基于薄膜铌酸锂异质集成硫系玻璃的中红外电光调制器的仿真研究

doi:10.16553/j.cnki.issn1000-985x.2025.0206

人工晶体学报 ›› 2026, Vol. 55 ›› Issue (2): 173-181.DOI: 10.16553/j.cnki.issn1000-985x.2025.0206

基于薄膜铌酸锂异质集成硫系玻璃的中红外电光调制器的仿真研究

潘凯彦¹^,²^,³(), 蔡和意¹^,²^,³, 杜清扬⁴, 秦琦⁵, 胡小鹏¹^,²^,³(), 祝世宁¹^,²^,³

^1.南京大学现代工程与应用科学学院，南京 210093
^2.南京大学固体微结构物理全国重点实验室，南京 210093
^3.南京大学智能光传感与调控技术教育部重点实验室，南京 210093
^4.之江实验室，杭州 311121
^5.香港城市大学，香港 999077

收稿日期:2025-09-24 出版日期:2026-02-20 发布日期:2026-03-06
通信作者: 胡小鹏，博士，教授。E-mail:xphu@nju.edu.cn
作者简介:潘凯彦（1997—），女，安徽省人，博士研究生。E-mail:602023340011@smail.nju.edu.cn
基金资助:
国家重点研发计划(2024YFA1408900);国家重点研发计划(2022YFA1205100);国家自然科学基金(92163216);国家自然科学基金(12192251);国家自然科学基金(62288101);量子科学技术创新计划(2021ZD0300700)

Simulation Study of Mid-Infrared Electro-Optic Modulators Based on Thin-Film Lithium Niobate Heterogeneously Integrated with Chalcogenide Glass

PAN Kaiyan¹^,²^,³(), CAI Heyi¹^,²^,³, DU Qingyang⁴, QIN Qi⁵, HU Xiaopeng¹^,²^,³(), ZHU Shining¹^,²^,³

^1.College of Engineering and Applied Sciences，Nanjing University，Nanjing 210093，China
^2.National Laboratory of Solid State Microstructures，Nanjing University，Nanjing 210093，China
^3.Key Laboratory of Intelligent Optical Sensing and Manipulation，Ministry of Education，Nanjing University，Nanjing 210093，China
^4.Zhejiang Lab，Hangzhou 311121，China
^5.City University of Hong Kong，Hong Kong 999077，China

Received:2025-09-24 Online:2026-02-20 Published:2026-03-06

摘要/Abstract

摘要： 中红外（MIR）波段在光谱学和通信等领域有重要的应用。高速、低损耗的中红外波段调制器是推进相关应用的关键器件，其研制目前仍存在较大挑战。本文提出了薄膜铌酸锂与硫系玻璃异质集成的中红外高速电光调制器，基于薄膜铌酸锂覆盖中红外波段的透明窗口和优异的电光特性，利用折射率可调的硫系材料作为光导引层并改变波导中的光场分布，系统研究了传输损耗、调制效率及带宽对器件参数的依赖关系。通过优化设计，在中红外4.1 μm处实现了0.67 dB/cm 的传输损耗，14.7 V·cm的半波电压长度积，以及超过110 GHz的3 dB带宽。本研究为中红外高速电光调制提供了新的思路，有望推进空间光通信、传感、量子信息等重要应用。

