极化聚合物电光开关微波电极系统的基础研究
摘要
本论文针对极化聚合物电光开关的微波电极系统进行了基础性的研究工作。首先介绍了光开关的研究意义,有机聚合物材料的优势以及聚合物电光开关在国内外的研究进展;通过晶体的电光调制理论引出了极化聚合物的电光效应,为极化聚合物电光开关的研究奠定了理论基础;比较分析了各种电极结构的差异,选取共面波导(CPW)行波电极进行研究;利用保角变换理论导出了CPW行波电极各参数的解析表达式,为电光开关微波电极的设计提供了理论依据;结合软件模拟与理论计算,详细分析了共面电极的有效电场分布,多节反相电极结构对定向耦合型电光开关特性的影响,讨论了电极尺寸、波导位置与各性能参数之间的变化关系,设计了基于极化聚合物的不同衬底材料的电光调制器以及单节、两节、三节、四节反相电极结构定向耦合型电光开关的共面行波电极系统;自制了高频测试用微波探针并搭建了一套行波电极的测试系统;利用半导体工艺制备了多个不同衬底材料、不同介质层的CPW行波电极;对行波电极、调制器、定向耦合型电光开关进行了性能测试,分析了测试结果,并阐明了Si衬底行波电极损耗较大的原因。
It has put forward higher requirements for the information processing speed, transmitting speed and storage capacity with the development of information science. But the traditional electricity network is unable to satisfy this requirement because of its "electronic bottleneck". Meanwhile, there has urgent need of optical integrated devices of large capacity, easy connectivity, and resistance to electromagnetic and wireless in the fields of computer, telecommunications, and optical information processing. As a result, the optical network becomes the main way to solution this problem. And as it precisely conforms to this demand, the polymer E-O (electro-optic) devices has gradually developed into a focus in recent years.
Besides a logic operation device, optical switch is also able to do the conversion to optical transmission line and integrated optical signal. It has one or a number of selected transmission ports. As important optoelectronics and integrated optical devices, optical switch and its arrays are one of the main factors that affect performance of the optical network, because of their core position. It completely depend on optical switches, optical filter, erbium-doped fiber amplifier (EDFA) of new generation, dense wavelength division multiplexing (DWDM) technology, and progress of other technology.
The poled polymer electro-optic switch discussed in this paper is a member of the optical switch family. With its favorable performance of high switching speed (speed of response in the order of picoseconds or femtoseconds), it shows wide applications in the new generation of all-optical network and system of RoF, and has become one of the international focus of many hot research. In order to achieve the goals and good performance, a detailed study of the microwave electrode system should be done. This paper mainly covers the following aspects:
1. By analyzing many kinds of configurations of the micro-wave electrode system of poled polymer electro-optic switches, we selected CPW traveling -wave electrode.
2. We got the analytical expression of the characteristic impedance Z 0, microwave equivalent refractive index n m, ohmic lossαc, dielectric lossαd, and other parameters of CPW traveling-wave electrode system according to conformal mapping theory. And all of this work provided a theoretical basis for designing the microwave electrode.
3. We analyzed the effective field distribution of CPW traveling-wave electrodes in detail. Additionally, by combining software (ADS2005a) simulation and theoretical calculations (the errors in the calculation are in the scope of the license), we discussed the relationship of parameters of electrode system such as Z 0、n m、α0、Vπ、Δf 3dB and its performance parameters such as W、G、t、εr、L and so on. Then the CPW traveling-wave electrode of poled polymer electro-optic modulator is designed finally with Vπ=12.4V、Δf 3 dB =22.8GHz(Si substrate); Vπ=13.1V、Δf 3 dB =156.5GHz(SiO2 substrate); and Vπ=13.4V、Δf 3 dB =35.4GHz(Glass substrate).
4. We analyzed the effect of multiple electrodes structure to the performance of the directional coupler electro-optical switch based on coupled mode theory, got the optical field dispersion of E0y0 mode by single-mode transmission condition, and optimized parameters of electrodes and waveguides. And finally, the directional coupler electro-optic switches with switching voltage of 21.7V、9.59V、6.47V、4.47V were designed.
