WO2023065499A1

WO2023065499A1 - Electro-optic modulator

Info

Publication number: WO2023065499A1
Application number: PCT/CN2021/137868
Authority: WO
Inventors: 薄方; 张茹; 张国权; 许京军
Original assignee: 南开大学
Priority date: 2021-10-22
Filing date: 2021-12-14
Publication date: 2023-04-27
Also published as: CN114089550B; CN114089550A

Abstract

An electro-optic modulator (10), wherein a power supply (400) may generate a relatively high varying electric field that excites a high-order electro-optical effect of lithium niobate between a first electrode (310) and a second electrode (320), and between the first electrode (310) and a third electrode (330). When the high-order electro-optic effect of lithium niobate is generated, a half-wave voltage of the electro-optic modulator (10) is significantly reduced. Therefore, the power supply (400) provides a relatively high direct-current bias voltage and a relatively low radio frequency voltage so that signal modulation may be achieved. The electro-optic modulator (10) does not need to use devices such as a radio frequency amplifier (12) to amplify radio frequency signals, and also meets the requirements of a CMOS driving voltage. Therefore, the circuit part of the electro-optic modulator (10) may be fully integrated on a chip. Thus, a relatively large modulation bandwidth may be achieved, radio frequency loss may be reduced, and the modulation rate may be ensured. The electro-optic modulator (10) achieves the beneficial effects of low half-wave voltage and relatively large modulation bandwidth.

Description

电光调制器electro-optic modulator

相关申请related application

本申请要求2021年10月22日申请的，申请号为202111235451.X，名称为“电光调制器”的中国专利申请的优先权，在此将其全文引入作为参考。This application claims the priority of the Chinese patent application filed on October 22, 2021, with application number 202111235451.X and titled "Electro-optic modulator", which is hereby incorporated by reference in its entirety.

技术领域technical field

本申请涉及光通信和光互联领域，特别是涉及一种电光调制器。The present application relates to the field of optical communication and optical interconnection, in particular to an electro-optical modulator.

背景技术Background technique

随着信息化社会的到来，互联网、物联网、5G通信、IPTV、数据中心等新型通信业务正经历着快速发展的时期。新型通信业务的发展，也推动着基于光纤通信技术的光传送网络向着大容量、低时延、低功耗等技术方向发展。光纤通信技术的进步，一方面得益于新型信号调制与解调技术等信息编码技术的发展；另一方面则来自于高带宽、低功耗、小型化、高集成度的新型光电子器件以及光模块等硬件技术的进步。With the advent of the information society, new communication services such as the Internet, the Internet of Things, 5G communications, IPTV, and data centers are experiencing a period of rapid development. The development of new communication services also promotes the optical transmission network based on optical fiber communication technology to develop in the direction of large capacity, low delay, and low power consumption. The progress of optical fiber communication technology, on the one hand, benefits from the development of information coding technology such as new signal modulation and demodulation technology; on the other hand, it comes from new optoelectronic devices and optical Advances in hardware technology such as modules.

电光调制器是光通信***的关键器件之一，其通过电光调制技术将需要传输的电信号调制到光载波上以进行远距离传输；在接收端通过接收机恢复出接收到的信号。电光调制器的优劣将影响着光通信***的传输质量。此外，电光调制器是利用电光晶体的电光效应制成的调制器。传统的电光调制器模块还无法完全集成在芯片上，这影响了电光调制器的广泛应用。The electro-optical modulator is one of the key components of the optical communication system. It modulates the electrical signal to be transmitted onto the optical carrier for long-distance transmission through the electro-optic modulation technology; at the receiving end, the received signal is recovered by the receiver. The quality of the electro-optic modulator will affect the transmission quality of the optical communication system. In addition, electro-optic modulators are modulators made using the electro-optic effect of electro-optic crystals. Traditional electro-optic modulator modules cannot be fully integrated on the chip, which affects the wide application of electro-optic modulators.

发明内容Contents of the invention

基于此，有必要针对目前的电光调制器模块还无法完全集成在芯片上的技术问题，提供一种低半波电压-长度积的电光调制器。Based on this, it is necessary to provide an electro-optic modulator with a low half-wave voltage-length product for the technical problem that the current electro-optic modulator module cannot be fully integrated on the chip.

本申请在第一方面提供了一种电光调制器，包括：The present application provides an electro-optic modulator in a first aspect, including:

基底；base;

第一电极和第二电极，间隔设置于所述基底上；The first electrode and the second electrode are arranged on the substrate at intervals;

第一铌酸锂波导，设置于所述基底上，并位于所述第一电极和所述第二电极之间，所述第一铌酸锂波导分别与所述第一电极和所述第二电极绝缘设置，以及The first lithium niobate waveguide is arranged on the substrate and is located between the first electrode and the second electrode, and the first lithium niobate waveguide is connected to the first electrode and the second electrode respectively. electrode insulation set, and

电源，与所述第一电极连接，用于在所述第一电极和所述第二电极之间产生偏置交流电场，以激发出铌酸锂的高阶电光效应的电场。A power supply, connected to the first electrode, is used to generate a bias AC electric field between the first electrode and the second electrode, so as to excite the electric field of the high-order electro-optic effect of lithium niobate.

在其中一个实施例中，用于在所述第一电极和所述第二电极之间产生激发出铌酸锂的高阶电光效应的电场大于6×10 ⁶V/m。 In one of the embodiments, the electric field used to generate the high-order electro-optic effect to excite lithium niobate between the first electrode and the second electrode is greater than 6×10 ⁶ V/m.

在其中一个实施例中，所述电源包括射频源和直流源，所述射频源和所述直流源分别与所述第一电极连接。In one of the embodiments, the power supply includes a radio frequency source and a direct current source, and the radio frequency source and the direct current source are respectively connected to the first electrode.

在其中一个实施例中，还包括T型偏置器，所述射频源和所述直流源分别与所述T型偏置器的射频端和直流端连接，所述T型偏置器的射频与直流端连接所述第一电极。In one of the embodiments, it also includes a T-type bias device, the radio frequency source and the DC source are respectively connected to the radio frequency end and the DC end of the T-type bias device, and the radio frequency of the T-type bias device The first electrode is connected to the DC terminal.

在其中一个实施例中，还包括：In one of the embodiments, it also includes:

第三电极，所述第三电极设置于所述第一电极远离所述第二电极的一侧，所述第三电极与所述第一电极间隔设置，所述第二电极和所述第三电极用于接地；The third electrode, the third electrode is arranged on the side of the first electrode away from the second electrode, the third electrode is spaced apart from the first electrode, the second electrode and the third electrode Electrodes are used for grounding;

第二铌酸锂波导，所述第二铌酸锂波导设置于所述第一电极和所述第三电极之间，所述第二铌酸锂波导与所述第一电极和所述第三电极绝缘设置。The second lithium niobate waveguide, the second lithium niobate waveguide is arranged between the first electrode and the third electrode, the second lithium niobate waveguide is connected to the first electrode and the third electrode Electrode insulation set.

在其中一个实施例中，所述基底表面设置有铌酸锂膜层，所述第一铌酸锂波导形成于所述铌酸锂膜层上，所述第一铌酸锂波导在所述铌酸锂膜层为凸起结构。In one of the embodiments, the substrate surface is provided with a lithium niobate film layer, the first lithium niobate waveguide is formed on the lithium niobate film layer, and the first lithium niobate waveguide is formed on the niobium niobate film layer. The lithium acid film layer has a raised structure.

在其中一个实施例中，所述基底包括层叠设置的二氧化硅膜层和硅膜层，所述二氧化硅膜层设置于所述硅膜层和所述铌酸锂膜层之间。In one of the embodiments, the substrate includes a silicon dioxide film layer and a silicon film layer stacked, and the silicon dioxide film layer is disposed between the silicon film layer and the lithium niobate film layer.

在其中一个实施例中，所述铌酸锂膜层的厚度为400纳米至900纳米，所述二氧化硅膜层的厚度为2微米至5微米，所述硅膜层的厚度为0.4毫米至0.8毫米。In one of the embodiments, the thickness of the lithium niobate film layer is 400 nanometers to 900 nanometers, the thickness of the silicon dioxide film layer is 2 micrometers to 5 micrometers, and the thickness of the silicon film layer is 0.4 millimeters to 5 micrometers. 0.8 mm.

在其中一个实施例中，所述射频源提供0.5伏至2伏的射频电压，所述直流源提供20伏至100伏的直流偏置电压。In one embodiment, the radio frequency source provides a radio frequency voltage of 0.5 volts to 2 volts, and the direct current source provides a direct current bias voltage of 20 volts to 100 volts.

在其中一个实施例中，所述第一电极包括层叠且绝缘设置的第一子电极和第二子电极。In one of the embodiments, the first electrode includes a first sub-electrode and a second sub-electrode that are laminated and insulated.

