WO2022016734A1

WO2022016734A1 - Integrated optical phased array and control method thereof

Info

Publication number: WO2022016734A1
Application number: PCT/CN2020/125444
Authority: WO
Inventors: 白雅文; 林天华; 储涛
Original assignee: 浙江大学
Priority date: 2020-07-21
Filing date: 2020-10-30
Publication date: 2022-01-27
Also published as: CN113960812A; CN113960812B

Abstract

The present application provides an integrated optical phased array and a control method therefor, for use in the technical field of optical phased arrays. The integrated optical phased array comprises: a laser, a beamsplitter, a phase shifter, a dense waveguide, a planar waveguide, and a curved grating; the laser is used for generating a light source, and inputting the light source into the beamsplitter, obtaining multiple beams of light; the phase shifter is used for phase modulation, and inputting each phase-modulated beam of light into the dense waveguide; the dense waveguide is used for coupling the phase-modulated light beam into the planar waveguide; and the planar waveguide is used for coupling multiple light beams into a single light beam, then deflecting light, and emitting the deflected light beams via the curved grating. Thus, the crosstalk problem in the prior art of optical phase arrays caused by poor mode field binding of a grating antenna is solved. Also solved is the problem of relatively large size because the spacing between optical phase array grating antenna units cannot be reduced to half of the wavelength.

Description

Integrated optical phased array and its control method

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on the Chinese patent application with the application number of 202010705016.8 and the filing date of July 21, 2020, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is incorporated herein by reference.

technical field

The present application relates to the technical field of optical phased arrays, and in particular, to an integrated optical phased array and a control method thereof.

Background technique

In the related art, as shown in Figure 1, a beam splitter is used to divide a laser beam into multiple beams, phase modulation is performed on each beam with a specific phase shift, and then the beam is emitted through an optical antenna to realize the laser beam in space. deflection or shaping.

Therefore, it can be seen that in silicon-based optoelectronic integrated chips, limited by optical diffraction and waveguide structure, it is difficult to reduce the spacing of grating antenna elements to half the wavelength. In order to avoid the appearance of redundant grating lobes, it is necessary to The high-order grating lobe is suppressed by the non-uniform arrangement of the array to achieve the effect of only one grating lobe output, resulting in a larger device size, and due to the limitation of the mode field of the grating antenna, the crosstalk when light is transmitted in the grating antenna. There is a point where it will not be possible to continue the optimization, higher than the crosstalk propagating in the waveguide.

SUMMARY OF THE INVENTION

The present application aims to solve one of the technical problems in the related art at least to a certain extent.

Therefore, one purpose of the present application is to propose an integrated optical phased array, which can realize on-chip optical rotation, solve the problem of crosstalk caused by the poor binding of the grating antenna to the mode field in the existing optical phased array, and can reduce the size of the device , to solve the problem of large size caused by the fact that the arrangement spacing of the existing optical phased array grating antenna units cannot be reduced to half of the wavelength.

Another object of the present application is to propose a control method using an integrated optical phased array.

In order to achieve the above purpose, an embodiment of the present application proposes an integrated optical phased array, including: a laser, a beam splitter, a phase shifter, a dense waveguide, a slab waveguide and a curved grating; the laser is used to generate a light source, and The light source is input into the beam splitter to obtain multiple beams of light; the phase shifter is used for phase modulation of each beam of light, and each beam of light after phase modulation is input into the dense waveguide; the dense waveguide uses The phase-modulated light beams are coupled into the slab waveguide, and the slab waveguide is used to lightly deflect each light beam, and each light beam after the light deflection is emitted through the curved grating.

In the integrated optical phased array of the embodiment of the present application, a laser is used to generate a light source, and the light source is input into a beam splitter to obtain multiple beams of light; the phase shifter is used to phase-modulate each beam of light, and convert each A beam of light is input into the dense waveguide; the dense waveguide is used to couple the phase-modulated beam into the slab waveguide, and the slab waveguide is used to couple the multiple beams into one beam and then deflect the light, and pass the deflected beam through the Curved grating emission. Therefore, the problem of crosstalk caused by the poor binding of the grating antenna to the mode field in the existing optical phased array is solved, and the problem of the existing optical phased array grating antenna unit arrangement spacing cannot be reduced to half of the wavelength. The size of the problem is larger, the purpose of realizing on-chip optical rotation, and reducing the size of the device.