5. After introducing the preparation process of CPW traveling-wave electrodes in detail, we prepared several CPW traveling-wave electrodes with different substrate materials and dielectric layers.
6. A microwave probe used for high-frequency test is designed and fabricated. And then we built a testing system for electrodes by using microwave vector network analyzer (Anritsu37269C), the six-axes stage, high-frequency microwave probe, infrared CCD camera, monitor, pneumatic vibration isolation platform, DC and AC sources.
7. We tested various of CPW traveling-wave electrode, illustrated the phenomenon of larger losses of CPW traveling-wave electrode based on Si substrate than other substrates. Besides that, poled polymer electro-optic modulator and the directional coupler electro-optical switches are tested preliminarily. Testing results showed that transmission loss was 31dB, return loss was 12dB, half-wave voltage was about 8V, and modulation bandwidth was 3.2GHz. In the end of the paper, we summarized the main problems of the current, and identified the future direction.
It has put forward higher requirements for the information processing speed, transmitting speed and storage capacity with the development of information science. But the traditional electricity network is unable to satisfy this requirement because of its "electronic bottleneck". Meanwhile, there has urgent need of optical integrated devices of large capacity, easy connectivity, and resistance to electromagnetic and wireless in the fields of computer, telecommunications, and optical information processing. As a result, the optical network becomes the main way to solution this problem. And as it precisely conforms to this demand, the polymer E-O (electro-optic) devices has gradually developed into a focus in recent years.
Besides a logic operation device, optical switch is also able to do the conversion to optical transmission line and integrated optical signal. It has one or a number of selected transmission ports. As important optoelectronics and integrated optical devices, optical switch and its arrays are one of the main factors that affect performance of the optical network, because of their core position. It completely depend on optical switches, optical filter, erbium-doped fiber amplifier (EDFA) of new generation, dense wavelength division multiplexing (DWDM) technology, and progress of other technology.
The poled polymer electro-optic switch discussed in this paper is a member of the optical switch family. With its favorable performance of high switching speed (speed of response in the order of picoseconds or femtoseconds), it shows wide applications in the new generation of all-optical network and system of RoF, and has become one of the international focus of many hot research. In order to achieve the goals and good performance, a detailed study of the microwave electrode system should be done. This paper mainly covers the following aspects:
1. By analyzing many kinds of configurations of the micro-wave electrode system of poled polymer electro-optic switches, we selected CPW traveling -wave electrode.
2. We got the analytical expression of the characteristic impedance Z 0, microwave equivalent refractive index n m, ohmic lossαc, dielectric lossαd, and other parameters of CPW traveling-wave electrode system according to conformal mapping theory. And all of this work provided a theoretical basis for designing the microwave electrode.
3. We analyzed the effective field distribution of CPW traveling-wave electrodes in detail. Additionally, by combining software (ADS2005a) simulation and theoretical calculations (the errors in the calculation are in the scope of the license), we discussed the relationship of parameters of electrode system such as Z 0、n m、α0、Vπ、Δf 3dB and its performance parameters such as W、G、t、εr、L and so on. Then the CPW traveling-wave electrode of poled polymer electro-optic modulator is designed finally with Vπ=12.4V、Δf 3 dB =22.8GHz(Si substrate); Vπ=13.1V、Δf 3 dB =156.5GHz(SiO2 substrate); and Vπ=13.4V、Δf 3 dB =35.4GHz(Glass substrate).
4. We analyzed the effect of multiple electrodes structure to the performance of the directional coupler electro-optical switch based on coupled mode theory, got the optical field dispersion of E0y0 mode by single-mode transmission condition, and optimized parameters of electrodes and waveguides. And finally, the directional coupler electro-optic switches with switching voltage of 21.7V、9.59V、6.47V、4.47V were designed.
5. After introducing the preparation process of CPW traveling-wave electrodes in detail, we prepared several CPW traveling-wave electrodes with different substrate materials and dielectric layers.
6. A microwave probe used for high-frequency test is designed and fabricated. And then we built a testing system for electrodes by using microwave vector network analyzer (Anritsu37269C), the six-axes stage, high-frequency microwave probe, infrared CCD camera, monitor, pneumatic vibration isolation platform, DC and AC sources.