本申请在第二方面提供了一种电光调制器的制作方法，包括：The present application provides a method for manufacturing an electro-optic modulator in a second aspect, including:

提供基片，其中所述基片为由0.6微米厚的X切铌酸锂膜层、2微米厚的二氧化硅膜层和500微米厚的硅膜层组成的键合片；A substrate is provided, wherein the substrate is a bonding sheet composed of a 0.6 micron thick X-cut lithium niobate film layer, a 2 micron thick silicon dioxide film layer and a 500 micron thick silicon film layer;

在所述基片上通过电子束曝光、显影工艺制备第一铌酸锂波导和第二铌酸锂波导的掩模；preparing masks for the first lithium niobate waveguide and the second lithium niobate waveguide by electron beam exposure and development processes on the substrate;

通过电感耦合等离子体反应离子刻蚀所述铌酸锂，将所述掩模的图形转移到所述铌酸锂膜层上；Etching the lithium niobate by inductively coupled plasma reactive ion etching, transferring the pattern of the mask to the lithium niobate film layer;

通过缓释氢氟酸去除电子束抗蚀剂，以完成所述第一铌酸锂波导和所述第二铌酸锂波导的制备；removing the electron beam resist by slow-release hydrofluoric acid to complete the preparation of the first lithium niobate waveguide and the second lithium niobate waveguide;

电子束曝光套刻，在所述第一铌酸锂波导和所述第二铌酸锂波导上进行第二次电子束曝光、显影，以定义第一电极、第二电极和第三电极的形状；Electron beam exposure overlay, performing a second electron beam exposure and development on the first lithium niobate waveguide and the second lithium niobate waveguide to define the shape of the first electrode, the second electrode and the third electrode ;

电子束蒸镀20纳米厚的铬和100纳米厚的金形成金属层；Electron beam evaporation of 20nm thick chromium and 100nm thick gold to form the metal layer;

剥离覆盖在所述第一铌酸锂波导和所述第二铌酸锂波导表面的光刻胶部分，留下由金形成的所述第一电极、所述第二电极和所述第三电极结构，完成电极的制备；peeling off the photoresist part covering the surface of the first lithium niobate waveguide and the surface of the second lithium niobate waveguide, leaving the first electrode, the second electrode and the third electrode formed by gold Structure, complete the preparation of the electrode;

采用等离子体化学气相沉积工艺沉积1微米厚的二氧化硅保护膜；A 1 micron thick silicon dioxide protective film is deposited by plasma chemical vapor deposition process;

通过紫外光刻，采用光刻胶在所述二氧化硅保护膜的表面定义出所述第一电极、所述第二电极和所述第三电极露出来的区域；Using photoresist to define the exposed regions of the first electrode, the second electrode and the third electrode on the surface of the silicon dioxide protective film by ultraviolet lithography;

缓释氢氟酸刻蚀所述二氧化硅保护膜，未被所述光刻胶保护的部分被刻蚀掉；Slow-release hydrofluoric acid etches the silicon dioxide protective film, and the part not protected by the photoresist is etched away;

去除残余的所述光刻胶。removing the remaining photoresist.

在其中一个实施例中，所述电感耦合等离子体反应离子刻蚀过程采用纯氩刻蚀。In one embodiment, the inductively coupled plasma reactive ion etching process uses pure argon etching.

在其中一个实施例中，所述铌酸锂膜层的刻蚀深度为350纳米，刻蚀倾角约为60°。In one embodiment, the etching depth of the lithium niobate film layer is 350 nanometers, and the etching inclination angle is about 60°.

在其中一个实施例中，所述第一铌酸锂波导和所述第二铌酸锂波导的宽度均为0.8微米。In one embodiment, the widths of the first lithium niobate waveguide and the second lithium niobate waveguide are both 0.8 microns.

本申请实施例提供的所述电光调制器，所述电源能够产生使所述第一电极和所述第二电极之间产生偏置交流电场。所述偏置交流电场能够激发出铌酸锂的高阶电光效应。当产生铌酸锂的高阶电光效应时，所述电光调制器的半波电压显著降低。因此，所述电源提供较高的直流偏置电压和较低的射频电压就能够实现对光信号的调制。所述电光调制器所需的射频电压能够符合CMOS驱动电压的要求，无需再使用射频放大器等器件进行射频信号放大。因此所述电光调制器的电路部分能够完全集成在芯片上。所述电光调制器在不需要增加电光作用区域长度的条件下就可以实现较低的半波电压，因此能够减小射频损耗，提高调制频宽，保证调制速率。所述电光调制器同时实现了低半波电压和较大的调制频宽。In the electro-optic modulator provided in the embodiment of the present application, the power supply can generate a bias AC electric field between the first electrode and the second electrode. The biased alternating electric field can excite the high-order electro-optical effect of lithium niobate. When the high-order electro-optic effect of lithium niobate is generated, the half-wave voltage of the electro-optic modulator is significantly reduced. Therefore, the power supply can realize the modulation of the optical signal by providing a higher DC bias voltage and a lower RF voltage. The radio frequency voltage required by the electro-optic modulator can meet the requirements of the CMOS drive voltage, and there is no need to use radio frequency amplifiers and other devices to amplify radio frequency signals. The circuit part of the electro-optic modulator can thus be fully integrated on the chip. The electro-optic modulator can realize a lower half-wave voltage without increasing the length of the electro-optic action region, so it can reduce radio frequency loss, increase modulation bandwidth, and ensure modulation rate. The electro-optical modulator realizes low half-wave voltage and large modulation bandwidth at the same time.

附图说明Description of drawings

为了更清楚地说明本申请实施例或传统技术中的技术方案，下面将对实施例或传统技术描述中所需要使用的附图作简单地介绍。显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。In order to more clearly illustrate the technical solutions in the embodiments of the present application or in the conventional technology, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the conventional technology. Apparently, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative efforts.

图1为本申请一实施例提供的传统技术中的电光调制器的结构示意图。FIG. 1 is a schematic structural diagram of an electro-optical modulator in a conventional technology provided by an embodiment of the present application.

图2为本申请一实施例提供的相位型电光调制器的结构示意图。FIG. 2 is a schematic structural diagram of a phase-type electro-optic modulator provided by an embodiment of the present application.

图3为本申请一实施例提供的强度型电光调制器的结构示意图。FIG. 3 is a schematic structural diagram of an intensity-type electro-optic modulator provided by an embodiment of the present application.

图4为本申请另一实施例提供的强度型电光调制器的结构示意图。FIG. 4 is a schematic structural diagram of an intensity-type electro-optic modulator provided by another embodiment of the present application.

图5为本申请一实施例提供的强度型电光调制器的电压-归一化光强的变化示意图。FIG. 5 is a schematic diagram of voltage-normalized light intensity variation of an intensity-type electro-optic modulator provided by an embodiment of the present application.

图6为本申请一实施例提供的强度型电光调制器在施加较高直流偏置的正弦交流电信号下输出光强的变化示意图。FIG. 6 is a schematic diagram of changes in output light intensity of an intensity-type electro-optic modulator provided by an embodiment of the present application under the application of a sinusoidal alternating current signal with a relatively high direct current bias.

图7为本申请一实施例提供的强度型电光调制器的立体结构示意图。FIG. 7 is a schematic diagram of a three-dimensional structure of an intensity-type electro-optic modulator provided by an embodiment of the present application.

图8为本申请一实施例提供的相位型电光调制器的俯视图。FIG. 8 is a top view of a phase-type electro-optic modulator provided by an embodiment of the present application.

图9为本申请一实施例提供的图8所示的相位型电光调制器的截面图。FIG. 9 is a cross-sectional view of the phase-type electro-optic modulator shown in FIG. 8 provided by an embodiment of the present application.

图10为本申请一实施例提供的强度型电光调制器的俯视图。Fig. 10 is a top view of an intensity-type electro-optic modulator provided by an embodiment of the present application.

图11为本申请一实施例提供的图10所示的强度型电光调制器的截面图。FIG. 11 is a cross-sectional view of the intensity-type electro-optic modulator shown in FIG. 10 provided by an embodiment of the present application.

图12为本申请一实施例提供的强度型电光调制器制作流程示意图。FIG. 12 is a schematic diagram of the manufacturing process of the intensity-type electro-optic modulator provided by an embodiment of the present application.

具体实施方式Detailed ways

为了使本申请的目的、技术方案及优点更加清楚明白，以下通过实施例，并结合附图，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅用以解释本申请，并不用于限定本申请。In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail through the following embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present application, not to limit the present application.

本文中为部件所编序号本身，例如“第一”、“第二”等，仅用于区分所描述的对象，不具有任何顺序或技术含义。而本申请所说“连接”、“联接”，如无特别说明，均包括直接和间接连接(联接)。在本申请的描述中，需要理解的是，术语“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”、“顺时针”、“逆时针”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。The serial numbers assigned to components in this document, such as "first", "second", etc., are only used to distinguish the described objects, and do not have any sequence or technical meaning. The "connection" and "connection" mentioned in this application all include direct and indirect connection (connection) unless otherwise specified. In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description , rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and thus should not be construed as limiting the application.

