The effect of longitudinal-offset radiating slots on a centered-inclined feeding slot in the common broad wall of the two crossed rectangular waveguides is analysed quantitatively. The corresponding equivalent paramet...The effect of longitudinal-offset radiating slots on a centered-inclined feeding slot in the common broad wall of the two crossed rectangular waveguides is analysed quantitatively. The corresponding equivalent parameters are computed by employing the moment method. The numerical results of resonant length of the feeding slot, VSWR and coupling parameter are showed and compared with the case of no radiating slots and short-end. The agreement between theory and experiment is good.展开更多
We study the spontaneous emission(SE) of an excited nonrelativistic two-level system(TLS) interacting with the vacuum in a waveguide of rectangular cross section. All TLS’s transitions and the center-of-mass motion o...We study the spontaneous emission(SE) of an excited nonrelativistic two-level system(TLS) interacting with the vacuum in a waveguide of rectangular cross section. All TLS’s transitions and the center-of-mass motion of the TLS are taken into account. The SE rate and the carried frequency of the emitted photon for the TLS initially being at rest are obtained, it is found that in the first order of the mass M, the frequency of the emitted photon is smaller than the transition frequency of the TLS and the SE rate is smaller than the SE rate Γfof the TLS fixed in the same waveguide. The SE rate for the TLS initially being moving is obtained in the second order of the mass M. The SE rate is smaller than Γfbut it is dependent not only on the atomic mass but also on the initial momentum. The carried frequency of the emitted photon is decreased when it travels along the direction of the initial momentum, whereas it is increased when it travels in the opposite direction of the initial momentum.展开更多
We study that the different-mode(waveguide-connected)power splitter[(W)PS]can provide different-mode testing points for the optical testing.With the PS or WPS providing two different-mode testing points,the measured i...We study that the different-mode(waveguide-connected)power splitter[(W)PS]can provide different-mode testing points for the optical testing.With the PS or WPS providing two different-mode testing points,the measured insertion losses(ILs)of the three-channel and dual-mode waveguide crossing(WC)for both the fundamental transverse electric(TE0)and TE1 modes are less than 1.8 dB or 1.9 dB from 1540 nm to 1560 nm.At the same time,the crosstalks(CTs)are lower than-17.4 dB or-18.2 dB.The consistent test results indicate the accuracy of the(W)PS-based testing circuit.Additionally,combining the tunable tap couplers,the(W)PS can provide multiple testing points with different modes and different transmittances.展开更多
With the increasing demand for optical interconnect communication capacity,waveguide crossings are crucial for highdensity photonic integrated circuits(PICs),especially for mode-division multiplexing(MDM)systems.Howev...With the increasing demand for optical interconnect communication capacity,waveguide crossings are crucial for highdensity photonic integrated circuits(PICs),especially for mode-division multiplexing(MDM)systems.However,designing multimode waveguide crossings on anisotropic platforms like lithium niobate on insulator(LNOI)remains challenging due to refractive index anisotropy and the limitations of the traditional waveguide crossing method.Here,we propose and experimentally demonstrate a low-loss multimode waveguide crossing on an X-cut LNOI platform,shaped by B-spline curves to support TE_(0),TE_(1),and TE_(2)modes.By independently optimizing Y-and Z-propagation paths,the structure achieves insertion losses as low as 0.11,0.22,0.32 dB(Y-propagation)and 0.19,0.40,0.53 dB(Z-propagation)at 1550 nm,with crosstalk below-16 dB over a 100 nm wavelength range.The design offers a practical solution for a multimode structure on anisotropic platforms,paving the way for higher integration density in MDM photonic circuits.展开更多