7. We tested various of CPW traveling-wave electrode, illustrated the phenomenon of larger losses of CPW traveling-wave electrode based on Si substrate than other substrates. Besides that, poled polymer electro-optic modulator and the directional coupler electro-optical switches are tested preliminarily. Testing results showed that transmission loss was 31dB, return loss was 12dB, half-wave voltage was about 8V, and modulation bandwidth was 3.2GHz. In the end of the paper, we summarized the main problems of the current, and identified the future direction.
引文
[1].程晓飞,方来付,王健全,顾畹仪等,光开关技术综述,通讯世界,2001,(7):11-16
[2].谢世钟,王国忠,禹培栋,光联网中的光开关器件,世界电子元器件,2001,(10):7-9
[3].禹培栋,王国忠,陈明华,谢世钟,光开关技术开展,半导体光电,2001,22(3):149-154
[4].杨建义,江晓清,王明华,用于光纤通信的光开关研究进展,光通信研究,2000,4:42-48
[5].Y. Enami,a D. Mathine, C. T. DeRose, and R. A. Norwood,Hybrid cross-linkable polymer/sol-gel waveguide modulators with 0.65 V half wave voltage at 1550 nm,Appl. Phys. Lett. 91, 093505,2007
[6]. W. Yuan, S. Kim, G. Sadowy, C. Zhang, C. Wang, W.H. Steier and H.R. Fetterman,Polymeric electro-optic digital optical switches with low switching voltage,Electronics Letters, 2004, 40(3):195-197
[7].Riza N.A., J. of Light-wave Technology,1999,17(9):1575-1584
[8].廖先炳,光开关的开发渐入佳境,国际线缆与连接(技术交流版),2004,(4):12-16
[9].陈钰杰、林旭彬、李宝军,硅发光研究新进展,激光与光电子学进展,2005,42(11):9-13
[10].陈钢进,应用于非线性光学技术中的极化聚合物材料,浙江师大学报,1999,22(4)
[11].Meredith GR,VanDusen JG,Williams DJ. Nonlinear Optical Properties of Organic and Polymer Materials,D.WilliamsEd.ACSSympSeries,1983,232,109
[12].Ando Setal,Polymer for Micro-electronics,1994,22,304
[13].马春生,刘式墉等,光波导模式理论,长春:吉林大学出版社,2006
[14].罗敬东,詹才茂,秦金贵,极化聚合物电光材料研究进展,高分子通报,2000,3:9-19
[15].Yoshito Shuto, Michiyuki Amano, Reflection measurement technique ofelectro-optic coefficients in lithium niobate crystals and poled polymer films. J. Appl. Phys. 1995, 77(9):4632-4638
[16].李淳飞,光纤通信光开关的物理基础,物理实验,2002,22(4):3-5
[17].鹿飞,梁琨,宋琼,彭海波,吴伯瑜,聚合物电光调制器行波电极系统,光电子.激光,2005,16(3):267-270
[18] G.. K. Gopalakrishnan, W. K. Burns, R. W. McElhanon et al., Performance and modeling of broadband LiNbO3 traveling-wave optical intensity modulators. J. Light-wave Technol.,1994,LT-12(10) :1807-1819
[19].陈福深,集成电光调制理论与技术[M],北京:国防工业出版社,1995
[20]. J. B. P. van Schoot, P. V. Lambeck , at al. Design And Realisation Of A MZI Type Polymer Based High Speed EO-Modulator. 22nd European Conference on Optical Communication.1996, 3, 281-284
[21].Yongqiang Shi,et al.,Low(Sub-1-Volt)Half-wave Voltage Polymeric Electro-optic Modulators Achieved by Controlling Chromophore Shape. Science, 2000, 288, 119-122
[22].Mark Lee , et al. , Broadband Modulation of Light by Using an Electro-optic Polymer. Science, 2002, 298, 1401-1403