在本申请中，除非另有明确的规定和限定，第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触，或第一和第二特征通过中间媒介间接接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一特征在第二特征正下方或斜下方，或仅仅表示第一特征水平高度小于第二特征。In the present application, unless otherwise clearly specified and limited, a first feature being "on" or "under" a second feature may mean that the first and second features are in direct contact, or that the first and second features are indirect through an intermediary. touch. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

发明人的研究基于铌酸锂晶体。在各种光学晶体之中，铌酸锂晶体的线性电光系数较高(r ₃₃＝30.9pm/V，r ₁₃＝8.6pm/V)、透明波长范围较大(0.35微米-5微米)以及本征频宽较宽，这使得基于它的设备可以完成极快的调制，因此铌酸锂晶体高速电光调制器具有广泛的应用前景。铌酸锂脊波导相较于传统的钛扩散波导和质子交换波导具有较高折射率对比度，因此可以将光束缚在亚微米尺寸范围内，这使得信号电极可以放置得更靠近光波导，从而在降低半波电压的同时不会引起不必要的光学损耗。 The inventor's research is based on lithium niobate crystals. Among various optical crystals, the linear electro-optic coefficient of lithium niobate crystal is relatively high (r ₃₃ =30.9pm/V, r ₁₃ =8.6pm/V), the transparent wavelength range is large (0.35 micron-5 micron) and the The characteristic bandwidth is wide, which enables the equipment based on it to complete extremely fast modulation, so the lithium niobate crystal high-speed electro-optic modulator has broad application prospects. Compared with the traditional titanium diffusion waveguide and proton exchange waveguide, the lithium niobate ridge waveguide has a higher refractive index contrast, so the light beam can be bound in the submicron size range, which allows the signal electrode to be placed closer to the optical waveguide, thus in Reduce the half-wave voltage without causing unnecessary optical loss.

传统技术中，铌酸锂电光调制器10大多基于线性电光效应，即泡克尔斯效应，其可实现的V _π·L(半波电压-长度积)为2.2V·cm。要想实现大约1V的半波电压，电光作用区域的长度需要大于2cm。调制器为实现较大的调制频宽，需要精确设计光波和微波的群速度匹配。然而较长的电光作用长度使得群速度匹配条件更加苛刻，射频损耗加大，限制了电光频宽的提升，导致调制速率的下降，即，低半波电压和调制频宽不能同时实现。 In the traditional technology, the lithium niobate electro-optic modulator 10 is mostly based on the linear electro-optic effect, that is, the Pockels effect, and its achievable V _π ·L (half-wave voltage-length product) is 2.2V·cm. To achieve a half-wave voltage of approximately 1V, the length of the electro-optic active region needs to be greater than 2cm. In order to achieve a large modulation bandwidth of the modulator, it is necessary to precisely design the group velocity matching of light waves and microwaves. However, the longer electro-optic action length makes the group velocity matching condition more stringent, and the radio frequency loss increases, which limits the improvement of electro-optic bandwidth and leads to the decrease of modulation rate, that is, low half-wave voltage and modulation bandwidth cannot be realized at the same time.

请参见图1，传统的铌酸锂相位型电光调制器基于铌酸锂的线性电光效应，施加在信号电极13和地电极15上的电压产生的电场引起铌酸锂脊波导14的折射率的变化，从而改变光波的相位。由于V _π·L较大，CMOS射频源11提供的射频信号引起的相位改变无法满足实际生产生活的需求。射频信号需要通过射频放大器12放大后再载入在所述信号电极13上，其中地电极15接地。 Please refer to Fig. 1, the traditional lithium niobate phase electro-optic modulator is based on the linear electro-optic effect of lithium niobate, and the electric field generated by the voltage applied to the signal electrode 13 and the ground electrode 15 causes the refractive index of the lithium niobate ridge waveguide 14 to change. change, thereby changing the phase of the light wave. Due to the large V _π ·L, the phase change caused by the radio frequency signal provided by the CMOS radio frequency source 11 cannot meet the requirements of actual production and life. The radio frequency signal needs to be amplified by the radio frequency amplifier 12 and then loaded on the signal electrode 13, wherein the ground electrode 15 is grounded.

请参见图2，本申请实施例提供了一种电光调制器10。所述电光调制器10包括基底100、第一电极310、第二电极320、第一铌酸锂波导340和电源400。所述第一电极310和所述第二电极320间隔设置于所述基底100上。所述第一铌酸锂波导340设置于所述基底100上。所述第一铌酸锂波导340位于所述第一电极310和所述第二电极320之间。所述第一铌酸锂波导340分别与所述第一电极310和所述第二电极320绝缘设置。所述电源400与所述第一电极310连接。所述电源400用于在所述第一电极310和所述第二电极320之间产生偏置交流电场，以激发出铌酸锂的高阶电光效应。即，使得所述电光调制器10在较低的交流电压下实现光强度的调制。Referring to FIG. 2 , the embodiment of the present application provides an electro-optic modulator 10 . The electro-optic modulator 10 includes a substrate 100 , a first electrode 310 , a second electrode 320 , a first lithium niobate waveguide 340 and a power source 400 . The first electrode 310 and the second electrode 320 are disposed on the substrate 100 at intervals. The first lithium niobate waveguide 340 is disposed on the substrate 100 . The first lithium niobate waveguide 340 is located between the first electrode 310 and the second electrode 320 . The first lithium niobate waveguide 340 is insulated from the first electrode 310 and the second electrode 320 respectively. The power source 400 is connected to the first electrode 310 . The power supply 400 is used to generate a bias AC electric field between the first electrode 310 and the second electrode 320 to excite the high-order electro-optic effect of lithium niobate. That is, the electro-optic modulator 10 realizes the modulation of light intensity at a lower AC voltage.

所述基底100可以为多膜层结构。所述基底100可以包括无机膜层材料。所述第一电极310和所述第二电极320可以为金属材料。在一个实施例中，所述第一电极310和所述第二电极320可以采用金制成。所述第一电极310和所述第二电极320的长度和形状可以相同。所述第一电极310可以用于连接所述电源400。所述第二电极320可以用于接地。所述第一铌酸锂波导340设置于所述基底100上。所述第一铌酸锂波导340分别与所述第一电极310和所述第二电极320间隔设置。在一个实施例中，所述第一电极310、所述第二电极320和所述第一铌酸锂波导340均为条状结构。所述第一电极310、所述第二电极320和所述第一铌酸锂波导340平行设置。所述电光调制器10可以构成相位型调制器。The substrate 100 may be a multi-layer structure. The substrate 100 may include inorganic film material. The first electrode 310 and the second electrode 320 may be metal materials. In one embodiment, the first electrode 310 and the second electrode 320 may be made of gold. The length and shape of the first electrode 310 and the second electrode 320 may be the same. The first electrode 310 can be used to connect to the power source 400 . The second electrode 320 can be used for grounding. The first lithium niobate waveguide 340 is disposed on the substrate 100 . The first lithium niobate waveguide 340 is spaced apart from the first electrode 310 and the second electrode 320 respectively. In one embodiment, the first electrode 310 , the second electrode 320 and the first lithium niobate waveguide 340 are all strip structures. The first electrode 310, the second electrode 320 and the first lithium niobate waveguide 340 are arranged in parallel. The electro-optic modulator 10 may constitute a phase modulator.

所述电光调制器10工作时，所述电源400连接所述第一电极310。所述第二电极320接地。所述第一电极310和所述第二电极320之间形成变化的电场。所述第一铌酸锂波导 340位于所述电场中。所述电场引起铌酸锂折射率的变化，从而改变光波的相位。所述第一电极310和所述第二电极320可以为行波电极型结构，也就是说，光在所述第一铌酸锂波导340中的传播方向与所述电源400加载在所述第一电极310上的射频信号的传输方向一致。相较于传统的铌酸锂体材料电光调制器，所述第一电极310和所述第二电极320可以更加靠近所述第一铌酸锂波导340，这样相同电压下光波受到的电场更强。所述电源400能够在所述第一电极310和所述第二电极320之间形成较高的电场。较高的电场强度会激发出铌酸锂的高阶电光效应。When the electro-optic modulator 10 is working, the power source 400 is connected to the first electrode 310 . The second electrode 320 is grounded. A variable electric field is formed between the first electrode 310 and the second electrode 320 . The first lithium niobate waveguide 340 is located in the electric field. The electric field causes a change in the refractive index of lithium niobate, thereby changing the phase of the light wave. The first electrode 310 and the second electrode 320 can be a traveling wave electrode structure, that is to say, the propagation direction of light in the first lithium niobate waveguide 340 is the same as that of the power source 400 loaded on the first lithium niobate waveguide. The transmission directions of the radio frequency signals on one electrode 310 are consistent. Compared with the traditional electro-optic modulator of lithium niobate bulk material, the first electrode 310 and the second electrode 320 can be closer to the first lithium niobate waveguide 340, so that the electric field received by the light wave under the same voltage is stronger . The power source 400 can form a relatively high electric field between the first electrode 310 and the second electrode 320 . Higher electric field strength will excite the high-order electro-optic effect of lithium niobate.

