聚合物微型谐振环波分复用器

研制出用于现代光通信密集波分复用（DWDM）系统的微型谐振环波分复用器（MRRWM）。微环与信道波导采用垂直耦合的方式,利用耦合模理论对器件参数进行了优化设计,设计出模板,并研制出符合器件光学性能要求的聚合物材料。利用反应离子刻蚀技术完成了硅基板上单级和八级的器件制作,波分复用器的中心波长为1．55μm,输出波长间隔Δλ=1．6nm,中心微环半径R=131．95μm,相邻微环半径差ΔR=500．0nm,器件测试结果表明实现了微环谐振输出。     

基于绝缘硅的微环谐振可调谐滤波器

采用电子束光刻和感应耦合等离子刻蚀等工艺,研制了一种基于绝缘硅材料的的微环谐振可调谐滤波器.滤波器微环半径为5μm左右,波导截面尺寸为(350～500 nm)×220 nm不等.测试结果表明,波导宽度为450 nm时器件性能最为理想,其自由频谱宽度为16.8 nm,1.55μm波长附近的消光比为22.1 dB.通过对微...     

聚合物波导微环谐振器的无热化设计

从波导微环谐振器的谐振方程出发,推导出了波导微环谐振器的无热化条件和谐振波长温度依赖特性表达式,分析了硅衬底PSQ聚合物波导微环谐振器滤波功能的温度特性。通过选择合适的聚合物衬底来取代传统的硅衬底,可极大地减小聚合物波导微环谐振器的温度敏感性,给出了聚合物衬底选择的方法。研究结果表明,所设计的全聚合物波导微环谐振器,在温度从20～65℃范围内谐振波长漂移量最大值为-0.0085 nm,温度依赖波长漂移率最大值为-0.00090 nm/K,实现了无热化。     

基于绝缘硅的微环谐振可调谐滤波器

采用电子束光刻和感应耦合等离子刻蚀等工艺,研制了一种基于绝缘硅材料的的微环谐振可调谐滤波器.滤波器微环半径为5 μm左右,波导截面尺寸为(350～500 nm)×220 nm不等.测试结果表明,波导宽度为450 nm时器件性能最为理想,其自由频谱宽度为16.8 nm,1.55 μm波长附近的消光比为22.1 dB.通过对微环滤波器进行热光调制,在21.4 ℃～60 ℃温度范围内实现了4.8 nm波长范围的可调谐滤波特性,热光调谐效率达到0.12 nm/℃.研究了基于单环和双环的多通道上下载滤波器,实验结果表明多通道滤波器的信号传输存在串扰,主要是不同信道之间的串扰,尤其在信号上载时,会在相邻信道产生较大串扰.     

SOI多环级联光学谐振腔滤波器

利用MEMS工艺制备了基于SOI的小尺寸、高集成光波导多环级联谐振腔滤波器,理论分析了多环级联微环腔的光场传输特性与光谱响应特性,实验验证并得到了不同级联环数与谐振谱线滚降垂直度的关系。研究表明:当波导宽度为450 nm、半径为5μm时,单环、双环和十环滤波器响应谱线的-3 dB带宽分别为0.313,0.279,0.239 nm,相应结果与理论吻合,即随着级联环数的增多,谐振谱线顶端趋于平坦,滚降垂直度增高。设计制备了环形与跑道形两种级联谐振腔滤波器,研究了相应的透射谱特性。     

聚合物微环谐振波分复用器传输特性的理论分析

根据耦合模理论,给出了1×N信道微环谐振波分复用器(MRRWM)的光强传递函数通用公式,并分析了微环谐振波分复用器的传输特性。利用参量优化结果,在中心工作波长约为 1.55μm、波长间隔约 5.6 nm的情况下,对1×8信道硅基聚合物微环谐振波分复用器进行了数值模拟。计算结果表明,该器件具有以下优良的性能:分波光谱准确,自由光谱区约为18 nm,对于半径10μm以上的微环弯曲损耗很小,且器件的插入损耗主要由波导的传输损耗决定,振幅耦合比率为0.2时对应的每条竖直输出信道的插入损耗在0.57 dB以下,信道间的串扰小于-18.5 dB,输出谐振峰3 dB带宽可达0.25 nm,最小背景光的强度约为3.8×10-4。     

自由光谱范围加倍的单微环谐振滤波器

基于两点耦合和光波干涉控制相移思想提出U型波导耦合单微环的谐振滤波器结构。利用传输矩阵法推导了此结构的数学模型,采用Matlab模拟了输出端口谱线形状。当微环与U型波导的两个耦合点之间的距离为微环周长的整数倍时,此新型微环谐振滤波器比传统的双直波导耦合单微环滤波器的自由光谱范围增加1倍。针对该结构参数,同时讨论了耦合系数对输出谱线的影响,得出当耦合系数为0.018时,输出谱线具有最佳的消光比,同时保持窄的带宽和高的品质因子。     

