CN116125592A - Tapered waveguide, design method and device thereof and optical fiber coupling system - Google Patents

Tapered waveguide, design method and device thereof and optical fiber coupling system Download PDF

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Publication number
CN116125592A
CN116125592A CN202211630834.1A CN202211630834A CN116125592A CN 116125592 A CN116125592 A CN 116125592A CN 202211630834 A CN202211630834 A CN 202211630834A CN 116125592 A CN116125592 A CN 116125592A
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China
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waveguide
tapered waveguide
model
conical
tapered
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张瑾
王敬好
王震
胡辰
李佳
储涛
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Zhejiang Lab
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Zhejiang Lab
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/1228—Tapered waveguides, e.g. integrated spot-size transformers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0012—Optical design, e.g. procedures, algorithms, optimisation routines
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Optical Couplings Of Light Guides (AREA)

Abstract

The application relates to a tapered waveguide, a design method and a device thereof and an optical fiber coupling system, wherein the tapered waveguide comprises: a first end and a second end, the cross section of the first end being smaller than the cross section of the second end; the tapered waveguide is provided with a plurality of through holes, and the through holes are used for reducing the effective refractive index of the tapered waveguide; the effective refractive index of the tapered waveguide gradually decreases from the first end to the second end. According to the invention, through the through hole is arranged in the conical waveguide, the effective refractive index of the conical waveguide is gradually reduced from the first end to the second end, or the light spot of the conical waveguide is gradually increased from the first end to the second end. The coupling device has the effect of directly coupling the small-size optical fiber with the large-size optical fiber, and solves the problem that the size of the optical fiber which can be coupled by the existing coupling device is not easy to amplify.

Description

Tapered waveguide, design method and device thereof and optical fiber coupling system
Technical Field
The present disclosure relates to the field of optical fiber communication technologies, and in particular, to a tapered waveguide, a method and an apparatus for designing the tapered waveguide, and an optical fiber coupling system.
Background
The wedge spot-size converter may adiabatically adjust the spot size so that it is matingly coupled to the optical fiber. With the advent and development of fields such as optical communication, optical storage, optical switching, and artificial intelligence, silicon optical spot-size converters have been increasingly put into practical use.
However, the size of the optical fiber which can be coupled by the coupling device in the prior art is not easy to amplify, that is, the defect that the small-size optical fiber and the large-size optical fiber cannot be directly coupled is overcome. Illustratively, for the scenario of standard single mode fiber (SMF-28) coupling, standard single mode fiber is widely used with lensed fiber coupled to single mode standard couplers (SSCs). One end of the lens optical fiber is connected with a standard single-mode optical fiber in a larger way, and the other end of the lens optical fiber is connected with an SSC in a conical way, and the lens optical fiber has the effect of reducing light spots, but has higher cost and needs customization. Furthermore, based on current experimental conditions and industry requirements, there is a need for coupling devices that can directly couple large-sized optical fibers, such as can be directly coupled with standard single-mode optical fibers.
Aiming at the problem that the size of the optical fiber which can be coupled by the existing coupling device is not easy to amplify, no effective solution is proposed at present.
Disclosure of Invention
The invention provides a tapered waveguide, a design method and a design device thereof and an optical fiber coupling system, which are used for solving the problem that the conventional coupling device cannot directly couple large-size optical fibers.
In a first aspect, the present invention provides a tapered waveguide comprising a first end and a second end, the first end having a cross-section smaller than the cross-section of the second end;
the tapered waveguide is provided with a plurality of through holes, and the through holes are used for reducing the effective refractive index of the tapered waveguide;
the effective refractive index of the tapered waveguide gradually decreases from the first end to the second end.
In some of these embodiments, the diameter of the through hole ranges from 2nm to 10nm.
In some of these embodiments, the diameter of the through hole increases gradually from the first end to the second end;
and/or the number of the through holes gradually increases from the first end to the second end.
In a second aspect, the present invention provides a method for designing a tapered waveguide, the method comprising:
acquiring an initial tapered waveguide model, wherein the tapered waveguide model comprises a first end and a second end, and the cross section of the first end is smaller than that of the second end;
on the premise of meeting preset arrangement conditions, randomly arranging through holes in the initial conical waveguide model to obtain a conical waveguide model to be tested;
performing simulation calculation on the conical waveguide model to be measured to obtain a simulation calculation result;
and determining an effective conical waveguide model from the conical waveguide models to be detected according to the simulation calculation result.