请参见图3和图4，在一个实施例中，所述电光调制器10还包括第三电极330和第二铌酸锂波导350。所述第三电极330设置于所述第一电极310远离所述第二电极320的一侧。所述第三电极330与所述第一电极310间隔设置。所述第一电极310和所述第三电极330用于接地。所述第二铌酸锂波导350设置于所述第一电极310和所述第三电极330之间。所述第二铌酸锂波导350与所述第一电极310和所述第三电极330绝缘设置。本实施例提供的所述电光调制器10可以构成强度型电光调制器。所述第一铌酸锂波导340、所述第二铌酸锂波导350构成2个相位调制臂，并构成两个Y型分支结构。每一个相位调制臂的相位随驱动电压的变化而变化。所述电光调制器10的输出光为2个所述相位调制臂输出光的相干叠加。Referring to FIG. 3 and FIG. 4 , in one embodiment, the electro-optic modulator 10 further includes a third electrode 330 and a second lithium niobate waveguide 350 . The third electrode 330 is disposed on a side of the first electrode 310 away from the second electrode 320 . The third electrode 330 is spaced apart from the first electrode 310 . The first electrode 310 and the third electrode 330 are used for grounding. The second lithium niobate waveguide 350 is disposed between the first electrode 310 and the third electrode 330 . The second lithium niobate waveguide 350 is insulated from the first electrode 310 and the third electrode 330 . The electro-optic modulator 10 provided in this embodiment may constitute an intensity-type electro-optic modulator. The first lithium niobate waveguide 340 and the second lithium niobate waveguide 350 form two phase modulation arms and form two Y-shaped branch structures. The phase of each phase modulation arm changes with the change of the driving voltage. The output light of the electro-optic modulator 10 is the coherent superposition of the output lights of the two phase modulation arms.

所述第三电极330和所述第一电极310之间的距离与所述第一电极310和所述第二电极320之前的距离可以相等。所述第一电极310、所述第二电极320和所述第三电极330可以平行设置。所述第一铌酸锂波导340和所述第二铌酸锂波导350可以平行设置。所述第二铌酸锂波导350可以分别与所述第一电极310和所述第三电极330间隔设置。所述电源400通电时，所述第一电极310和所述第二电极320之间，以及所述第一电极310和所述第三电极330之间可以形成能够激发出铌酸锂的高阶电光效应的电场。图3中的射频源410和直流源420可以通过T型偏置器430与所述第一电极310连接。图4中的射频源410和直流源420可以分别直接与所述第一电极310连接。The distance between the third electrode 330 and the first electrode 310 may be equal to the distance between the first electrode 310 and the second electrode 320 . The first electrode 310, the second electrode 320 and the third electrode 330 may be arranged in parallel. The first lithium niobate waveguide 340 and the second lithium niobate waveguide 350 may be arranged in parallel. The second lithium niobate waveguide 350 may be spaced apart from the first electrode 310 and the third electrode 330 respectively. When the power supply 400 is energized, a high-order electrode that can excite lithium niobate can be formed between the first electrode 310 and the second electrode 320, and between the first electrode 310 and the third electrode 330. Electric field for the electro-optic effect. The RF source 410 and the DC source 420 in FIG. 3 may be connected to the first electrode 310 through a T-shaped biaser 430 . The radio frequency source 410 and the direct current source 420 in FIG. 4 may be directly connected to the first electrode 310 respectively.

在一个实施例中，所述电光调制器10基于X切铌酸锂膜层材料，所加电场方向与铌酸锂晶轴方向平行。In one embodiment, the electro-optic modulator 10 is based on an X-cut lithium niobate film layer material, and the direction of the applied electric field is parallel to the crystal axis of lithium niobate.

下面对所述相位型调制器和所述强度型调制器的工作原理进行解释。The working principles of the phase modulator and the intensity modulator are explained below.

所述相位调制器的工作原理为，通过加载在所述第一电极310和第二电极320上的电压产生的电场引起铌酸锂折射率的变化，从而改变通过铌酸锂波导的光波的相位。The working principle of the phase modulator is that the electric field generated by the voltage applied on the first electrode 310 and the second electrode 320 causes a change in the refractive index of lithium niobate, thereby changing the phase of the light wave passing through the lithium niobate waveguide .

所述强度型电光调制器的工作原理为，所述光经过第一个所述Y型分支结构后被分成两束光，每一束光均通过一个对应的相位调制臂进行相位的调制。通过所述相位调制臂的两束光进行的相位改变的方向相反。通过两个所述相位调制臂的两束光通过第二个所述Y型分支结构，由于两束光相位不同会发生光的干涉，引起光强的变化，即相位的调制转变为强度的调制。也就是说，所述强度调制器是由两个所述相位调制器组成，两束相位不同的光发生干涉引起的光强度的调制。The working principle of the intensity-type electro-optic modulator is that the light is divided into two beams after passing through the first Y-shaped branch structure, and each beam is phase-modulated by a corresponding phase modulation arm. The phase changes of the two beams passing through the phase modulating arm are in opposite directions. The two beams of light passing through the two phase modulation arms pass through the second Y-shaped branch structure. Due to the different phases of the two beams of light, light interference will occur, causing a change in light intensity, that is, phase modulation is transformed into intensity modulation. . That is to say, the intensity modulator is composed of two phase modulators, and the light intensity is modulated by interference between two beams of light with different phases.

对于所述相位调制器，半波电压是指相位改变π需要的电压值。对于所述强度调制器，半波电压是指输出光强由极小值变化到极大值所需要的电压。所述强度调制器电极结构可以采用推挽式结构，因此每一个所述相位调制器的相位改变π/2就可以使得强度由极小值变化为极大值。For the phase modulator, the half-wave voltage refers to the voltage value required to change the phase by π. For the intensity modulator, the half-wave voltage refers to the voltage required for the output light intensity to change from a minimum value to a maximum value. The electrode structure of the intensity modulator can adopt a push-pull structure, so the phase change of each phase modulator by π/2 can make the intensity change from a minimum value to a maximum value.

请参见图5和图6为强度调制器的实验结果。由图5可知，在一个实施例中，光波长固定为1550纳米。在所述第一电极310和所述第二电极320之间载入0-60伏的电信号，光通过所述电光调制器10的强度变化如图5所示。随着电压的升高，光强正弦变化的周期减小，大致在30伏及以下时显示线性电光效应；在30伏及更高的电压时出现了高阶电光效应。在较低电场下，也就是在出现线性电光效应的电压下，所述电光调制器10的半波电压约为7伏。在较高电场强度下，也就是出现高阶电光效应的电压下，所述电光调制器10的半波电压降至3伏左右。在一个实施例中，电光作用区域长度采用0.3cm。此时高电场对应的半波电压-长度积V _π×L＝3V×0.3cm＝0.9V·cm，即如果电光相互作用长度为1厘米时候，所需的半波电压为0.9伏。 Please refer to Figure 5 and Figure 6 for the experimental results of the intensity modulator. It can be seen from FIG. 5 that in one embodiment, the light wavelength is fixed at 1550 nanometers. An electrical signal of 0-60 volts is loaded between the first electrode 310 and the second electrode 320 , and the intensity variation of light passing through the electro-optic modulator 10 is shown in FIG. 5 . As the voltage increases, the period of the sinusoidal change of the light intensity decreases, and a linear electro-optic effect is displayed at approximately 30 volts and below; a high-order electro-optic effect appears at a voltage of 30 volts and higher. At a lower electric field, that is, at the voltage at which the linear electro-optic effect occurs, the half-wave voltage of the electro-optic modulator 10 is about 7 volts. At higher electric field strengths, that is, voltages where high-order electro-optic effects occur, the half-wave voltage of the electro-optic modulator 10 drops to about 3 volts. In one embodiment, the length of the electro-optic active region is 0.3 cm. At this time, the half-wave voltage-length product corresponding to the high electric field V _π × L = 3V × 0.3cm = 0.9V·cm, that is, if the electro-optic interaction length is 1 cm, the required half-wave voltage is 0.9 volts.

如图6所示，给所述强度电光调制器载入51.5伏到54.5伏的正弦电信号即可输出对应的正弦光信号。通过一个几十伏的直流源420和一个低压射频源410可以实现信号0101的调制。在一个实施例中，可以采用53伏的直流源420和3伏的射频源410实现信号0101的调制。As shown in FIG. 6 , loading a sinusoidal electrical signal of 51.5 volts to 54.5 volts into the intensity electro-optic modulator can output a corresponding sinusoidal optical signal. The modulation of the signal 0101 can be realized by a DC source 420 of tens of volts and a low-voltage RF source 410 . In one embodiment, the signal 0101 can be modulated by using a 53V DC source 420 and a 3V RF source 410 .

