共查询到20条相似文献,搜索用时 31 毫秒
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A new high-speed, ultrahigh cross-talk-suppression multiwavelength add-drop optical filter structure is demonstrated with two bulk acousto-optic tunable filters. With simple spatial blocks, an average -47-dB optical suppression is measured for the unwanted wavelengths at the filter output ports. The filter is tested for the three standard visible wavelengths, red, green, and blue, and demonstrates a switching time of 0.65micros and an average optical loss of 5 dB. Applications for this filter include multiwavelength switching applications such as wavelength-division-multiplexed optical communications. 相似文献
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We apply liquid crystal on silicon (LCOS) in 0.8-$mUm standard complementary metal-oxide semiconductor (CMOS) technology to demonstrate a low-cost, high-performance pixelized liquid crystal variable optical attenuator (VOA) with pulse width modulation. We then build a prototype tunable filter by using this VOA along with a grating in the Littrow configuration. With the application of 5-V pulse width modulation, the proposed VOA achieves a 5.6-dB insertion loss, a dynamic range of more than 20 dB, a 50-GHz channel spacing capability, and a polarization-dependent loss (PDL) of less than 0.6 dB at 15-dB attenuation. Our VOA is suitable for applications such as dynamic channel gain equalizers, channel-blocking filters, sub-components of re-configurable add-drop modules, and wavelength selectors. 相似文献
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A stable and broad bandwidth multiwavelength erbium-doped fiber laser is proposed and demonstrated successfully. A nonlinear optical loop mirror which induces wavelength-dependent cavity loss and behaves as an amplitude equalizer is employed to ensure stable room-temperature multiwavelength operation. Up to 50 wavelengths lasing oscillations with wavelength spacing of 0.8 nm within a 3-dB spectral range of 1562-1605 nm has been achieved. The measured power fluctuation of each wavelength is about 0.1 dB within a 2-h period. 相似文献
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聚合物弥散液晶材料在1550nm的电光特性研究 总被引:2,自引:0,他引:2
实验研究了不同配方及工艺条件下,聚合物弥散液晶(PDLC)材料在1550nm处的电控光透射特性。由此筛选合适的配方和工艺,研制了聚合物弥散液晶电控可调光衰减器样品。实验说明,在1550nm工作点,50%左右合适的液晶含量的聚合物弥散液晶样品能够获得更好的电控光学性能。采用配方质量比ω(DHPA):ω(E7):ω(RB):ω(NVP):ω(NPG)=100:100:3:2:1.5的配方,制作在1550nm工作的聚合物弥散液晶光衰减器样品。经检测,输入光源为1550mm,223μW时,器件插入损耗为2.3dB,衰减调节范围为13dB,线性工作区域为20~70V。 相似文献
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An InGaAsP/InP waveguide variable optical attenuator (VOA) is proposed in this paper. The device consists of straight input and output waveguides and an S-bend waveguide. An electrode is deposited on a portion of the waveguide to form an active region so that its refractive index can be modified by a current injection, resulting in the variation of the transmitted optical power. The beam propagation method is employed in the numerical simulation and the device structure is optimized using a genetic algorithm. The optimized VOA has a low excess loss (<1 dB) and a large dynamic range of about 40 dB. 相似文献
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A 3-dB optical coupler (power splitter) based on a Y-junction waveguide with a channel profile of proton-exchanged lithium niobate has been modeled. Finite difference beam propagation method has been used to investigate light wave propagation in axially varying waveguides. It is found that the structure splits the input power equally at the Y-junction with an efficiency of 99% and an average excess loss ?0.04 dB. The novelty of the coupling structure proposed is its capability to function as a wavelength-independent 3-dB coupler while maintaining very low-power imbalance for widespread optical communication wavelengths of 1.3 and 1.55 µm. 相似文献
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Avoltage -controlled variabl optical attenuator (VOA) based on silica-b a sed planar ligh t wa ve circu its (P LC) was fabricated by flame hydrolysis deposition (FHD). The variable attenuator with Cr heater achieves 20dB attenuation with 318mW electrical power at 1550 nm. The insertion loss and the polarization dependent loss (PDL) at 0 attenuation are 1dB and 0.23dB, respectively. 相似文献
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Jiajun Tian Yong Yao Jun Jun Xiao Xuelian Yu Deying Chen 《Optics Communications》2012,285(9):2426-2429
A tunable multiwavelength erbium-doped fiber laser is proposed and experimentally studied. The intensity-dependent loss (IDL) in a nonlinear optical loop mirror is utilized for stable multiwavelength lasing output. The accurate switch operation, i.e., the lasing lines emerge/disappear one by one at the longer wavelength side of the initial one, is achieved by adjusting the intra-cavity loss using a variable attenuator. The effect of the intra-cavity loss on the lasing characteristics is theoretically analyzed. Numerical results confirm the experiment measurements and suggest that both the IDL and the gain spectrum, which vary with the intra-cavity loss, lead to the observed tunable lasing behavior. 相似文献
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To reduce the crosstalk of the polymer waveguide optical switches, waveguide attenuators are integrated with the switch on the same substrate. The switch and attenuator shares a single connected electrode which is controlled by a single current source. Due to the simple structure of the integrated attenuator, the device length is reduced to 10 mm so as to provide low insertion loss of 0.8 and 1.1 dB for 1300 and 1550 nm, respectively. Further radiation of the remained optical signal on the switch-off branch is induced by the integrated attenuator so that the switching crosstalk is reduced to −70 dB with an applied electrical power of 200 mW. The low crosstalk is maintained for the environmental temperature range of −10 to 55 °C. 相似文献
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一种新型微机电系统可调光衰减器 总被引:4,自引:4,他引:0
一种新型的低成本、小体积的电磁驱动微机电系统可调光衰减器,可用于密集波分复用系统中各信道的动态增益平衡。该器件采用电磁线圈驱动绕100微轴转动的微反射镜,运动部件行程极小。驱动电压为0~8V,工作范围0~35dB,动态响应时间小于2ms,插入损耗小于0.8dB,回波损耗小于-50.5dB。器件采用微细电火花加工技术制作,加工精度为微米量级。技术成熟,工艺简单,易于批量生产。采用有限元分析软件ANSYS对器件的结构建模,对电磁场及衰减曲线进行了理论分析,并与实测数据进行了比较,得出了相当满意的结果。 相似文献
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利用电控改变固液界面湿润角的电润湿微棱镜(EMPs)技术以及双自聚焦透镜组合设计了一类新颖的可调光衰减器,并对该衰减器的衰减性能进行了原理分析和实验测量.理论分析和实验结果表明其具有良好的光衰减控制效应,在不大的电压变化范围(例如135—139V)内即可实现2—60dB的光衰减范围.该器件构思新颖,具有结构简单、容易制作的优点,经过优化后将会在光通信领域得到广泛的应用.缺点是工作电压偏高,需要进一步筛选出介电系数高的物质来作为介电绝缘层材料,以便降低工作电压,达到实际可以使用的目的.