In some of these embodiments, the simulation calculations include an effective refractive index and an output loss.
In some of these embodiments, the diameter of the through hole ranges from 2nm to 10nm.
In some embodiments thereof, the preset arrangement condition includes: the diameter of the through hole gradually increases from the first end to the second end;
and/or the number of the through holes gradually increases from the first end to the second end.
In some embodiments, the determining an effective tapered waveguide model from the tapered waveguide models to be measured according to the simulation calculation result includes:
when the simulation calculation result of the conical waveguide to be measured meets a preset simulation condition, determining the conical waveguide to be measured as an effective conical waveguide;
and rearranging the through holes in the conical waveguide to be detected and rearranging the simulation calculation of the conical waveguide to be detected when the simulation calculation result of the conical waveguide to be detected does not meet the preset simulation condition.
In a third aspect, the present invention provides a tapered waveguide design apparatus, the apparatus comprising:
the model acquisition module is used for acquiring an initial conical waveguide model;
the through hole arrangement module is used for randomly arranging through holes in the initial conical waveguide model on the premise of meeting preset arrangement conditions to obtain a conical waveguide model to be tested;
the simulation calculation module is used for performing simulation calculation on the conical waveguide model to be measured to obtain a simulation calculation result;
and the model determining module is used for determining an effective tapered waveguide model from the tapered waveguide models to be tested according to the simulation calculation result.
In a fourth aspect, the present invention provides a fiber optic coupling system, the system comprising: tapered waveguides, straight waveguides, and standard single mode fibers;
the first end of the conical waveguide is coupled with the straight waveguide, and the second end of the conical waveguide is coupled with the standard single-mode fiber;
the tapered waveguide is the tapered waveguide of the first aspect;
alternatively, the tapered waveguide is designed by using the design method described in the second aspect.
In a third aspect, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the method for designing a tapered waveguide according to the second aspect.
In a fourth aspect, the present invention provides a storage medium having stored thereon a computer program which, when executed by a processor, implements the method of designing a tapered waveguide according to the second aspect described above.
Compared with the prior art, the tapered waveguide, the design method and the design device thereof and the optical fiber coupling system provided by the invention can enable the effective refractive index of the tapered waveguide to be gradually reduced from the first end to the second end or enable the light spot of the tapered waveguide to be gradually increased from the first end to the second end by arranging the through hole in the tapered waveguide. The coupling device has the effect of directly coupling the small-size optical fiber with the large-size optical fiber, and solves the problem that the size of the optical fiber which can be coupled by the existing coupling device is not easy to amplify.
The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below to provide a more thorough understanding of the other features, objects, and advantages of the application.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:
fig. 1 is a block diagram of a hardware configuration of a terminal performing a design method of a tapered waveguide of the present invention;
FIG. 2 is a schematic diagram of the structure of a tapered waveguide in an embodiment of the invention;
FIG. 3 is a flow chart of a method of designing a tapered waveguide in an embodiment of the invention;
FIG. 4 is a flow chart of a method of designing a tapered waveguide in an embodiment of the present invention;
fig. 5 is a block diagram of a design apparatus of a tapered waveguide in an embodiment of the present invention.
Detailed Description
For a clearer understanding of the objects, technical solutions and advantages of the present application, the present application is described and illustrated below with reference to the accompanying drawings and examples.
Unless defined otherwise, technical or scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terms "a," "an," "the," "these," and the like in this application are not intended to be limiting in number, but rather are singular or plural. The terms "comprising," "including," "having," and any variations thereof, as used in the present application, are intended to cover a non-exclusive inclusion; for example, a process, method, and system, article, or apparatus that comprises a list of steps or modules (units) is not limited to the list of steps or modules (units), but may include other steps or modules (units) not listed or inherent to such process, method, article, or apparatus. The terms "connected," "coupled," and the like in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Reference to "a plurality" in this application means two or more. "and/or" describes an association relationship of an association object, meaning that there may be three relationships, e.g., "a and/or B" may mean: a exists alone, A and B exist together, and B exists alone. Typically, the character "/" indicates that the associated object is an "or" relationship. The terms "first," "second," "third," and the like, as referred to in this application, merely distinguish similar objects and do not represent a particular ordering of objects.
