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CN120909018A - Low-loss optical delay line capable of being switched rapidly and optical switch calibration regulation and control method - Google Patents

Low-loss optical delay line capable of being switched rapidly and optical switch calibration regulation and control method

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Publication number
CN120909018A
CN120909018A CN202511182514.8A CN202511182514A CN120909018A CN 120909018 A CN120909018 A CN 120909018A CN 202511182514 A CN202511182514 A CN 202511182514A CN 120909018 A CN120909018 A CN 120909018A
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China
Prior art keywords
waveguide
low
loss
ferroelectric material
layer
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CN202511182514.8A
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Chinese (zh)
Inventor
戴道锌
师存予
李晨蕾
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Zhejiang University ZJU
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Zhejiang University ZJU
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Priority to CN202511182514.8A priority Critical patent/CN120909018A/en
Publication of CN120909018A publication Critical patent/CN120909018A/en
Pending legal-status Critical Current

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/0009—Materials therefor
    • G02F1/0018—Electro-optical materials
    • G02F1/0027—Ferro-electric materials
    • 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
    • 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
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
    • G02B6/2861—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using fibre optic delay lines and optical elements associated with them, e.g. for use in signal processing, e.g. filtering
    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/354—Switching arrangements, i.e. number of input/output ports and interconnection types
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/21—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  by interference
    • G02F1/212—Mach-Zehnder type
    • 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
    • G02B2006/12035—Materials
    • 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
    • G02B2006/12035—Materials
    • G02B2006/12061—Silicon
    • 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
    • G02B2006/12133—Functions
    • G02B2006/12145—Switch
    • 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
    • G02B2006/12133—Functions
    • G02B2006/12159—Interferometer

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Signal Processing (AREA)
  • Theoretical Computer Science (AREA)
  • Optical Integrated Circuits (AREA)

Abstract

本发明公开了一种可快速切换的低损耗光延迟线和光开关校准调控方法。多个铁电材料层开关相移区沿光传播方向依次布置，内设置有铁电材料；低损耗波导层连接波导，连接在相邻铁电材料层开关相移区之间和铁电材料层开关相移区的末端；低损耗波导层延迟线，连接在相邻铁电材料层开关相移区之间；层间垂直耦合器，连接在低损耗波导层延迟线/低损耗波导层连接波导和铁电材料层开关相移区之间。本发明方案解决了传统可切换光延迟线难以同时实现长延时和高效快速切换的问题，校准后的开关在使用时无须施加能量维持校准状态，降低了能耗，有望应用于光信号处理、微波光子学、光交换、光缓存等领域。

This invention discloses a rapidly switchable low-loss optical delay line and a method for calibrating and controlling an optical switch. Multiple ferroelectric material layer switch phase shift regions are arranged sequentially along the light propagation direction, each containing ferroelectric material. A low-loss waveguide connecting waveguide connects adjacent ferroelectric material layer switch phase shift regions and their ends. A low-loss waveguide layer delay line connects adjacent ferroelectric material layer switch phase shift regions. An interlayer vertical coupler connects the low-loss waveguide layer delay line/low-loss waveguide layer connecting waveguide and the ferroelectric material layer switch phase shift region. This invention solves the problem that traditional switchable optical delay lines cannot simultaneously achieve long delay and efficient rapid switching. The calibrated switch does not require energy to maintain the calibration state during use, reducing energy consumption and promising applications in optical signal processing, microwave photonics, optical switching, and optical buffering.

Description

Low-loss optical delay line capable of being switched rapidly and optical switch calibration regulation and control method
Technical Field
The invention relates to the field of integrated optics and microwave photonics, in particular to a low-loss optical delay line capable of being switched rapidly and an optical switch calibration and regulation method.
Background
The optical delay line with switchable delay has wide application in the fields of optical signal processing, microwave photonics, optical switching, optical caching and the like. Switchable optical delay lines based on optical fibers and other discrete components are bulky, slow to respond, costly and inconvenient to install and deploy, and thus researchers have received attention to integrating discrete components on a single chip using integrated optical technology. The mode of realizing optical delay line on chip can be divided into two main kinds, one is to utilize the dispersion of the device to regulate and control group refractive index to realize the change of optical path, such as microring, bragg grating, etc., this method can realize the continuous adjustable of time delay, but because of the restriction of the characteristic of resonant device, the bandwidth of time delay is limited, another kind is to utilize the waveguide of different length to realize the change of optical path, this method can only set up discrete time delay with certain step size, but the bandwidth of time delay is very large, the time delay duration can be controlled more accurately. Optical delay lines based on waveguide lengths, where the delay time is proportional to the waveguide length, typically require waveguide lengths on the order of centimeters to achieve nanosecond delays, and therefore the propagation loss of the waveguide presents a challenge for long delays. Among the many material systems, low-loss waveguides, represented by silicon nitride, are the materials of choice for long-delay lines due to their potential for ultra-low transmission loss.
On the other hand, the wave beam forming of the phased array in microwave photonics and the route switching of data in an optical switching scene not only need to delay the optical delay line sufficiently, but also need to delay the fast switching. However, many low-loss waveguide materials do not have an electro-optic effect, and can only be switched and regulated by using a thermo-optic effect, the switching speed is usually in the order of microseconds or even milliseconds, and meanwhile, the low-loss waveguide prepared from silicon nitride has a lower thermo-optic coefficient and requires more energy consumption for switching. Silicon on insulator and indium phosphide platforms can utilize carrier dispersion effect to realize nanosecond speed switching, but carrier absorption brings larger loss and lower on-off extinction ratio. The rapid switchable optical delay line based on the lithium niobate platform can realize nanosecond rapid switching by utilizing the electro-optic effect, but the waveguide transmission loss of the lithium niobate has a certain gap compared with low-loss waveguides such as silicon nitride and the like, and meanwhile, the lithium niobate-based switch can only be arranged in a specific direction and cannot be flexibly folded and occupies a larger space size because of the obvious birefringence effect and the relatively lower electro-optic coefficient of the lithium niobate. Meanwhile, the optical switch for time delay switching inevitably has certain processing errors, calibration is needed before use, and all the material systems do not have nonvolatile characteristics, so that the energy consumption required by calibration is required to be kept all the time in use, and the energy consumption is increased. The unique polarization non-volatility and higher electro-optic coefficient of ferroelectric materials provide new possibilities for achieving fast switching of optical delay line delays. The ferroelectric material may change domain orientation by polarization, under certain conditions, such domain orientation change is non-volatile, and the domain orientation change may bring about a corresponding change in refractive index of the material, so that the non-volatility of the ferroelectric material polarization may be utilized to non-volatile calibrate such that the energy required for calibration need not be applied at all times during use. However, the waveguide loss of the ferroelectric material is relatively high, and long delay is difficult to realize.
