有机聚合物电光调制器的电极研究
摘要
本论文详细的阐述了电光调制器的类型和基本原理,重点研究了Mach-Zehnder电光调制器的共面波导(CPW)行波电极系统。通过对电极系统互作用区微波特性阻抗的分析,和对中心电极宽度、中心电极和地电极间距及电极厚度等对特性阻抗的影响进行了研究。同时,采用Advanced Design System (ADS)计算出特性阻抗满足需求的电极参数。同时在引入了重叠积分因子之后,对采用CPW行波电极的器件的驱动电压和电极参数的关系进行了详细的分析。本文还对有机聚合物电光调制器电极系统两种制备工艺(腐蚀法和剥离法)方案进行了详细分析比较后,认为剥离法是可取的。通过实验,总结出一套完备的工艺流程,制备出电极样品。
Due to the advantages of frequency bandwidth, low loss, large capacity, high reliability, light weight, small size and no short circuit, optical fiber communication has rapidly become the main form of information transmission nowadays. Particularly the high-speed optical transmission systems have been developed rapidly in recent years. The requirements of bandwidth are getting higher and higher. It is a key device for high-speed and long-distance communication. High-speed electro-optical modulator has become a hot spot in recent years. The organic polymer based on the nonlinear optical has been used as a new type of photoelectron materials. It has great research and development space in the field of integrated optics. Compared with the inorganic materials (LiNbO3、KH2PO4), these materials have a lower microwave dielectric constant, a higher electro-optic coefficient as well as good compatibility of preparation. It is applicable to the production of high-speed electro-optical modulator. Moreover, organic polymers can produce the electro-optical modulator with low half-wave voltage, high-bandwidth.
The electro-optic modulator is one type of the modulation devices to modulate transmission beam realized by the characteristic, which is influenced by refraction index of electro-field of electro-optic materials. According to the different structures of the devices, electro-optic modulator can be divided into two types: electro-optical modulator and waveguide transmission electro-optical modulator. Waveguide type EO-modulator has high-speed, chirp noise of wavelength is zero theoretically. It almost does not limited by the fiber dispersion. It has been used widely home and abroad. There are many types of waveguide transmission electro-optical modulators. Mach-Zehnder type (M-Z) electro-optic modulator is a more practical one. The M-Z modulator uses of a traveling wave electrodes. It has the advantages of high-speed modulate rate and little chirp noise of wavelengths. It has become the important parts in optical fiber communication systems.
Firstly, the kinds of electro-optical modulator and the research progress of organic polymer electro-optic modulator in recent years are described here in detail. And it is discovered that the research progress of organic polymer electro-optic modulator is developing in depth gradually and its indexes are incessantly enhanced. It becomes a hotspot and will be a good prospect for future research. According to the request of electro-optical modulator performance index the organic polymer materials have some advantages:
1) Low dielectric constant, which provides high-frequency response and speed matching between light and microwave of broadband traveling wave structure;
2) Higher electro-optic coefficient, which makes it more accessible to obtain a low half-wave voltage and very beneficial to prepare the modulator.
3) Can form good films on different substrates, and can execute multi-layer structure. They have a better compatibility of preparation.
These all provide a convenient condition to integrate polymer modulator with semiconductor devices. Thus it can be seen that organic polarized polymer electro-optic modulator has a good development prospect.
Secondly, the basic principle of polarized polymer electro-optic modulator has been described. Not only the electro-optic effect has been introduced in detail, but also the work principles of two basic types of polymer electro-optic modulator (M-Z and directional coupler) have been analyzed. Due to the M-Z electro-optic modulator uses a simple mathematical model. And the full switching effect should be obtained to the directional coupler. The technological allowance error to the length of coupled waveguide section is very small. It should require higher requirements of the technological level in the actual preparation progress. Therefore, we can conclude that: the preparation progress of M-Z modulator is easier than that of directional coupler. Then the theory of M-Z modulator has been analyzed. The parameters which have a good relationship between their performances, such as the modulation bandwidth, the driving power of unit bandwidth, modulation depth and insertion loss are introduced. At the same time, the electrode structure of M-Z electro-optical modulator is analyzed, including the interaction area, the transition zone and the input and output areas.
In theory, microwave characteristic impedance at electrode system interaction zone has been analyzed. The effect of the centre electrode width, the clearance between center electrode and the ground electrode and the thickness of the electrode to the characteristic impedance also has been studied. After study, it shows that, under the condition of ensuring the preparation processes of electrode unchanged, the microwave characteristic impedance of electrode system increases with the width of centre electrode and the interval of electrode. But for the latter the scope of effect, it is much smaller, due to the limitation of process conditions, and for the thickness of electrode too. The microwave electrode impedance parameters have been calculated using Advanced Design System. The overlap integral factor has been introduced. At the same time, the relationship between drive voltage and electrode parameters of devices with CPW traveling-wave has been analyzed.
