Integrated waveguides with slot structures have attracted increasing attention due to their advantages of tight mode confinement and strong light-matter interaction.Although extensively studied,the issue of mode misma...Integrated waveguides with slot structures have attracted increasing attention due to their advantages of tight mode confinement and strong light-matter interaction.Although extensively studied,the issue of mode mismatch with other strip waveguide-based optical devices is a huge challenge that prevents integrated waveguides from being widely utilized in large-scale photonic-based circuits.In this paper,we demonstrate an ultra-compact low-loss slot-strip converter with polarization insensitivity based on the multimode interference(MMI)effect.Sleek sinusoidal profiles are adopted to allow for smooth connection between the slot and strip waveguide,resulting reflection reduction.By manipulating the MMI effect with structure optimization,the self-imaging positions of the TE0 and TM0 modes are aligned with minimized footprint,leading to low-loss transmission for both polarizations.The measurement results show that high coupling efficiencies of−0.40 and−0.64 dB are achieved for TE_(0) and TM_(0) polarizations,respectively.The device has dimensions as small as 1.1μm×1.2μm and composed of factory-available structures.The above characteristics of our proposed compact slot-strip converter makes it a promising device for future deployment in multi-functional integrated photonics systems.展开更多
Strip Wireless Sensor Networks(SWSNs)have drawn much attention in many applications such as monitoring rivers,highways and coal mines.Packet delivery in SWSN usually requires a large number of multi-hop transmissions ...Strip Wireless Sensor Networks(SWSNs)have drawn much attention in many applications such as monitoring rivers,highways and coal mines.Packet delivery in SWSN usually requires a large number of multi-hop transmissions which leads to long transmission latency in low-duty-cycle SWSNs.Several pipeline scheduling schemes have been proposed to reduce latency.However,when communication links are unreliable,pipeline scheduling is prone to failure.In this paper,we propose a pipeline scheduling transmission protocol based on constructive interference.The protocol first divides the whole network into multiple partitions and uses a pipelined mechanism to allocate active time slots for each partition.The nodes in the same partition wake up at the same time for concurrent transmission.Multiple identical signals interfere constructively at the receiver node,which enhances received signal strength and improves link quality.Simulations show that the proposed scheme can significantly reduce the transmission latency while maintaining low energy consumption compared with other schemes.展开更多
In a strip winding process,the sleeve is a hollow cylinder that is mounted between a strip coil and a mandrel to maintain uniform coil shape when the strip coil is very thin,but its deformation behavior has not been i...In a strip winding process,the sleeve is a hollow cylinder that is mounted between a strip coil and a mandrel to maintain uniform coil shape when the strip coil is very thin,but its deformation behavior has not been investigated before.Thus,a finite element（FE）model was presented to calculate the stress distribution in a sleeve and strip coil when 1-3mm-thick stainless steel was wound around the sleeve.The FE model was developed by extending aprevious model by adding a sleeve between the mandrel and strip,and by modifying the boundary and interaction conditions.The strip winding process was divided into an initial process and a steady-state process.During the initial process,the minimum and maximum pressure required on the belt wrapper to maintain coil shape by self-friction of the strip was calculated by the FE model when the belt wrapper is ejected at the end of the initial process.After the initial process,an analytical model of the steady-state process was established to calculate the stress distribution and was compared with the FE model to validate it.The suggested analytical model took 11 sto give the same stress distribution that the FE model took 30 dto produce.展开更多
基金This work was funded by the National Key Research and Development Program of China(No.2018YFB2201704)the National Natural Science Foundation of China(Grant Nos.61635001 and 62105008)+2 种基金China National Postdoctoral Program for Innovative Talents(No.BX20200017)China Postdoctoral Science Foundation(No.2021T140004)the Major Key Project of PCL(No.PCL2021A14)。
文摘Integrated waveguides with slot structures have attracted increasing attention due to their advantages of tight mode confinement and strong light-matter interaction.Although extensively studied,the issue of mode mismatch with other strip waveguide-based optical devices is a huge challenge that prevents integrated waveguides from being widely utilized in large-scale photonic-based circuits.In this paper,we demonstrate an ultra-compact low-loss slot-strip converter with polarization insensitivity based on the multimode interference(MMI)effect.Sleek sinusoidal profiles are adopted to allow for smooth connection between the slot and strip waveguide,resulting reflection reduction.By manipulating the MMI effect with structure optimization,the self-imaging positions of the TE0 and TM0 modes are aligned with minimized footprint,leading to low-loss transmission for both polarizations.The measurement results show that high coupling efficiencies of−0.40 and−0.64 dB are achieved for TE_(0) and TM_(0) polarizations,respectively.The device has dimensions as small as 1.1μm×1.2μm and composed of factory-available structures.The above characteristics of our proposed compact slot-strip converter makes it a promising device for future deployment in multi-functional integrated photonics systems.