硅基槽式微环谐振腔型偏振解复用器全矢量分析

提出一种紧凑型偏振解复用器, 其中两条常规硅基波导作为输入/输出信号通道, 居于其中的槽式微环谐振腔用于偏振态/波长选择组件. 采用全矢量频域有限差分法详细分析了硅基常规及槽波导的模式特性, 结果发现其横磁模的模场布及其有效折射率相似, 而其横电模相应的特性则差异明显, 结果输入横磁模能够在谐振工作波长下从下路端口输出, 而输入横电模与微环耦合可以忽略, 直接从直通端口输出, 从而实现两偏振态的高效分离. 采用全矢量时域有限差分法详细分析了该偏振解复用器的光波传输特性, 结果表明, 当微环半径为3.489 μm时, 在1.55 μm工作波长下, 横磁模与横电模的消光比与插入损耗分别为 ～ 26.12 (36.67) dB与 ～ 0.49 (0.09) dB. 另外, 论文详细讨论了器件关键结构参数的制作容差, 并给出了输入模场在器件中的传输演变情况.     

一种热光可调谐级联微环滤波器的理论分析

根据Vernier效应可大幅度提高滤波器自由光谱范围和调谐范围,设计了一种热光可调谐级联微环滤波器. 利用传输矩阵方法和有限元方法从理论上计算了对于第一级微环半径为48 μm,第二级半径为50 μm的级联微环滤波器的自由光谱范围和调谐范围可以达到75.6 nm,而功耗仅为103.1 mW,这是目前为止我们 所知的基于微环谐振腔的硅基热光可调谐滤波器中最大的自由光谱范围和在如此低功耗下最大的调谐范围. 利用有限元方法,还计算了半径为50 μm微环的热光调谐响应时间,上升沿时间为3.5 μs,下降沿时间仅为0.8 μs.     

聚合物串联耦合双环电光开关的优化

利用耦合模理论、电光调制理论和微环谐振理论,提出一个聚合物串联耦合双环电光开关器件模型,在1.55 μm谐振波长下对该器件进行了模拟和优化.结果为：微环波导芯截面尺寸为1.6×1.6 μm2,波导芯与电极间的限制层厚度为1.6 μm,电极厚度为0.15 μm,微环半径为15.2 μm,微环与信道间的耦合间距为0.14 μm,微环与微环间的耦合间距为0.6 μm,输出光谱的3 dB带宽约为0.06 nm,开关电压约为6 V左右,插入损耗约为2.2 dB,串扰约为－20 dB.所设计的双环电光开关较单环型电光开关不仅输出光谱更加平坦陡峭,非谐振光更弱,而且开关电压更低.     

High-performance and fabrication friendly polarization demultiplexer

A compact and fabrication friendly polarization demultiplexer (P-DEMUX) is proposed and characterized to enable wavelength-division-multiplexing and polarization-division-multiplexing simultaneously. The proposed structure is composed of a polarization-selective microring resonator in ultrathin waveguide and two bus channels in the silicon nitride-silica-silicon horizontal slot waveguides. In the slot waveguide, the transverse electric (TE) mode propagates through the silicon layer, while the transverse magnetic (TM) mode is confined in the slot region. In the designed ultra-thin waveguide, the TM mode is cut-off. The effective indexes of the TE modes for ultrathin and slot waveguides have comparable values. Thanks for these distinguishing features, the input TE mode can be efficiently filtered through the ultra-thin microring at the resonant wavelength, while the TM mode can directly output from the through port. Simulation results show that the extinction ratio of the proposed P-DEMUX for TE and TM modes are 33.21 dB and 24.97 dB, and the insertion losses are 0.346 dB and 0.324 dB, respectively, at the wavelength of 1551.64 nm. Furthermore, the device shows a broad bandwidth ($>100$ nm) for an extinction ratio (ER) of $>20$ dB. In addition, the proposed P-DEMUX also has a good fabrication tolerance for the waveguide width variation of $-20$ nm$\le \Delta w_{\rm g}\le 20$ nm and the microring width variation of $-20$ nm$\le \Delta w_{\rm r}\le $20 nm for a low insertion loss of $<0.75$ dB and low ER of $<-18$ dB.     