Experimentally, two methods (Corrosion and lift-off) to prepare polymer electro-optic modulator electrode system have been introduced in detail. The process of prepare polymer electro-optic modulator electrode has been created and developed, lift-off has been analyzed, and a comprehensive process has been summed up. At the same time, some problems have been already solved, as follows: serious side etch in etching method, bad adhesion of metal film, imprecise exposure time in dissection method, lower success rate in removing photo resist .This part of the experimental work has important reference values to the relative future work.?
Due to the advantages of frequency bandwidth, low loss, large capacity, high reliability, light weight, small size and no short circuit, optical fiber communication has rapidly become the main form of information transmission nowadays. Particularly the high-speed optical transmission systems have been developed rapidly in recent years. The requirements of bandwidth are getting higher and higher. It is a key device for high-speed and long-distance communication. High-speed electro-optical modulator has become a hot spot in recent years. The organic polymer based on the nonlinear optical has been used as a new type of photoelectron materials. It has great research and development space in the field of integrated optics. Compared with the inorganic materials (LiNbO3、KH2PO4), these materials have a lower microwave dielectric constant, a higher electro-optic coefficient as well as good compatibility of preparation. It is applicable to the production of high-speed electro-optical modulator. Moreover, organic polymers can produce the electro-optical modulator with low half-wave voltage, high-bandwidth.
The electro-optic modulator is one type of the modulation devices to modulate transmission beam realized by the characteristic, which is influenced by refraction index of electro-field of electro-optic materials. According to the different structures of the devices, electro-optic modulator can be divided into two types: electro-optical modulator and waveguide transmission electro-optical modulator. Waveguide type EO-modulator has high-speed, chirp noise of wavelength is zero theoretically. It almost does not limited by the fiber dispersion. It has been used widely home and abroad. There are many types of waveguide transmission electro-optical modulators. Mach-Zehnder type (M-Z) electro-optic modulator is a more practical one. The M-Z modulator uses of a traveling wave electrodes. It has the advantages of high-speed modulate rate and little chirp noise of wavelengths. It has become the important parts in optical fiber communication systems.
Firstly, the kinds of electro-optical modulator and the research progress of organic polymer electro-optic modulator in recent years are described here in detail. And it is discovered that the research progress of organic polymer electro-optic modulator is developing in depth gradually and its indexes are incessantly enhanced. It becomes a hotspot and will be a good prospect for future research. According to the request of electro-optical modulator performance index the organic polymer materials have some advantages:
1) Low dielectric constant, which provides high-frequency response and speed matching between light and microwave of broadband traveling wave structure;
2) Higher electro-optic coefficient, which makes it more accessible to obtain a low half-wave voltage and very beneficial to prepare the modulator.
3) Can form good films on different substrates, and can execute multi-layer structure. They have a better compatibility of preparation.
These all provide a convenient condition to integrate polymer modulator with semiconductor devices. Thus it can be seen that organic polarized polymer electro-optic modulator has a good development prospect.
Secondly, the basic principle of polarized polymer electro-optic modulator has been described. Not only the electro-optic effect has been introduced in detail, but also the work principles of two basic types of polymer electro-optic modulator (M-Z and directional coupler) have been analyzed. Due to the M-Z electro-optic modulator uses a simple mathematical model. And the full switching effect should be obtained to the directional coupler. The technological allowance error to the length of coupled waveguide section is very small. It should require higher requirements of the technological level in the actual preparation progress. Therefore, we can conclude that: the preparation progress of M-Z modulator is easier than that of directional coupler. Then the theory of M-Z modulator has been analyzed. The parameters which have a good relationship between their performances, such as the modulation bandwidth, the driving power of unit bandwidth, modulation depth and insertion loss are introduced. At the same time, the electrode structure of M-Z electro-optical modulator is analyzed, including the interaction area, the transition zone and the input and output areas.
In theory, microwave characteristic impedance at electrode system interaction zone has been analyzed. The effect of the centre electrode width, the clearance between center electrode and the ground electrode and the thickness of the electrode to the characteristic impedance also has been studied. After study, it shows that, under the condition of ensuring the preparation processes of electrode unchanged, the microwave characteristic impedance of electrode system increases with the width of centre electrode and the interval of electrode. But for the latter the scope of effect, it is much smaller, due to the limitation of process conditions, and for the thickness of electrode too. The microwave electrode impedance parameters have been calculated using Advanced Design System. The overlap integral factor has been introduced. At the same time, the relationship between drive voltage and electrode parameters of devices with CPW traveling-wave has been analyzed.
Experimentally, two methods (Corrosion and lift-off) to prepare polymer electro-optic modulator electrode system have been introduced in detail. The process of prepare polymer electro-optic modulator electrode has been created and developed, lift-off has been analyzed, and a comprehensive process has been summed up. At the same time, some problems have been already solved, as follows: serious side etch in etching method, bad adhesion of metal film, imprecise exposure time in dissection method, lower success rate in removing photo resist .This part of the experimental work has important reference values to the relative future work.?
引文
[1] 赵策洲.半导体导波光学器件理论及技术(第一版)[M].国防工业出版社,1998:161-162.
[2] 蔡伯荣.集成光学.电子科技大学出版社.1990:115- 118.
