ROADM的偏振分束器设计
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摘要
可重构光分插复用器(ROADM)是实现现行的WDM网络迈向全光网络过程的关键节点器件,它不仅能够从多波长线路信号中下载某特定波长到本地,最重要的是具有动态可重构的能力,加快了光网络的智能化进程。
偏振分束器与偏振转换单元构成了整个ROADM器件,集成偏振分束器(PBS)的作用是分离或者合并TE模和TM模,因此为满足ROADM器件的性能要求,本文中设计的偏振分束器必须具有高消光比、高透射率等特点。
现行的PBS技术大多基于光纤或波导型器件,成品率低、消光比低、可控性差,不利于集成化。为适应新型光网络对偏振分束器的要求,本论文提出一种基于Ti扩散铌酸锂波导的偏振分束器。该器件采用Ti扩散铌酸锂波导结构,利用两耦合臂的模式耦合将TE模和TM模分离,由输出端口分别输出。
本论文从分析偏振分束器铌酸锂晶体的双折射效应、电光效应等理论出发,讨论了两种常用的扩散铌酸锂波导制作方法,尤其是Ti热扩散过程中影响偏振分束效果的各种参数。在此基础上,论文运用模式耦合理论推导出两种结构下设计的偏振分束器的理论模型,计算了偏振分束器分束条件,确定器件波导的几何参数和波导制备参数。本文最后针对偏振分束器制作过程无法精确控制扩散后的消光比和折射率差等缺点,提出了一种电极优化设计方案并论证其可行性。
经仿真研究表明,本论文设计的偏振分束器,具有集成度高、消光比高、传输损耗低等特点。并且可在不改变器件结构的条件下实现消光比可调、折射率差可控。
Reconfigurable optical add/drop multiplexer (ROADM) is a significant node equipment which can achieve the process that nowadays WDM system evolves into All Optical Network. It can download certain wavelength from the multi-wavelength input signal to local, but also has the foremost capability of dynamically reconfiguration. Thereby, it accelerates the process of intelligentizing the optical network.
Polarization beam splitter and the polarization conversion unit constitutes the entire ROADM devices, integrated polarization beam splitter (PBS) is the role of split or merger TE mode and TM mode. So this paper aims to design a PBS with high extinction ratio and high transmittance.
Most of the existing PBS technology based on fiber or waveguide type devices, which induce low finished products ratio, low extinction ratio, hard to control, and unsuitable for integration. In order to meet the new generation optical network requirements, this paper proposes a PBS based on Ti:diffuse lithium niobate waveguide. The device produced in Ti:LiNbO3, utilizing the mode coupling to split TE and TM mode which propagate through the output port respectively.
This thesis starts with the fundamental principles of crystal birefringence, mode-coupled and some other theories and then discuss two common fabrication method especially deduces how the device's parameters affect its performances. Moreover, the paper uses mode coupling theory to derive the theoretical model of two kinds of PBS structure and the mode splitting conditions, finally calculate the geometric parameters of the device and the fabrication parameters. In the end, the paper proposes an optimization of using electrodes to improve the performance.
The simulation results show that the design of PBS in this paper performs high integration, high extinction ratio and low transmission loss. Furthermore, it can modulate the extinction ratio and index difference without changing the device structure.
偏振分束器与偏振转换单元构成了整个ROADM器件,集成偏振分束器(PBS)的作用是分离或者合并TE模和TM模,因此为满足ROADM器件的性能要求,本文中设计的偏振分束器必须具有高消光比、高透射率等特点。
现行的PBS技术大多基于光纤或波导型器件,成品率低、消光比低、可控性差,不利于集成化。为适应新型光网络对偏振分束器的要求,本论文提出一种基于Ti扩散铌酸锂波导的偏振分束器。该器件采用Ti扩散铌酸锂波导结构,利用两耦合臂的模式耦合将TE模和TM模分离,由输出端口分别输出。
本论文从分析偏振分束器铌酸锂晶体的双折射效应、电光效应等理论出发,讨论了两种常用的扩散铌酸锂波导制作方法,尤其是Ti热扩散过程中影响偏振分束效果的各种参数。在此基础上,论文运用模式耦合理论推导出两种结构下设计的偏振分束器的理论模型,计算了偏振分束器分束条件,确定器件波导的几何参数和波导制备参数。本文最后针对偏振分束器制作过程无法精确控制扩散后的消光比和折射率差等缺点,提出了一种电极优化设计方案并论证其可行性。
经仿真研究表明,本论文设计的偏振分束器,具有集成度高、消光比高、传输损耗低等特点。并且可在不改变器件结构的条件下实现消光比可调、折射率差可控。
Reconfigurable optical add/drop multiplexer (ROADM) is a significant node equipment which can achieve the process that nowadays WDM system evolves into All Optical Network. It can download certain wavelength from the multi-wavelength input signal to local, but also has the foremost capability of dynamically reconfiguration. Thereby, it accelerates the process of intelligentizing the optical network.