In view of the above, it is difficult to achieve both the long delay and fast switching of switchable optical delay lines with a single material system.
Disclosure of Invention
In order to solve the problems, the invention provides a fast switchable low-loss optical delay line, and aims to provide a solution capable of realizing long delay and meeting the fast switching of delay, and simultaneously, the advantages of low-loss waveguide ultralow transmission loss, high electro-optic coefficient and nonvolatile polarization of ferroelectric materials are exerted, the long delay of the delay line is realized by using a long low-loss waveguide, the fast switching of delay is realized by using the high electro-optic coefficient of the ferroelectric materials, and the nonvolatile calibration of a delay change-over switch is realized by using the nonvolatile polarization of the ferroelectric materials.
In order to achieve the above purpose, the technical scheme provided by the invention is as follows:
1. A fast delay controlled switching low loss optical delay line comprising:
a plurality of ferroelectric material layer switching phase shift regions sequentially arranged along a light propagation direction, each ferroelectric material layer switching phase shift region being provided with a ferroelectric material;
the low-loss waveguide layer is connected with the waveguide and is connected between the adjacent ferroelectric material layer switching phase shifting regions and at the tail ends of the two ferroelectric material layer switching phase shifting regions along the light propagation direction;
a low loss waveguide layer delay line connected between switching phase shift regions of adjacent ferroelectric material layers;
The interlayer vertical coupler is a section of tapered waveguide with gradually changing width, is provided with ferroelectric material, is connected between the low-loss waveguide layer delay line and the ferroelectric material layer switching phase shift region and between the low-loss waveguide layer connecting waveguide and the ferroelectric material layer switching phase shift region, and is used for reducing loss caused by optical mode mutation caused by the occurrence of the ferroelectric material above the low-loss waveguide layer.
The tapered waveguide of the interlayer vertical coupler needs to be long enough to meet the adiabatic coupling requirement.
The invention sets the switch phase shift region of the ferroelectric material layer with electro-optic effect in the low-loss structure of the silicon nitride waveguide with only the thermo-optic effect, so that the optical switch which adopts the electro-optic effect to switch quickly is combined with the delay transmission of the low-loss waveguide, and the control of the delay can be switched quickly while the delay transmission with low loss is realized.
The low loss refers to the loss lower than 1dB/cm, and the loss of the low-loss waveguide delay line is lower than that of the delay line directly using the ferroelectric material waveguide.
The low-loss waveguide layer is connected with the waveguide, the interlayer vertical coupler and the ferroelectric material layer switch phase shifting region to jointly form an optical switch of the Mach-Zehnder interferometer structure, and the optical transmission path is controlled through the selection of the switch state, so that the optical delay is controlled.
The low-loss waveguide layer monitoring waveguide is arranged between the adjacent ferroelectric material layer switching phase shifting regions, and is connected with the side of the waveguide in a coupling mode.
Between every two adjacent ferroelectric material layer switch phase shifting regions, one end of the output side of one ferroelectric material layer switch phase shifting region is connected with one end of the input side of the other ferroelectric material layer switch phase shifting region through a low-loss waveguide layer delay line, the other end of the output side of one ferroelectric material layer switch phase shifting region is connected with the other end of the input side of the other ferroelectric material layer switch phase shifting region through a low-loss waveguide layer connecting waveguide, and a bending waveguide which is connected in a coupling way is arranged at the side of the low-loss waveguide layer connecting waveguide as a low-loss waveguide layer monitoring waveguide.
Each low-loss waveguide layer delay line has a different waveguide length, and the different waveguide lengths correspond to different optical paths, so that light can be transmitted in the waveguides with different delay times.
The lengths of the low-loss waveguide layer delay line waveguides sequentially arranged along the light propagation direction sequentially increase and exponentially increase.
The ferroelectric material layer switch phase shift region is a ferroelectric material waveguide, and metal electrodes are arranged on two sides of the waveguide and used for applying an electric field to polarize or modulate the ferroelectric material.
The waveguide structure of the low-loss waveguide layer connecting waveguide and the low-loss waveguide layer delay line mainly comprises a waveguide silicon dioxide cladding serving as a cladding and a silicon nitride waveguide serving as a core layer;
The waveguide structure of the interlayer vertical coupler mainly comprises a waveguide silicon dioxide cladding layer serving as a cladding layer, a silicon nitride waveguide serving as a core layer and a ferroelectric material waveguide arranged on the waveguide silicon dioxide cladding layer;
The waveguide structure of the ferroelectric material layer switch phase shift region mainly comprises a waveguide silicon dioxide cladding layer as a cladding layer, a ferroelectric material waveguide arranged on the waveguide silicon dioxide cladding layer and a metal electrode arranged on the ferroelectric material waveguide;
Or the waveguide structure of the ferroelectric material layer switch phase shift region is mainly composed of a waveguide silica cladding layer as a cladding layer, a silicon nitride waveguide as a core layer, a ferroelectric material waveguide arranged on the waveguide silica cladding layer, and a metal electrode arranged on the ferroelectric material waveguide.
The width of the ferroelectric material waveguide at the interlayer vertical coupler gradually becomes smaller from the ferroelectric material layer switch phase shift region to the low-loss waveguide layer delay line/low-loss waveguide layer connecting waveguide, and the width of the silicon nitride waveguide in the low-loss waveguide layer delay line/low-loss waveguide layer connecting waveguide at the interlayer vertical coupler gradually becomes larger from the ferroelectric material layer switch phase shift region to the low-loss waveguide layer delay line/low-loss waveguide layer connecting waveguide.