因此，光强由极小值变化到极大值时对应每一臂的相位改变π/2，即可以得到电光相互作用长度为0.3cm的所述相位调制器在较低电场下的半波电压为大约为14伏。在较高电场强度下，所述相位调制器的半波电压降至6伏左右，此时高电场对应的半波电压-长度积V _π·L＝6V·0.3cm＝1.8V·cm，即如果电光相互作用长度为1厘米时候，所需的半波电压为1.8伏。 Therefore, when the light intensity changes from a minimum value to a maximum value, the phase of each arm changes by π/2, that is, the half-wave voltage of the phase modulator with an electro-optical interaction length of 0.3 cm under a lower electric field can be obtained is approximately 14 volts. Under higher electric field strength, the half-wave voltage of the phase modulator drops to about 6 volts, at this time the half-wave voltage-length product V _π L=6V·0.3cm=1.8V·cm corresponding to the high electric field, namely If the electro-optic interaction length is 1 cm, the required half-wave voltage is 1.8 volts.

因此，对于所述相位调制器和所述强度调制器，所述电源400能够使所述第一电极310和所述第二电极320之间产生偏置交流电场。所述偏置交流电场能够激发出铌酸锂的高阶电光效应。当产生铌酸锂的高阶电光效应时，所述电光调制器10的半波电压显著降低。因此，所述电源400提供较高的直流偏置电压和较低的射频电压就能够实现对光信号的调制。所述电光调制器10所需的射频电压能够符合CMOS驱动电压的要求，无需再使用射频放大器12等器件进行射频信号放大。因此所述电光调制器10的电路部分能够完全集成在芯片上。所述电光调制器10在不需要增加电光作用区域长度的条件下就可以实现较低的半波电压，因此能够减小射频损耗，提高调制频宽保证调制速率。所述电光调制器10同时实现了低半波电压和较大的调制频宽。Therefore, for the phase modulator and the intensity modulator, the power supply 400 can generate a bias AC electric field between the first electrode 310 and the second electrode 320 . The biased alternating electric field can excite the high-order electro-optical effect of lithium niobate. When the high-order electro-optic effect of lithium niobate is generated, the half-wave voltage of the electro-optic modulator 10 is significantly reduced. Therefore, the power supply 400 can realize the modulation of the optical signal by providing a higher DC bias voltage and a lower RF voltage. The radio frequency voltage required by the electro-optic modulator 10 can meet the requirements of the CMOS drive voltage, and there is no need to use devices such as radio frequency amplifier 12 to amplify radio frequency signals. Therefore, the circuit part of the electro-optic modulator 10 can be fully integrated on the chip. The electro-optic modulator 10 can achieve a lower half-wave voltage without increasing the length of the electro-optic active region, so it can reduce radio frequency loss, increase the modulation bandwidth and ensure the modulation rate. The electro-optic modulator 10 realizes low half-wave voltage and large modulation bandwidth at the same time.

另外，对于所述强度调制器，可以极大降低射频源410的输出电压。而且所述电光调制器10可以仅通过所述第一电极310、所述第二电极320和所述第三电极330就能够使得所述电光调制器10正常工作，而不需要额外的直流偏置电极。In addition, for the intensity modulator described, the output voltage of the radio frequency source 410 can be greatly reduced. Moreover, the electro-optic modulator 10 can make the electro-optic modulator 10 work normally only through the first electrode 310, the second electrode 320 and the third electrode 330, without additional DC bias electrode.

在一个实施例中，用于使所述第一电极310和所述第二电极320之间产生铌酸锂的高阶电光效应的电场大于6×10 ⁶V/m。 In one embodiment, the electric field used to generate the high-order electro-optic effect of lithium niobate between the first electrode 310 and the second electrode 320 is greater than 6×10 ⁶ V/m.

请参见图6，通过给所述第一铌酸锂波导340施加变化的电场，使得电场强度大于6×10 ⁶V/m，电场变化的幅度约0.6×10 ⁶V/m，可以实现信号0101的调制。 Please refer to FIG. 6, by applying a variable electric field to the first lithium niobate waveguide 340, the electric field intensity is greater than 6×10 ⁶ V/m, and the amplitude of the electric field change is about 0.6×10 ⁶ V/m, and the signal 0101 can be realized modulation.

在一个实施例中，所述电源400包括射频源410和直流源420。所述射频源410和所述直流源420分别与所述第一电极310连接。所述射频源410可以为3伏。所述直流源420可以为53伏。也就是说，当射频源410的射频信号电压为3伏，直流源420的信号电压为53伏时，已激发铌酸锂的高阶电光效应。In one embodiment, the power supply 400 includes a radio frequency source 410 and a direct current source 420 . The RF source 410 and the DC source 420 are respectively connected to the first electrode 310 . The radio frequency source 410 may be 3 volts. The DC source 420 may be 53 volts. That is to say, when the RF signal voltage of the RF source 410 is 3V and the signal voltage of the DC source 420 is 53V, the high-order electro-optic effect of lithium niobate has been excited.

在一个实施例中，电光调制器10还包括T型偏置器430。所述射频源410和所述直流源420分别与所述T型偏置器430的射频端和直流端连接。所述T型偏置器430的射频端与直流端连接所述第一电极310。所述射频源410和所述直流源420通过所述T型偏置器430形成正弦电压信号载入在所述第一电极310和所述第二电极320之间。所述T型偏置器430可以用于向射频信号中注入直流信号而不影响通过主传输通路的射频信号，以产生有偏置的射频信号。In one embodiment, the electro-optic modulator 10 further includes a T-type biaser 430 . The RF source 410 and the DC source 420 are respectively connected to the RF end and the DC end of the T-shaped biaser 430 . The RF end and the DC end of the T-shaped biaser 430 are connected to the first electrode 310 . The RF source 410 and the DC source 420 form a sinusoidal voltage signal loaded between the first electrode 310 and the second electrode 320 through the T-shaped biaser 430 . The T-shaped biaser 430 can be used to inject a DC signal into the radio frequency signal without affecting the radio frequency signal passing through the main transmission path, so as to generate a biased radio frequency signal.

在一个实施例中，所述基底100的表面设置有铌酸锂膜层200。所述第一铌酸锂波导340形成于所述铌酸锂膜层200上，其中所述第一铌酸锂波导340在所述铌酸锂膜层200为凸起结构。In one embodiment, the surface of the substrate 100 is provided with a lithium niobate film layer 200 . The first lithium niobate waveguide 340 is formed on the lithium niobate film layer 200 , wherein the first lithium niobate waveguide 340 is a convex structure on the lithium niobate film layer 200 .

请参见图7，在一个实施例中，所述基底100包括层叠设置的二氧化硅膜层110和硅膜层120。所述二氧化硅膜层110设置于所述硅膜层120和所述铌酸锂膜层200之间。Referring to FIG. 7 , in one embodiment, the substrate 100 includes a silicon dioxide film layer 110 and a silicon film layer 120 stacked. The silicon dioxide film layer 110 is disposed between the silicon film layer 120 and the lithium niobate film layer 200 .

在一个实施例中，所述铌酸锂膜层200的表面还可以设置二氧化硅保护膜230以保护所述电光调制器10。在所述第一电极310、所述第二电极320和所述第三电极330对应的所述二氧化硅保护膜230的部分可以开设窗口250，便于后期电极和外部电路的封装。In one embodiment, the surface of the lithium niobate film layer 200 may also be provided with a silicon dioxide protective film 230 to protect the electro-optic modulator 10 . A window 250 may be provided in the portion of the silicon dioxide protective film 230 corresponding to the first electrode 310 , the second electrode 320 and the third electrode 330 , so as to facilitate the packaging of later electrodes and external circuits.

在一个实施例中，所述铌酸锂膜层200的厚度为400纳米到900纳米。所述二氧化硅膜层110的厚度为2微米到5微米。所述硅膜层120的厚度为0.4毫米到0.8毫米。在该结构下，所述电光调制器10具有较小的体积，有利于在较高的电场下出现高阶电光效应。In one embodiment, the thickness of the lithium niobate film layer 200 is 400 nm to 900 nm. The silicon dioxide film layer 110 has a thickness of 2 microns to 5 microns. The thickness of the silicon film layer 120 is 0.4 mm to 0.8 mm. Under this structure, the electro-optic modulator 10 has a smaller volume, which is conducive to the occurrence of high-order electro-optic effects under higher electric fields.

在一个实施例中，所述铌酸锂膜层200的厚度为500纳米到700纳米。所述二氧化硅膜层110的厚度为3微米到4微米。所述硅膜层120的厚度为0.6毫米到0.7毫米。In one embodiment, the thickness of the lithium niobate film layer 200 is 500 nm to 700 nm. The silicon dioxide film layer 110 has a thickness of 3 microns to 4 microns. The thickness of the silicon film layer 120 is 0.6 mm to 0.7 mm.

在一个实施例中，所述第一铌酸锂波导340的宽度为0.6微米到4微米，高度为150纳米到900纳米。所述第二铌酸锂波导350的宽度为0.6微米到4微米，高度为150纳米到900纳米。In one embodiment, the width of the first lithium niobate waveguide 340 is 0.6 micrometers to 4 micrometers, and the height is 150 nanometers to 900 nanometers. The second lithium niobate waveguide 350 has a width of 0.6 microns to 4 microns and a height of 150 nanometers to 900 nanometers.

