extension length of the piezoelectric material layer 303 along the thickness direction of the substrate 10 is H1, and the extension length of the first electrode layer 301 along the thickness direction of the substrate 10 is H2. The thickness direction of the substrate 10 is the second direction Y. Wherein, H1 and H2 satisfy the relation: H1/H2 is more than or equal to 5 and less than or equal to 15. In the technical scheme, the half-wave voltage of the waveguide layer is minimum, and the modulation efficiency is high.

Referring to table two, the half-wave voltage value of the optical signal phase modulation device 1 is measured when the ratio of the extension length H1 of the piezoelectric material layer 303 along the thickness direction of the substrate 10 to the extension length H2 of the first electrode layer 301 along the thickness direction of the substrate 10 is different.

Watch II

Typically, the half-wave voltage value of the optical signal phase modulation device 1 is less than or equal to 6.5v.cm to be an acceptable range. As can be seen from Table II, in comparative example III, H1/H2 was 0.5, and half-wave voltage reached 9.1V.cm. In comparative example four, H1/H2 was 1 and half-wave voltage reached 15.0V.cm. In the fifth comparative example, H1/H2 was 20, and the half-wave voltage reached 6.6V.cm. The half-wave voltages of the optical signal phase modulation devices 1 of the third, fourth and fifth comparative examples all exceed the standard value, and thus the modulation loss is large and the modulation efficiency is low.

In the fourth, fifth and sixth embodiments, the half-wave voltage is less than 6.5v.cm, the modulation loss is low, and the manufacturing efficiency is high.

Specifically, when the ratio H1/H2 of the extension length H1 of the piezoelectric material layer 303 in the thickness direction of the substrate 10 to the extension length H2 of the first electrode layer 301 in the thickness direction of the substrate 10 is in the range of 5 to 15, the modulation efficiency is high.

Illustratively, when H1/H2 is less than 5, the thickness of the piezoelectric material layer 303 is relatively small, the deformation of the piezoelectric material layer 303 under the action of the electric field is also small, and the influence of the deformation of the piezoelectric material layer 303 on the core layer 203 is reduced, so that the modulation efficiency is reduced and the half-wave voltage is increased. When H1/H2 is greater than 15, the thickness of the piezoelectric material layer 303 is relatively large, and the first electrode 301 applies a large electric field to the piezoelectric material layer 303, so that the modulation efficiency thereof is reduced and the half-wave voltage is increased. In summary, the ratio H1/H2 of the extension length H1 of the piezoelectric material layer 303 in the thickness direction of the substrate 10 to the extension length H2 of the first electrode layer 301 in the thickness direction of the substrate 10 is controlled within the range of 5-15, so that the modulation efficiency of the piezoelectric control unit 30 can be ensured.

The embodiment of the application also provides a gyroscope, which comprises the optical signal phase modulation device 1 in any embodiment.

The optical signal phase modulation device 1 and the gyroscope provided by the embodiments of the present application provide a good growth crystal orientation for the optical waveguide layer 20 by arranging the substrate 10, and the piezoelectric control unit 30 can change the refractive index of the optical waveguide layer 20 so as to control the phase of optical transmission in the optical waveguide layer 20. Wherein the isolation layer 40 is disposed between the piezoelectric control unit 30 and the optical waveguide layer 20, and first, the isolation layer 40 can act as a diffusion barrier layer with low optical absorption, ensuring the light transmission efficiency in the core layer 203; second, the isolation layer 40 provides a good crystal orientation for the piezoelectric control unit 30, improving the manufacturing efficiency of the piezoelectric control unit 30. Therefore, the structure can effectively reduce the power consumption of optical signal transmission and improve the efficiency of phase modulation.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application, and are intended to be included within the scope of the appended claims and description. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims

1. An optical signal phase modulation apparatus, comprising:

a substrate;

an optical waveguide layer provided on the substrate, the optical waveguide layer being configured to transmit an optical signal;

the piezoelectric control unit is arranged on one side of the optical waveguide layer, which is away from the substrate, and can apply pressure to the optical waveguide layer so as to adjust the refractive index of the optical waveguide layer to the optical signal;

the isolation layer is arranged between the piezoelectric control unit and the optical waveguide layer and is used for blocking the diffusion of the piezoelectric material in the piezoelectric control unit to the optical waveguide layer.

