集成光学声光可调谐波长滤波器的研制

阐述了中心波长为１．５２３μｍ的集成光学声光可调谐波长滤波器的各项理论参数、制作工艺以及性能测试。在有效声光相互作用长度１６ｍｍ、射频驱动功率３５ｍＷ时,获得了模式转换效率大于９９％、插入损耗小于－４．ｄＢ、带宽１．６ｎｍ、３ｄＢ调谐范围为１４０ｎｍ的实验结果。     

Compact polarization rotators for integrated polarization diversity in InP-based waveguides

We present the design, fabrication, and operation of a polarization converter based on angled waveguides in the InP/InGaAsP material system. By combining design elements from mode evolution and birefringent devices, the total device length is kept short (less than 50 microm) and the insertion efficiency high at 81%+/-19%, which corresponds to an insertion loss of 1 dB. Devices operate broadband, i.e., the polarization conversion exceeds 15 dB over a 100 nm wavelength range. A polarization rotator with these specifications is a prime candidate for use in an integrated polarization diversity scheme.     

Compact polarization rotator on silicon for polarization-diversified circuits

We demonstrate a polarization rotator based on adiabatic mode evolution on silicon for polarization-diversified circuits. The rotator has a device length of 420?μm, a polarization-conversion efficiency of more than 90%, and an insertion loss less than 1?dB for a wavelength range of 80?nm. Combining the rotator with a compact, broadband polarization beam splitter based on cascaded directional couplers enhances the polarization conversion extinction ratio to over 30?dB with less than 1.5?dB total insertion loss over a 60?nm spectral range.     

All-fiber narrowband polarization controller based on coherent acousto-optic mode coupling in single-mode fiber

An all-fiber, narrowband, tunable polarization controller is proposed and demonstrated. The device is based on coherent acousto-optic mode coupling induced by two orthogonal acoustic waves on a dispersion-compensating fiber. The cooperative coupling between the two polarizations of the core mode and the TE01 cladding mode through the two gratings permits indirect coupling between the two polarizations of the core mode with nearly 100% efficiency, which makes the polarization-controlling function possible. Experimental results verify the operation of the polarization controller with an insertion loss of <1 dB.     

High-efficiency ultrasmall polarization converter in InP membrane

An ultrasmall (<10 μm length) polarization converter in InP membrane is fabricated and characterized. The device relies on the beating between the two eigenmodes of chemically etched triangular waveguides. Measurements show a very high polarization conversion efficiency of >99% with insertion losses of <-1.2 dB at a wavelength of 1.53?μm. Furthermore, our design is found to be broadband and tolerant to dimension variations.     

Theoretical simulation of a polarization splitter based on dual-core soft glass PCF with micron-scale gold wire

A polarization splitter based on dual-core soft glass photonic crystal fiber(PCF) filled with micron-scale gold wire is proposed. The characteristics of the polarization splitter are studied by changing the structural parameters of the PCF and the diameter of the gold wire with the finite element method(FEM). The simulation results reveal that the coupling length ratio of the soft glass-based PCF is close to 2 and the corresponding curve is more flat than that of the silica-based PCF.The broadband bandwidth is 226 nm in which the extinction ratio is lower than-20 d B by the soft glass-based PCF, i.e.,from 1465 nm to 1691 nm which is competitive in the reported polarization splitters, and the bandwidth is just 32 nm by the silica-based PCF. The insertion loss by our polarization splitter is just 0.00248 d B and 0.43 d B at the wavelength of 1.47 μm and 1.55 μm. The birefringence is obviously increased and the coupling length is decreased by filling gold wire into the soft glass-based or the silica-based PCF. Also the birefringence based on the silica-based PCF is much larger than that based on the soft glass-based PCF whether or not the gold wire is introduced. The fabrication tolerance of the polarization splitter is also considered by changing the structural parameters. The polarization splitter possesses broad bandwidth, low insertion loss, simple structure and high fabrication tolerance.     