2. An optical switch calibration regulation method based on a low-loss optical delay line, which is based on an optical switch of a Mach-Zehnder interferometer structure with heterogeneous integration of a low-loss waveguide and a ferroelectric material in the low-loss optical delay line capable of being switched in a quick delay way, comprises the following steps:
s11, before the fast switchable low-loss optical delay line is used, applying a calibration voltage to metal electrodes on two sides of the ferroelectric material layer switching phase shift region waveguide, wherein the calibration voltage is a voltage value capable of enabling the refractive index of the ferroelectric material to generate nonvolatile change, so that the nonvolatile change of the refractive index of the ferroelectric material layer switching phase shift region waveguide is realized;
maintaining a calibration voltage, and monitoring the optical power of the waveguide by monitoring the low-loss waveguide layer, so that an optical switch of the Mach-Zehnder interferometer structure works in a design state, namely a straight-through state or a crossed state, and compensating state offset caused by processing errors;
s12, after calibration is completed, the calibration voltage is removed, and the calibrated light-on state is not changed;
S13, when the low-loss optical delay line capable of being switched rapidly is used, modulating voltage is applied to metal electrodes on two sides of the switch phase shift region waveguide of the ferroelectric material layer, the modulating voltage is lower than the calibrating voltage, the refractive index of the material can be changed by using the electro-optical characteristic of the ferroelectric material when the modulating voltage is applied, but the refractive index value is restored to the value before the modulating voltage is applied after the modulating voltage is removed, the electro-optical characteristic of the ferroelectric material is used for regulating and controlling the state of the Mach-Zehnder interferometer structure optical switch, so that the transmission path of light is regulated and the time delay length of light is regulated and controlled.
The switchable optical delay line adopts low-loss waveguide as delay line, can realize long delay, adopts ferroelectric material as change-over switch, utilizes nonvolatile polarization of domain direction of ferroelectric material to regulate refractive index of waveguide in nonvolatile mode to realize nonvolatile calibration of switch state, and utilizes high electro-optic coefficient of ferroelectric material to realize high-efficiency quick switch of switch state.
When the delay line using the low-loss waveguide performs optical signal delay processing, low-loss delay propagation can be realized. However, if the low-loss waveguide material is used as the switching phase shift region to perform switching control on the delay line of the next stage by utilizing the thermo-optic effect, the delay switching is very slow, the switching time is usually in the millisecond order, and the transmission of optical signals is seriously affected.
The invention combines the low-loss waveguide and the ferroelectric material, solves the problem that the traditional switchable optical delay line is difficult to realize long delay and high-efficiency and fast switching at the same time, and the calibrated switch does not need to apply energy to maintain a calibration state when in use, thereby reducing energy consumption and being expected to be applied to the fields of optical signal processing, microwave photonics, optical exchange, optical cache and the like.
The invention has the beneficial effects that:
(1) By adopting a heterogeneous integration process of the low-loss waveguide and the ferroelectric material, the potential of the ultra-low-loss waveguide with the advantages of high electro-optic coefficient and nonvolatile polarization of the ferroelectric material are combined, and the problem that the current switchable optical delay line cannot simultaneously meet the requirements of low-loss long-delay and quick switching is solved;
(2) The ferroelectric material is introduced after the processes of low-loss waveguide layer growth, annealing, patterning and the like are all completed, and the process of the low-loss waveguide layer is not limited and influenced, so that the mature low-loss waveguide preparation process of a wafer factory can be utilized, and the large-scale production and manufacture can be realized;
(3) The interlayer vertical coupler is utilized to realize adiabatic coupling of the optical fields of the low-loss waveguide layer and the ferroelectric material layer, so that the optical field in the low-loss delay line is completely restrained in the low-loss waveguide, thereby being beneficial to reducing transmission loss;
(4) The characteristic of nonvolatile polarization of the ferroelectric material is utilized to calibrate the Mach-Zehnder interferometer structure optical switch with heterogeneous integration of the low-loss waveguide and the ferroelectric material, and calibration voltage is not required to be continuously applied after calibration is completed to maintain a calibration state, so that the energy consumption of the device in use is reduced;
(5) Compared with lithium niobate, certain ferroelectric material crystals such as lead zirconate titanate have no obvious birefringence phenomenon, so that the ferroelectric material layer switch phase shifting region can be folded through the combination of a straight waveguide and a curved waveguide, so that the structure of the ferroelectric material layer switch phase shifting region is more compact.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic cross-sectional view of a waveguide at various locations in the present invention, where
Figure 2 (a) is a schematic cross-sectional view of a waveguide with a low loss layer as an example of a silicon nitride single mode waveguide,
Figure 2 (b) is a schematic cross-sectional view of a waveguide of an interlayer vertical coupler,
FIG. 2 (c) is a schematic cross-sectional view of a waveguide of a switching phase shift region of a first ferroelectric material layer, with the optical field being fully coupled into the ferroelectric material layer by an interlayer vertical coupler;
FIG. 2 (d) is a schematic cross-sectional view of a waveguide of a switching phase shift region of a second ferroelectric material layer, the optical field being partially coupled into the ferroelectric material layer by an interlayer vertical coupler, and partially still in the low loss waveguide layer, being transmitted in mixed mode;
FIG. 3 is a schematic diagram of a silicon nitride layer delay line in accordance with an embodiment of the present invention;
Fig. 4 is a schematic structural diagram of a mach-zehnder interferometer structured optical switch with heterogeneous integration of silicon nitride and ferroelectric material in accordance with an embodiment of the present invention.