2. The optical signal phase modulation device according to claim 1, wherein the isolation material comprises at least one of strontium titanate, silica, lanthanide, ytterbium nitrate compounds.

3. The optical signal phase modulation apparatus according to claim 2, wherein the optical waveguide layer comprises:

the first cladding layer is arranged on the substrate;

the second cladding layer is arranged on one side of the first cladding layer, which is away from the substrate;

the core layer is arranged between the first cladding layer and the second cladding layer, the refractive index of the core layer is larger than that of the first cladding layer, and the refractive index of the core layer is larger than that of the second cladding layer.

4. An optical signal phase modulation apparatus according to claim 3 wherein the isolation layer is disposed on a side of the second cladding layer facing away from the first cladding layer, the isolation layer comprising an isolation material having a greater uniformity of crystal orientation than the second cladding layer.

5. The optical signal phase modulation device according to claim 3, wherein the optical waveguide layer further comprises a detection unit capable of acquiring the optical signal in the core layer and converting the optical signal into an electrical signal.

6. An optical signal phase modulation device according to claim 3 wherein the surface of the second cladding layer facing away from the first cladding layer is convex to form a convex portion, the orthographic projection of the convex portion onto the substrate at least partially coinciding with the orthographic projection of the core layer onto the substrate.

7. An optical signal phase modulation device according to claim 3 wherein the surface of the substrate facing the optical waveguide layer is concave to form a recess for receiving at least part of the optical waveguide layer.

8. The optical signal phase modulation device of claim 7, wherein an orthographic projection of the core layer on the substrate at least partially coincides with the groove.

9. The optical signal phase modulation device according to any one of claims 3 to 8, wherein the piezoelectric control unit includes:

the first electrode is arranged on one side of the optical waveguide layer, which is away from the substrate;

the second electrode is arranged on one side of the first electrode, which is away from the substrate;

a piezoelectric material layer arranged between the first electrode and the second electrode,

wherein the first electrode and the second electrode are capable of applying a voltage to the piezoelectric material layer to deform the piezoelectric material layer.

10. The optical signal phase modulation device according to claim 9, wherein the number of the piezoelectric control units is two, and the two piezoelectric control units are disposed at intervals along a first direction on a side of the optical waveguide layer facing away from the substrate, the first direction intersecting a direction in which the optical signal in the core layer propagates.

11. The optical signal phase modulation device according to any one of claims 1-8, wherein the piezoelectric control unit comprises a layer of piezoelectric material, a first electrode and a second electrode, the layer of piezoelectric material being disposed on a side of the isolation facing away from the substrate, the first electrode and the second electrode being disposed on a side of the layer of piezoelectric material facing away from the substrate.

12. The optical signal phase modulation device according to claim 9, wherein the front projection of the piezoelectric material layer onto the substrate has an extension width W1 in a first direction, the front projection of the core layer onto the substrate has an extension width W2 in the first direction, the first direction intersects with a direction in which the optical signal propagates in the core layer,

wherein, W1 and W2 satisfy the relation: W1/W2 is more than or equal to 13 and less than or equal to 20.

13. The optical signal phase modulation device according to claim 9, wherein the extension length of the piezoelectric material layer in the thickness direction of the substrate is H1, the extension length of the first electrode layer in the thickness direction of the substrate is H2,

wherein, H1 and H2 satisfy the relation: H1/H2 is more than or equal to 5 and less than or equal to 15.

14. A gyroscope comprising an optical signal phase modulation apparatus as claimed in any of claims 1 to 13.