In addition, the integrated optical phased array according to the above embodiments of the present application may also have the following additional technical features:

Further, in an embodiment of the present application, the beam splitter is composed of a cascade of 1×2 multi-mode interference beam splitters or a star coupler.

Further, in an embodiment of the present application, the phase shifter is formed of a thermo-optic phase shifter or an electro-optic phase shifter.

Further, in an embodiment of the present application, the phase shifter is used to perform phase modulation on each beam of light, including:

Add a specific phase shift to each beam, when the deflection angle is θ, the additional phase is:

in,

Among them, λ is the wavelength, d is the adjacent waveguide, and i is the waveguide sequence (i=0, 1, 2...).

Further, in an embodiment of the present application, the dense waveguide uses a waveguide array structure based on sinusoidal spatial modulation.

Further, in an embodiment of the present application, each light beam is emitted from the dense waveguide, and the transmission field in the slab waveguide is:

Wherein, | En | is the field size, r _n is the distance monitoring points from the emission ^point, e j2πrn ^/ λ is a phase factor generated during propagation, ψ _n is the additional phase, In (θ, φ) is the The far-field direction function of the slab waveguide is described; when the light deflection angle is θ, the additional phase ψn of the phase-shift arm is calculated by the above formula, and the beam is deflected.

Further, in an embodiment of the present application, when no phase shift is added,

Among them, λ is the working wavelength, d ₀ is the array element interval, when the order m≠0,

In order to achieve the above purpose, a second aspect embodiment of the present application proposes a control method using an integrated optical phased array, including: acquiring a light source, and splitting the light source to obtain multiple beams of light; Each beam of light in the light is phase-modulated; each beam of light after phase modulation is coupled into a slab waveguide through a dense waveguide; the slab waveguide is used for optically deflecting each beam, and deflecting the Each beam is emitted through the curved grating.

In the control method of the application of the integrated optical phased array according to the embodiment of the present application, the light source is obtained, and the light source is subjected to beam splitting to obtain multiple beams of light; phase modulation is performed on each beam of the multiple beams of light; Each modulated light beam is coupled into the slab waveguide through the dense waveguide; the slab waveguide is used to lightly deflect the coupled light beam, and the deflected light beam is emitted through the curved grating. Thus, on-chip optical rotation is achieved, and the purpose of reducing the size of the device is achieved.

In addition, the control method using the integrated optical phased array according to the above embodiments of the present application may also have the following additional technical features:

Further, in an embodiment of the present application, the performing phase modulation on each of the multiple beams of light includes:

in,

Further, in an embodiment of the present application, the slab waveguide is used to deflect each beam of light, including:

Each beam emanates from the dense waveguide, where the slab waveguide has a transmission field of:

Additional aspects and advantages of the present application will be set forth, in part, from the following description, and in part will be apparent from the following description, or learned by practice of the present application.

Description of drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is a schematic diagram of an existing optical phased array according to an embodiment of the application;

FIG. 2 is a structural example diagram of an integrated optical phased array according to an embodiment of the application;

3 is a schematic diagram of an on-chip integrated optical phased array without crosstalk according to an embodiment of the present application;

4 is a simulation diagram of an optical phased array implementation process according to an embodiment of the application;

FIG. 5 is a schematic flowchart of a control method for applying an integrated optical phased array provided by an embodiment of the present application.

detailed description

The following describes in detail the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to be used to explain the present application, but should not be construed as a limitation to the present application.

The integrated optical phased array and its control method according to the embodiments of the present application will be described below with reference to the accompanying drawings.

FIG. 2 is a structural example diagram of an integrated optical phased array according to an embodiment of the present application. As shown in Figure 2, the integrated optical phased array method for generating high-speed video from a single motion blurred image includes: a laser 1, a beam splitter 2, a phase shifter 3, a dense waveguide 4, a slab waveguide 5 and a curved grating 6 .

