High efficiency and broad bandwidth grating coupler between nanophotonic waveguide and fibre

A high efficiency and broad bandwidth grating coupler between a silicon-on-insulator (SOI) nanophotonic waveguide and fibre is designed and fabricated. Coupling efficiencies of 46\% and 25\% at a wavelength of 1.55~μ m are achieved by simulation and experiment, respectively. An optical 3~dB bandwidth of 45~nm from 1530~nm to 1575~nm is also obtained in experiment. Numerical calculation shows that a tolerance to fabrication error of 10~nm in etch depth is achievable. The measurement results indicate that the alignment error of ±2~μ m results in less than 1~dB additional coupling loss.     

BPM-FSRM混合法分析SOI脊形波导与光纤耦合

用束传播-自由空间辐射模（BPM-FSRM）混合法计算了SOI脊形波导和光纤耦合时的透射率, 提出计算反射率的积分公式. 将该混合法和一般FSRM、菲涅尔公式-重叠积分法的计算结果相比较, 提出只有在弱导条件下, 传统的菲涅尔公式法和重叠积分法才可以同时使用.     

硅基光子集成研究进展

报道了国际上关于硅基光子集成的最新研究进展和本课题组在该领域的研究成果,包括对一些光收发模块、III-V族/硅基激光器等集成器件的结构改进和工艺的探索,展示了兼容互补金属氧化物半导体工艺的硅基光子集成在信息技术领域中的巨大前景.可以预见,硅基光子集成已成为硅光子学的主要研究内容,硅光子学及硅基光子集成的发展目标是趋向更高速率、更低功耗及更大集成密度.     

High-efficiency focusing grating coupler with optimized ultra-short taper

A novel high-efficiency focusing non-uniform grating coupler is proposed to couple light into or off silicon photonic chips for large-scale silicon photonic integration. This kind of grating coupler decreases the transition length of the linking taper between the grating and the single-mode waveguide by at least 80%. The radian of the grating lines and the size of the taper are optimized to improve the coupling efficiency. An experimental coupling efficiency of ~ 68% at 1556.24 nm is obtained after optimization and the whole size of the grating is 12 μm × 30 μm, with a very short taper transition of ~15 μm long.     

A Two-Dimensional Photonic Crystal Slab Mirror with Silicon on Insulator for Wavelength 1.3μm

A concrete two-dimensional photonic crystal slab with triangular lattice used as a mirror for the light at wavelength 1.3μm with a silicon-on-insulator （SOI） substrate is designed by the three-dimensional plane wave expansion method. For TE-like modes, the bandgap in the Г-K direction is from 1087nm to 1559nm. The central wavelength in the bandgap is about 1.3μm, hence the incident light at wavelength 1.3μm will be strongly reflected. Experimentally, such a photonic crystal slab is fabricated on an SOI substrate by the combination of EBL and ICP etching. The measurement of its transmission characteristics shows the bandgap edge in a longer wavelength is about 1540 nm. The little discrepancy between the experimental data and the theoretical values is mainly due to the size discrepancy of the fabricated air holes.     

一种分析三维楔脊形光波导与光纤耦合的方法

和直波导的不同在于，三维楔脊形波导中的光场都是不稳定的.分别对波导-光纤耦合、光纤-波导耦合两种情况，将三维楔脊形波导等效为多段短的直波导，利用束传播法同时对三维楔脊形波导内不稳定的入射、反射场，及它们在传播方向上的偏导进行处理，再用自由空间辐射模法计算透射率和反射率.以SOI楔脊形波导和光纤的耦合为例，验证了该方法的可行性. 关键词： 自由空间辐射模法 束传播法 耦合 透射 楔脊形光波导 绝缘体上硅(SOI)     

Sub-nanosecond silicon-on-insulator optical micro-ring switch with low crosstalk

<正>We demonstrate a sub-nanosecond electro-optical switch with low crosstalk in a silicon-on-insulator(SOI) dual-coupled micro-ring embedded with p-i-n diodes.A crosstalk of -23 dB is obtained in the 20-μm-radius micro-ring with the well-designing asymmetric dual-coupling structure.By optimizations of the doping profiles and the fabrication processes,the sub-nanosecond switch-on/off time of400 ps is finally realized under an electrical pre-emphasized driving signal.This compact and fast-response micro-ring switch,which can be fabricated by complementary metal oxide semiconductor(CMOS) compatible technologies,have enormous potential in optical interconnects of multicore networks-on-chip.     

Wafer-Level Testable High-Speed Silicon Microring Modulator Integrated with Grating Couplers

A wafer-level testable silicon-on-insulator-based microring modulator is demonstrated with high modulation speed, to which the grating couplers are integrated as the fiber-to-chip interfaces. Cost-efflcient fabrications are realized with the help of optical structure and etching depth designs. Grating couplers and waveguides are patterned and etched together with the same slab thickness. Finally we obtain a 3-dB coupling bandwidth of about 6Ohm and 10 Gb/s nonreturn-to-zero modulation by wafer-level optical and electrical measurements.     

一种改进的2×2 SOI Mach-Zehnder热光开关

本文设计并制作了基于强限制多模干涉耦合器的2×2 SOI马赫-曾德热光开关.这种光开关采用了深刻蚀结构的多模干涉耦合器和输入/输出波导,较大地提高了干涉耦合器的性能并减少了连接耦合损耗.同时,在调制臂区域采用浅刻蚀结构,保持其单模调制状态.深刻蚀多模干涉耦合器具有优越的特性,在实验中测得不均衡度只有0.03 dB,插入损耗－0.6 dB.基于这种耦合器的新型热光开关,其插入损耗为－6.8 dB,其中包括光纤-波导耦合损耗－4.3 dB,开关时间为6.8 μs.     

A comparison of silicon oxide and nitride as host matrices on the photoluminescence from Er+ ions

This paper compares the properties of silicon oxide and nitride as host matrices for Er ions.Erbium-doped silicon nitride films were deposited by a plasma-enhanced chemical-vapour deposition system.After deposition,the films were implanted with Er3+ at different doses.Er-doped thermal grown silicon oxide films were prepared at the same time as references.Photoluminescence features of Er3+ were inspected systematically.It is found that silicon nitride films are suitable for high concentration doping and the thermal quenching effect is not severe.However,a very high annealing temperature up to 1200° C is needed to optically activate Er3+,which may be the main obstacle to impede the application of Er-doped silicon nitride.