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
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 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.