Towards athermal optically-interconnected computing system using slotted silicon microring resonators and RF-photonic comb generation

We report that completely athermal design of a slotted silicon waveguide is possible by combining the negative thermo-optic (TO) coefficient of, for example, polymethyl methacrylate (PMMA) with the positive TO coefficient of silicon. When used in a microring resonator structure, the filled overcladding slotted waveguide and the unfilled (air-filled) overcladding slotted waveguide can both achieve athermal characteristics. Simulations indicate a wide range of realizations with proper design parameters of the slotted waveguides, namely, the silicon strip and slot widths. Preliminary experimental results on fabricated devices demonstrate that the temperature dependence is reduced from 91 pm/°C for a regular microring resonator to 52 pm/°C for the PMMA-clad microring resonator. Completely athermal realization is expectable in similar devices with improved fabrication techniques. For the external optical source, we demonstrate a stable 3.5 THz wide (175 modes×20 GHz) optical comb source with nearly flat spectral phase. Adjustable mode spacing and wavelength tunability across the C-band are maintained so that comb lines can be matched to the specified wavelength grid of the computing system. With such schemes, temperature controls of individual optical components in the optically interconnected computing chips become unnecessary, greatly reducing the complexity of the computing system.     

Modeling and analysis of silicon-on-insulator elliptical microring resonators for future high-density integrated photonic circuits

We propose a novel resonator containing an elliptical microring based on a silicon-on-insulator platform. Simulations using the three-dimensional finite-difference time-domain method show that the novel elliptical microring can efficiently enhance the mode coupling between straight bus waveguides and resonator waveguides or between adjacent resonators while preserving relatively high intrinsic quality factors with large free spectral range. The proposed resonator would be an alternative choice for future high-density integrated photonic circuits.     

基于硅基二氧化硅阵列波导光栅宽带低串扰单纤三向器

采用硅基二氧化硅阵列波导光栅设计并制作了宽带低串扰单纤三向器.为使三个波长间隔相差较大的输出谱获得相同的带宽,在输出波导与罗兰圆交界采用了不同结构的多模干涉器.二维有限差分束传播法的模拟结果表明,理论上1310nm、1490nm和1550nm波长的3dB带宽分别达到23nm、23.5nm和25nm,插入损耗均为4dB,1310nm波长的串扰小于-40dB,1490nm与1550nm波长间串扰小于-40dB;采用宽带光源测试结果表明,1550nm波长的3dB带宽为23nm,采用三个独立窄带光源测试结果表明,三个波长的插入损耗均为7dB,1310nm波长的串扰小于-40dB,1490nm与1550nm波长间的串扰小于-39dB,测试与模拟结果基本一致.     

Slotted Photonic Crystal Microring Resonators

We propose using a slotted photonic crystal nanobeam to construct a microring resonator. The transmission characteristics of the slotted photonic crystal nanobeam and the microring resonator are demonstrated by two-dimensional finite-difference time-domain simulation, and the mechanism of these characteristics is analyzed considering the introduction of the slot. The refractive index sensitivity of the slotted photonic crystal microring resonator is evaluated to be larger than those of a slot waveguide microring resonator and a nonslotted photonic crystal microring resonator.     

Slotted microcavity ring resonators for optical storage applications

In this paper, slotted microcavity ring resonators based optical storage devices are proposed and analyzed by means of multiresolution time domain technique. The effect of the structure geometrical parameters on the coupling efficiency, normalized transmission spectra and quality factor has been thoroughly investigated and compared to that of the conventional no-slot microring resonator. The suggested slotted configurations increase the quality factor at a fixed gap size between the central ring and input/output waveguides. In addition, the desired compromise between the coupling efficiency and resonance effect inside the ring can be achieved by mere optimization of the slot geometrical characteristics.     

Photonic microring resonator modulated resonance response analysis

This paper presents the resonance response analysis of a photonic microring resonator. It covers the mathematical as well as simulation analysis on the modulated signals. The mathematical formulation provides a relation of several microring resonator parameters that could potentially affect the ring resonator performances. The simulation shows a graphical representation of the ring resonator full-width at half-max, quality factor (Q-factor) as well as the depth of the resonance at different modulation voltages applied to the ring. Several parameters have also been altered which is the ring radius, the coupling coefficient of the waveguides as well as the waveguide material group index. With this investigation, we determine the possible cause of the change in Q factor of a silicon microring resonator when the resonance is modulated and the possible solution to minimize the problem.     

1×|N 信道聚合物微环谐振器电光开关阵列的开关特性

利用耦合模理论、电光调制理论和微环谐振理论,提出了一个完善合理的聚合物微环谐振器电光开关阵列模型.该器件由1条水平信道、N条竖直信道和N个微环构成,在微环上施加不同方式的驱动电压,可以实现N＋1条信道的开关功能.以1×8信道结构为例,在1 550 nm谐振波长下对该器件进行了优化设计和模拟分析.其结果是：微环波导芯的截面尺寸为1.7×1.7 μm2,波导芯与电极间的缓冲层厚度为2.5 μm,电极厚度为0.2 μm,微环半径为13.76 μm,微环与信道间的耦合间距为0.14 μm,输出光谱的3 dB带宽约为0.05 nm,开关电压约为12.6 V,插入损耗约为0.67~1.26 dB,串扰小于－20 dB,开关时间约为11.35 ps.