Waveguide crossings are crucial components in large-scale photonic integrated circuits.In this work,we introduce the design and fabrication of a polarization-insensitive waveguide crossing based on two-dimensional(2D)...Waveguide crossings are crucial components in large-scale photonic integrated circuits.In this work,we introduce the design and fabrication of a polarization-insensitive waveguide crossing based on two-dimensional(2D)-Gaussian beam synthesis,fabricated using the multi-project wafer(MPW)processes on the 220-nm-thick silicon-on-insulator(SOI)platform.This device exhibits low insertion loss(0.018-0.099 dB/0.090-0.162 dB for the TE_(0)/TM_(0)mode),low crosstalk(<-44.1 dB/<-38.8 dB for the TE_(0)/TM_(0)mode),and low polarization-dependent loss(PDL)of 0.104 dB within the wavelength range of 1520-1580 nm.These characteristics make it highly promising for applications in large-scale polarizationinsensitive silicon photonics chips.展开更多
As a promising spectral window for optical communication and sensing, it is of great significance to realize on-chip devices at the 2 μm waveband.The development of the 2 μm silicon photonic platform mainly depends ...As a promising spectral window for optical communication and sensing, it is of great significance to realize on-chip devices at the 2 μm waveband.The development of the 2 μm silicon photonic platform mainly depends on the performance of passive devices.In this work, the passive devices were fabricated in the silicon photonic multi-project wafer process.The designed micro-ring resonator with a 0.6 μm wide silicon ridge waveguide based on a 220 nm silicon-on-insulator platform achieves a high intrinsic quality factor of 3.0 × 105.The propagation loss is calculated as 1.62 d B/cm.In addition,the waveguide crossing, multimode interferometer, and Mach–Zehnder interferometer were demonstrated at 2 μm with good performances.展开更多
文摘The effect of longitudinal-offset radiating slots on a centered-inclined feeding slot in the common broad wall of the two crossed rectangular waveguides is analysed quantitatively. The corresponding equivalent parameters are computed by employing the moment method. The numerical results of resonant length of the feeding slot, VSWR and coupling parameter are showed and compared with the case of no radiating slots and short-end. The agreement between theory and experiment is good.
基金supported by the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, China (Grant No. 2020RC4047)the National Natural Science Foundation of China (Grant Nos. 11975095, 12075082, and 11935006)。
文摘We study the spontaneous emission(SE) of an excited nonrelativistic two-level system(TLS) interacting with the vacuum in a waveguide of rectangular cross section. All TLS’s transitions and the center-of-mass motion of the TLS are taken into account. The SE rate and the carried frequency of the emitted photon for the TLS initially being at rest are obtained, it is found that in the first order of the mass M, the frequency of the emitted photon is smaller than the transition frequency of the TLS and the SE rate is smaller than the SE rate Γfof the TLS fixed in the same waveguide. The SE rate for the TLS initially being moving is obtained in the second order of the mass M. The SE rate is smaller than Γfbut it is dependent not only on the atomic mass but also on the initial momentum. The carried frequency of the emitted photon is decreased when it travels along the direction of the initial momentum, whereas it is increased when it travels in the opposite direction of the initial momentum.
基金supported by the National Key Research&Development Program of China(Grant No.2022YFF0706005)National Natural Science Foundation of China(Grant Nos.12272407,62275269,62275271,and 62305387)+4 种基金Foundation of National University of Defense Technology of China(Grant No.ZK23-03)Hunan Provincial Natural Science Foundation of China(Grant Nos.2022JJ40552 and 2023JJ40683)State Key Laboratory of High Performance Computing,National University of Defense Technology of China(Grant No.202201-12)the Hunan Provincial Innovation Foundation for Postgraduate,China(Grant No.CX20230009)State Key Laboratory of High Performance Computing,National University of Defense Technology of China(Grant No.202201-12).
