Since the first observation of parity-time（PT） symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, whi...Since the first observation of parity-time（PT） symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, which turns PT-symmetric optics into a hotspot in research. Here, we report on the one-way localized Fabry-Pérot（FP） resonance, where a welldesigned PT optical resonator may operate at exceptional points with bidirectional transparency but unidirectional field localization. Overtones of such one-way localized FP resonance can be classified into a blue shifted branch and a red shifted branch. Therefore, the fundamental resonant frequency is not the lowest one. We find that the spatial field distributions of the overtones at the same absolute order are almost the same, even though their frequencies are quite different.展开更多
Grating couplers are widely investigated as coupling interfaces between silicon-on-insulator waveguides and optical fibers.In this work,a high-efficiency and complementary metal-oxide-semiconductor（CMOS） process com...Grating couplers are widely investigated as coupling interfaces between silicon-on-insulator waveguides and optical fibers.In this work,a high-efficiency and complementary metal-oxide-semiconductor（CMOS） process compatible grating coupler is proposed.The poly-Si layer used as a gate in the CMOS metal-oxide-semiconductor field effect transistor（MOSFET） is combined with a normal fully etched grating coupler,which greatly enhances its coupling efficiency.With optimal structure parameters,a coupling efficiency can reach as high as ～ 70% at a wavelength of 1550 nm as indicated by simulation.From the angle of fabrication,all masks and etching steps are shared between MOSFETs and grating couplers,thereby making the high performance grating couplers easily integrated with CMOS circuits.Fabrication errors such as alignment shift are also simulated,showing that the device is quite tolerant in fabrication.展开更多
We report a self-collimating demonstration in planar photonic crystals （PhCs） fabricated in silicon-on-insulator （SOI） wafers using 0.18 μm silicon complimentary metal oxide semiconductor （CMOS） techniques. The...We report a self-collimating demonstration in planar photonic crystals （PhCs） fabricated in silicon-on-insulator （SOI） wafers using 0.18 μm silicon complimentary metal oxide semiconductor （CMOS） techniques. The emphasis was on demonstrating the self-collimation effect by using the standard CMOS equipment and process development of an optical test chip using a high-volume manufacturing facility. The PhCs are designed on the 230-nm-top-Si layer using a square lattice of air holes 280 nm in diameter. The lattice constant of the PhCs is 380 nm. The experimentally obtained wavelengths for self-collimation are in excellent agreement with theory.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674119,11404125,and 11574389)the financial support from the Bird Nest Plan of HUST,Chinasupported by One Hundred-Talent Plan of Chinese Academy of Sciences
文摘Since the first observation of parity-time（PT） symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, which turns PT-symmetric optics into a hotspot in research. Here, we report on the one-way localized Fabry-Pérot（FP） resonance, where a welldesigned PT optical resonator may operate at exceptional points with bidirectional transparency but unidirectional field localization. Overtones of such one-way localized FP resonance can be classified into a blue shifted branch and a red shifted branch. Therefore, the fundamental resonant frequency is not the lowest one. We find that the spatial field distributions of the overtones at the same absolute order are almost the same, even though their frequencies are quite different.
基金Project supported by the Natural Science Foundation of Shanghai,China (Grant No. 11ZR1443700)the Funds from the Science and Technology Commission of Shanghai Municipality,China (Grant Nos. 10DJ1400400 and 10706200500)the National Natural Science Foundation of China (Grant No. 61106051)
文摘Grating couplers are widely investigated as coupling interfaces between silicon-on-insulator waveguides and optical fibers.In this work,a high-efficiency and complementary metal-oxide-semiconductor（CMOS） process compatible grating coupler is proposed.The poly-Si layer used as a gate in the CMOS metal-oxide-semiconductor field effect transistor（MOSFET） is combined with a normal fully etched grating coupler,which greatly enhances its coupling efficiency.With optimal structure parameters,a coupling efficiency can reach as high as ～ 70% at a wavelength of 1550 nm as indicated by simulation.From the angle of fabrication,all masks and etching steps are shared between MOSFETs and grating couplers,thereby making the high performance grating couplers easily integrated with CMOS circuits.Fabrication errors such as alignment shift are also simulated,showing that the device is quite tolerant in fabrication.
基金Supported by the National Natural Science Foundation of China under Grant No 60721004, and the Shanghai Institute of Microsystern and Information Technology Fund for Young Scholars.
文摘We report a self-collimating demonstration in planar photonic crystals （PhCs） fabricated in silicon-on-insulator （SOI） wafers using 0.18 μm silicon complimentary metal oxide semiconductor （CMOS） techniques. The emphasis was on demonstrating the self-collimation effect by using the standard CMOS equipment and process development of an optical test chip using a high-volume manufacturing facility. The PhCs are designed on the 230-nm-top-Si layer using a square lattice of air holes 280 nm in diameter. The lattice constant of the PhCs is 380 nm. The experimentally obtained wavelengths for self-collimation are in excellent agreement with theory.