In the figure, 10, low-loss waveguide layer connection waveguides, 20, low-loss waveguide layer monitoring waveguides, 301, 302, & 30j (j=1, 2, 3..N) low-loss delay lines of different lengths;
40. A ferroelectric material layer switching phase shift region and a connecting waveguide;
50. An interlayer vertical coupler;
100. Waveguide silicon dioxide cladding, 101, silicon nitride waveguide, 401, metal electrode, 402, ferroelectric material waveguide.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings:
As shown in fig. 1, the present invention designs a low-loss optical delay line capable of fast delay control switching, comprising:
The plurality of ferroelectric material layer switching phase shift regions 40 are sequentially arranged along the light propagation direction, each ferroelectric material layer switching phase shift region 40 is provided with a ferroelectric material, the ferroelectric material performs electro-optic effect control to realize the calibration of a switching state by the nonvolatile characteristic of the ferroelectric material, and the ferroelectric material realizes the switching of the switching state by the electro-optic effect of the ferroelectric material;
A low-loss waveguide layer connecting waveguide 10 connected between adjacent ferroelectric material layer switching phase shift regions 40 and at the ends of the two ferroelectric material layer switching phase shift regions 40 at the head and tail in the light propagation direction;
Low loss waveguide layer delay lines 301, 302,..30j connected between adjacent ferroelectric material layer switching phase shift regions 40;
The interlayer vertical coupler 50, which is a tapered waveguide of gradually varying width, is provided with a ferroelectric material connected between the low-loss waveguide layer delay lines 301, 302,..30j and the ferroelectric material layer switching phase shift region 40 and between the low-loss waveguide layer connecting waveguide 10 and the ferroelectric material layer switching phase shift region 40, for reducing loss due to abrupt change of optical mode caused by the ferroelectric material occurring above the low-loss waveguide layer, so that switching can be rapidly controlled with delay in case of low loss.
The low-loss waveguide layer connecting waveguide 10, the interlayer vertical coupler 50 and the ferroelectric material layer switching phase shift region 40 together form an optical switch of a Mach-Zehnder interferometer structure, and the optical transmission path is controlled by the selection of the switching state, so that the optical delay is controlled.
A low loss waveguide layer monitoring waveguide 20 may also be included in the implementation, with the low loss waveguide layer disposed between adjacent ferroelectric material layer switching phase shift regions 40 connecting laterally and coupled to waveguide 10.
The low-loss waveguide layer monitoring waveguide 20 is arranged beside the low-loss waveguide layer connecting waveguide 10, the low-loss waveguide layer monitoring waveguide 20 utilizes evanescent field coupling of an optical field to couple a small part of optical power from the low-loss waveguide layer connecting waveguide to the low-loss waveguide layer monitoring waveguide, and a grating coupler or an end face coupler or an on-chip detector is arranged at the tail end of the monitoring waveguide and used for coupling the optical coupling of the monitoring waveguide to the on-chip or external detector so as to measure the optical power in the monitoring waveguide. The detection of the optical power of the low-loss waveguide layer monitoring waveguide can be used for helping the calibration and regulation of the Mach-Zehnder interferometer structure optical switch.
The ferroelectric material layer switching phase shifting region 40 is a2 x 2 port phase shifting structure, i.e., having two inputs and two outputs.
When two ports of the adjacent ferroelectric material layer switch phase shifting region 40 are correspondingly connected, the waveguide 10 and one low-loss waveguide layer delay line 301, 302 are respectively connected through one low-loss waveguide layer:
Between every two adjacent ferroelectric material layer switch phase shift regions 40, one end of the output side of one ferroelectric material layer switch phase shift region 40 is connected with one end of the input side of the other ferroelectric material layer switch phase shift region 40 through a low-loss waveguide layer delay line 301, 302,. 30j, and the other end of the output side of one ferroelectric material layer switch phase shift region 40 is connected with the other end of the input side of the other ferroelectric material layer switch phase shift region 40 through a low-loss waveguide layer connecting waveguide 10, and a curved waveguide which is connected in a coupling way is arranged at the side of the low-loss waveguide layer connecting waveguide 10 as a low-loss waveguide layer monitoring waveguide 20.
The respective low loss waveguide layer delay lines 301, 302, 30j are precisely designed to have different waveguide lengths corresponding to different optical paths such that light is transmitted in the waveguides with different delay times.
The respective low-loss waveguide layer delay lines 301, 302, 30j, which are sequentially arranged along the light propagation direction, sequentially increase in waveguide length, and the waveguide length increases exponentially. For example, the first low-loss waveguide layer delay line 301 has a waveguide length of 1τ, the second low-loss waveguide layer delay line 302 has a waveguide length of 2τ, the third low-loss waveguide layer delay line 301 has a waveguide length of 4τ, and the nth low-loss waveguide layer delay line 301 has a waveguide length of 2 n-1 τ.
The ferroelectric material layer switching phase shift region 40 is a ferroelectric material waveguide of a certain length, and metal electrodes are disposed at a certain distance on both sides of the waveguide, and the metal electrodes are used for applying an electric field to polarize or modulate the ferroelectric material.
The ferroelectric material layer switching phase shift region 40 is internally connected by a combination of a straight waveguide and a curved waveguide to allow the waveguide structure to be folded, thereby making the ferroelectric material layer switching phase shift region more compact.
As shown in fig. 4, the low-loss waveguide layer delay line 301, 302,..30j reduces the area occupied by the low-loss waveguide layer delay line by waveguide routing that satisfies the euler curve equation or the constant velocity spiral equation.
As shown in fig. 2 (a), the waveguide structure of the low-loss waveguide layer connecting the waveguide 10 and the low-loss waveguide layer delay lines 301, 302,..30j is mainly composed of a waveguide silica cladding 100 as a cladding and a silicon nitride waveguide 101 as a core, the waveguide silica cladding 100 being clad outside the silicon nitride waveguide 101.
As shown in fig. 2 (b), the waveguide structure of the interlayer vertical coupler 50 is mainly composed of a waveguide silica cladding 100 as a cladding, a silicon nitride waveguide 101 as a core, and a ferroelectric material waveguide 402 arranged above the waveguide silica cladding 100, the waveguide silica cladding 100 being clad outside the silicon nitride waveguide 101.
As shown in fig. 2 (c), the waveguide structure of the first ferroelectric material layer switching phase shift region 40 is mainly composed of a waveguide silica cladding 100 as a cladding, a ferroelectric material waveguide 402 disposed over the waveguide silica cladding 100, and a metal electrode 401 disposed over the ferroelectric material waveguide 402.
As shown in fig. 2 (d), the waveguide structure of the second ferroelectric material layer switching phase shift region 40 is mainly composed of a waveguide silica cladding 100 as a cladding, a silicon nitride waveguide 101 as a core, a ferroelectric material waveguide 402 disposed over the waveguide silica cladding 100, and a metal electrode 401 disposed over the ferroelectric material waveguide 402.
As shown in fig. 3, an interlayer vertical coupler 50 is provided between the low loss waveguide layer delay lines 301, 302,..30j and the ferroelectric material layer switching phase shift region 40, and between the low loss waveguide layer connecting waveguide 10 and the ferroelectric material layer switching phase shift region 40.