Polarization beam splitter and the polarization conversion unit constitutes the entire ROADM devices, integrated polarization beam splitter (PBS) is the role of split or merger TE mode and TM mode. So this paper aims to design a PBS with high extinction ratio and high transmittance.
Most of the existing PBS technology based on fiber or waveguide type devices, which induce low finished products ratio, low extinction ratio, hard to control, and unsuitable for integration. In order to meet the new generation optical network requirements, this paper proposes a PBS based on Ti:diffuse lithium niobate waveguide. The device produced in Ti:LiNbO3, utilizing the mode coupling to split TE and TM mode which propagate through the output port respectively.
This thesis starts with the fundamental principles of crystal birefringence, mode-coupled and some other theories and then discuss two common fabrication method especially deduces how the device's parameters affect its performances. Moreover, the paper uses mode coupling theory to derive the theoretical model of two kinds of PBS structure and the mode splitting conditions, finally calculate the geometric parameters of the device and the fabrication parameters. In the end, the paper proposes an optimization of using electrodes to improve the performance.
The simulation results show that the design of PBS in this paper performs high integration, high extinction ratio and low transmission loss. Furthermore, it can modulate the extinction ratio and index difference without changing the device structure.
引文
[1]邱劲, 卜志军,光纤通信技术的现状及发展趋势,数字技术与应用,2010,1： 52～53
[2]王勋,李坤,郝中军,浅析光纤网络的发展,数字技术与应用,2010,1：18～19
[3]刘晓枫,ROADM技术简介及演进方向,邮电设计技术,2008,(2)：40～43
[4]黄照祥,张阳安,黄永清等,可重构光分插复用器(ROADM)的技术实现与性能评估,光通信技术,2004,12：4-9
[5]车伟扬,刘少兵,ROADM技术的发展及其应用,光通信技术,2007,31(4)：34～36
[6]郑力明,曾思敏,可重构光分插复用器的设计与实现,光子学报,2009,38(4)：858～864
[7]刘志强,龙玉章,郑达,ROADM与城域核心光网络,2008,28(2)：2-6
[8]李可佳,基于铌酸锂波导的电光调谐ROADM设计,2008,2-3
[9]方云团,辛立民,基于各向异性介质一维光子晶体缺陷模的偏振分束器,人工晶体学报,2009,38(5)：1199～1201
[10]文科,汪井源,王荣,矩形晶格结构双芯光子晶体光纤偏振分束器的研究,量子电子学报,2008,25(4)：505～508
[11]赵华君,亚波长介质偏振分束光栅的衍射特性,强激光与粒子束,2008,10(20)：1629～1632
[12]杨健,颜树华,吕海宝等,基于耦合波理论设计偏振分束光栅,光学技术,2005,5(31)：695～697
[13]李香华,刘永智,代志勇,一种新型偏振分束器的研制,电子科技,2008,21(12)：24～27
