Design and fabrication of 25-channel 200 GHz AWG based on Si nanowire waveguides

A 25-channel 200 GHz arrayed waveguide grating (AWG) based on Si nanowire waveguides is designed, simulated and fabricated. Transfer function method is used in the simulation and error analysis of AWG with width fluctuations. The 25-channel 200 GHz AWG exhibits central channel insertion loss of 6.7 dB, crosstalk of ?13 dB, and central wavelength of 1 560.55 nm. The error analysis can explain the experimental results of 25-channel 200 GHz AWG well. By using deep ultraviolet lithography (DUV) and inductively coupled plasma etching (ICP) technologies, the devices are fabricated on silicon-on-insulator (SOI) substrate. This work has been supported by the National Key Research and Development Program of China (No.2016YFB0402504), and the National Natural Science Foundation of China (Nos.61435013 and 61405188). E-mail:zhangjiashun@semi.ac.cn      

基于绝缘体上硅材料的25通道200 GHz的阵列波导光栅

报道了基于绝缘体上硅材料的25通道、信道间隔200 GHz的阵列波导光栅, 分别优化了输入波导/输出波导/阵列波导间的最小间距 (Δxi/Δxo/d) , 及其自由传播区和阵列波导之间边界结构 (W2/L2/L3) .实验结果表明, 该阵列波导光栅的插入损耗为5～7 dB, 串扰为13～15 dB, 该阵列波导光栅的性能得到有效提升.同时也提出了减小插损与串扰的进一步优化方案.     

16 channel 200 GHz arrayed waveguide grating based on Si nanowire waveguides

A 16 channel arrayed waveguide grating demultiplexer with 200 GHz channel spacing based on Si nanowire waveguides is designed.The transmission spectra response simulated by transmission function method shows that the device has channel spacing of 1.6 nm and crosstalk of 31 dB.The device is fabricated by 193 nm deep UV lithography in silicon-on-substrate.The demultiplexing characteristics are observed with crosstalk of 5-8 dB,central channel’s insertion loss of 2.2 dB,free spectral range of 24.7 nm and average channel spacing of 1.475 nm.The cause of the spectral distortion is analyzed specifically.     

基于硅纳米线波导的16通道200GHz阵列波导光栅

设计了基于硅纳米线波导的16通道,通道间隔为200GHz的阵列波导光栅(AWG)。传输函数法模拟了器件传输谱,结果表明器件的通道间隔为1.6nm,通道间串扰为31dB。器件利用SOI材料,由193nm深紫外光刻工艺制备。光谱测试结果分析表明,通道串扰为5-8dB,中心通道损耗2.2dB,自由光谱区长度24.7nm,平均信道间隔1.475nm。详细分析了器件谱线畸变的原因。     

基于Si纳米线AWG的超紧凑单纤三向滤波器设计

采用绝缘层上Si(SOI)纳米线阵列波导光栅(AWG)结构设计了超紧凑光纤到户(FTTH)单纤三向滤波器。二维时域有限差分(2D-FDTD)模拟输出光场表明,3个波长光信号输出光场清晰,实现了1490 nm和1550nm下行波长的解复用和1310 nm波长的上传复用功能;进一步的输出功率模拟表明,当各波长信号输入功率为1 mW时,1490 nm端口输出功率为0.49 mW,1550 nm端口输出功率为0.49 mW,1310 nm上传信号功率为0.55 mW,相应的插入损耗分别约为-3.1、-3.1和-2.6 dB。各端口的串扰光功率可被抑制到-25.2 dBm以下,相应的串扰小于-22.6 dB。采用电子束(EB)光刻结合诱导耦合等离子干法(ICP-RIE)刻蚀,制备出了Si纳米线单纤三向滤波器,经红外CCD成像观察到器件具有3个波长的分波功能。     

128-channel polarization-insensitive frequency-selection-switchusing high-silica waveguides on Si

A 128-channel polarization-insensitive frequency-selection-switch (FS-SW) with 10-GHz frequency spacing is discussed. The FS-SW was fabricated on Si using low-loss GeO₂-doped high-silica waveguides, and its frequency-insensitive operation was attained by the laser trimming adjustment of a-Si film which controls waveguide birefringence. The fiber-to-fiber loss of the transmitted channel was 6.7 dB in the pigtailed FS-SW and the total crosstalk level was less than -13 dB. By using this FS-SW, a 100-channel optical frequency division multiplexing (FDM) transmission-distribution experiment at 622 M b/s over a 50-km fiber length was achieved     