The method embodiments provided in the present embodiment may be executed in a terminal, a computer, or similar computing device. Such as on a terminal, fig. 1 is a block diagram of the hardware architecture of a terminal that performs the tapered waveguide design method of the present invention. As shown in fig. 1, the terminal may include one or more (only one is shown in fig. 1) processors 102 and a memory 104 for storing data, wherein the processors 102 may include, but are not limited to, a microprocessor MCU, a programmable logic device FPGA, or the like. The terminal may also include a transmission device 106 for communication functions and an input-output device 108. It will be appreciated by those skilled in the art that the structure shown in fig. 1 is merely illustrative and is not intended to limit the structure of the terminal. For example, the terminal may also include more or fewer components than shown in fig. 1, or have a different configuration than shown in fig. 1.
The memory 104 may be used to store a computer program, for example, a software program of application software and a module, such as a computer program corresponding to a method of designing a tapered waveguide in the present invention, and the processor 102 performs various functional applications and data processing by executing the computer program stored in the memory 104, that is, implements the above-described method. Memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include memory remotely located relative to the processor 102, which may be connected to the terminal via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The transmission device 106 is used to receive or transmit data via a network. The network includes a wireless network provided by a communication provider of the terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, simply referred to as NIC) that can connect to other network devices through a base station to communicate with the internet. In one example, the transmission device 106 may be a Radio Frequency (RF) module, which is configured to communicate with the internet wirelessly.
Fig. 2 is a schematic structural view of a tapered waveguide in an embodiment of the present invention. Referring to fig. 2, in the present invention, there is provided a tapered waveguide, the tapered waveguide 100 including a first end 110 and a second end 120, the first end 110 having a smaller cross section than the second end 120; the tapered waveguide 100 is provided therein with a plurality of through holes 200, the through holes 200 being for reducing the effective refractive index of the tapered waveguide 100; the effective refractive index of tapered waveguide 100 gradually decreases from first end 110 to second end 120.
Specifically, the optical fiber coupling device is a main device for coupling optical fibers in the field of communication, and in one coupling device, it mainly includes a substrate and a tapered waveguide 100, and a cladding. Wherein, the tapered waveguide 100 is made of silicon material on the substrate, and the cladding is made of silicon dioxide and wraps the tapered waveguide 100. The optical fibers of different sizes have different spot sizes, so that the tapered waveguide 100 needs to have the effect of changing the spot size when coupling the optical fibers of different sizes. In the present invention, the tapered waveguide 100 is provided with the through-hole 200, and the through-hole 200 is filled with air without processing the through-hole 200, and thus may be referred to as an air hole. Where the waveguide is typically made of silicon material and the light has a lower index of refraction in air than in silicon. Therefore, by providing the air holes, the refractive index of the tapered waveguide 100 can be reduced. For any cross section of the tapered waveguide 100 perpendicular to the propagation direction, the effective refractive index of light on that cross section (the component of the refractive index in the propagation direction) is related to the proportion of air holes in that cross section, and the higher the proportion is, the lower the effective refractive index is, and the lower the proportion is, the higher the effective refractive index is. Further specifically, the expression of the effective refractive index is:
n eff ＝β x /k 0
wherein n is eff For effective index, β refers to the propagation constant of an optical wave, described as the phase change of light per unit distance traveled in a medium or waveguide. Beta x Is the wave vector component along the propagation direction, beta y Is the wave vector component perpendicular to the propagation direction. k is the wave vector of the light wave, k 0 The wave vector k of light in the medium is the wave vector of light in vacuum 1 ＝k 0 n 1 ，n 1 Is the refractive index of light in the medium. Wherein beta is x ＝kcosθ，β y =ksinθ. Thus, n as light propagates in the waveguide eff ＝β x /k 0 ＝k 1 cosθ/k 0 ＝k 0 n 1 cosθ/k 0 ＝n 1 cosθ≤n 1 . Thus n when the via 200 structure is added to the tapered waveguide 100 1 The effective refractive index is reduced.