[14]许放,刘颖力,萧尚清,光通信用偏振分束器的分析与验证,压电与声光,2007,29(3)：8-10
[15]张瑞峰,葛春风,李世忱,熔融拉锥过程中的偏振调制效应及应用,量子电子学报,2006,23(4)547～550
[16]魏道平,赵玉成,熔锥型光纤偏振分束器的一种新型制作方法,铁道学报,1999,21(1)：58～61
[17]崔建民,冯立辉,吕敏等,基于Ti扩散铌酸锂偏振分束器的研制,光学技术,2007,33(1)：92～94
[18]Pingsheng Tang, Ohannes Eknoyan, Henry F. Taylor, Rapidly tunable optical add-drop multiplexer (OADM) using a static-strain-induced grating in LiNbO3, Journal of Lightwave Technology,2003,23(1):236-244
[19]R. C. Alferness, R. V. Schmidt, E. H. Turner, Characteristics of Ti-diffused lithium niobate optical directional couplers, APPLIED OPTICS,1979,18(23): 4012-4016
[20]Henry F. Taylor, Ohannes. Eknoyan, Guided wave acousto-optic and electro-optic tunable filter designs with relaxed beam-splitter requirements, APPLIED OPTICS,2000,39(1):124-128
[21]Hongsik JUNG, Youngsik CHUNG, Polarization-Independent Electro-Optically Tuned Add/Drop Multiplexers in LiNbO3 utilizing Strain Optic Effect, Japanese Journal of Applied Physics,2008,47(3):1579-1583
[22]Pingsheng Tang, Ohannes Eknoyan, Henry F. Taylor, Rapidly tunable polarization independent optical add drop multiplexer in Ti:LiNbO3, Electronics Letters,2002, 38(5):242-244
[23]Vadim Dobrusin, Shlomo Ruschin, Larisa Shpisman, Fabrication method of low-loss large single mode ridge Ti:LiNbO3 waveguides, Optical Materials,2007, 29:1630-1634
[24]张青云,LiNbO3电光调制器的优化设计与制作,现代电子技术,2007,30(6)：190～192
[25]张谦述,刘永智,杨亚培等,质子交换LiNbO3波导表面裂纹的研究,激光技术,2006,30(4)：385～389
[26]高晓萍,金轸裕,质子交换LiNbO3光波导路和Ti扩散LiNbO3光波导的光感应折射率变化的比较,光机电信息,1995,1：35
[27]HSIN-HUI KUO,INVESTIGATION OF AN ELECTROOPTIC TUNABLE FILTER IN LITHIUM NIOBATE,2006,38-42
[28]胡鸿璋,詹仰钦,赵慈等,钛扩散铌酸锂条形波导的有效折射率截面随扩散参数的变化,中国激光,1996,23(4)：333～337
[29]何希红,胡鸿璋,赵慈,钛扩散LiNbO3单模波导场分布,光子学报,1996,25(3)：256～260
[30]Delong Zhang, Guilan Ding, Caihe Chen, Theoretical Analysis of Guided Mode and Effective Refractive Index at 1.53μm in Ti:LiNbO3 Strip Waveguides, JOURNAL OF LIGHTWAVE TECHNOLOGY,1998,16(3):459-464
[31]R.C. Alferness, Efficient waveguide electro-optic TE-TM mode converter/ wavelength filter, Apple. Phys. Lett 1980,36(7),1:513-515
[32]W. Warzanski, F. Heismann, and R.C. Alferness, Polarization-independent electrooptically tunable narrow-band wavelength filter, Appl. Phys. Lett.,1988, 53:13-15.