在一个实施例中，所述第一电极310、所述第二电极320和所述第三电极330的厚度均为0.1微米到2微米。所述第一电极310和所述第二电极320之间的距离为3微米到10微米。所述第一电极310和所述第三电极330之间的距离为3微米到10微米。本实施例提供的电光调制器10中所设置的所述第一电极310、所述第二电极320和所述第三电极330的厚度以及所述第一电极310、所述第二电极320和所述第三电极330之间的相互距离，便于所述电光调制器10实现高电场，以及实现铌酸锂高阶电光效应，使得通过一个几十伏的直流源420和一个低压射频源410可以实现信号0101的调制。In one embodiment, the thicknesses of the first electrode 310 , the second electrode 320 and the third electrode 330 are all 0.1 μm to 2 μm. The distance between the first electrode 310 and the second electrode 320 is 3 microns to 10 microns. The distance between the first electrode 310 and the third electrode 330 is 3 microns to 10 microns. The thicknesses of the first electrode 310, the second electrode 320 and the third electrode 330 and the thicknesses of the first electrode 310, the second electrode 320 and the The mutual distance between the third electrodes 330 is convenient for the electro-optic modulator 10 to realize high electric field and high-order electro-optic effect of lithium niobate, so that a direct current source 420 of tens of volts and a low-voltage radio frequency source 410 can The modulation of signal 0101 is realized.

在一个实施例中，所述第一电极310、所述第二电极320和所述第三电极330的厚度均为0.8微米到1微米。所述第一电极310和所述第二电极320之间的距离为5微米到8微米；所述第一电极310和所述第三电极330之间的距离为5微米到8微米。发明人研究发现，电极越厚，微波损耗越低，最后趋于一个定值。但是电极过厚或者过薄会引起微波折射率的降低或增加，会导致微波和光波的折射率不匹配，进而影响调制器的调制频宽。例如：相同结构下电极厚度为0.1微米、1微米和2微米的调制器的射频损耗为18.1dB/cm、5.8dB/cm和5.8dB/cm；微波折射率为2.32、2.26和2.21；其中光波的折射率为2.26。而当所述第一电极310、所述第二电极320和所述第三电极330的厚度范围为本实施例所述的范围时，能够减少调制器的射频损耗，并使得微波和光波的折射率匹配。In one embodiment, the thicknesses of the first electrode 310 , the second electrode 320 and the third electrode 330 are all 0.8 micron to 1 micron. The distance between the first electrode 310 and the second electrode 320 is 5 microns to 8 microns; the distance between the first electrode 310 and the third electrode 330 is 5 microns to 8 microns. The inventor found that the thicker the electrode, the lower the microwave loss, and finally tends to a constant value. However, if the electrode is too thick or too thin, the refractive index of the microwave will decrease or increase, which will cause a mismatch between the refractive index of the microwave and the light wave, thereby affecting the modulation bandwidth of the modulator. For example: under the same structure, the RF loss of the modulator with the electrode thickness of 0.1 micron, 1 micron and 2 micron is 18.1dB/cm, 5.8dB/cm and 5.8dB/cm; the refractive index of microwave is 2.32, 2.26 and 2.21; The refractive index of 2.26. And when the thickness range of the first electrode 310, the second electrode 320, and the third electrode 330 is within the range described in this embodiment, the radio frequency loss of the modulator can be reduced, and the refraction of microwaves and light waves can be reduced. rate match.

而电极间距越小，调制器所需的调制电压越低。但是较小的电极间距会引起较大的光波损耗。在一个实施例中，所述第一电极310和所述第二电极320之间的距离为5微米；并且所述第一电极310和所述第三电极330之间的距离为5微米时，施加大于30伏的电压就会产生大于6×10 ⁶V/m的电场，光波损耗为1dB/cm。如果电极间距为10微米，对应需要60伏的电压，光波损耗为1.6×10 ^-5dB/cm。如果电极间距为3微米，对应需要18伏的电压，光波损耗为79.4dB/cm。在所述第一电极310和所述第二电极320之间的距离为5微米到8微米，并且所述第一电极310和所述第三电极330之间的距离为5微米到8微米时，能够减少光波损耗。 The smaller the electrode spacing, the lower the modulation voltage required by the modulator. However, a smaller electrode spacing will cause a larger optical loss. In one embodiment, the distance between the first electrode 310 and the second electrode 320 is 5 microns; and when the distance between the first electrode 310 and the third electrode 330 is 5 microns, Applying a voltage greater than 30 volts will generate an electric field greater than 6×10 ⁶ V/m, and the light wave loss is 1dB/cm. If the distance between the electrodes is 10 microns, correspondingly, a voltage of 60 volts is required, and the light wave loss is 1.6×10 ^-5 dB/cm. If the distance between the electrodes is 3 microns, corresponding to a voltage of 18 volts, the optical loss is 79.4dB/cm. When the distance between the first electrode 310 and the second electrode 320 is 5 microns to 8 microns, and the distance between the first electrode 310 and the third electrode 330 is 5 microns to 8 microns , can reduce light loss.

在一个实施例中，所述射频源410提供0.5伏到2伏的射频电压。在一个实施例中，所述射频源410提供3伏的射频电压。在一个实施例中，所述直流源420提供20伏到100伏的直流偏置电压。所述直流源420提供53伏的直流偏置电压，从而实现信号的0101的调制。电压范围与电极间的距离相关，在上述实施例的基础上，在一个实施例中，所述直流源420提供40伏至60伏的直流偏置电压，其对应电场范围为8×10 ⁶V/m至12×10 ⁶V/m。电压过高产生的电场会发生电击穿。当电压接近100V及以上时已接近薄膜铌酸锂材料的矫顽场，会引起铌酸锂光轴的反转。 In one embodiment, the RF source 410 provides an RF voltage of 0.5 volts to 2 volts. In one embodiment, the RF source 410 provides an RF voltage of 3 volts. In one embodiment, the DC source 420 provides a DC bias voltage of 20V to 100V. The DC source 420 provides a DC bias voltage of 53 volts, so as to achieve 0101 modulation of the signal. The voltage range is related to the distance between the electrodes. On the basis of the above embodiments, in one embodiment, the DC source 420 provides a DC bias voltage of 40 volts to 60 volts, and the corresponding electric field range is 8×10 ⁶ V /m to 12×10 ⁶ V/m. The electric field generated by the voltage is too high will cause electrical breakdown. When the voltage is close to 100V and above, it is close to the coercive field of the thin-film lithium niobate material, which will cause the inversion of the optical axis of lithium niobate.

请参见图8-图11，图8为一个实施例提供的相位型电光调制器的俯视图；图9为一个实施例提供的图8的相位型电光调制器的截面图；图10为一个实施例提供的强度型电光调制器的俯视图；图11为一个实施例提供的图10的强度型电光调制器的截面图。本实施例提供的所述相位型电光调制器和所述强度型电光调制器的均可以省去所述T型偏置器。Please refer to Fig. 8-Fig. 11, Fig. 8 is a top view of a phase-type electro-optic modulator provided by an embodiment; Fig. 9 is a cross-sectional view of the phase-type electro-optic modulator of Fig. 8 provided by an embodiment; Fig. 10 is an embodiment A top view of the intensity-type electro-optic modulator provided; FIG. 11 is a cross-sectional view of the intensity-type electro-optic modulator of FIG. 10 provided by an embodiment. Both the phase-type electro-optic modulator and the intensity-type electro-optic modulator provided in this embodiment can omit the T-type bias device.

在一个实施例中，所述第一电极310包括层叠且绝缘设置的第一子电极311和第二子电极312。所述第一子电极311可以设置于所述基底100的表面上。所述第二子电极312可以设置于所述第一子电极311远离所述基底100的表面上。所述第一子电极311可以用来连接所述直流源420。所述第二子电极312可以用来连接所述射频源410。在可选实施例中，所述第二子电极312可以用来连接所述直流源420；所述第一子电极311可以用来连接所述射频源410。所述第一子电极311和所述第二子电极312之间绝缘设置，因此能够防止所述射频信号和所述直流偏置信号相互串扰。In one embodiment, the first electrode 310 includes a stacked and insulated first sub-electrode 311 and a second sub-electrode 312 . The first sub-electrodes 311 may be disposed on the surface of the substrate 100 . The second sub-electrode 312 may be disposed on a surface of the first sub-electrode 311 away from the substrate 100 . The first sub-electrode 311 can be used to connect to the DC source 420 . The second sub-electrode 312 can be used to connect to the radio frequency source 410 . In an optional embodiment, the second sub-electrode 312 can be used to connect to the direct current source 420 ; the first sub-electrode 311 can be used to connect to the radio frequency source 410 . The first sub-electrode 311 and the second sub-electrode 312 are insulated, so the radio frequency signal and the DC bias signal can be prevented from interfering with each other.