关键词: 薄膜铌酸锂; 硫系玻璃; 异质集成; 电光调制器; 中红外波段; 集成光子技术

Abstract: The mid-infrared （MIR） 3~5 μm band spans both an atmospheric transmission window and the molecular fingerprint region，enabling important applications in free-space optical communications，spectroscopic sensing，and thermal imaging. High-speed，low-loss modulators in this band are essential for advancing MIR photonic integrated systems，yet remain challenging to realize. Conventional platforms such as silicon，silicon nitride，aluminum nitride，and gallium arsenide often suffer from carrier absorption，thermo-optic effects，or limited electro-optic （EO） bandwidth in the MIR，making it difficult to simultaneously achieve high modulation efficiency and broad bandwidth. Thin-film lithium niobate （LNOI），featuring a wide transparency window and a strong Pockels effect，is a promising platform for ultrahigh-speed EO modulation；however，commercial LNOI wafers typically incorporate a SiO₂ buried-oxide （BOX） layer whose pronounced absorption in the MIR band introduces excess propagation loss，thereby limiting MIR device performance and system-level integration.In this work，the BOX-absorption-induced loss bottleneck was addressed by aiming to develop a low-loss，high-efficiency，and ultrabroadband MIR EO modulator compatible with standard commercial LNOI wafers. A heterogeneously integrated LNOI/chalcogenide-glass （ChG） platform was proposed and numerically investigated. The key idea is to employ refractive-index-tunable ChG as an optical guiding layer，with a ChG strip waveguide integrated on the LNOI surface. This design pulls the optical mode upward and markedly reduces modal overlap with the SiO₂ BOX layer. This mode-engineering strategy suppresses MIR absorption loss while introducing additional degrees of freedom—via the ChG refractive index and waveguide geometry—for co-optimizing propagation loss，modulation efficiency，and EO bandwidth.A Mach-Zehnder modulator was designed on a representative X-cut LNOI/SiO₂/Si stack，consisting of a ~900-nm-thick lithium niobate film，a ~4.7-μm-thick SiO₂ BOX layer，and a ~500-μm-thick silicon substrate. The device incorporated 1×2 multimode-interference splitters/combiners and a push-pull traveling-wave electrode phase shifter. A multiphysics co-simulation framework was employed for joint optical-RF optimization：on the optical side，the ChG refractive index and key geometric parameters were systematically swept to tailor the modal distribution and minimize propagation loss；on the RF side，electromagnetic simulations were used to optimize electrode dimensions and spacing，enabling optical-microwave group-index matching，reduced microwave attenuation，and favorable impedance matching，thereby enhancing the EO 3 dB bandwidth.After comprehensive optimization，the proposed device achieves，at 4.1 μm，a low propagation loss of 0.67 dB/cm，a half-wave voltage-length product of 14.7 V·cm，and an EO 3 dB bandwidth exceeding 110 GHz，demonstrating a compelling combination of low loss，high efficiency，and ultrabroad bandwidth. Overall，these results establish refractive-index-engineered ChG-assisted mode engineering as an effective route to mitigate BOX absorption on commercial LNOI wafers. Compared with alternative approaches relying on deep etching，BOX removal，or substrate re-engineering，this hetero-integration strategy achieves substantial performance improvements with low process invasiveness，offering enhanced platform compatibility and scalability. These findings provide a transferable design paradigm for compact，high-performance MIR EO modulators and may facilitate further advances in high-speed on-chip modulation for MIR communications，sensing，and quantum information processing.

Key words: thin-film lithium niobate; chalcogenide glass; heterogeneous integration; electro-optic modulator; mid-infrared band; integrated photon technique

中图分类号:

TN256

潘凯彦, 蔡和意, 杜清扬, 秦琦, 胡小鹏, 祝世宁. 基于薄膜铌酸锂异质集成硫系玻璃的中红外电光调制器的仿真研究[J]. 人工晶体学报, 2026, 55(2): 173-181.

PAN Kaiyan, CAI Heyi, DU Qingyang, QIN Qi, HU Xiaopeng, ZHU Shining. Simulation Study of Mid-Infrared Electro-Optic Modulators Based on Thin-Film Lithium Niobate Heterogeneously Integrated with Chalcogenide Glass[J]. Journal of Synthetic Crystals, 2026, 55(2): 173-181.

图/表 7

图1 不同折射率下ChG波导结构中SiO2层的光场限制因子与吸收损耗特性。（a）随ChG厚度变化的关系；（b）随ChG波导宽度变化的关系

Fig.1 Optical field confinement factors and absorption loss characteristics in SiO2 layer of ChG waveguide structure with different refractive index. （a） Change with ChG thickness；（b） change with ChG waveguide width

图2 半波电压长度积及群折射率匹配随ChG折射率的变化。插图：折射率在2.18~2.22变化时的局部放大图

Fig.2 Half-wave voltage-length product and group refractive index matching varying with refractive index of ChG. Inset：zoom in view for 2.18~2.22 refractive index range

图3 MIR薄膜铌酸锂调制器的整体结构及MMI结构示意图。（a）MIR电光调制器的整体结构，插图：调制区截面图；（b）MMI结构示意图，插图：在4.1 μm处模拟的双端口透过率及电场分布图