Among them, the laser 1 is used to generate a light source, and the light source is input into the beam splitter 2 to obtain multiple beams of light.

The phase shifter 3 is used to perform phase modulation on each beam of light, and input each beam of light after phase modulation into the dense waveguide 4 .

The dense waveguide 4 is used to couple the phase-modulated light beams into the slab waveguide 5 , and the slab waveguide 5 is used to couple multiple light beams into one beam and then deflect the light, and transmit the deflected light beam through the curved grating 6 .

That is to say, the light emitted by the laser 1 is divided into multiple beams by the beam splitter 2, and then coupled to the slab waveguide 5 through the dense waveguide 4, and phase modulation is performed on each beam on the dense waveguide 4 with a specific phase shift added. The phase deflection is completed on the chip, and it is emitted through the curved grating, so as to realize the deflection or shaping of the laser beam on the chip.

Therefore, the difference is that the existing optical phased array realizes light deflection in space, while the present application realizes beam deflection and on-chip light rotation in a slab waveguide. Due to the limitation of the mode field of the grating antenna, the crosstalk of light in the waveguide is smaller than that in the grating antenna, so the optical phased array that eliminates the crosstalk is realized. The size of the existing optical phased array is too large due to the spacing requirement of the grating antenna, the present application reduces the size of the device by using a waveguide.

In the embodiment of the present application, the beam splitter 2 realizes the function of uniform light splitting, and may be composed of a cascade connection of 1×2 multi-mode interference beam splitters or a star coupler.

In the embodiment of the present application, the phase shifter 3 is constituted by a thermo-optical phase shifter or an electro-optical phase shifter.

In the embodiment of the present application, the phase shifter 3 is used to perform phase modulation on each beam of light, including:

in,

In the embodiment of the present application, the dense waveguide 4 uses a waveguide array structure based on sinusoidal spatial modulation. It can be understood that the dense waveguide 4 couples the phase-modulated beam into the slab waveguide 5, and the structure has large bandwidth, low loss, and crosstalk. It can reach below -40dB, and the spacing of the output waveguide array arrangement can be reduced to half of the wavelength, avoiding the appearance of grating lobes and solving the large crosstalk caused by the use of grating antennas in the existing optical phased arrays The problem.

In the embodiment of the present application, the slab waveguide 5 is used to complete the on-chip light rotation, each light beam is emitted from the dense waveguide 4, and the transmission field in the slab waveguide 5 is:

In this embodiment of the present application, when no phase shift is added,

It is understandable that in silicon-based optoelectronic integrated chips, limited by optical diffraction and waveguide structures, it is difficult to reduce the spacing of grating antenna elements to half the wavelength. However, in this application, due to The design of dense waveguide 4 effectively avoids this problem and achieves on-chip beam deflection.

In the embodiment of the present application, the curved grating 6 can realize the emission of light beams with a specific deflection angle from the flat plate area, thereby realizing the function of an optical phased array.

In order to make the integrated optical phased array of the present application more clear to those skilled in the art, as shown in FIG. 3 , an integrated optical phased array on a chip without crosstalk, from left to right, includes: a laser 1, a beam splitter 2, a shifter Phase device 3, dense waveguide 4, slab waveguide 5 and curved grating 6.

Specifically, the beam splitter 2 can be composed of a cascade of 1×2 multi-mode interference (MMI) beam splitters or a star coupler to realize the function of uniform light splitting.

Among them, the phase shifter 3 can be composed of an electro-optical phase shifter or a thermo-optical phase shifter, which can realize the phase modulation of each beam of light and add a specific phase shift function.

Among them, the dense waveguide 4 uses a waveguide array structure based on sinusoidal spatial modulation, which can realize the coupling of the phase-modulated light beam into the slab waveguide 5 .

Among them, the slab waveguide 5 is used to complete the on-chip optical rotation. After adjusting the phase shift arm to generate a phase difference, the equiphase plane is no longer perpendicular to the waveguide direction, but has a certain deflection, and the beams satisfying the equiphase relationship will be coherent and constructive. The beams that do not meet the equal-phase condition will cancel each other, so the direction of the beam is always perpendicular to the equal-phase plane, thereby realizing on-chip light deflection.