Polarization beam splitter with wide bandwidth in air-hole-based periodic dielectric waveguides

A polarization beam splitter with wide bandwidth and simple structure in air-hole-based periodic dielectric waveguides has been proposed and designed. Operation principle of the device is based on different directional coupling properties of beams in TE and TM polarizations in parallel periodic dielectric waveguides. Performances have been evaluated by a finite-difference time-domain simulation. Results show that the polarization beam splitter provides a wide bandwidth of 113 nm with both a high extinction ratio (higher than 21 dB) and a low insertion loss (less than 1.5 dB) for optical communication wavelengths at ∼1.55 μm. Moreover, the performances of the polarization beam splitter are insensitive to longitudinal alignment errors in the coupling region, which is desirable for device fabrication and practical application.     

Tapered fused fiber bundle coupler capable of 1 kW laser combining and 300 W laser splitting

A high efficiency 7 × 1 multimode fiber coupler using the method of fusion and tapering is reported. This coupler can be applied to combine laser power, ad it can be used as a 1 × 7 splitter with reversible simultaneously. In the experiment, for combiner, coupling output power of 1032 W is obtained with the input power of 1066 W. The total coupling efficiency is 96.8%. The average insertion loss of each input fiber is 0.14 dB at ∼150 W input power. To splitter, the sum of 7 output ports power is 294 W with the input power of 341 W, and the insertion loss is about 13.8%. This fiber coupler can be applied in pumping all-fiber double clad fiber laser, as well as power combination and splitting of fiber lasers.     

一种T形高功率微波功率合成器

提出了一种新型功率合成器,其工作原理为:通过在两个相互垂直的过模矩形波导中放置两组相互垂直的金属插板,对具有不同极化方向的矩形波导TE10模进行隔离传输,实现高功率微波的双路通道功率合成。基于这一原理初步设计了一个中心频率为9.55 GHz的功率合成器,并进行了数值模拟。模拟结果表明:这种功率合成器可以承受高功率,单通道工作时的功率容量分别大于7.31 GW和6.83 GW,中心频率上两个通道的单模功率传输效率分别达到了98%和99%,反射损耗分别小于-36 dB和-21 dB,通道之间的耦合损耗分别小于-30 dB和-45 dB。     

圆波导TM_(01)-矩形波导TE_(10)模式转换器

设计了一种高功率圆波导TM01-矩形波导TE10模式转换器,可以实现圆波导TM01模式与矩形波导TE10模式之间的相互转换。仿真结果表明:中心频率为9.7GHz时该模式转换器转换效率大于99.99%,回波损耗小于-40dB,转换效率大于90%时的带宽大于0.4GHz。调节底面短路圆波导长度可以实现模式转换器在9.2~10.1GHz范围内调谐(模式转换效率大于99%)。在圆波导和耦合段连接处引入倒角可有效降低场强,提高功率容量,注入功率0.7GW,其表面场强小于1 MV/cm。     

1.3μm光学环行器正向损耗及反向隔离比的理论及实验研究

在理论及实验上分析了影响光环行器插入损耗及反向隔离比的因素,讨论了环行器中起、检偏镜参数对其性能的影响.结果表明,起、检偏镜的各组参数存在最佳选择,以保证环行器具有低插损、高隔离比及与偏振无关的特性.作者研制的环行器正向损耗小于1dB,反向隔离比在25.5dB与28dB之间.     

Design of Multi-core Fiber Patch Panel for Space Division Multiplexing Implementations

A multi-core fiber (MCF) patch panel was designed, allowing easy coupling of individual signals to and from a 7-core MCF. The device was characterized, measuring insertion loss and cross talk, finding highest insertion loss and lowest crosstalk at 1300 nm with values of 9.7 dB and -36.5 dB respectively, while at 1600 nm insertion loss drops to 4.8 dB and crosstalk increases to -24.1 dB. Two MCF splices between the fan-in module, the MCF, and the fan-out module are included in the characterization, and splicing parameters are discussed.     

1.5-microm-band wavelength conversion based on difference-frequency generation in LiNbO3 waveguides with integrated coupling structures

We report wavelength conversion within the 1.5-mum telecommunications band based on difference-frequency generation in periodically poled lithium niobate waveguides with integrated coupling structures. A conversion efficiency of -7 dB and a normalized efficiency of 260%/W are demonstrated. Static tests show that the conversion bandwidth is 72 nm and the conversion efficiency is constant over the 20-dB range of input powers tested.     