For any cross section, the higher the proportion of air holes, the lower the effective refractive index of that cross section, and the lower the proportion of air holes, the higher the effective refractive index of that cross section. Therefore, in the present invention, different air holes may be provided at different portions of the tapered waveguide 100, so as to adjust the effective refractive index variation of the tapered waveguide 100 along the propagation direction. Further, the through-holes 200 may be provided in the tapered waveguide 100 such that the proportion of the through-holes 200 in the cross section of the tapered waveguide 100 from the first end 110 to the second end 120 is higher and higher, and further such that the effective refractive index of the tapered waveguide 100 gradually decreases from the first end 110 to the second end 120. Further, the spot size in tapered waveguide 100 is inversely related to the effective refractive index. Thus, in the tapered waveguide 100, the light spot gradually increases from the first end 110 to the second end 120, that is, the light spot on the second end 120 is larger than the light spot on the first end 110, so that the second end 120 of the tapered waveguide 100 can directly couple with a large-size optical fiber with a large light spot, such as a standard single-mode optical fiber, without using a lensed fiber to achieve the light spot size adjustment.
The position, diameter, number, etc. of the through holes 200 need to be calculated and determined according to practical situations, such as the reduction amplitude of the effective refractive index, the propagation loss threshold value, etc. The effective refractive index of tapered waveguide 100 as a whole may be gradually reduced from first end 110 to second end 120.
Based on this, the present invention can gradually decrease the effective refractive index of the tapered waveguide 100 from the first end 110 to the second end 120, or gradually increase the light spot of the tapered waveguide 100 from the first end 110 to the second end 120, by providing the through hole 200 in the tapered waveguide 100. The coupling device has the effect of directly coupling the small-size optical fiber with the large-size optical fiber, and solves the problem that the size of the optical fiber which can be coupled by the existing coupling device is not easy to amplify.
It should be further noted that, in the case where the through-hole 200 is not subjected to any treatment, the through-hole 200 is generally an air hole, that is, the through-hole 200 is filled with air. The refractive index of light in vacuum is lower, so that the vacuum process can be performed on the through-hole 200. However, considering that the refractive index of light in air is already very close to vacuum, the through-hole 200 is not generally treated to naturally form an air hole.
In some of these embodiments, the diameter of the via 200 ranges from 2nm to 10nm.
In this embodiment, since the size of the through hole 200 has a great influence on the optical field distribution and scattering loss during light propagation, the size of the air hole is designed at the nanometer level, and thus the diameter of the through hole 200 needs to be controlled at the nanometer level. Among them, the diameter of the through-hole 200 is preferably between 2nm and 10nm. For example, it may be 4nm, 6nm, 8nm, etc. It should be noted that 2nm to 10nm is only a preferred diameter of the through hole 200, and the specific diameter of the through hole 200 needs to be determined according to the actual size of the tapered waveguide 100, the variation range of the effective refractive index, the requirement of light propagation loss, and the like. Accordingly, the diameter of the through-hole 200 may be 1nm, 12nm, 15nm, or the like.
In some of these embodiments, the diameter of the through-hole 200 increases gradually from the first end 110 to the second end 120; and/or the number of through holes 200 increases gradually from the first end 110 to the second end 120.
In this embodiment, two specific means are provided for gradually decreasing the effective refractive index of the tapered waveguide 100 from the first end 110 to the second end 120. One is to gradually increase the diameter of the through-hole 200 from the first end 110 to the second end 120, so that the area of the through-hole 200 in the cross section of the tapered waveguide 100 is increasingly higher, and finally, the effective refractive index of the tapered waveguide 100 gradually decreases from the first end 110 to the second end 120. Another is to gradually increase the number of through holes 200 from the first end 110 to the second end 120, so that the area ratio of the through holes 200 in the cross section of the tapered waveguide 100 is higher and higher, and finally, the effective refractive index of the tapered waveguide 100 gradually decreases from the first end 110 to the second end 120. The two means may then also be used in combination such that the effective refractive index of tapered waveguide 100 gradually decreases from first end 110 to second end 120.
Based on the tapered waveguide provided by the invention, the invention also provides a design method of the tapered waveguide, which is used for specifically designing the tapered waveguide.
