波分复用系统中基于法布里—珀罗腔的光学薄膜滤波器研究

【作者】 陈海星；

【导师】 顾培夫；

【作者基本信息】 浙江大学 ， 光学工程， 2005， 博士

【摘要】 基于薄膜法布里-珀罗滤波器的原理,本文对波分复用系统中的Interleaver、液晶可调谐滤波器以及利用光子晶体中超棱镜效应设计的薄膜解复用器件进行了研究。 1、多腔级联薄膜法布里-珀罗滤波器型Interleaver的研究。我们对G-T腔与反射镜组合型的Interleaver进行了分析并提出了薄膜固体腔型的G-T结构,运用特征矩阵法对这种结构进行了详细的分析,阐述了反射相位匹配是实现其梳状滤波功能的关键。在此基础上,进一步提出了使用多腔级联的方法来构建使用于DWDM系统中的Interleaver器件。讨论了器件的设计方法并分析了影响器件光学特性的主要因素。提出了利用多镜(Multi-Mirror)理论来分析多腔之间的反射率匹配对通带内波纹度(Ripple)的影响。实际制备了100GHz的多腔级联型薄膜法布里-珀罗滤波器型Interleaver,并搭建了测试器件的装置系统,对器件的实际测试表明器件在-24dB处的带宽为0.8nm,在-0.5dB处的带宽约0.12nm,器件的插入损耗为0.6dB,满足DWDM系统使用的要求。 2、液晶可调谐滤波器的研究。利用法布里-珀罗腔的厚度改变来实现输出光波长改变的原理,我们设计了使用向列相液晶材料的液晶可调谐滤波器,通过施加电压的方式驱动液晶分子的转动实现可调谐滤波功能。详细分析了影响其性能的参数并讨论了器件在测试中出现的“模式跳跃”现象,理论上分析了其出现的原因并进行了数值模拟,正确地解释了这种现象。分析了在实际使用中,液晶法布里-珀罗腔可调谐滤波器在C波段工作时所需的液晶折射率差大并不能增大线性调谐范围,而必须根据所设计的器件要求合适地选择液晶参数。探讨了电介质反射镜膜堆的反射相位穿透深度对液晶法布里-珀罗腔的等效腔厚的影响,数值模拟并分析了其对液晶法布里-珀罗腔可调谐滤波器的调谐过程的影响。实际制备和测试了液晶法布里-珀罗腔器件的光谱特性,测试结果表明制备的器件在C波段调谐范围达到28nm,FWHM为0.8nm。最后,我们基于液晶法布里-珀罗腔可调谐的特性,设计了一种基于液晶折射率电调制的微腔有机电致发光二极管,对所设计的结构进行了模拟计算,数值验证了这种结构的可行性,器件的可更多还原

【Abstract】 Based on the principle of thin-film Fabry-Perot filter, the dissertation is mainly focused on the study of the thin-film interleaver device and tunable filter with liquid crystal Fabry-Perot etalon, which both are used in DWDM System, as well as the thin film mux/demultiplexer utilizing the superprism effect in photonic crystal.1. Research on the interleaver based on multi-cavity thin film Fabry-Perot filter. The interleaver structure combined by Gires-Tournois (G-T) etalon and reflector was analyzed and the thin film G-T etalon with solid cavity was presented. By characteristic matrix method, the device was simulated in detailed and we disclosed that the match of the phase on reflectance is the key factor to achieve the interleaver function. Furthermore, we presented the method to design the interleaver device which is used in DWDM system by multi-cavity cascade. The novel design was discussed and the important factors that would affect the optical performance of the device were analyzed. We introduce the multi-mirror theory to analyze the relation of the reflectance of each etalon that has influence on the ripple in passband. Experimentally, the thin-film Fabry-Perot interleaver by multj-cavity cascaded was fabricated, which has 100GHz-spaced channel and the measurement system was built. The test result showed that the interleaver achieved to the bandwidth with 0.8nm@ -24dB, 0.12nm@ -0.5dB and the insertion loss nearly 0.6dB or so, which meet the requirement of the DWDM system.2. Research on the tunable filter with liquid crystal Fabry-Perot etalon. According to the principle of the output wavelength tuning by changing the thickness of Fabry-Perot etalon, the tunable filter was designed with nematic liquid crystal, which could achieve tunable filter by rotating the molecule of liquid crystal when applied the voltage. We analyzed the factors which could affect the performance of the device and discussed the "Mode Jumping" phenomenon in the measuring process of the tunable filter, studied the reason in theory and made numerical simulation, which elucidated the phenomenon properly. Our research result showed that in practice, the big difference of the refractive index of the liquid crystal material can not always increase the tunable range of the device yet; however, it should be selected suitably according to the designed parameter of the device. The influence of penetrate depth of reflective phase in dielectric reflective-mirror stack on the effective cavity length of the liquid crystal Fabry-Perot etalon was discussed and analyzed.the tuning processwas also simulated numerically. We fabricated the tunable filter with liquid crystal Fabry-Perot etalon and tested the spectrum of the sample, the result showed that the device was achieved to the tunable range from 1534.5nm to 1562.5nm and the full width of the half maximum is nearly 0.8nm in C-band. Finally, we presented a novel designed method for tunable wavelength micro-cavity organic electroluminescent diode based on the tunable feature of the liquid crystal Fabry-Perot etalon. The device was simulated numerically and proved its feasibility. The simulated result showed that the tunable range could reach to 60nm and the full width of half maximum is 5.5nm, furthermore, the device possesses good orientation in light-emission space.3. Research on thin-film mux/demultiplexer based on the superprism effect in Photonic Crystal, we designed and achieved to observe the micrometer-level shift by space dispersion in the 1D thin-film periodic structure, in the case of the thin-film stack like as Air| (HL)10|Sub, the dispersion shift of the reflective beam was detected and reached to 22μm or so.which is consisted with the designed one. The influence of the beam size on the calculation of group delay was analyzed and the condition in which the Bloch theory could be applied was also discussed. In order to enhance the intensity of the reflective beam, we made the analysis on the superprism effect of the 1D thin-film periodic structure with reflective layer更多还原