[23]. Kazuto Noguchi, Osama Mitomi,Hiroshi Miyazawa. Millimeter-wave Ti:LiNbO3 Optical Modulators. J. of Lightwave Technology, 1998, 16(4): 615-619
[24].D. Chen, H. R. Tetterman, A. Chen, W. H. Steier, et al. Demonstration of 110GHz electro-optic polymer modulators. Appl. Phys. Lett. 1997, 70(25): 3335-3337
[25].M. Lee, H. E. Katz, C. Erben, et al. Broadband Modulation of Light by Using an Electro-Optic Polymer. Science 2002, 298: 1401-1403
[26]. Yongqiang Shi, Weiping Lin, W. H. Steier, et al. Electro-optic polymer modulators with 0.8v half-wave voltage. ApplPhys. Lett. 2000, 77: 1-3
[27]. J. I. Thackara,J. C. Chon,G. C. Bjorklund,W. Volksen,and D. M. Burland,Polymeric electro-optic Mach–Zehnder switches, 1995, Appl. Phys. Lett. 67 (26):3874-3877
[28].O.G.RAMER. , Integrated Optic Electro-optic Modulator ElectrodeAnalysis,IEEE J. of Quantum Electronics, 1982, 18(3):386-392
[29]. F.S. Chu,P.L. Liu.,IEEE. J. Light-wave Technol. 1990,8:1492
[30]. N. Anwar., C. Thermistor, B.M.A. Rahman, K.T.V. Grattan. IEEE J. Light-wave Technol. 1999, 17, 598-601
[31]. D. Marcuse, Electrostatic field of coplanar lines computed with the point matching method, IEEE J. Quantum electronics, 1989,25(5):939-947
[32].Ahmed Sharkaw, Shouyuan Shi and Dennis W. Prather, Electro-optical switching using coupled photonic crystal waveguides, OPTICS EXPRESS, 2002, 10(20):1048-1052
[33].P. Ganguly, J. C. Biswas, S. K. Lahiri, Modelling of titanium indiffused lithium-niobate channel waveguide bends: a matrix approach, OPTICS COMMUNI-CATIONS, 1998, 155:125-134
[34].R.Chakraborty, J.C.Biswas, S.K.Lahiri. Analysis of directional coupler electro-optic switches using effective-index-based matrix method, OPTICS COMMUNICATIONS, 2003, 219: 157-163
[35].C. P. Wen, Coplanar Waveguide, A Surface Strip Transmission Line Suitable for Non-Reinhold Gyromagnetic Device Application , IEEE Trans. , 1969, vol. MTT-17, 1087-1090
[36].C. VEYRES and V. FOUAD HANNA, “Extension of the application of conformal mapping techniques to coplanar lines with finite dimensions”, INT. J. ELECTRONICS, Vol.48, pp47-56, 1979-1983
[37].T. KITAZAWA and R. MITTRA, “Quasi-static Characteristics of Asymmetrical and Coupled Coplanar-Type Transmission Lines”, IEEE Trans. Microwave Theory Tech., 1985, 33(9):771-778
[38].Giovanni Ghione and Carlo U. Naldi, “Coplanar Waveguides for MMIC Applications: Effect of Upper Shielding Conductor Backing, Finite-Extent Ground Planes, and Line-to-Line Coupling”, IEEE Trans. Microwave Theory Tech., 1987, 35(3):260-267
[39].Ninghua Zhu and Ziqian Wang, “On the Accuracy of Analytical Expressions for Calculating the Parameters of Coplanar Strips on A Finitely Thick Substrate”, Microwave and Optical Technology Letters, 1995,8(3):160-164
[40].曹伟杰,保形变换理论及其应用,上海:上海科学技术文献出版社,1988.