在一个实施例中，第一子电极311的宽度大于所述第二子电极312的宽度，因此，所述第一子电极311的边缘可以从所述第二子电极312的边缘露出，以便于所述第一子电极311连接所述直流源420或者所述射频源410。In one embodiment, the width of the first sub-electrode 311 is larger than the width of the second sub-electrode 312, therefore, the edge of the first sub-electrode 311 can be exposed from the edge of the second sub-electrode 312, so that The first sub-electrode 311 is connected to the DC source 420 or the RF source 410 .

在一个实施例中，所述第一子电极311和所述第二子电极312可以设置有二氧化硅形成的膜层。所述二氧化硅形成的膜层可以起到将所述第一子电极311和所述第二子电极312绝缘的目的。In one embodiment, the first sub-electrode 311 and the second sub-electrode 312 may be provided with a film layer formed of silicon dioxide. The film layer formed by the silicon dioxide can serve the purpose of insulating the first sub-electrode 311 and the second sub-electrode 312 .

在一个实施例中，所述第一子电极311的厚度为100纳米到300纳米。所述第二子电极312的厚度为0.1微米到2微米。所述二氧化硅形成的膜层的厚度为100纳米到300纳米。In one embodiment, the thickness of the first sub-electrode 311 is 100 nm to 300 nm. The thickness of the second sub-electrode 312 is 0.1 μm to 2 μm. The film layer formed by the silicon dioxide has a thickness of 100 nanometers to 300 nanometers.

请参见图12，本申请实施例还提供了所述电光调制器10的一种制作方法。所述方法包括：Referring to FIG. 12 , the embodiment of the present application also provides a manufacturing method of the electro-optic modulator 10 . The methods include:

步骤1：基片准备。所述基片可以是由0.6微米厚的X切铌酸锂膜层200、2微米厚的二氧化硅膜层110和500微米厚的硅膜层120组成的键合片。对基片进行清洁处理。可以使用丙酮、酒精和去离子水对所述基片进行冲洗或超声清洗，以去除所述基片表面的有机和无机污染物。Step 1: Substrate preparation. The substrate may be a bonding sheet composed of a 0.6 micron thick X-cut lithium niobate film layer 200 , a 2 micron thick silicon dioxide film layer 110 and a 500 micron thick silicon film layer 120 . Clean the substrate. The substrate can be rinsed or ultrasonically cleaned with acetone, alcohol and deionized water to remove organic and inorganic pollutants on the surface of the substrate.

步骤2：通过电子束曝光、显影工艺制备第一铌酸锂波导340和第二铌酸锂波导350的掩模210。电子束曝光过程可以采用负胶Fox-16，曝光束流为2nA。Step 2: Prepare the masks 210 of the first lithium niobate waveguide 340 and the second lithium niobate waveguide 350 through electron beam exposure and development processes. The electron beam exposure process can use negative gel Fox-16, and the exposure beam current is 2nA.

步骤3：通过电感耦合等离子体反应离子刻蚀铌酸锂，将掩模的图形转移到所述铌酸锂膜层200上。电感耦合等离子体反应离子刻蚀过程可以采用纯氩刻蚀。所述铌酸锂膜层200的刻蚀深度为350纳米，刻蚀倾角约为60°。Step 3: Etching the lithium niobate by inductively coupled plasma reactive ion etching, and transferring the pattern of the mask to the lithium niobate film layer 200 . The inductively coupled plasma reactive ion etching process can use pure argon etching. The etching depth of the lithium niobate film layer 200 is 350 nm, and the etching inclination angle is about 60°.

步骤4：通过缓释氢氟酸去除掩模210，所述第一铌酸锂波导340和所述第二铌酸锂波导350制备完成；其中所述第一铌酸锂波导340和所述第二铌酸锂波导350宽度均可以为0.8微米。Step 4: Remove the mask 210 by slow-release hydrofluoric acid, and the first lithium niobate waveguide 340 and the second lithium niobate waveguide 350 are prepared; wherein the first lithium niobate waveguide 340 and the second lithium niobate waveguide The width of the lithium diniobate waveguide 350 can be 0.8 μm.

步骤5：电子束曝光套刻，在所述第一铌酸锂波导340和所述第二铌酸锂波导350上进行第二次电子束曝光，显影，定义所述第一电极310、所述第二电极320和所述第三电极330的形状。Step 5: Electron beam exposure overlay, perform a second electron beam exposure on the first lithium niobate waveguide 340 and the second lithium niobate waveguide 350, develop, define the first electrode 310, the The shape of the second electrode 320 and the third electrode 330 .

步骤6：电子束蒸镀20纳米厚的铬和100纳米厚的金形成金属层220。使用铬的目的是增加金和铌酸锂层的粘附性。Step 6: The metal layer 220 is formed by E-beam evaporation of chromium with a thickness of 20 nm and gold with a thickness of 100 nm. The purpose of using chromium is to increase the adhesion of the gold and lithium niobate layers.

步骤7：剥离，使得覆盖在所述第一铌酸锂波导340和所述第二铌酸锂波导350表面的光刻胶240部分被剥离，留下由金形成的所述第一电极310、所述第二电极320和所述第三电极330结构，电极部分制备完成。所述第一电极310、所述第二电极320和所述第三电极330的长度均可以为3000微米。所述第一电极310的宽可以为50微米，所述第二电极320和所述第三电极330的宽均可以为100微米。所述第一电极310和所述第二电极320、以及所述第一电极310和所述第三电极330之间的间距均可以为5微米。Step 7: peeling off, so that the photoresist 240 covering the surface of the first lithium niobate waveguide 340 and the second lithium niobate waveguide 350 is partially peeled off, leaving the first electrode 310 formed of gold, The structures of the second electrode 320 and the third electrode 330 are completed, and the electrode part is prepared. The lengths of the first electrode 310 , the second electrode 320 and the third electrode 330 may all be 3000 microns. The width of the first electrode 310 may be 50 micrometers, and the width of the second electrode 320 and the third electrode 330 may be 100 micrometers. The distance between the first electrode 310 and the second electrode 320 and between the first electrode 310 and the third electrode 330 may be 5 microns.

步骤8：采用等离子体化学气相沉积工艺沉积1微米厚的二氧化硅保护膜230；所述二氧化硅保护膜230对整个器件起保护作用。Step 8: Deposit a silicon dioxide protective film 230 with a thickness of 1 micron by plasma chemical vapor deposition; the silicon dioxide protective film 230 protects the entire device.

步骤9：紫外光刻；采用光刻胶240在所述二氧化硅保护膜230的表面定义出所述第一电极310、所述第二电极320和所述第三电极330露出来的区域。光刻过程可以采用负胶AR-N 4340。Step 9: UV lithography: using photoresist 240 to define exposed areas of the first electrode 310 , the second electrode 320 and the third electrode 330 on the surface of the silicon dioxide protection film 230 . The photolithography process can use negative resist AR-N 4340.

步骤10：缓释氢氟酸刻蚀所述二氧化硅保护膜230，未被光刻胶240保护的部分被刻蚀掉，即所述第一电极310、所述第二电极320和所述第三电极330分别露出一个窗口250，方便后期电极和外部电路的封装。Step 10: Slow-release hydrofluoric acid etches the silicon dioxide protective film 230, and the parts not protected by the photoresist 240 are etched away, that is, the first electrode 310, the second electrode 320 and the The third electrodes 330 respectively expose a window 250, which facilitates the packaging of later electrodes and external circuits.

步骤11：去除残余的光刻胶240，所述电光调制器10制备完成。Step 11: Removing the remaining photoresist 240, and the preparation of the electro-optic modulator 10 is completed.

上述方法可以为所述强度调制器的制作方法。The above-mentioned method may be a manufacturing method of the intensity modulator.

以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为本专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请专利的保护范围应以所附权利要求为准。The above-mentioned embodiments only express several implementation modes of the present application, and the description thereof is relatively specific and detailed, but should not be construed as a limitation of the scope of the present patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of protection of the patent application should be based on the appended claims.