For example, as shown in Figure 4, mode solutions (multi-functional waveguide mode solving and propagation simulation simulation software) are used to verify the above process. The optical phased array with a sweep angle of 60° at 1550 nm is simulated, and the slab waveguide material is SiON. , the simulation results are shown in Figure 3, and it has been verified that on-chip light deflection can be achieved. Among them, Figure 4(a) is a -30° light field diagram; Figure 4(b) is a 30° light field diagram; Figure 4(c) is -30° far-field image; Figure 4(d) is a 30° far-field image.

Therefore, the curved grating 6 can realize the function of emitting light beams that have completed a specific deflection angle from the plate area, thereby realizing the function of optical phased array beam deflection.

In the integrated optical phased array of the embodiment of the present application, a laser is used to generate a light source, and the light source is input into a beam splitter to obtain multiple beams of light; the phase shifter is used to phase-modulate each beam of light, and convert each A beam of light is input into the dense waveguide; the dense waveguide is used to couple the phase-modulated beam into the slab waveguide, and the slab waveguide is used to optically deflect the coupled beam and emit the deflected beam through the curved grating. Therefore, the problem of crosstalk caused by the poor binding of the grating antenna to the mode field in the existing optical phased array is solved, and the problem of the existing optical phased array grating antenna unit arrangement spacing cannot be reduced to half of the wavelength. The size of the problem is larger, the purpose of realizing on-chip optical rotation, and reducing the size of the device.

In order to realize the above embodiments, the present application also proposes a control method using an integrated optical phased array.

As shown in Figure 5, the method includes:

In step 101, a light source is acquired, and multiple beams of light are obtained by splitting the light source.

Step 102: Perform phase modulation on each of the multiple beams of light.

In step 103, each beam of light after phase modulation is coupled into the slab waveguide through the dense waveguide.

In step 104, the slab waveguide is used for light deflection of the coupled light beam, and the light beam after the light deflection is emitted through the curved grating.

In this embodiment of the present application, phase modulation is performed on each of the multiple beams of light, including:

in,

In the embodiments of the present application, the slab waveguide is used to deflect each beam of light, including:

Each beam is emitted from a dense waveguide, and the propagation field in the slab waveguide is:

When no phase shift is added,

It should be noted that the foregoing explanations on the embodiment of the integrated optical phased array are also applicable to the method of this embodiment, and are not repeated here.

In the high-speed video generation device of the embodiment of the present application, multiple beams of light are obtained by acquiring a light source, and the light source is subjected to beam splitting processing; phase modulation is performed on each beam of the multiple beams; The beam of light is coupled into the slab waveguide through the dense waveguide; the slab waveguide is used to lightly deflect the coupled light beam, and the deflected light beam is emitted through the curved grating. Thus, on-chip optical rotation is achieved, and the purpose of reducing the size of the device is achieved.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise.

Any process or method description in the flowcharts or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing custom logical functions or steps of the process , and the scope of the preferred embodiments of the present application includes alternative implementations in which the functions may be performed out of the order shown or discussed, including performing the functions substantially concurrently or in the reverse order depending upon the functions involved, which should It is understood by those skilled in the art to which the embodiments of the present application belong.

The logic and/or steps represented in flowcharts or otherwise described herein, for example, may be considered an ordered listing of executable instructions for implementing the logical functions, may be embodied in any computer-readable medium, For use with, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch instructions from and execute instructions from an instruction execution system, apparatus, or apparatus) or equipment. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport the program for use by or in connection with an instruction execution system, apparatus, or apparatus. More specific examples (non-exhaustive list) of computer readable media include the following: electrical connections with one or more wiring (electronic devices), portable computer disk cartridges (magnetic devices), random access memory (RAM), Read Only Memory (ROM), Erasable Editable Read Only Memory (EPROM or Flash Memory), Fiber Optic Devices, and Portable Compact Disc Read Only Memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program may be printed, as the paper or other medium may be optically scanned, for example, followed by editing, interpretation, or other suitable medium as necessary process to obtain the program electronically and then store it in computer memory.