Fig. 3 is a flow chart of a method of designing a tapered waveguide in an embodiment of the invention. Referring to fig. 3, the process includes the steps of:
in step S310, an initial tapered waveguide model is obtained, the tapered waveguide model including a first end and a second end, the cross section of the first end being smaller than the cross section of the second end.
In this step, the computer device first obtains or generates an initial tapered waveguide model, which is a conventional tapered waveguide model without through holes.
Step S320, on the premise of meeting preset arrangement conditions, randomly arranging through holes in the initial conical waveguide model to obtain the conical waveguide model to be tested.
In the step, under the limitation of preset arrangement conditions, the computer equipment randomly generates through holes in the initial conical waveguide, so that a conical waveguide model to be tested with the through holes is obtained. It should be noted that the preset arrangement conditions may be in various different forms, so that the randomly generated arrangement manner of the through holes can be more similar to the arrangement manner which can be implemented. Therefore, the preset arrangement condition needs to be set according to the actual situation.
And step S330, performing simulation calculation on the conical waveguide model to be tested to obtain a simulation calculation result.
In the step, simulation test is needed to be carried out on the conical waveguide model to be tested, and indexes such as effective refractive index, output loss and the like of the end face of the conical waveguide model to be tested are mainly calculated. Illustratively, when an end face of the model is coupled to a standard single mode fiber, then it is desirable to have the effective refractive index of the end face meet the criteria for matching with the standard single mode fiber, while ensuring that the output loss is as small as possible. It should be noted that, when the through hole is not processed, the simulation test is performed according to the through hole being an air hole, and of course, the situation that the vacuum hole or the through hole is filled with other materials may be simulated.
And step S340, determining an effective conical waveguide model from the conical waveguide models to be tested according to the simulation calculation result.
In the step, a simulation result obtained by simulation is compared with a preset simulation condition. If the preset simulation conditions are met, the corresponding through hole arrangement mode is required and can be implemented, so that the corresponding conical waveguide model to be tested is determined to be an effective waveguide model, the design flow of the conical waveguide is completed, and the conical waveguide can be manufactured according to the effective waveguide model structure.
It should be noted that, the steps S320, S330 and S340 are required to be repeated or performed multiple times. In one embodiment, step S320 may be performed multiple times at the same time, that is, a large number of random taper waveguide models to be measured are generated at the same time, and then simulation calculation is performed on these models, and based on the simulation calculation result, a model satisfying the condition is selected from these models as an effective taper waveguide model. In another embodiment, the above three steps may be repeatedly performed. Step S340 thus specifically includes:
step S341, determining the tapered waveguide model to be tested as an effective tapered waveguide model when the simulation calculation result of the tapered waveguide model to be tested meets the preset simulation condition; and S342, rearranging through holes in the conical waveguide model to be detected and rearranging the simulation calculation of the conical waveguide model to be detected when the simulation calculation result of the conical waveguide model to be detected does not meet the preset simulation condition.
Specifically, the preset simulation conditions are indexes such as the required effective refractive index and the output loss. Only one conical waveguide model to be detected can be generated at one time, and if the simulation calculation result of the model meets the preset simulation condition, the model is determined to be an effective conical waveguide model; if the simulation calculation result of the model does not meet the preset simulation condition, continuing to execute the step S320, randomly distributing the through holes in the taper waveguide model to be tested again, and repeatedly executing the subsequent steps until the simulation result of the taper waveguide model to be tested meets the preset simulation condition.
Through the steps, on the premise that the preset arrangement condition is met, through holes (usually air holes) are randomly added in the conical waveguide model, and then indexes such as effective refractive index, output loss and the like of the connecting end face of the conical waveguide model are calculated through simulation. If the index meets the preset simulation standard, namely meets the design requirement, the conical waveguide model structure is led out, and the conical waveguide is manufactured based on the structure. If the index does not meet the design requirement, randomly arranging the through holes in the tapered waveguide model again, and re-simulating calculation until the simulation calculation result of the tapered waveguide model meets the design requirement. By the design method, the implementation distribution mode of the through holes in the tapered waveguide can be obtained, and the tapered waveguide meeting the requirements is finally obtained.
In some of these embodiments, the diameter of the through holes is in the range of 2nm-10nm.