Claims

一种电光调制器，包括：An electro-optic modulator comprising:

基底(100)；base(100);

第一电极(310)和第二电极(320)，间隔设置于所述基底(100)上；a first electrode (310) and a second electrode (320), arranged at intervals on the substrate (100);

第一铌酸锂波导(340)，设置于所述基底(100)上，并位于所述第一电极(310)和所述第二电极(320)之间，所述第一铌酸锂波导(340)分别与所述第一电极(310)和所述第二电极(320)绝缘设置，以及A first lithium niobate waveguide (340), disposed on the substrate (100), and located between the first electrode (310) and the second electrode (320), the first lithium niobate waveguide (340) are respectively insulated from said first electrode (310) and said second electrode (320), and

电源(400)，与所述第一电极(310)连接，用于在所述第一电极(310)和所述第二电极(320)之间产生偏置交流电场，以激发出铌酸锂的高阶电光效应。A power supply (400), connected to the first electrode (310), for generating a bias AC electric field between the first electrode (310) and the second electrode (320), to excite lithium niobate high-order electro-optic effect.
如权利要求1所述的电光调制器，其中，用于在所述第一电极(310)和所述第二电极(320)之间产生激发出铌酸锂的高阶电光效应的电场大于6×10 ⁶V/m。 The electro-optic modulator according to claim 1, wherein the electric field used to generate a high-order electro-optic effect that excites lithium niobate between the first electrode (310) and the second electrode (320) is greater than 6 ×10 ⁶ V/m.
如权利要求1所述的电光调制器，其中，所述电源(400)包括射频源(410)和直流源(420)，所述射频源(410)和所述直流源(420)分别与所述第一电极(310)连接。The electro-optical modulator according to claim 1, wherein the power supply (400) includes a radio frequency source (410) and a direct current source (420), and the radio frequency source (410) and the direct current source (420) are respectively connected to the The first electrode (310) is connected.
如权利要求3所述的电光调制器，还包括T型偏置器，其中所述射频源(410)和所述直流源(420)分别与所述T型偏置器的射频端和直流端连接，所述T型偏置器的射频与直流端连接所述第一电极(310)。The electro-optic modulator according to claim 3, further comprising a T-type bias, wherein the radio frequency source (410) and the DC source (420) are respectively connected to the radio frequency end and the DC end of the T-type bias connected, the RF and DC ends of the T-type biaser are connected to the first electrode (310).
如权利要求4所述的电光调制器，还包括：The electro-optic modulator of claim 4, further comprising:

第三电极(330)，所述第三电极(330)设置于所述第一电极(310)远离所述第二电极(320)的一侧，所述第三电极(330)与所述第一电极(310)间隔设置，所述第二电极(320)和所述第三电极(330)用于接地；The third electrode (330), the third electrode (330) is arranged on the side of the first electrode (310) away from the second electrode (320), and the third electrode (330) is connected to the first electrode (320). An electrode (310) is arranged at intervals, and the second electrode (320) and the third electrode (330) are used for grounding;

第二铌酸锂波导(350)，所述第二铌酸锂波导(350)设置于所述第一电极(310)和所述第三电极(330)之间，所述第二铌酸锂波导(350)与所述第一电极(310)和所述第三电极(330)绝缘设置。The second lithium niobate waveguide (350), the second lithium niobate waveguide (350) is arranged between the first electrode (310) and the third electrode (330), the second lithium niobate The waveguide (350) is insulated from the first electrode (310) and the third electrode (330).
如权利要求5所述的电光调制器，其中，所述基底(100)表面设置有铌酸锂膜层(200)，所述第一铌酸锂波导(340)形成于所述铌酸锂膜层(200)上，所述第一铌酸锂波导(340)在所述铌酸锂膜层(200)为凸起结构。The electro-optic modulator according to claim 5, wherein a lithium niobate film layer (200) is provided on the surface of the substrate (100), and the first lithium niobate waveguide (340) is formed on the lithium niobate film On the layer (200), the first lithium niobate waveguide (340) has a convex structure on the lithium niobate film layer (200).
如权利要求6所述的电光调制器，其中，所述基底(100)包括层叠设置的二氧化硅膜层(110)和硅膜层(120)，所述二氧化硅膜层(110)设置于所述硅膜层(120)和所述铌酸锂膜层(200)之间。The electro-optical modulator according to claim 6, wherein the substrate (100) comprises a silicon dioxide film layer (110) and a silicon film layer (120) stacked, and the silicon dioxide film layer (110) is set between the silicon film layer (120) and the lithium niobate film layer (200).
如权利要求7所述的电光调制器，其中，所述铌酸锂膜层(200)的厚度为400纳米至900纳米，所述二氧化硅膜层(110)的厚度为2微米至5微米，所述硅膜层(120)的厚度为0.4毫米至0.8毫米。The electro-optic modulator according to claim 7, wherein the lithium niobate film layer (200) has a thickness of 400 nm to 900 nm, and the silicon dioxide film layer (110) has a thickness of 2 microns to 5 microns , the thickness of the silicon film layer (120) is 0.4 mm to 0.8 mm.
如权利要求8所述的电光调制器，其中，所述射频源(410)提供0.5伏至2伏的射频电压，所述直流源(420)提供20伏至100伏的直流偏置电压。The electro-optic modulator according to claim 8, wherein the radio frequency source (410) provides a radio frequency voltage of 0.5 volts to 2 volts, and the direct current source (420) provides a direct current bias voltage of 20 volts to 100 volts.
如权利要求1所述的电光调制器，其中，所述第一电极(310)包括层叠且绝缘设置的第一子电极(311)和第二子电极(312)。The electro-optic modulator according to claim 1, wherein the first electrode (310) comprises a first sub-electrode (311) and a second sub-electrode (312) which are laminated and insulated.
一种电光调制器的制作方法，包括：A method of manufacturing an electro-optic modulator, comprising:

提供基片，其中所述基片为由0.6微米厚的X切铌酸锂膜层(200)、2微米厚的二氧化硅膜层(110)和500微米厚的硅膜层(120)组成的键合片；A substrate is provided, wherein the substrate is composed of a 0.6 micron thick X-cut lithium niobate film layer (200), a 2 micron thick silicon dioxide film layer (110) and a 500 micron thick silicon film layer (120) bonded sheet;

在所述基片上通过电子束曝光、显影工艺制备第一铌酸锂波导(340)和第二铌酸锂波导(350)的掩模(210)；Preparing masks (210) for the first lithium niobate waveguide (340) and the second lithium niobate waveguide (350) by electron beam exposure and developing processes on the substrate;

通过电感耦合等离子体反应离子刻蚀所述铌酸锂，将所述掩模(210)的图形转移到所述铌酸锂膜层(200)上；Etching the lithium niobate by inductively coupled plasma reactive ion etching, transferring the pattern of the mask (210) to the lithium niobate film layer (200);

通过缓释氢氟酸去除掩模210，以完成所述第一铌酸锂波导(340)和所述第二铌酸锂波导(350)的制备；removing the mask 210 by slow-release hydrofluoric acid to complete the preparation of the first lithium niobate waveguide (340) and the second lithium niobate waveguide (350);

电子束曝光套刻，在所述第一铌酸锂波导(340)和所述第二铌酸锂波导(350)上进行第二次电子束曝光、显影，以定义第一电极(310)、第二电极(320)和第三电极(330)的形状；Electron beam exposure overlaying, performing a second electron beam exposure and development on the first lithium niobate waveguide (340) and the second lithium niobate waveguide (350), to define the first electrode (310), the shape of the second electrode (320) and the third electrode (330);

电子束蒸镀20纳米厚的铬和100纳米厚的金形成金属层(220)；Electron beam evaporation of 20 nanometers of chromium and 100 nanometers of gold to form a metal layer (220);

剥离覆盖在所述第一铌酸锂波导(340)和所述第二铌酸锂波导(350)表面的光刻胶(240)部分，留下由金形成的所述第一电极(310)、所述第二电极(320)和所述第三电极(330)结构，完成电极的制备；peeling off the photoresist (240) portion covering the surface of the first lithium niobate waveguide (340) and the second lithium niobate waveguide (350), leaving the first electrode (310) formed of gold , the structure of the second electrode (320) and the third electrode (330), completing the preparation of the electrode;

采用等离子体化学气相沉积工艺沉积1微米厚的二氧化硅保护膜(230)；Depositing a silicon dioxide protective film (230) with a thickness of 1 micron by using a plasma chemical vapor deposition process;

通过紫外光刻，采用光刻胶(240)在所述二氧化硅保护膜(230)的表面定义出所述第一电极(310)、所述第二电极(320)和所述第三电极(330)露出来的区域；Using photoresist (240) to define the first electrode (310), the second electrode (320) and the third electrode on the surface of the silicon dioxide protective film (230) by ultraviolet lithography (330) exposed areas;

缓释氢氟酸刻蚀所述二氧化硅保护膜(230)，未被所述光刻胶(240)保护的部分被刻蚀掉；Slow-release hydrofluoric acid etches the silicon dioxide protective film (230), and the part not protected by the photoresist (240) is etched away;

去除残余的所述光刻胶(240)。The remaining photoresist (240) is removed.
根据权利要求11所述的制作方法，其中，所述电感耦合等离子体反应离子刻蚀过程采用纯氩刻蚀。The manufacturing method according to claim 11, wherein the inductively coupled plasma reactive ion etching process adopts pure argon etching.
根据权利要求11所述的制作方法，其中，所述铌酸锂膜层(200)的刻蚀深度为350纳米，刻蚀倾角约为60°。The manufacturing method according to claim 11, wherein the etching depth of the lithium niobate film layer (200) is 350 nanometers, and the etching inclination angle is about 60°.
根据权利要求11所述的制作方法，其中，所述第一铌酸锂波导(340)和所述第二铌酸锂波导(350)的宽度均为0.8微米。The manufacturing method according to claim 11, wherein the widths of the first lithium niobate waveguide (340) and the second lithium niobate waveguide (350) are both 0.8 microns.