It should be understood that various parts of this application may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented by any one of the following techniques known in the art, or a combination thereof: discrete with logic gates for implementing logic functions on data signals Logic circuits, application specific integrated circuits with suitable combinational logic gates, Programmable Gate Arrays (PGA), Field Programmable Gate Arrays (FPGA), etc.

Those skilled in the art can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, and the program can be stored in a computer-readable storage medium. When executed, one or a combination of the steps of the method embodiment is included.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing module, or each unit may exist physically alone, or two or more units may be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware, and can also be implemented in the form of software function modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium.

The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, and the like. Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations to the present application. Embodiments are subject to variations, modifications, substitutions and variations.

Claims

An integrated optical phased array, characterized by comprising: a laser, a beam splitter, a phase shifter, a dense waveguide, a slab waveguide and a curved grating;

The laser is used to generate a light source, and the light source is input into the beam splitter to obtain multiple beams of light;

The phase shifter is used for phase modulation of each beam of light, and each beam of light after phase modulation is input into the dense waveguide;

The dense waveguide is used for coupling the phase-modulated light beams into the slab waveguide, and the slab waveguide is used for coupling multiple light beams into one beam and then deflecting the light, and passing the deflected light beam through the bend Raster emission.
The integrated optical phased array of claim 1, wherein:

The beam splitter is composed of a cascade of 1×2 multimode interference beam splitters or a star coupler.
The integrated optical phased array of claim 1, wherein:

The phase shifter is composed of a thermo-optical phase shifter or an electro-optical phase shifter.
The integrated optical phased array of claim 1, wherein:

The phase shifter is used to phase modulate each beam of light, including:

Add a specific phase shift to each beam, when the deflection angle is θ, the additional phase is:
in,
x i = id;

Among them, λ is the wavelength, d is the adjacent waveguide, and i is the waveguide sequence (i=0, 1, 2...).
The integrated optical phased array of claim 1, wherein:

The dense waveguide uses a waveguide array structure based on sinusoidal spatial modulation.
The integrated optical phased array of claim 1, wherein each light beam is emitted from the dense waveguide, and a transmission field in the slab waveguide is:

Wherein, | En | is the field size, r n is the distance monitoring points from the emission point, e j2πrn / λ is a phase factor generated during propagation, ψ n is the additional phase, In (θ, φ) is the The far-field direction function of the slab waveguide is described; when the light deflection angle is θ, the additional phase ψn of the phase-shift arm is calculated by the above formula, and the beam is deflected.
The integrated optical phased array of claim 6, wherein when no phase shift is added,

Among them, λ is the working wavelength, d 0 is the array element interval, when the order m≠0,
A control method applying the integrated optical phased array described in any one of claims 1-7, characterized in that, comprising:

acquiring a light source, and subjecting the light source to beam splitting to obtain multiple beams of light;

performing phase modulation on each of the multiple beams of light;

Coupling each beam of light after phase modulation into the slab waveguide through the dense waveguide;

The slab waveguide is used for light deflection of the coupled light beam, and the light beam after the light deflection is emitted through the curved grating.
The method of claim 8, wherein the performing phase modulation on each of the multiple beams of light comprises:

Add a specific phase shift to each beam, when the deflection angle is θ, the additional phase is:
in,
x i = id;

Among them, λ is the wavelength, d is the adjacent waveguide, and i is the waveguide sequence (i=0, 1, 2...).
The method of claim 8, wherein the slab waveguide is used to lightly deflect each beam of light, comprising:

Each beam emanates from the dense waveguide, where the slab waveguide has a transmission field of:

Wherein, | En | is the field size, r n is the distance monitoring points from the emission point, e j2πrn / λ is a phase factor generated during propagation, ψ n is the additional phase, In (θ, φ) is the The far-field direction function of the slab waveguide is described; when the light deflection angle is θ, the additional phase ψn of the phase-shift arm is calculated by the above formula, and the beam is deflected.