In this embodiment, since the size of the through hole has a great influence on the light field distribution and scattering loss during light propagation, the size of the air hole is designed at the nanometer level, and thus the diameter of the through hole needs to be controlled at the nanometer level. Wherein preferably the diameter of the through holes is between 2nm and 10nm. For example, it may be 4nm, 6nm, 8nm, etc. It should be noted that 2nm to 10nm is only a preferred choice of the diameter of the through hole, and the specific diameter of the through hole needs to be determined according to the actual taper waveguide size, the variation range of the effective refractive index, the requirement of light propagation loss, and the like. Thus, the diameter of the through hole may be 1nm, 12nm, 15nm, or the like.
In some of these embodiments, the preset arrangement condition includes: the diameter of the through hole is gradually increased from the first end to the second end; and/or the number of through holes gradually increases from the first end to the second end.
In this embodiment, the effective refractive index of the tapered waveguide eventually meeting the design requirement must gradually decrease from the first end to the second end. Therefore, the distribution of the through holes can be primarily limited, that is, the diameter of the through holes is gradually increased from the first end to the second end, or the number of the through holes is gradually increased from the first end to the second end as a preset arrangement condition, or a combination of the two is used as the preset arrangement condition, so that the effective refractive index of the tapered waveguide in an initial state can meet the gradually reduced change trend from the first end to the second end, and the specific indexes such as the change amplitude, the output loss and the like are determined based on simulation. Therefore, when the through holes are arranged randomly, the through hole arrangement mode meeting the requirements can be more quickly and randomly achieved.
It should be noted that, in other embodiments, in order to reduce the difficulty of preliminary design or reduce the user operation, the preset arrangement conditions may be simplified, and the preset arrangement conditions may be set to be arranged in rows and columns.
The invention also provides a fiber coupling system, comprising: tapered waveguides, straight waveguides, and standard single mode fibers; the first end of the conical waveguide is coupled with the straight waveguide, and the second end of the conical waveguide is coupled with the standard single-mode fiber; the tapered waveguide is provided by the invention; alternatively, the tapered waveguide is designed by using the design method provided in the present invention.
Specifically, the invention also provides a use scene of the tapered waveguide, wherein the first end of the tapered waveguide is coupled with the straight waveguide, and the second end of the tapered waveguide is coupled with the standard single-mode fiber. Accordingly, in this scenario, the tapered waveguide has a first end diameter of 0.5 microns and a second end diameter of 9 microns.
The technical scheme of the invention is described below through a specific embodiment.
In the optical fiber coupling device in the specific embodiment, a silicon waveguide on a substrate is designed into a forward conical waveguide, one end of the silicon waveguide is connected with a straight waveguide, the width of the silicon waveguide is designed to be the same as the width of the straight waveguide, the other end of the silicon waveguide is connected with a standard single mode optical fiber, and the width of the silicon waveguide is designed to be the same as the diameter of the optical fiber. The effective refractive index of each section is adjusted by adding the air hole structure into the waveguide, so that the effective refractive index gradient from the connecting straight waveguide end to the connecting optical fiber end is realized, and the matching with a standard single-mode fiber is realized.
The number, size, arrangement, and other designs of the air holes are determined based on the effective refractive index of the tapered waveguide. The size of the air hole is designed at the nanometer level and primarily designed at about 2-10 nanometers because the size of the air hole has great influence on the light field distribution and scattering loss during light transmission. Considering the design of the widths of the two ends of the end face coupler, the width of one end of the waveguide connected with the chip is designed to be 0.5 micron, and the width of one end of the optical fiber connected with the waveguide is designed to be 9 microns, so that the requirement that the number of the air holes arranged from the waveguide end to the optical fiber end is increased or the size is increased or the number is increased and the size is increased simultaneously should be followed when the air holes are arranged and designed.