[3] Dechang An, Zan Shi, Lin Sun, John M., et al. Polymeric Electro- optic modulator based on 1×2 Y-fed directional coupler. Appl.Phys.Lett. 2000, 76:1972.
[4] Suntak Park, Jung Jin Ju, Jung Yun Do, Seung Koo Park, et al. Thermalstability enhancement of electrooptic polymer modulator. IEEE Photonics Technology Letters. 2004, 16(1):93-95.
[5] D.Chen, H.R. Tetterman, A.Chen, W.H.Steier, et al. Demonstration of 110GHz electro-optic polymer modulators. Appl.Phys.Lett. 1997, 70:3335-3337.
[6] Lee Mark , Katz H E, Erben C, et al . Broadband modulation of light by using an electro-optic polymer. Science 2002, 298 (5597):1401-1403.
[7] 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.
[8] PWC 公司官方网站 http://www.pacificwaveind.com.
[9] M.Lee, H.E.Katz, C.Erben, et al. Broadband Modulation of Light by Usingan Electro-Optic Polymer.Science 2002,298:1401.
[10] 董小伟,裴丽,李彬,简水生.新型高速电光调制器.光通信研究. 2003 4:67-70.
[11] 张克从,王希敏.非线性光学晶体材料科学.科学出版社.1996.
[12]L.R.Dalton, A.W.Harper, B Wu, et al. Polymeric electro-optic modulators: materials synthesis and processing, Advanced Materials.1995,7(6),519-540.
[13] 陈福深.集成电光调制理论与技术[第一版].国防工业出版社. 1995:61.
[14]董小伟,裴丽等.有机聚合物电光调制器.光子技术.2003 9(1):11-14.
[15] 鹿飞,梁琨,宋琼,彭海波,吴伯瑜等.聚合物电光调制器行波电极系统.光电子激光,2005 16:267-270.
[16]QUIRK M, SERDA J. Semiconductor Manufacturing Technology. Publishing House of Electronics Industry. 2004: 384-387.
[17]于映,赵晨,罗仲梓,翁心桥.Al、Au 溅射薄膜的剥离技术研究.真空科学与技术学报.2005 25 增刊:112-114.
[18]李淑红,杜春雷,董小春.光刻胶烘培特性研究.光电工程.2005 32: 17-19.
[19]蒋玉荣,何永,李志伟,周建,欧阳世翕.BN-303 光刻胶前烘工艺对 MEMS三维结构的影响.武汉理工大学学报.2007 29:5-7.
[2] 蔡伯荣.集成光学.电子科技大学出版社.1990:115- 118.
[3] Dechang An, Zan Shi, Lin Sun, John M., et al. Polymeric Electro- optic modulator based on 1×2 Y-fed directional coupler. Appl.Phys.Lett. 2000, 76:1972.
[4] Suntak Park, Jung Jin Ju, Jung Yun Do, Seung Koo Park, et al. Thermalstability enhancement of electrooptic polymer modulator. IEEE Photonics Technology Letters. 2004, 16(1):93-95.
[5] D.Chen, H.R. Tetterman, A.Chen, W.H.Steier, et al. Demonstration of 110GHz electro-optic polymer modulators. Appl.Phys.Lett. 1997, 70:3335-3337.
[6] Lee Mark , Katz H E, Erben C, et al . Broadband modulation of light by using an electro-optic polymer. Science 2002, 298 (5597):1401-1403.
[7] 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.
[8] PWC 公司官方网站 http://www.pacificwaveind.com.
[9] M.Lee, H.E.Katz, C.Erben, et al. Broadband Modulation of Light by Usingan Electro-Optic Polymer.Science 2002,298:1401.
[10] 董小伟,裴丽,李彬,简水生.新型高速电光调制器.光通信研究. 2003 4:67-70.
[11] 张克从,王希敏.非线性光学晶体材料科学.科学出版社.1996.
[12]L.R.Dalton, A.W.Harper, B Wu, et al. Polymeric electro-optic modulators: materials synthesis and processing, Advanced Materials.1995,7(6),519-540.
[13] 陈福深.集成电光调制理论与技术[第一版].国防工业出版社. 1995:61.
[14]董小伟,裴丽等.有机聚合物电光调制器.光子技术.2003 9(1):11-14.
[15] 鹿飞,梁琨,宋琼,彭海波,吴伯瑜等.聚合物电光调制器行波电极系统.光电子激光,2005 16:267-270.
[16]QUIRK M, SERDA J. Semiconductor Manufacturing Technology. Publishing House of Electronics Industry. 2004: 384-387.
[17]于映,赵晨,罗仲梓,翁心桥.Al、Au 溅射薄膜的剥离技术研究.真空科学与技术学报.2005 25 增刊:112-114.
[18]李淑红,杜春雷,董小春.光刻胶烘培特性研究.光电工程.2005 32: 17-19.
[19]蒋玉荣,何永,李志伟,周建,欧阳世翕.BN-303 光刻胶前烘工艺对 MEMS三维结构的影响.武汉理工大学学报.2007 29:5-7.