[41].何炜瑜,共面微波探针的设计理论与校准方法的研究,吉林大学硕士学位论文,2005
[42]. K. C. Gupta , Microstrip Lines and Slotlines , Dedham , Mass;Artech House , 1979
[43].梁昌洪,计算微波,西安:西北电讯工程学院出版社,1985
[44].黎滨洪,周希朗,毫米波技术及其应用,上海:上海交通大学出版社,1990
[45].K. C. Gupta,Ramesh Garg,Inder Bahl,Prakash Bhartia,Micro-strip Lines and Slot-lines,1996
[46].吴伯瑜,铌酸锂光波导电光调制器的原理、测试方法及设计计算,清华大学,1992
[47].Chen Fushen. Theory and Technology of Integrated Electro-Optic Modulator [M]. Beijing: National Defence Industry Press, 1995
[48].谷京华,复合电极超带宽 Ti:LiNbO3 电光调制器研究,清华大学硕士学位论文,1997
[49].张克潜,微波与光电子学中的电磁理论,电子工业出版社,2001
[2].谢世钟,王国忠,禹培栋,光联网中的光开关器件,世界电子元器件,2001,(10):7-9
[3].禹培栋,王国忠,陈明华,谢世钟,光开关技术开展,半导体光电,2001,22(3):149-154
[4].杨建义,江晓清,王明华,用于光纤通信的光开关研究进展,光通信研究,2000,4:42-48
[5].Y. Enami,a D. Mathine, C. T. DeRose, and R. A. Norwood,Hybrid cross-linkable polymer/sol-gel waveguide modulators with 0.65 V half wave voltage at 1550 nm,Appl. Phys. Lett. 91, 093505,2007
[6]. W. Yuan, S. Kim, G. Sadowy, C. Zhang, C. Wang, W.H. Steier and H.R. Fetterman,Polymeric electro-optic digital optical switches with low switching voltage,Electronics Letters, 2004, 40(3):195-197
[7].Riza N.A., J. of Light-wave Technology,1999,17(9):1575-1584
[8].廖先炳,光开关的开发渐入佳境,国际线缆与连接(技术交流版),2004,(4):12-16
[9].陈钰杰、林旭彬、李宝军,硅发光研究新进展,激光与光电子学进展,2005,42(11):9-13
[10].陈钢进,应用于非线性光学技术中的极化聚合物材料,浙江师大学报,1999,22(4)
[11].Meredith GR,VanDusen JG,Williams DJ. Nonlinear Optical Properties of Organic and Polymer Materials,D.WilliamsEd.ACSSympSeries,1983,232,109
[12].Ando Setal,Polymer for Micro-electronics,1994,22,304
[13].马春生,刘式墉等,光波导模式理论,长春:吉林大学出版社,2006
[14].罗敬东,詹才茂,秦金贵,极化聚合物电光材料研究进展,高分子通报,2000,3:9-19
[15].Yoshito Shuto, Michiyuki Amano, Reflection measurement technique ofelectro-optic coefficients in lithium niobate crystals and poled polymer films. J. Appl. Phys. 1995, 77(9):4632-4638
[16].李淳飞,光纤通信光开关的物理基础,物理实验,2002,22(4):3-5
[17].鹿飞,梁琨,宋琼,彭海波,吴伯瑜,聚合物电光调制器行波电极系统,光电子.激光,2005,16(3):267-270
[18] G.. K. Gopalakrishnan, W. K. Burns, R. W. McElhanon et al., Performance and modeling of broadband LiNbO3 traveling-wave optical intensity modulators. J. Light-wave Technol.,1994,LT-12(10) :1807-1819
[19].陈福深,集成电光调制理论与技术[M],北京:国防工业出版社,1995
[20]. J. B. P. van Schoot, P. V. Lambeck , at al. Design And Realisation Of A MZI Type Polymer Based High Speed EO-Modulator. 22nd European Conference on Optical Communication.1996, 3, 281-284
[21].Yongqiang Shi,et al.,Low(Sub-1-Volt)Half-wave Voltage Polymeric Electro-optic Modulators Achieved by Controlling Chromophore Shape. Science, 2000, 288, 119-122
[22].Mark Lee , et al. , Broadband Modulation of Light by Using an Electro-optic Polymer. Science, 2002, 298, 1401-1403
[23]. Kazuto Noguchi, Osama Mitomi,Hiroshi Miyazawa. Millimeter-wave Ti:LiNbO3 Optical Modulators. J. of Lightwave Technology, 1998, 16(4): 615-619
[24].D. Chen, H. R. Tetterman, A. Chen, W. H. Steier, et al. Demonstration of 110GHz electro-optic polymer modulators. Appl. Phys. Lett. 1997, 70(25): 3335-3337