The calculation formula of the effective refractive index is as follows:
n eff ＝β x /k 0
wherein n is eff Beta is the propagation constant of the light wave, and is described as the light in the effective refractive indexThe phase change per unit distance propagated in the medium or waveguide. Beta x Is the wave vector component along the propagation direction, beta y Is the wave vector component perpendicular to the propagation direction. k is the wave vector of the light wave, k 0 The wave vector k of light in the medium is the wave vector of light in vacuum 1 ＝k 0 n 1 ，n 1 Is the refractive index of light in the medium. Wherein beta is x ＝kcosθ，β y =ksinθ. Thus, n as light propagates in the waveguide eff ＝β x /k 0 ＝k 1 cosθ/k 0 ＝k 0 n 1 cosθ/k 0 ＝n 1 cosθ≤n 1 . Thus when a via structure is added to a tapered waveguide, n 1 The effective refractive index is reduced. When the effective refractive index near the end face reaches the same as the effective refractive index of the optical fiber, a perfect match of the end face is achieved.
In order to implement the tapered waveguide described above, a specific design method is also provided in this specific embodiment.
Fig. 4 is a flow chart of a method of designing a tapered waveguide in an embodiment of the invention. Referring to fig. 4, the process includes:
in step S410, the random arrangement of the nano pixel structures is performed.
Specifically, the air holes are characterized by nano pixel structures in a computer. In an ideal state, after the air holes meet the basic requirements of design, the positions of the air holes are distributed randomly. Wherein the basic requirements are as follows: the number of air holes arranged from the waveguide end to the optical fiber end is increased, or the size is increased at the same time when the number is increased. However, the difficulty can be reduced in the preliminary design, and the preliminary design can be arranged according to rows and columns.
In step S420, a parameter value is selected as a reference, such as the effective refractive index of the end surface and the output loss.
Specifically, the reference value is a preset simulation condition, and needs to be determined according to actual design requirements.
Step S430, simulating the arrangement structure and obtaining a corresponding result.
In step S440, the result is compared with the reference value.
Step S450, if the result meets the design requirement, outputting the result; if the result does not meet the design requirement, repeating the steps.
Specifically, if the result does not meet the design requirement, the random arrangement of the nano pixel structures is performed again until the result meets the design requirement, and finally the optimal structure is output.
The embodiment also provides a device for designing a tapered waveguide, which is used for implementing the above embodiment and the preferred implementation, and is not described in detail. The terms "module," "unit," "sub-unit," and the like as used below may refer to a combination of software and/or hardware that performs a predetermined function. While the means described in the following embodiments are preferably implemented in software, implementations in hardware, or a combination of software and hardware, are also possible and contemplated.
Fig. 5 is a block diagram of a design apparatus of a tapered waveguide in an embodiment of the present invention. As shown in fig. 5, the apparatus includes:
a model acquisition module 510 for acquiring an initial tapered waveguide model;
the through hole arrangement module 520 is configured to randomly arrange through holes in the initial tapered waveguide model on the premise of meeting a preset arrangement condition, so as to obtain a tapered waveguide model to be tested;
the simulation calculation module 530 is used for performing simulation calculation on the tapered waveguide model to be measured to obtain a simulation calculation result;
the model determining module 540 is configured to determine an effective tapered waveguide model from the tapered waveguide models to be tested according to the simulation calculation result.
Through the module, on the premise of meeting the preset arrangement condition, through holes (usually air holes) can be randomly added in the conical waveguide model, and then indexes such as effective refractive index, output loss and the like of the connecting end face of the conical waveguide model are calculated through simulation. If the index meets the preset simulation standard, namely meets the design requirement, the conical waveguide model structure is led out, and the conical waveguide is manufactured based on the structure. If the index does not meet the design requirement, randomly arranging the through holes in the tapered waveguide model again, and re-simulating calculation until the simulation calculation result of the tapered waveguide model meets the design requirement. By the design method, the implementation distribution mode of the through holes in the tapered waveguide can be obtained, and the tapered waveguide meeting the requirements is finally obtained.
The above-described respective modules may be functional modules or program modules, and may be implemented by software or hardware. For modules implemented in hardware, the various modules described above may be located in the same processor; or the above modules may be located in different processors in any combination.
There is also provided in this embodiment an electronic device comprising a memory having stored therein a computer program and a processor arranged to run the computer program to perform the steps of any of the method embodiments described above.
Optionally, the electronic apparatus may further include a transmission device and an input/output device, where the transmission device is connected to the processor, and the input/output device is connected to the processor.
It should be noted that, specific examples in this embodiment may refer to examples described in the foregoing embodiments and alternative implementations, and are not described in detail in this embodiment.