Fig.3 Overall structure of MIR thin-film lithium niobate modulator and schematic diagram of MMI structure. （a） Schematic diagram of MIR LNOI EO modulator，inset：cross-sectional of modulation area；（b） schematic diagram of MMI structure，inset：simulated transmissions from two ports and electric field distribution at 4.1 μm

图4 半波电压与传播损耗随电极间距变化关系

Fig.4 Half-wave voltage and loss varying with spacing between electrodes

图5 电极结构参数对射频特性的影响。不同电极间距（a）、电极宽度（b）和电极厚度（c）下微波折射率、特征阻抗及微波损耗的仿真分析

Fig.5 Influence of electrode structural parameters on RF characteristics. Simulation analysis of microwave refractive index，characteristic impedance and microwave loss under different electrode gap （a），different electrode widths （b） and different electrode thickness （c）

图6 MIR电光调制器的频率响应。不同频率下的微波折射率（a）、微波损耗（b）、特征阻抗（c）及电光响应（d）仿真分析

Fig.6 Frequency response of the MIR LNOI EO modulator. Simulation analysis of micro wave refractive index （a），microwave loss （b），characteristic impedance （c），and electro-optic response at different frequencies （d）

表1 不同异质集成平台的MIR电光调制器性能

Table 1 Comparison of different heterogeneous platform of EOM in the MIR band

Modulator type	Wavelength/μm	V_πL/（V∙cm）	3 dB EO bandwidth	Reference
Si-on-LN	3.39	26	^a10 GHz	［24］
TiO₂-on-LN	2.5	50	—	［25］
Ge-on-Si	3.8	0.47	^b0.06 GHz	［26］
ChG-on-LN	4.1	14.7	^a110 GHz	This work