[25].M. Lee, H. E. Katz, C. Erben, et al. Broadband Modulation of Light by Using an Electro-Optic Polymer. Science 2002, 298: 1401-1403
[26]. Yongqiang Shi, Weiping Lin, W. H. Steier, et al. Electro-optic polymer modulators with 0.8v half-wave voltage. ApplPhys. Lett. 2000, 77: 1-3
[27]. J. I. Thackara,J. C. Chon,G. C. Bjorklund,W. Volksen,and D. M. Burland,Polymeric electro-optic Mach–Zehnder switches, 1995, Appl. Phys. Lett. 67 (26):3874-3877
[28].O.G.RAMER. , Integrated Optic Electro-optic Modulator ElectrodeAnalysis,IEEE J. of Quantum Electronics, 1982, 18(3):386-392
[29]. F.S. Chu,P.L. Liu.,IEEE. J. Light-wave Technol. 1990,8:1492
[30]. N. Anwar., C. Thermistor, B.M.A. Rahman, K.T.V. Grattan. IEEE J. Light-wave Technol. 1999, 17, 598-601
[31]. D. Marcuse, Electrostatic field of coplanar lines computed with the point matching method, IEEE J. Quantum electronics, 1989,25(5):939-947
[32].Ahmed Sharkaw, Shouyuan Shi and Dennis W. Prather, Electro-optical switching using coupled photonic crystal waveguides, OPTICS EXPRESS, 2002, 10(20):1048-1052
[33].P. Ganguly, J. C. Biswas, S. K. Lahiri, Modelling of titanium indiffused lithium-niobate channel waveguide bends: a matrix approach, OPTICS COMMUNI-CATIONS, 1998, 155:125-134
[34].R.Chakraborty, J.C.Biswas, S.K.Lahiri. Analysis of directional coupler electro-optic switches using effective-index-based matrix method, OPTICS COMMUNICATIONS, 2003, 219: 157-163
[35].C. P. Wen, Coplanar Waveguide, A Surface Strip Transmission Line Suitable for Non-Reinhold Gyromagnetic Device Application , IEEE Trans. , 1969, vol. MTT-17, 1087-1090
[36].C. VEYRES and V. FOUAD HANNA, “Extension of the application of conformal mapping techniques to coplanar lines with finite dimensions”, INT. J. ELECTRONICS, Vol.48, pp47-56, 1979-1983
[37].T. KITAZAWA and R. MITTRA, “Quasi-static Characteristics of Asymmetrical and Coupled Coplanar-Type Transmission Lines”, IEEE Trans. Microwave Theory Tech., 1985, 33(9):771-778
[38].Giovanni Ghione and Carlo U. Naldi, “Coplanar Waveguides for MMIC Applications: Effect of Upper Shielding Conductor Backing, Finite-Extent Ground Planes, and Line-to-Line Coupling”, IEEE Trans. Microwave Theory Tech., 1987, 35(3):260-267
[39].Ninghua Zhu and Ziqian Wang, “On the Accuracy of Analytical Expressions for Calculating the Parameters of Coplanar Strips on A Finitely Thick Substrate”, Microwave and Optical Technology Letters, 1995,8(3):160-164
[40].曹伟杰,保形变换理论及其应用,上海:上海科学技术文献出版社,1988.
[41].何炜瑜,共面微波探针的设计理论与校准方法的研究,吉林大学硕士学位论文,2005
[42]. K. C. Gupta , Microstrip Lines and Slotlines , Dedham , Mass;Artech House , 1979
[43].梁昌洪,计算微波,西安:西北电讯工程学院出版社,1985
[44].黎滨洪,周希朗,毫米波技术及其应用,上海:上海交通大学出版社,1990
[45].K. C. Gupta,Ramesh Garg,Inder Bahl,Prakash Bhartia,Micro-strip Lines and Slot-lines,1996
[46].吴伯瑜,铌酸锂光波导电光调制器的原理、测试方法及设计计算,清华大学,1992
[47].Chen Fushen. Theory and Technology of Integrated Electro-Optic Modulator [M]. Beijing: National Defence Industry Press, 1995
[48].谷京华,复合电极超带宽 Ti:LiNbO3 电光调制器研究,清华大学硕士学位论文,1997
[49].张克潜,微波与光电子学中的电磁理论,电子工业出版社,2001