共查询到19条相似文献,搜索用时 156 毫秒
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调制偏振光在光学相位延迟测量中的频谱分析 总被引:1,自引:0,他引:1
介绍了光调制器的调制原理,在时间域和频率域对其调制特性进行了理论分析,得到了相应的光强分布曲线。基于偏振光调制理论,提出了一种新型光学相位延迟测量方法,并对该方法从时域和频域两方面进行了分析。频谱分析的结果表明,当出射光信号的奇次谐频分量为零时,满足完全补偿条件,此时可由补偿器的补偿量直接得到待测器件的光学相位延迟量。这种方法能够对光学相位延迟量进行直接量的测量,和其他间接测量方法相比有其明显的优势。在理论分析的基础上,还进行了相应的实验,并得到了高精度的实验结果。 相似文献
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针对快焦比特大非球面度离轴非球面反射镜,设计了3片式Offner补偿器。为应对3片式补偿器对中心偏差及镜间隔严格的公差要求,设计了相应的补偿器镜筒结构。该结构使透镜中心倾斜及平移调整相分离,实现补偿器的高精度装调。根据中心偏差测量仪的测量结果,2片补偿镜之间倾斜误差4.4″,平移误差3.5 μm, 镜间隔误差3.8 μm;补偿镜组与场镜之间倾斜误差5.3″,平移误差4.2 μm, 镜间隔误差7.2 μm,满足检测使用要求。利用该补偿器及4D动态干涉仪对精抛光阶段的离轴非球面进行检测,面形结果PVq值达到0.135λ,RMS值达到0.019 5λ,优于设计要求。 相似文献
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The dispersion compensation effect of the chirped fiber grating (CFG) is analyzed theoretically, and analytic expressions are derived for composite second-order (CSO) distortion in analog modulated sub-carrier multiplexed (AM-SCM) cable television (CATV) systems with externally and directly modulated transmitters. Simulations are given for the two kinds of modulations and for standard single mode fiber and non-zero dispersion shift fiber (NZDSF) systems. The results show that CFG could be used as a dispersion compensator in directly modulated systems, but its dispersion coefficient should be adjusted much more precisely than the externally modulated system. The requirements for the NZDSF system could be loosened much. It is proposed that directly modulated source may be used as a transmitter in CATV systems combined with tunable CFG dispersion compensator being adjusted precisely, which may be more cost-effective than externally modulation technology. 相似文献
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系统分析了三镜级联结构G-T谐振腔的色散特性,表明三镜级联结构G-T谐振腔具有不同于两镜级联结构G-T谐振腔的特有色散特性.利用该特性以三镜级联结构G-T谐振腔作为色散补偿元件可有效改善MGTI型interleaver的色散性能,并给出了以三镜级联结构G-T谐振腔为补偿元件的具体补偿实例.模拟结果表明:对50 GHz的MGTI型光交错复用器,可实现中心波长附近±0.08 nm、±0.09 nm和±0.1 nm范围内的色散绝对值分别小于1 ps/nm、2.4 ps/nm和6.6 ps/nm的良好的补偿结果.与文献报道的两镜级联结构G-T腔补偿结果相比,色散绝对值小于1 ps/nm的波长范围扩大了60%;在中心波长附近±0.09 nm范围内的色散绝对值降低了92%. 相似文献
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用计算全息标校补偿器的技术 总被引:3,自引:1,他引:3
用计算全息(CGH)模拟理想非球面主镜的反射波面,用补偿器对该计算全息进行检验,只要计算全息的制作误差能够满足要求,就能实现直接对补偿器的标校。介绍了计算全息标校补偿器的原理、方法,并进行了误差分析。实验采用电子束制作的计算全息实现了对850 mm F/2抛物面主镜补偿器的标校,补偿器产生的标准非球面精度不低于计算全息模拟的主镜面形精度,均方根(RMS)误差为0.012λ。研究表明,用计算全息模拟主镜反射波面对补偿器进行标校是一种行之有效的方法,结合先进的微电子制造技术,可实现对补偿器的高精度标校。 相似文献
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A theory is developed for the self-phase compensated optical waveguide isolator recently reported in the literature. The operation principle of such device is explained in terms of synchronization of phase and power conversion. The effect of balancing phase mismatches of the two convertors on achieving a proper percentage of mode conversion is revealed. The way to make use of the phase mismatches of different sections to accommodate the different requirements in phase relationship for the reciprocal and nonreciprocal mode convertors is discussed. The theory is extended to the case where phase compensator is used. It is demonstrated that the introduction of phase compensator separates the adjustment of phase from the adjustment of power for the mode convertors so that relaxes fabrication tolerances of such devices. An isolator consists of three phase mismatched waveguide sections is designed and simulated. The simulation results confirm the self-phase compensation theory. 相似文献
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Analytical performance evaluation of an adjustable PMD compensator using high-birefringence linearly chirped FBG 总被引:1,自引:0,他引:1
System performance of a high-speed WDM transmission system in the presence of PMD can be improved significantly by using an adjustable PMD compensator. We have analytically evaluated the performance of a tunable PMD compensator based on high-birefringence linearly chirped fiber Bragg grating. The device can adjust differential group delay in a linearly continuous way without affecting the wavelength outside the bandwidth. Various properties of the device such as relative group delay, differential group delay, reflectivity, etc. are investigated in terms of wavelength and grating length. Results show that under stretched condition the device generates a time delay between fast and slow polarization axes, which is adjustable from 0 to 55 ps and is tunable within 2.4 nm wavelength range. 相似文献
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Wen-Shing Tsai Shah-Jye Tzeng Shih-Hung Chen Tzu-Shen Chien 《Optics Communications》2006,263(2):201-206
A bidirectional hybrid dense-wavelength-division-multiplexing (DWDM)-passive optical network (PON) employing optical injection locking technique on vertical-cavity surface-emitting lasers (VCSELs) and data comparator, as well as optical injection locking technique on distributed feedback laser diodes (DFB LDs) and amplitude/phase compensator is proposed and demonstrated. Improved performances of bit error rate (BER) and carrier-to-noise ratio/composite second order/composite triple beat (CNR/CSO/CTB) were observed in our proposed bidirectional hybrid DWDM-PON. Bidirectional transmission in bidirectional hybrid DWDM-PON architecture is a very attractive option, the capacity of the optical network can be expanded relatively easily by bidirectional transmission technology. 相似文献
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设计非球面检测用补偿器应注意的几个问题 总被引:2,自引:0,他引:2
介绍了补偿法检测非球面的原理,举例说明了在补偿器的设计中应注意事项。在补偿器中的每个面及其球心都不要位于其前面的光学元件组成的光学系统的焦点附近,以避免其反射光在有效干涉场内与参考光干涉,从而影响检测结果;补偿器中入射角大的面尽量前移,以降低公差要求;对补偿器材料的光学均匀性要认真核算以确保最后的检测结果有效。 相似文献