关键词:
微流控光学
电湿效应
可调光衰减器
电润湿微棱镜 相似文献
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We report the experimental demonstration of a reconfigurable multiwavelength fiber laser source with switchable wavelength channels and tunable wavelength spacing by spectrum slicing a broadband light source using a tunable comb filter. The tunable comb filter is based on a thermally-induced linearly-chirped fiber Bragg grating (LCFBG). As an example to demonstrate the effectiveness of the method, two wavelength channels with various wavelength spacings and eight wavelength channels with ∼1.6 nm wavelength spacing were experimentally demonstrated. All the wavelength channels have rejection ratios of greater than 20 dB, and very small 3-dB linewidths of ∼10 pm. The multiwavelength optical source has such unique advantages as simple all-fiber structure, switchable wavelength channels, tunable wavelength spacing, very narrow linewidths, and stable room-temperature operation. 相似文献
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A stable dual-wavelength erbium-doped fiber ring laser with switchable spacing is proposed and experimentally demonstrated. An arrayed waveguide grating (AWG) incorporating two fiber optic switches (OS) is used to as the wavelength selector. The ring cavity is divided into two cavities by a 30:70 optical coupler. Equalized dual-wavelength outputs are achieved by controlling the variable optical attenuator (VOA) inserted in the lower loss cavity. The wavelength spacing can be tuned from 0.80 to 12.05 nm. The fiber laser has good optical quality with maximum power fluctuation of 1.5 dB and side mode suppression ratios (SMSRs) higher than 71 dB. 相似文献
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We describe a fiber-optic sensor capable of detecting high humidity. The device is constructed from standard telecommunications single-mode fiber and is compatible with deployment in a serial array, permitting interrogation by optical time-domain reflectometry for network monitoring. The sensors exhibit a reversible change in insertion loss between their dry (lossy) and humid (transmissive) states. The loss can be tailored to take any value; the current devices were designed to change by approximately 2.5 dB at a wavelength of 1.31 mum. The sensors are simple to construct and are compatible with installation in an existing passive optical network. The transduction mechanism is based on the humidity-induced change in refractive index in a polymer overlay on a polished half-block single-mode fiber device. 相似文献
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A binary multichannel photonic delay line (PDL) module is introduced that gives balanced loss switched states and a polarization-insensitive operation via the use of binary operation Digital Micromirror Devices (DMDs). Experimental demonstration of a DMD-based PDL architecture is performed for a 6.84-ns time delay design. Experimental results include a 25-beam feed interchannel crosstalk test indicating a <−60 dB optical interchannel crosstalk level for a 0.381 mm interchannel distance in the multichannel PDL. An average optical signal-to-leakage noise ratio of 35.33 dB is measured for this PDL. A butterfly design PDL optical architecture is proposed for minimizing loss and improving assembly accuracy. These DMD-based variable PDLs can be used in applications ranging from radio frequency (RF) fiber-optic signal processing systems to adaptive optics for astronomical and laser radar arrays. 相似文献
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高动态范围的图像可用于同时探测具有较大对比度的亮暗目标,利用数字微镜(DMD)获取高动态范围图像是目前最为先进的一种技术。本文在分析DMD工作原理的基础上,设计了一种像素级的高动态范围图像获取系统,该系统由光学系统、机械系统、DMD像素级调光算法及成像单元组成。光学系统采用二次成像光路,其中第一次成像物镜采用像方远心光路,第二次成像的转置镜头采用放大倍率近似1: 1的准对称结构,机械系统采用光学元件的包边设计和定心车工艺,达到秒级的光学装配精度;DMD像素级调光算法采用搜索单个微镜像素在图像帧周期间的控制权值实现,成像单元可同时兼顾科学级12 bit sCMOS和8 bit CCD,设计完成的原理样机验证了系统设计的正确性,其获取的图像动态范围可达140 dB以上,远高于传统摄像机78 dB的动态范围。 相似文献