参考文献 32

[1]	SOREF R. Mid-infrared photonics in silicon and germanium［J］. Nature Photonics，2010，4（8）：495-497.
[2]	SOREF R A，EMELETT S J，BUCHWALD W R. Silicon waveguided components for the long-wave infrared region［J］. Journal of Optics A：Pure and Applied Optics，2006，8（10）：840-848.
[3]	HU T，DONG B W，LUO X S，et al. Silicon photonic platforms for mid-infrared applications［J］. Photonics Research，2017，5（5）：417-430.
[4]	LIN H T，LUO Z Q，GU T，et al. Mid-infrared integrated photonics on silicon：a perspective［J］. Nanophotonics，2017，7（2）：393-420.
[5]	JIA J，KANG Z，HUANG Q S，et al. Mid-infrared highly efficient，broadband，and flattened dispersive wave generation via dual-coupled thin-film lithium-niobate-on-insulator waveguide［J］. Applied Sciences，2022，12（18）：9130.
[6]	WU J W，YUE G C，CHEN W C，et al. On-chip optical gas sensors based on group-IV materials［J］. ACS Photonics，2020，7（11）：2923-2940.
[7]	VAN CAMP M A，ASSEFA S，GILL D M，et al. Demonstration of electrooptic modulation at 2165 nm using a silicon Mach-Zehnder interferometer［J］. Optics Express，2012，20（27）：28009-28016.
[8]	THOMSON D J，SHEN L，ACKERT J J，et al. Optical detection and modulation at 2 µm-2.5 µm in silicon［J］. Optics Express，2014，22（9）：10825-10830.
[9]	KHAN S，CHILES J，MA J C，et al. Silicon-on-nitride waveguides for mid- and near-infrared integrated photonics［J］. Applied Physics Letters，2013，102（12）：121104.
[10]	LIU S，XU K，SONG Q H，et al. Design of mid-infrared electro-optic modulators based on aluminum nitride waveguides［J］. Journal of Lightwave Technology，2016，34（16）：3837-3842.
[11]	LIU X W，SUN C Z，XIONG B，et al. Aluminum nitride-on-sapphire platform for integrated high-Q microresonators［J］. Optics Express，2017，25（2）：587-594.
[12]	BALRAM K C，DAVANÇO M，LIM J Y，et al. Moving boundary and photoelastic coupling in GaAs optomechanical resonators［J］. Optica，2014，1（6）：414-420.
[13]	STEPANOV S，RUSCHIN S. Modulation of light by light in silicon-on-insulator waveguides［J］. Applied Physics Letters，2003，83（25）：5151-5153.
[14]	SHEN L，HEALY N，MITCHELL C J，et al. Mid-infrared all-optical modulation in low-loss germanium-on-silicon waveguides［J］. Optics Letters，2015，40（2）：268-271.
[15]	WEIS R S，GAYLORD T K. Lithium niobate：summary of physical properties and crystal structure［J］. Applied Physics A Solids and Surfaces，1985，37（4）：191-203.
[16]	WONG K K. Properties of lithium niobate［M］. London：The Institution of Electrical Engineers，2002.
[17]	SHIH C C，YARIV A. A theoretical model of the linear electro-optic effect［J］. Journal of Physics C：Solid State Physics，1982，15（4）：825-846.
[18]	WANG C，ZHANG M，CHEN X，et al. Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages［J］. Nature，2018，562（7725）：101-104.
[19]	MASHANOVICH G Z，MILOŠEVIĆ M M，NEDELJKOVIC M，et al. Low loss silicon waveguides for the mid-infrared［J］. Optics Express，2011，19（8）：7112.
[20]	LIN P T，SINGH V，CAI Y，et al. Air-clad silicon pedestal structures for broadband mid-infrared microphotonics［J］. Optics Letters，2013，38（7）：1031-1033.
[21]	BAEHR-JONES T，SPOTT A，ILIC R，et al. Silicon-on-sapphire integrated waveguides for the mid-infrared［J］. Optics Express，2010，18（12）：12127-12135.
[22]	SHANKAR R，BULU I，LONCAR M. Integrated high-quality factor silicon-on-sapphire ring resonators for the mid-infrared［C］//10th International Conference on Group IV Photonics. August 28-30，2013，Seoul，Korea. IEEE，2013：17-18.
[23]	LEE C H，REN X Y，OU S Y，et al. Mid-infrared integrated electro-optic modulator on a suspended lithium niobate platform［C］//CLEO 2024. Charlotte，North Carolina. Optica Publishing Group，2024：SW4P.4.
[24]	CHILES J，FATHPOUR S. Mid-infrared integrated waveguide modulators based on silicon-on-lithium-niobate photonics［J］. Optica，2014，1（5）：350.
[25]	JIN T N，ZHOU J C，LIN P T. Mid-infrared electro-optical modulation using monolithically integrated titanium dioxide on lithium niobate optical waveguides［J］. Scientific Reports，2019，9：15130.
[26]	LI T T，NEDELJKOVIC M，HATTASAN N，et al. Ge-on-Si modulators operating at mid-infrared wavelengths up to 8 μm［J］. Photonics Research，2019，7（8）：828.
[27]	LIN H T，SONG Y，HUANG Y Z，et al. Chalcogenide glass-on-graphene photonics［J］. Nature Photonics，2017，11（12）：798-805.
[28]	SHEN W H，ZENG P Y，YANG Z L，et al. Chalcogenide glass photonic integration for improved 2 μm optical interconnection［J］. Photonics Research，2020，8（9）：1484-1490.
[29]	EGGLETON B J，LUTHER-DAVIES B，RICHARDSON K. Chalcogenide photonics［J］. Nature Photonics，2011，5（3）：141-148.
[30]	ROUIFED M S，LITTLEJOHNS C G，TINA G X，et al. Low loss SOI waveguides and MMIs at the MIR wavelength of 2 μm［J］. IEEE Photonics Technology Letters，2016，28（24）：2827-2829.
[31]	HAN H P，XIANG B X. Integrated electro-optic modulators in x-cut lithium niobate thin film［J］. Optik，2020，212：164691.
[32]	ZHU D，SHAO L B，YU M J，et al. Integrated photonics on thin-film lithium niobate［J］. Advances in Optics and Photonics，2021，13（2）：242-352.

基于薄膜铌酸锂异质集成硫系玻璃的中红外电光调制器的仿真研究

Simulation Study of Mid-Infrared Electro-Optic Modulators Based on Thin-Film Lithium Niobate Heterogeneously Integrated with Chalcogenide Glass

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