基金This work is supported in part by the National Natural Science Foundation of China(Grant No.61672282)the Basic Research Program of Jiangsu Province(Grant No.BK20161491).
文摘Strip Wireless Sensor Networks(SWSNs)have drawn much attention in many applications such as monitoring rivers,highways and coal mines.Packet delivery in SWSN usually requires a large number of multi-hop transmissions which leads to long transmission latency in low-duty-cycle SWSNs.Several pipeline scheduling schemes have been proposed to reduce latency.However,when communication links are unreliable,pipeline scheduling is prone to failure.In this paper,we propose a pipeline scheduling transmission protocol based on constructive interference.The protocol first divides the whole network into multiple partitions and uses a pipelined mechanism to allocate active time slots for each partition.The nodes in the same partition wake up at the same time for concurrent transmission.Multiple identical signals interfere constructively at the receiver node,which enhances received signal strength and improves link quality.Simulations show that the proposed scheme can significantly reduce the transmission latency while maintaining low energy consumption compared with other schemes.
基金supported by the POSCO Research Project(2015Y011)from POSCO Engineering Solution Centerthe Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government Ministry of Trade Industry and Energy(MOTIE).(2015 Establishment of GEM,No.H2001-13-1001)
文摘In a strip winding process,the sleeve is a hollow cylinder that is mounted between a strip coil and a mandrel to maintain uniform coil shape when the strip coil is very thin,but its deformation behavior has not been investigated before.Thus,a finite element（FE）model was presented to calculate the stress distribution in a sleeve and strip coil when 1-3mm-thick stainless steel was wound around the sleeve.The FE model was developed by extending aprevious model by adding a sleeve between the mandrel and strip,and by modifying the boundary and interaction conditions.The strip winding process was divided into an initial process and a steady-state process.During the initial process,the minimum and maximum pressure required on the belt wrapper to maintain coil shape by self-friction of the strip was calculated by the FE model when the belt wrapper is ejected at the end of the initial process.After the initial process,an analytical model of the steady-state process was established to calculate the stress distribution and was compared with the FE model to validate it.The suggested analytical model took 11 sto give the same stress distribution that the FE model took 30 dto produce.
文摘微带线发夹型滤波器具有结构紧凑、尺寸小、指标优良等优点,在射频和微波通信系统中应用广泛。由于目前设计的多数带通滤波器没有考虑交调畸变的影响,导致通带内波纹起伏较大,衰减严重。本文提出了一种用于抑制通带内波纹起伏及减小带内衰减的新方法。首先,在传统发夹滤波器结构之后加入短路短截线与谐波四分之一波长开路短截线并联谐振结构,能够在不影响有用信号的情况下,很好地抑制交调干扰。接着,通过采用微带径向短截线(MRSTU)扩大抑制干扰带宽,实现通带内宽频带干扰的有效抑制。最后,基于本文方法设计了一款2.3GHz到2.5GHz的五阶发夹型带通滤波器,ADS仿真及版图分析证明了本文方法设计的滤波器具有较为平坦的带通特性,并且将带内衰减降低了近10d B.