The width of the ferroelectric material waveguide 402 at the interlayer vertical coupler 50 gradually becomes smaller from the ferroelectric material layer switching phase shift region 40 to the low-loss waveguide layer delay line 301, 302,..30j/low-loss waveguide layer connection waveguide 10, and the width of the silicon nitride waveguide 101 in the low-loss waveguide layer delay line 301, 302,..30j/low-loss waveguide layer connection waveguide 10 at the interlayer vertical coupler 50 gradually becomes larger from the ferroelectric material layer switching phase shift region 40 to the low-loss waveguide layer delay line 301, 302,..30j/low-loss waveguide layer connection waveguide 10.
The ferroelectric material in the ferroelectric material layer switching phase shift region 40 and the interlayer vertical coupler 50 is specifically a ferroelectric material, and the ferroelectric material is lead zirconate titanate material, and can be prepared on a silicon dioxide SiO 2/silicon Si substrate by adopting a low-temperature Sol-Gel spin coating process through adopting lead zirconate titanate Pb (Zr 1-xTix)O3. Lead zirconate titanate PZT material), and has good crystal orientation, consistent film thickness control and excellent electro-optic modulation performance.
Specifically, the lead zirconate titanate material is prepared by the following method:
S1, uniformly spreading a PZT precursor solution on the surface of a substrate in a spin coating mode, and performing hot plate pre-baking at the temperature of 250 ℃ to remove organic components;
S2, annealing the film to 450 ℃ in an oxygen environment by adopting a Rapid Thermal Annealing (RTA) process, and preserving heat for one hour to obtain a perovskite phase structure with higher crystallinity;
and S3, repeating the steps S1 and S2 in sequence for spin coating and annealing for a plurality of times, so that the target film thickness is achieved, and further preparing and obtaining the lead zirconate titanate film.
The obtained lead zirconate titanate material has low surface roughness and excellent thickness uniformity, is favorable for enhancing the electro-optic effect and has wide application prospect.
The solute of the PZT precursor solution comprises lead acetate trihydrate (Pb (CH 3COO)2·3H2 O), zirconium isopropoxide (Zr (OCH (CH 3)2)4) and tetrabutyl titanate (Ti (OCH 2CH2CH2CH3)4)), the total metal ion concentration is 0.3mol/L, and the solvent is ethylene glycol methyl ether and acetylacetone.
The invention adopts a preparation process of heterogeneous integration of a low-loss waveguide and a ferroelectric material to prepare the low-loss optical delay line capable of rapidly controlling and switching, and the process flow is as follows:
S01, growing a low-loss waveguide material with a certain thickness on a wafer which comprises a substrate and a lower cladding in advance;
S02, transferring patterns of delay lines, connecting waveguides, tapered waveguides of an interlayer vertical coupler and the like of the low-loss waveguide layer onto a mask by adopting ultraviolet lithography or electron beam exposure technology, and transferring the patterns on the mask into a low-loss waveguide structure by etching;
S03, growing interlayer silicon dioxide, flattening the surface of the interlayer silicon dioxide through chemical mechanical polishing, and controlling the thickness of the interlayer silicon dioxide;
S04, spin-coating ferroelectric materials with a certain thickness on interlayer silicon dioxide by adopting a sol-gel process;
S05, transferring patterns of a switch phase shift region waveguide, a connecting waveguide, a conical waveguide vertically coupled between layers and the like of the ferroelectric material layer onto a mask by adopting ultraviolet lithography or electron beam exposure technology, and transferring the patterns on the mask into a structure of the ferroelectric material by etching;
S06, preparing the electrode by adopting a metal stripping process.
Based on the optical switch of the Mach-Zehnder interferometer structure with heterogeneous integration of low-loss waveguide and ferroelectric material in the low-loss optical delay line capable of fast delay switching, the invention provides a calibration method of optical switch state to compensate state shift caused by processing error, which comprises the following steps:
S11, before the low-loss optical delay line capable of being switched rapidly is used, calibrating an optical switch of a Mach-Zehnder interferometer structure in which a low-loss waveguide and a ferroelectric material are heterogeneous integrated, and applying a calibration voltage with a certain strength to metal electrodes 401 on two sides of a waveguide of a switching phase shift region 40 of the ferroelectric material layer to realize nonvolatile polarization of the waveguide of the switching phase shift region of the ferroelectric material layer so as to cause nonvolatile change of refractive index;
The magnitude of the calibration voltage is determined by the optical power in the monitor waveguide. The end of the monitoring waveguide is provided with a grating coupler or an end face coupler or an on-chip detector for coupling the light of the monitoring waveguide to the on-chip or external detector so as to measure the light power in the monitoring waveguide. And if the design state of the optical switch is in a crossed state, the calibration voltage is adjusted to minimize the optical power in the monitoring waveguide, thereby compensating for state deviation caused by processing errors.
S12, after calibration is completed, the calibration voltage is removed, and the calibrated light-on state is not changed;
s13, when the low-loss optical delay line capable of being switched rapidly is used, modulation voltage with certain intensity is applied to the metal electrodes 401 on the two sides of the waveguide of the switching phase shifting region 40 of the ferroelectric material layer, the electro-optical characteristics of the ferroelectric material are utilized to change the refractive index of the waveguide of the ferroelectric material of the phase shifting region, so that the state of the optical switch of the Mach-Zehnder interferometer structure is changed, the transmission path of light is changed, and the time delay length of light experience is regulated. For example, the optical switch calibrated in the steps S11 and S12 is in a straight-through state, if light is required to pass through the current-stage delay, the optical switch is changed into a crossed state, and if light is not required to pass through the current-stage delay, the optical switch is kept in the straight-through state.
As shown more particularly in fig. 1, the embodied low-loss optical delay line includes:
The low-loss waveguide layer is connected with the waveguide 10, and is used for connecting a delay line and a vertical coupler of the low-loss waveguide layer, wherein the delay line and the vertical coupler comprise a straight waveguide for realizing optical field transmission, and a multimode interference coupler for realizing beam splitting and beam combining of light, as shown in fig. 3.
