Nonlinear Optical Polymeric Materials: From Chromophore Design to Commercial Applications
Nonlinear Optical Polymeric Materials: From Chromophore Design to Commercial Applications
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DOI：
10.1007/3-540-44608-7_1
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发表时间：
2002
影响因子：
--
通讯作者：
L. Dalton
中科院分区：
文献类型：
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作者：
L. Dalton
聚合物电光材料最近被开发出来，当制造成诸如马赫-曾德尔干涉仪之类的器件时，允许在1.30微米和1.55微米的通信波长下实现小于1V的驱动(Vπ)电压。聚合物电光调制器的工作频率(带宽)已超过100 GHz。聚合物电光调制器的总插入损耗已降至5dB值，与铌酸锂调制器相当，远低于砷化镓电吸收调制器的插入损耗。聚合物电光调制器可以在100°C左右的温度下长时间工作。已开发出将聚合物电光电路与无源低损耗光电路(例如，二氧化硅长途传输光纤和中程氟聚合物光纤)以及超大规模集成(VLSI)半导体电子设备无缝集成的技术。这些进展引起了人们对聚合物电光材料商业化的浓厚兴趣。目前正在评估聚合物电光材料的应用，如相控阵雷达、卫星和光纤通信、有线电视、光学陀螺仪、电子对抗系统、高速计算机的背板互连、超高速(100Gbit/S)模数(A/D)转换器、地雷探测、射频(RF)光子学和空间光调制器。这篇综述讨论了在生产适合商业化的材料之前必须确定的结构-功能关系以及所取得的合成和加工进展。讨论的主题包括设计和合成同时表现出大分子超极化率、低光吸收、可加工性(例如，在各种处理介质中的溶解性)以及在聚合物电光器件的制造和操作中遇到的条件下生存的先决条件(热、化学、电化学和光化学)稳定性的发色团。生色团-生色团分子间的静电相互作用已被证明是阻碍有机材料电光活性优化的最严重问题。讨论了用平衡态和蒙特卡罗统计力学方法对这种相互作用进行定量的理论处理。讨论了具有最大可获得电光活性的发色团的设计原则，并对这种结构的综合实现进行了综述。文中还讨论了静电相互作用对工艺条件选择的影响。需要多个处理步骤，包括旋转浇注、电场极化、晶格硬化、埋入沟道波导的制造(包括包覆层的沉积)、电极沉积和与电子电路的连接、以及有源和无源光学电路的集成。这些步骤中的每一个都会影响器件性能(例如，影响光学损耗、电光活性和稳定性)。回顾了这些步骤中每一个步骤的系统优化。最后，对装置的设计和运行进行了回顾，并对该领域的未来进行了展望。
Polymeric electro-optic materials have recently been developed that, when fabricated into devices such as Mach-Zehnder interferometers, permit drive ( Vπ) voltages of less than 1 V to be realized at the telecommunications wavelength of 1.3 and 1.55 microns. Operation of polymeric electro-optic modulators to frequencies (bandwidths) of greater than 100 GHz has been demonstrated. The total insertion loss of polymeric electro-optic modulators has been reduced to values as low as 5 dB, which is competitive with values obtained for lithium niobate modulators and is much lower than that obtained for gallium arsenide electro-absorptive modulators. Polymeric electro-optic modulators can be operated for long periods of time at temperatures on the order of 100 °C. Techniques have been developed for seamlessly integrating polymeric electro-optic circuitry with passive low loss optical circuitry (e.g., silica long-haul transmission fiber and medium-range fluoropolymer fibers) and with very large scale integration (VLSI) semiconductor electronics. These advances have created a considerable interest in the commercialization of polymeric electrooptic materials. Polymeric electro-optic materials are now being evaluated for applications such as phased array radar, satellite and fiber telecommunications, cable television (CATV), optical gyroscopes, electronic counter measure (ECM) systems, backplane interconnects for high-speed computers, ultrafast (100 Gbit/s) analog-to-digital (A/D) converters, land mine detection, radio frequency (rf) photonics, and spatial light modulators. This review discusses the structure-function relationships that had to be defined and the synthesis and processing advances achieved before materials appropriate for commercialization could be produced. Topics discussed include the design and synthesis of chromophores that simultaneously exhibit large molecular hyperpolarizability, low optical absorption, processability (e.g., solubility in various processing media), and the prerequisite (thermal, chemical, electrochemical, and photochemical) stability to survive conditions encountered in the fabrication and operation of polymeric electro-optic devices. Chromophore-chromophore intermolecular electrostatic interactions have been shown to be the most serious problem impeding the optimization of electro-optic activity in organic materials. The quantitative theoretical treatment of such interactions by equilibrium and Monte Carlo statistical mechanical methods is discussed. Rules for designing chromophores with shapes leading to maximum obtainable electro-optic activity are discussed and the synthetic realization of such structures is reviewed. The role of electrostatic interactions in influencing the choice of processing conditions is also discussed. A number of processing steps, including spin casting, electric-field poling, lattice hardening, fabrication of buried channel waveguides (including deposition of cladding layers), electrode deposition and connection with electronic circuitry, and integration of active and passive optical circuitry, are required. Each of these steps can affect device performance (e.g., influence optical loss, electro-optic activity, and stability). The systematic optimization of each of these steps is reviewed. Finally, device design and operation are reviewed and speculation on the future of the field is expressed.