In addition, in combination with the design method of the tapered waveguide provided in the above embodiment, a storage medium may be provided in this embodiment. The storage medium has a computer program stored thereon; the computer program, when executed by a processor, implements the method of designing a tapered waveguide of any of the above embodiments.
It should be noted that, user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, presented data, etc.) referred to in the present application are information and data authorized by the user or sufficiently authorized by each party.
It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to be limiting. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present application, are within the scope of the present application in light of the embodiments provided herein.
It is evident that the drawings are only examples or embodiments of the present application, from which the present application can also be adapted to other similar situations by a person skilled in the art without the inventive effort. In addition, it should be appreciated that while the development effort might be complex and lengthy, it would nevertheless be a routine undertaking of design, fabrication, or manufacture for those of ordinary skill having the benefit of this disclosure, and thus should not be construed as an admission of insufficient detail.
The term "embodiment" in this application means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive. It will be clear or implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict.
The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the patent. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application shall be subject to the appended claims.

Claims (10)

1. A tapered waveguide, wherein the tapered waveguide comprises a first end and a second end, the first end having a cross-section that is smaller than the cross-section of the second end;
the tapered waveguide is provided with a plurality of through holes, and the through holes are used for reducing the effective refractive index of the tapered waveguide;
the effective refractive index of the tapered waveguide gradually decreases from the first end to the second end.
2. The tapered waveguide of claim 1, wherein the diameter of the through hole ranges from 2nm to 10nm.
3. The tapered waveguide of claim 2, wherein the diameter of the through-hole increases gradually from the first end to the second end;
and/or the number of the through holes gradually increases from the first end to the second end.
4. A method of designing a tapered waveguide, the method comprising:
acquiring an initial tapered waveguide model, wherein the tapered waveguide model comprises a first end and a second end, and the cross section of the first end is smaller than that of the second end;
on the premise of meeting preset arrangement conditions, randomly arranging through holes in the initial conical waveguide model to obtain a conical waveguide model to be tested;
performing simulation calculation on the conical waveguide model to be measured to obtain a simulation calculation result;
and determining an effective conical waveguide model from the conical waveguide models to be detected according to the simulation calculation result.
5. The method of designing a tapered waveguide according to claim 4, wherein the simulation calculation result includes an effective refractive index and an output loss.
6. The method of designing a tapered waveguide according to claim 4, wherein the diameter of the through hole is in the range of 2nm to 10nm.
7. The method of designing a tapered waveguide according to claim 4,
the preset arrangement conditions comprise: the diameter of the through hole gradually increases from the first end to the second end;
and/or the number of the through holes gradually increases from the first end to the second end.
8. The method of designing a tapered waveguide according to claim 4, wherein determining an effective tapered waveguide model from the tapered waveguide models to be tested based on the simulation calculation result comprises:
when the simulation calculation result of the conical waveguide model to be measured meets a preset simulation condition, determining the conical waveguide model to be measured as an effective conical waveguide model;
and rearranging the through holes in the conical waveguide model to be detected and rearranging the simulation calculation of the conical waveguide model to be detected when the simulation calculation result of the conical waveguide model to be detected does not meet the preset simulation conditions.
9. A tapered waveguide design apparatus, the apparatus comprising:
the model acquisition module is used for acquiring an initial conical waveguide model;
the through hole arrangement module is used for randomly arranging through holes in the initial conical waveguide model on the premise of meeting preset arrangement conditions to obtain a conical waveguide model to be tested;
the simulation calculation module is used for performing simulation calculation on the conical waveguide model to be measured to obtain a simulation calculation result;
and the model determining module is used for determining an effective tapered waveguide model from the tapered waveguide models to be tested according to the simulation calculation result.
10. A fiber optic coupling system, the system comprising: tapered waveguides, straight waveguides, and standard single mode fibers;
the first end of the conical waveguide is coupled with the straight waveguide, and the second end of the conical waveguide is coupled with the standard single-mode fiber;
the tapered waveguide is the tapered waveguide of any one of claims 1 to 3;
alternatively, the tapered waveguide is designed by the design method according to any one of claims 4 to 8.
CN202211630834.1A 2022-12-19 2022-12-19 Tapered waveguide, design method and device thereof and optical fiber coupling system Pending CN116125592A (en)

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