The low-loss waveguide layer monitors the waveguide 20, and a small part of optical power in the straight waveguide with the low-loss waveguide layer connected with the waveguide 10 is coupled to the output of the monitoring waveguide 20 through evanescent field coupling for subsequent calibration and regulation.
Low loss delay lines 301, 302,..30 j (j=1, 2, 3..n), j is used to distinguish between different waveguide lengths, typically the waveguide lengths meet, corresponding to the minimum delay time of the optical delay line. The low-loss delay line can be formed by arranging an S-shaped bending waveguide by using Euler curve equation and arranging a spiral waveguide by using constant velocity spiral equation, as shown in fig. 4, the occupied area of the delay line can be reduced, the cross section of the low-loss waveguide layer connecting the waveguide and the delay line waveguide, which is exemplified by silicon nitride, is shown in fig. 2 (a), and the silicon nitride waveguide is embedded in the silicon dioxide cladding 100.
The interlayer vertical coupler 50 is formed by overlapping a tapered waveguide with a gradually changing low-loss waveguide width and a tapered waveguide with a gradually changing ferroelectric material layer width, the gradually narrowing direction of the tapered waveguide of the low-loss waveguide corresponds to the gradually widening direction of the tapered waveguide of the ferroelectric material layer, the length of the tapered waveguide is designed to satisfy adiabatic coupling, the cross section of the vertical coupler waveguide is shown in fig. 2 (b), wherein 101 is a gradually narrowing silicon nitride waveguide, and 402 is a gradually widening ferroelectric material waveguide.
The ferroelectric material layer switch phase shift region 40 is used to form the modulation part of the fast switch optical switch, the cross section of the waveguide is as shown in fig. 2 (c) or fig. 2 (d), the optical field is fully or partially confined in the ferroelectric material ridge waveguide 402, the voltage is applied to the electrodes 401 at the two sides of the waveguide to form the electric field between the signal electrode and the ground electrode, and the electric field overlaps with the optical field confined in the ferroelectric material, so that the electro-optic modulation can be performed.
The low-loss waveguide layer is connected with the waveguide 10, the interlayer vertical coupler 50 and the ferroelectric material layer switch phase shifting region 40 to form a Mach-Zehnder interferometer structure optical switch (electrodes are not shown) shown in fig. 3, and the electro-optic modulation effect of the ferroelectric material is utilized to regulate the ratio of the optical power of the upper path to the lower path of the multimode interference coupler so as to realize the rapid switching of different switch states.
The following is one embodiment of the present invention:
Selecting a 6-inch silicon substrate, generating a 2-micrometer silicon dioxide lower cladding layer by adopting a thermal oxidation process, adopting a low-pressure chemical vapor deposition to grow a 400-nm thick silicon nitride film and performing high-temperature annealing treatment at 1150 ℃, adopting an ultraviolet lithography and etching process to write a designed waveguide pattern on the silicon nitride film, wherein the waveguide is a 400-nm fully etched strip waveguide, adopting a plasma enhanced chemical vapor deposition to grow 1-um interlayer silicon dioxide, flattening the surface of the interlayer silicon dioxide by adopting chemical mechanical polishing, controlling the thickness of the interlayer silicon dioxide to remain 400nm, spin-coating a 300-nm thick film lead zirconate titanate material on the silicon dioxide by adopting a sol-gel process, adopting an ultraviolet lithography and etching process to write a designed waveguide pattern on the lead zirconate titanate film, and manufacturing a 10-nm/400-nm titanium/gold electrode by adopting an evaporation and stripping process.
The delay time of the silicon nitride layer delay line shown in fig. 4 is respectively set to 25ps, 50ps, 100ps, 200ps, 400ps and 800ps, namely, the delay time of 1575ps can be realized at the highest, so that the advantage of long delay can be realized by the low loss of the silicon nitride waveguide is reflected.
The optical switch phase shift region of the Mach-Zehnder interferometer structure with heterogeneous integration of silicon nitride and ferroelectric material is selected as shown in the scheme of fig. 2 (c), and the optical field completely enters the lead zirconate titanate waveguide through the interlayer vertical coupler.
In the pre-calibration process of the mach-zehnder interferometer structured optical switch in which silicon nitride and ferroelectric materials are heterogeneously integrated as shown in fig. 3, a calibration voltage of 10-40V is applied to each switch, and all switches are calibrated into a cross output state by monitoring the silicon nitride layer monitoring waveguide 20 as shown in fig. 1. After the calibration voltage is removed, the cross output state of the switch can be observed to be unchanged for a long time, and the reduction of the calibration energy consumption of the switch state caused by nonvolatile polarization of lead zirconate titanate is reflected.
In the high-speed switching process of the Mach-Zehnder interferometer structured optical switch with heterogeneous integration of silicon nitride and ferroelectric materials as shown in fig. 3, rectangular pulses applied to the switch can realize nanosecond or even subnanosecond-level switching response, and the characteristic of high modulation efficiency brought by high electro-optic coefficient of lead zirconate titanate is reflected.
On one hand, the potential of long delay of silicon nitride can be realized due to low light transmission loss, compared with the situation that only ferroelectric materials are used as phase shifting areas and delay waveguides, the loss of the silicon nitride serving as the delay waveguides is lower, and long delay of more than 1.5ns can be realized, on the other hand, the defect that no electro-optical effect of the silicon nitride can only be used for realizing millisecond-speed switching by adopting a thermo-optical effect is overcome by introducing the ferroelectric materials, the switching speed can reach nanoseconds or even subnanoseconds so as to realize the rapid switching of delay time, and meanwhile, the unique refractive index nonvolatile of the ferroelectric materials such as the lead zirconate titanate can be used for calibrating the switching state so as to compensate the deviation of the switching state and the design state caused by processing errors.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the technical scope of the present invention, so that any minor modifications, equivalent changes and modifications made to the above embodiments according to the technical principles of the present invention still fall within the scope of the technical solutions of the present invention.