Design and fabrication of ultra-small overlapped AWG demultiplexer based on /spl alpha/-Si nanowire waveguides

A novel layout for an ultra-compact arrayed-waveguide grating (AWG) demultiplexer is presented. The present layout has two overlapped free propagation regions, and is more compact than a conventional layout. Using /spl alpha/Si-on-SiO/sub 2/ nanowire waveguides, an ultra-small 4/spl times/4 AWG (about 40/spl times/50 /spl mu/m/sup 2/) with channel spacing of 11 nm is fabricated and characterised.     

400-channel arrayed-waveguide grating with 25 GHz spacing using1.5%-Δ waveguides on 6-inch Si wafer

A large-scale arrayed-waveguide grating with a 400-channel and 25 GHz spacing using 1.5%-Δ silica-based waveguides on a 6-inch Si wafer has been realised. Good demultiplexing properties have been obtained over the full Cand L-band range with an on-chip loss of 3.8 to 6.4 dB and a far-end crosstalk of -30 dB     

Design and fabrication of ultrasmall arrayed waveguide grating multiplexers based on Si nanowire waveguides

In the past decades, integrated optical devices based on planar lightwave circuits (PLCs) have been developed rap- idly and used in various areas, such as optical communications, optical sensing and, etc. Because of their excellent performances and the feasibility for massive productions, PLC-based integrated optical devices may take the place of discrete devices more and more in the future. In order to satisfy the increasing demands of the optical net- works with a large capacity and high s…     

50/100GHz AWG型光学梳状滤波器的设计与制备

以Si基SiO2平面光波导为基础,设计并制备了50/100GHz AWG型光学梳状滤波器．制备得到的AWG型光学梳状滤波器可以覆盖1520～1585nm的波长范围,共有160个信道．功率输出不均匀度＜0.5dB,插入损耗＜8dB,相邻通道的串扰＞13dB,在距离中心频率最远的信道,输出频率偏离ITU标准15GHz．分析了影响器件串扰和信道频率偏移的原因,并提出了相应的解决办法．     

50/100GHz AWG型光学梳状滤波器的设计与制备

以Si基SiO2平面光波导为基础,设计并制备了50/100GHz AWG型光学梳状滤波器.制备得到的AWG型光学梳状滤波器可以覆盖1520～1585nm的波长范围,共有160个信道.功率输出不均匀度＜0.5dB,插入损耗＜8dB,相邻通道的串扰＞13dB,在距离中心频率最远的信道,输出频率偏离ITU标准15GHz.分析了影响器件串扰和信道频率偏移的原因,并提出了相应的解决办法.     

100 GHz Binary counter based on DC SQUID's

A binary counter using bistable dc SQUID's as flip flop circuits is demonstrated. All of the functions: LOAD, COUNT, STORE, READ, and CLEAR can be performed. The use of single flux quantum logic results in high sensitivity (10^-18J input pulse energy), high speed (100 GHz count rate) and low power (10^-7W at 100 GHz count rate).     

Design of ultra-compact wavelength splitter based on lithium niobate nanowire optical waveguides

A wavelength splitter with ultra-compact and simple structure is proposed and analyzed by using both plane wave expansion(PWE) method and finite difference time domain(FDTD) method.The device is based on directional coupling between two parallel lithium niobate(LiNbO3,LN) nanowire optical waveguides.The wavelength splitter with a coupling region length of 5 μm can separate 1.31μm and 1.55 μm wavelengths for corresponding outputs with transmittance higher than 97%.     