文摘We study that the different-mode(waveguide-connected)power splitter[(W)PS]can provide different-mode testing points for the optical testing.With the PS or WPS providing two different-mode testing points,the measured insertion losses(ILs)of the three-channel and dual-mode waveguide crossing(WC)for both the fundamental transverse electric(TE0)and TE1 modes are less than 1.8 dB or 1.9 dB from 1540 nm to 1560 nm.At the same time,the crosstalks(CTs)are lower than-17.4 dB or-18.2 dB.The consistent test results indicate the accuracy of the(W)PS-based testing circuit.Additionally,combining the tunable tap couplers,the(W)PS can provide multiple testing points with different modes and different transmittances.
基金supported by the National Key Research and Development Program of China(No.2021YFB2800102)the National Natural Science Foundation of China(No.62101198)+3 种基金the International Cooperation Projects in Hubei Province(No.2024EHA040)the Key Research and Development Program of Hubei Province(No.2022BAA005)the JD Key Project of of Hubei Province(No.2023BAA012)the Innovation Project of Optics Valley Laboratory(No.OVL2023ZD004)。
文摘With the increasing demand for optical interconnect communication capacity,waveguide crossings are crucial for highdensity photonic integrated circuits(PICs),especially for mode-division multiplexing(MDM)systems.However,designing multimode waveguide crossings on anisotropic platforms like lithium niobate on insulator(LNOI)remains challenging due to refractive index anisotropy and the limitations of the traditional waveguide crossing method.Here,we propose and experimentally demonstrate a low-loss multimode waveguide crossing on an X-cut LNOI platform,shaped by B-spline curves to support TE_(0),TE_(1),and TE_(2)modes.By independently optimizing Y-and Z-propagation paths,the structure achieves insertion losses as low as 0.11,0.22,0.32 dB(Y-propagation)and 0.19,0.40,0.53 dB(Z-propagation)at 1550 nm,with crosstalk below-16 dB over a 100 nm wavelength range.The design offers a practical solution for a multimode structure on anisotropic platforms,paving the way for higher integration density in MDM photonic circuits.
基金supported by the National Natural Science Foundation of China(Nos.62120106010,62090052,and 62135010)the Shanghai Science and Technology Committee Explorer Program(No.24TA1401200)the Henan Science and Technology Major Project of the Department of Science and Technology of Henan Province(No.241100210400)。
文摘Waveguide crossings are crucial components in large-scale photonic integrated circuits.In this work,we introduce the design and fabrication of a polarization-insensitive waveguide crossing based on two-dimensional(2D)-Gaussian beam synthesis,fabricated using the multi-project wafer(MPW)processes on the 220-nm-thick silicon-on-insulator(SOI)platform.This device exhibits low insertion loss(0.018-0.099 dB/0.090-0.162 dB for the TE_(0)/TM_(0)mode),low crosstalk(<-44.1 dB/<-38.8 dB for the TE_(0)/TM_(0)mode),and low polarization-dependent loss(PDL)of 0.104 dB within the wavelength range of 1520-1580 nm.These characteristics make it highly promising for applications in large-scale polarizationinsensitive silicon photonics chips.
基金supported by the National Key Research and Development Program of China (No.2019YFB2203003)National Natural Science Foundation of China (Nos.91950204and 61975179)+2 种基金Open Fund of the State Key Laboratory of Integrated Optoelectronics (No.IOSKL2020KF05)Fundamental Research Funds for the Central UniversitiesZJU Micro-Nano Fabrication Center at Zhejiang University。
文摘As a promising spectral window for optical communication and sensing, it is of great significance to realize on-chip devices at the 2 μm waveband.The development of the 2 μm silicon photonic platform mainly depends on the performance of passive devices.In this work, the passive devices were fabricated in the silicon photonic multi-project wafer process.The designed micro-ring resonator with a 0.6 μm wide silicon ridge waveguide based on a 220 nm silicon-on-insulator platform achieves a high intrinsic quality factor of 3.0 × 105.The propagation loss is calculated as 1.62 d B/cm.In addition,the waveguide crossing, multimode interferometer, and Mach–Zehnder interferometer were demonstrated at 2 μm with good performances.