Claims (10)

1.一种可快速切换的低损耗光延迟线，其特征在于包括：1. A low-loss optical delay line with fast switching capability, characterized in that it comprises: 多个铁电材料层开关相移区(40)，沿光传播方向依次布置，每个铁电材料层开关相移区(40)设置有铁电材料；Multiple ferroelectric material layer switch phase shift regions (40) are arranged sequentially along the light propagation direction, and each ferroelectric material layer switch phase shift region (40) is provided with ferroelectric material; 低损耗波导层连接波导(10)，连接在相邻铁电材料层开关相移区(40)之间以及沿光传播方向头尾的两个铁电材料层开关相移区(40)的末端；The low-loss waveguide layer connects the waveguide (10) and connects between adjacent ferroelectric material layer switch phase shift regions (40) and at the ends of the two ferroelectric material layer switch phase shift regions (40) along the optical propagation direction; 低损耗波导层延迟线(301、302、…30j)，连接在相邻铁电材料层开关相移区(40)之间；Low-loss waveguide layer delay lines (301, 302, ... 30j) are connected between adjacent ferroelectric material layer switching phase shift regions (40); 层间垂直耦合器(50)，为一段宽度逐渐变化的锥形波导，设置有铁电材料，连接在低损耗波导层延迟线(301、302、…30j)和铁电材料层开关相移区(40)之间以及在低损耗波导层连接波导(10)和铁电材料层开关相移区(40)之间，用于降低铁电材料在低损耗波导层上方出现引起的光模式突变带来的损耗。The interlayer vertical coupler (50) is a tapered waveguide with a gradually changing width, which is provided with ferroelectric material and is connected between the delay lines (301, 302, ... 30j) of the low-loss waveguide layer and the switching phase shift region (40) of the ferroelectric material layer, as well as between the connecting waveguide (10) of the low-loss waveguide layer and the switching phase shift region (40) of the ferroelectric material layer. It is used to reduce the loss caused by the optical mode abrupt change caused by the appearance of ferroelectric material above the low-loss waveguide layer. 2.如权利要求1所述的一种可快速切换的低损耗光延迟线，其特征在于，2. The fast-switchable low-loss optical delay line as described in claim 1, characterized in that, 所述低损耗波导层连接波导(10)、层间垂直耦合器(50)和铁电材料层开关相移区(40)共同构成马赫-曾德尔干涉仪结构的光开关，通过开关状态的选择，控制光传输的路径，从而控制光经历的延时。The low-loss waveguide layer connecting the waveguide (10), the interlayer vertical coupler (50), and the ferroelectric material layer switching phase shift region (40) together constitute the optical switch of the Mach-Zehnder interferometer structure. By selecting the switching state, the path of light transmission is controlled, thereby controlling the delay experienced by the light. 3.根据权利要求1所述的一种可快速切换的低损耗光延迟线，其特征在于，3. The fast-switchable low-loss optical delay line according to claim 1, characterized in that, 还包括低损耗波导层监控波导(20)，布置在相邻铁电材料层开关相移区(40)之间的低损耗波导层连接波导(10)的侧方并耦合连接。It also includes a low-loss waveguide monitoring waveguide (20), which is arranged on the side of the low-loss waveguide connecting waveguide (10) between adjacent ferroelectric material layer switching phase shift regions (40) and coupled together. 4.根据权利要求1或2所述的一种可快速切换的低损耗光延迟线，其特征在于，每相邻两个铁电材料层开关相移区(40)之间，其中一个铁电材料层开关相移区(40)输出侧的一端经一根低损耗波导层延迟线(301、302、…30j)和另一个铁电材料层开关相移区(40)输入侧的一端连接，其中一个铁电材料层开关相移区(40)输出侧的另一端经一根低损耗波导层连接波导(10)和另一个铁电材料层开关相移区(40)输入侧的另一端连接，低损耗波导层连接波导(10)侧方设置有相耦合连接的弯曲波导作为低损耗波导层监控波导(20)。4. A fast-switching low-loss optical delay line according to claim 1 or 2, characterized in that, between each two adjacent ferroelectric material layer switch phase shift regions (40), one end of the output side of one ferroelectric material layer switch phase shift region (40) is connected to one end of the input side of the other ferroelectric material layer switch phase shift region (40) via a low-loss waveguide layer delay line (301, 302, ... 30j), and the other end of the output side of one ferroelectric material layer switch phase shift region (40) is connected to the other end of the input side of the other ferroelectric material layer switch phase shift region (40) via a low-loss waveguide layer connecting waveguide (10), and a phase-coupled curved waveguide is provided on the side of the low-loss waveguide layer connecting waveguide (10) as a low-loss waveguide layer monitoring waveguide (20). 5.根据权利要求1所述的一种可快速切换的低损耗光延迟线，其特征在于，各个低损耗波导层延迟线(301、302、…30j)具有不同的波导长度，不同波导长度对应不同的光程，使得光在波导中传输会有不同的延迟时间。5. A fast-switchable low-loss optical delay line according to claim 1, characterized in that each low-loss waveguide layer delay line (301, 302, ... 30j) has a different waveguide length, and different waveguide lengths correspond to different optical paths, so that the light will have different delay times when it propagates in the waveguide. 6.根据权利要求1或5所述的一种可快速切换的低损耗光延迟线，其特征在于，沿光传播方向依次布置的各个低损耗波导层延迟线(301、302、…30j)波导长度依次递增，且呈指数递增。6. A fast-switchable low-loss optical delay line according to claim 1 or 5, characterized in that the waveguide lengths of the various low-loss waveguide layer delay lines (301, 302, ... 30j) arranged sequentially along the optical propagation direction increase sequentially and exponentially. 7.如权利要求1所述的一种可快速切换的低损耗光延迟线，其特征在于，7. The fast-switchable low-loss optical delay line as described in claim 1, characterized in that, 所述铁电材料层开关相移区(40)为铁电材料波导，波导两侧有金属电极，金属电极用于施加电场对铁电材料进行极化或调制。The ferroelectric material layer switch phase shift region (40) is a ferroelectric material waveguide with metal electrodes on both sides. The metal electrodes are used to apply an electric field to polarize or modulate the ferroelectric material. 8.如权利要求1所述的一种可快速切换的低损耗光延迟线，其特征在于，8. The fast-switchable low-loss optical delay line as described in claim 1, characterized in that, 所述低损耗波导层连接波导(10)和低损耗波导层延迟线(301、302、…30j)的波导结构主要由作为包层的波导二氧化硅包层(100)以及作为芯层的氮化硅波导(101)构成；The waveguide structure connecting the low-loss waveguide layer to the waveguide (10) and the low-loss waveguide layer delay lines (301, 302, ... 