银纳米线表面等离子体波导的传输损耗特性研究

通过远场聚焦光斑激发银纳米线表面等离子体激元(SPP: Surface Plasmon Polariton),并搭建银纳米线路由传输结构改变SPP的传输距离,研究了SPP的传输损耗特性。实验上测量了置于玻璃衬底表面的银纳米线在不同激发波长时SPP的传输损耗系数,发现SPP的传输损耗具有波长依赖性：632.8nm激光激发时,传输损耗系数为0.115 ,780nm激光激发时,传输损耗系数为0.0923 ,即传输损耗系数在长波激发时小,而在短波激发时大。测量结果对基于银纳米线波导的集成微纳光学系统设计有很好的指导作用。     

Effect of growth conditions on zinc oxide nanowire array synthesized on Si (100) without catalyst

A uniformly distributed ZnO nanowire array has been grown on silicon (100) substrates by catalyst-free chemical vapor transport and condensation. The effect of growth conditions including source heating temperature, substrate temperature, and gas flow rate on growth properties of ZnO nanowire arrays are studied. Scanning electron microscopy, X-ray diffraction, and room temperature photoluminescence are employed to study the structural features and optical properties of the samples. The results show a correlation among experimental growth parameters. There is a zone for substrate temperature, by controlling gas flow rate, that uniformly distributed and well aligned ZnO nanowire arrays can be grown. Also, experiments indicate that ZnO nanowire arrays with different diameter along their length have been formed under various growth conditions in the same distance from source material. It is found that supersaturation is a crucial parameter determining the growth behavior of ZnO nanowire arrays. The growth mechanism of ZnO nanowires is discussed. The room temperature photoluminescence spectrums of ZnO nanowire array show two emission bands. One is the exciton emission band (centered at 380 nm) and the other is a broad visible emission band centered at around 490 nm. As the substrate temperature decreases, the intensity of UV emission increases while the intensity of visible emission peak decreases.     

Porous SiC layers on Si nanowire surface

The preparation method and characterization data are described for porous SiC layers grown on the surface of porous silicon (P-Si) wires. Raman scattering spectroscopy, energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM) were employed for the characterization. It is shown that in the first approximation, the wire structure of the porous SiC repeats the surface morphology of the porous Si. Some peculiarities of P-SiC surface structure were also observed whose connection with the P-Si surface is not yet clarified. The study of the Raman spectra has permitted to determine the crystalline structure (polytypes) for the SiC layers and shown a feature specific for nano-crystallite materials, which has been analyzed and discussed.     

A Low Noise 100 GHz Sideband-Separating Receiver

We have built a 100 GHz sideband-separating receiver. The receiver, a breadboard for the band 3 cartridges for ALMA, achieves a SSB noise temperature of 6hf/k with a 4–8 GHz IF. We show that it is possible to meet the ALMA specifications. The design of the receiver is reviewed and the relationships between the receiver noise temperature and properties of the components used in the receiver are discussed.     

High efficiency n-ZnO/p-Si core–shell nanowire photodiode based on well-ordered Si nanowire array with smooth surface

A highly efficient n-ZnO/p-Si core–shell nanowire (NW) photodiode was fabricated using ZnO grown by atomic layer deposition (ALD) on a well-ordered Si NW array. Si NW arrays were prepared by metal-assisted chemical etching, for which a metal mesh with a well-organized nanohole array was made using anodic aluminum oxide. This resulted in a good arrangement, smooth surface, and small diameter distribution of the Si NW array. Consequently, ZnO layers with various thicknesses from 15 to 30 nm were deposited by the ALD method. Because of the smooth surface of the well-ordered Si NWs yielding low surface roughness scattering, the resulting photodiode showed significantly improved device characteristics.     

Vertically integrated high-silica channel waveguides on Si

For the first time the vertical integration of high-silica content low-loss channel waveguide on an Si substrate is reported. The fabrication process, which has made the vertical integration feasible, consists of a practical multistep combination of flame hydrolysis deposition (FHD), photolithographic patterning and reactive ion etching. The successful application to a double integration of singlemode waveguides at 1.55 mu m is also reported. This result, which has been possible thanks to the FHD peculiarities, by extending the optical interaction to a third dimension, opens a wide range of original and promising applications, such as vertically coupled devices or parallel optical signal processors, and it effectively increases the density of optical guided-wave functions available on the same substrate.<>     

A 100 kW, 140 GHz pulsed gyrotron

The design and operation of a 100 kW, 140 GHz pulsed gyrotron are reported. To our knowledge, this is the highest frequency at which high gyrotron output power (>-100 kW) has been achieved. Results are presented for gyrotron operation in the range of magnetic field from 4 to 7 T, voltage from 23 to 80 kV and current up to 7.5 A. Near a value of magnetic field of 5.4 T, and output power of 100 kW was obtained at 140.4 GHz in single mode operation in the TE₀₃₁ resonator mode.