基于十字变形结构的高效超宽带线性极化转换超表面

提出了一种基于十字变形结构超表面的极化转换器,在反射模式下获得了高效超宽带的交叉极化反射.在8.4到20.7GHz频段内交叉极化反射率大于-0.2dB,而共极化反射率小于-12dB,在谐振频率点处交叉极化反射率大于-0.03dB,而共极化反射率达到-60dB,即在谐振点处几乎可实现完全的交叉极化转换;相对带宽达84.5%,交叉极化的平均转换效率为96.7%;此外,利用电路板刻蚀制备了此极化转换器样品,实验测试其交叉极化反射率在工作频段内大于-1dB,而共极化反射率小于-10dB,实验结果与模拟结果吻合,验证了此超表面可以在超宽的频带内实现线极化电磁波的交叉极化转换.本文设计的超宽带极化转换超表面具有转换效率高和几何结构简单的优点,可被扩展到太赫兹甚至是可见光频段.     

基于TE-TM模变换的新型相位自补偿磁光隔离器

讨论了由45°非互易模变换器与45°互易模变换器构成波导型光隔离器时两者之间须满足的条件,并由此设计了一种新型的相位自补偿磁光隔离器. 利用全矢量有限差分光束传输法对隔离器进行仿真,得到了插入损耗为-12dB,隔离度为-34dB的结果. 关键词： 集成光学 磁光隔离器 非互易模变换器 互易模变换器     

All-fiber zero-insertion-loss add-drop filter for wavelength-division multiplexing

We developed and fabricated an all-fiber add-drop filter by recording a Bragg grating in the waist of an asymmetric mode converter-coupler formed by adiabatic tapering and fusing of two locally dissimilar, single-mode optical fibers. The insertion loss of the device was ~0.1 dB .A narrow spectral bandwidth (<1 nm) and a large add-drop efficiency (>90%) were also demonstrated. In addition, the filter was polarization independent.     

基于少模光纤的全光纤熔融模式选择耦合器的设计及实验研究

提出了三种基于少模光纤的全光纤熔融模式选择耦合器. 根据模式匹配原理采用单模光纤与少模光纤熔融连接方式, 运用耦合模理论及光束传播法模拟分析了模式选择耦合器的结构参数对模式选择及耦合特性的影响, 实现了单模光纤中基模到少模光纤中不同阶模式的转换, 以满足不同的应用需求. 实验上以2× 2熔融光纤耦合器为例, 采用对称和非对称熔融拉锥方式, 分别实现了从基模到LP₁₁, LP₂₁模式的转换. 实验结果表明所得到的LP₁₁, LP₂₁模式在1530–1560 nm的波长带宽范围内均有较高的模式纯净度, 且模式耦合效率高于80%, 与理论模拟结果基本一致.     

与偏振无关光隔离器的插入损耗和隔离度的理论分析与实验研究

在理论上用琼斯矩阵法得到了与偏振无关的Walk－off型光隔离器的插入损耗及反向隔离度的表达式，讨论了偏振分束器、法拉第旋转器、1／2波片的参数对其性能的影响。作者设计制作的光隔离器光纤到光纤的插入损耗为1.46dB，隔离度为34．2dB，外型尺寸为13×10×46mm3。     

Acoustooptic collinear TE-TM mode conversion in a two-layer Ti-indiffused and proton-exchanged waveguide structure in LiNbO3

Acoustooptic collinear TE-TM mode conversion was investigated in a two-layer Ti-indiffused and proton-exchanged waveguide structure in LiNbO₃. A very narrowband interaction of only 130 kHz (0.31 nm optical bandwidth) was achieved with about 25 mW acoustic power for 96% conversion efficiency. This structure is especially suitable for constructing novel-type acoustooptical gas sensors.     

S弯曲聚合物热光型可变衰减器的特性

提出一种热光聚合物可变光衰减器(VOA)的设计分析,利用S弯曲的波导提高衰减效率,BPM法模拟中验证其衰减动态范围可达60 dB,实现60 dB的衰减计算功耗为60 mW,附加弯曲损耗小于0.3 dB.并且具有很好的极化独立性,串扰低,尺寸小,易于集成.