30j) is mainly composed of a waveguide silicon dioxide cladding (100) as the cladding layer and a silicon nitride waveguide (101) as the core layer. 所述层间垂直耦合器(50)的波导结构主要由作为包层的波导二氧化硅包层(100)、作为芯层的氮化硅波导(101)以及布置在波导二氧化硅包层(100)之上的铁电材料波导(402)构成；The waveguide structure of the interlayer vertical coupler (50) is mainly composed of a waveguide silicon dioxide cladding (100) as the cladding layer, a silicon nitride waveguide (101) as the core layer, and a ferroelectric material waveguide (402) arranged on the waveguide silicon dioxide cladding (100). 所述铁电材料层开关相移区(40)的波导结构主要由作为包层的波导二氧化硅包层(100)、布置在波导二氧化硅包层(100)之上的铁电材料波导(402)和布置在铁电材料波导(402)之上的金属电极(401)构成；The waveguide structure of the ferroelectric material layer switch phase shift region (40) is mainly composed of a waveguide silicon dioxide cladding (100) as a cladding, a ferroelectric material waveguide (402) arranged on the waveguide silicon dioxide cladding (100), and a metal electrode (401) arranged on the ferroelectric material waveguide (402). 或者所述铁电材料层开关相移区(40)的波导结构主要由作为包层的波导二氧化硅包层(100)、作为芯层的氮化硅波导(101)、布置在波导二氧化硅包层(100)之上的铁电材料波导(402)以及布置在铁电材料波导(402)之上的金属电极(401)构成。Alternatively, the waveguide structure of the ferroelectric material layer switching phase shift region (40) is mainly composed of a waveguide silicon dioxide cladding (100) as the cladding layer, a silicon nitride waveguide (101) as the core layer, a ferroelectric material waveguide (402) arranged on the waveguide silicon dioxide cladding (100), and a metal electrode (401) arranged on the ferroelectric material waveguide (402). 9.如权利要求8所述的一种可快速切换的低损耗光延迟线，其特征在于，9. A fast-switchable low-loss optical delay line as described in claim 8, characterized in that, 所述层间垂直耦合器(50)处的铁电材料波导(402)宽度从铁电材料层开关相移区(40)开始到低损耗波导层延迟线(301、302、…30j)/低损耗波导层连接波导(10)逐渐渐变变小，且所述层间垂直耦合器(50)处的低损耗波导层延迟线(301、302、…30j)/低损耗波导层连接波导(10)中的氮化硅波导(101)宽度从铁电材料层开关相移区(40)开始到低损耗波导层延迟线(301、302、…30j)/低损耗波导层连接波导(10)逐渐渐变变大。The width of the ferroelectric waveguide (402) at the interlayer vertical coupler (50) gradually decreases from the ferroelectric layer switching phase shift region (40) to the low-loss waveguide layer delay lines (301, 302, ... 30j)/low-loss waveguide layer connecting waveguide (10), and the width of the silicon nitride waveguide (101) in the low-loss waveguide layer delay lines (301, 302, ... 30j)/low-loss waveguide layer connecting waveguide (10) at the interlayer vertical coupler (50) gradually increases from the ferroelectric layer switching phase shift region (40) to the low-loss waveguide layer delay lines (301, 302, ... 30j)/low-loss waveguide layer connecting waveguide (10). 10.一种基于权利要求1-9任一所述低损耗光延迟线的光开关校准调控方法，所述方法步骤为：10. A method for calibrating and controlling an optical switch based on any one of the low-loss optical delay lines according to claims 1-9, wherein the method comprises the following steps: S11.在所述可快速切换的低损耗光延迟线使用前，通过向所述铁电材料层开关相移区(40)波导两侧的金属电极(401)施加校准电压，校准电压是指能够使所述铁电材料折射率产生非易失变化的电压值，实现所述铁电材料层开关相移区波导折射率的非易失改变；S11. Before using the fast-switchable low-loss optical delay line, a calibration voltage is applied to the metal electrodes (401) on both sides of the waveguide of the ferroelectric material layer switch phase shift region (40). The calibration voltage is a voltage value that can cause the refractive index of the ferroelectric material to change non-volatilely, thereby realizing the non-volatile change of the refractive index of the waveguide of the ferroelectric material layer switch phase shift region. 保持校准电压，通过监控所述低损耗波导层监控波导(20)的光功率，使得所述马赫-曾德尔干涉仪结构的光开关工作在设计状态，即直通状态或是交叉状态，补偿加工误差所造成的状态偏移；Maintaining the calibration voltage, the optical power of the monitoring waveguide (20) is monitored by the low-loss waveguide layer, so that the optical switch of the Mach-Zehnder interferometer structure operates in the designed state, i.e., the through state or the cross state, to compensate for the state shift caused by the processing error. S12.校准完成后，撤去校准电压，校准过的开光状态不发生改变；S12. After calibration, remove the calibration voltage; the calibrated switch status will not change. S13.在所述可快速切换的低损耗光延迟线使用时，通过向所述铁电材料层开关相移区(40)波导两侧的金属电极(401)施加调制电压，调制电压低于校准电压，施加调制电压可以利用铁电材料的电光特性改变材料的折射率，但撤去调制电压后折射率值又恢复到施加调制电压之前的值，利用所述铁电材料的电光特性调控所述马赫-曾德尔干涉仪结构光开关的状态，从而调控光的传输路径，调控光经历的延时长短。S13. When the fast-switchable low-loss optical delay line is used, a modulation voltage is applied to the metal electrodes (401) on both sides of the waveguide of the phase shift region (40) of the ferroelectric material layer. The modulation voltage is lower than the calibration voltage. Applying the modulation voltage can change the refractive index of the material by utilizing the electro-optic properties of the ferroelectric material. However, after removing the modulation voltage, the refractive index value returns to the value before the modulation voltage was applied. The state of the structured optical switch of the Mach-Zehnder interferometer is controlled by utilizing the electro-optic properties of the ferroelectric material, thereby controlling the light transmission path and the length of the delay experienced by the light.
CN202511182514.8A 2025-08-22 2025-08-22 Low-loss optical delay line capable of being switched rapidly and optical switch calibration regulation and control method Pending CN120909018A (en)

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