[2]王勋,李坤,郝中军,浅析光纤网络的发展,数字技术与应用,2010,1：18～19
[3]刘晓枫,ROADM技术简介及演进方向,邮电设计技术,2008,(2)：40～43
[4]黄照祥,张阳安,黄永清等,可重构光分插复用器(ROADM)的技术实现与性能评估,光通信技术,2004,12：4-9
[5]车伟扬,刘少兵,ROADM技术的发展及其应用,光通信技术,2007,31(4)：34～36
[6]郑力明,曾思敏,可重构光分插复用器的设计与实现,光子学报,2009,38(4)：858～864
[7]刘志强,龙玉章,郑达,ROADM与城域核心光网络,2008,28(2)：2-6
[8]李可佳,基于铌酸锂波导的电光调谐ROADM设计,2008,2-3
[9]方云团,辛立民,基于各向异性介质一维光子晶体缺陷模的偏振分束器,人工晶体学报,2009,38(5)：1199～1201
[10]文科,汪井源,王荣,矩形晶格结构双芯光子晶体光纤偏振分束器的研究,量子电子学报,2008,25(4)：505～508
[11]赵华君,亚波长介质偏振分束光栅的衍射特性,强激光与粒子束,2008,10(20)：1629～1632
[12]杨健,颜树华,吕海宝等,基于耦合波理论设计偏振分束光栅,光学技术,2005,5(31)：695～697
[13]李香华,刘永智,代志勇,一种新型偏振分束器的研制,电子科技,2008,21(12)：24～27
[14]许放,刘颖力,萧尚清,光通信用偏振分束器的分析与验证,压电与声光,2007,29(3)：8-10
[15]张瑞峰,葛春风,李世忱,熔融拉锥过程中的偏振调制效应及应用,量子电子学报,2006,23(4)547～550
[16]魏道平,赵玉成,熔锥型光纤偏振分束器的一种新型制作方法,铁道学报,1999,21(1)：58～61
[17]崔建民,冯立辉,吕敏等,基于Ti扩散铌酸锂偏振分束器的研制,光学技术,2007,33(1)：92～94
[18]Pingsheng Tang, Ohannes Eknoyan, Henry F. Taylor, Rapidly tunable optical add-drop multiplexer (OADM) using a static-strain-induced grating in LiNbO3, Journal of Lightwave Technology,2003,23(1):236-244
[19]R. C. Alferness, R. V. Schmidt, E. H. Turner, Characteristics of Ti-diffused lithium niobate optical directional couplers, APPLIED OPTICS,1979,18(23): 4012-4016
[20]Henry F. Taylor, Ohannes. Eknoyan, Guided wave acousto-optic and electro-optic tunable filter designs with relaxed beam-splitter requirements, APPLIED OPTICS,2000,39(1):124-128
[21]Hongsik JUNG, Youngsik CHUNG, Polarization-Independent Electro-Optically Tuned Add/Drop Multiplexers in LiNbO3 utilizing Strain Optic Effect, Japanese Journal of Applied Physics,2008,47(3):1579-1583
[22]Pingsheng Tang, Ohannes Eknoyan, Henry F. Taylor, Rapidly tunable polarization independent optical add drop multiplexer in Ti:LiNbO3, Electronics Letters,2002, 38(5):242-244
[23]Vadim Dobrusin, Shlomo Ruschin, Larisa Shpisman, Fabrication method of low-loss large single mode ridge Ti:LiNbO3 waveguides, Optical Materials,2007, 29:1630-1634
[24]张青云,LiNbO3电光调制器的优化设计与制作,现代电子技术,2007,30(6)：190～192
[25]张谦述,刘永智,杨亚培等,质子交换LiNbO3波导表面裂纹的研究,激光技术,2006,30(4)：385～389
[26]高晓萍,金轸裕,质子交换LiNbO3光波导路和Ti扩散LiNbO3光波导的光感应折射率变化的比较,光机电信息,1995,1：35
[27]HSIN-HUI KUO,INVESTIGATION OF AN ELECTROOPTIC TUNABLE FILTER IN LITHIUM NIOBATE,2006,38-42
[28]胡鸿璋,詹仰钦,赵慈等,钛扩散铌酸锂条形波导的有效折射率截面随扩散参数的变化,中国激光,1996,23(4)：333～337
[29]何希红,胡鸿璋,赵慈,钛扩散LiNbO3单模波导场分布,光子学报,1996,25(3)：256～260
[30]Delong Zhang, Guilan Ding, Caihe Chen, Theoretical Analysis of Guided Mode and Effective Refractive Index at 1.53μm in Ti:LiNbO3 Strip Waveguides, JOURNAL OF LIGHTWAVE TECHNOLOGY,1998,16(3):459-464
[31]R.C. Alferness, Efficient waveguide electro-optic TE-TM mode converter/ wavelength filter, Apple. Phys. Lett 1980,36(7),1:513-515
[32]W. Warzanski, F. Heismann, and R.C. Alferness, Polarization-independent electrooptically tunable narrow-band wavelength filter, Appl. Phys. Lett.,1988, 53:13-15.