SiOxNy films are deposited by reactive sputtering from a Si target in Ar/O2/N2 atmospheres. In order to achieve the control of film composition and to keep a high deposition rate at the same time, a new sputtering mod...SiOxNy films are deposited by reactive sputtering from a Si target in Ar/O2/N2 atmospheres. In order to achieve the control of film composition and to keep a high deposition rate at the same time, a new sputtering model based on Berg＇s work is provided for the condition of double reactive gases. Analysis based on this model shows that the deposition process can easily enter the target-poisoning mode when the preset gas flow （N2 in this work） is too high, and the film composition will change from nitrogen-rich to SiO2-like with the increase of oxygen supply while keeping the N2 supply constant. The modelling results are confirmed in the deposition process of SiOxNy. Target self-bias voltages during sputtering are measured to characterize the different sputtering modes. FTIR-spectra and dielectric measurements are used to testify the model prediction of composition. Finally, an optimized sputtering condition is selected with the O2/N2 flow ratio varying from 0 to I and N2 supply fixed at I sccm. Average deposition rate of 17nm/min is obtained under this selected condition, which has suggested the model validity and potential for industry applications.展开更多
A monolithic optoelectronic integrated circuit chip on a silicon-on-insulator is designed and fabricated based on complementary metal oxide semiconductor compatible technology.The chip integrates an optical Mach-Zehnd...A monolithic optoelectronic integrated circuit chip on a silicon-on-insulator is designed and fabricated based on complementary metal oxide semiconductor compatible technology.The chip integrates an optical Mach-Zehnder modulator (MZM) and a CMOS driving circuit with the amplification function.Test results show that the extinction ratio of the MZM is close to 20dB and the small-signal gain of the CMOS driving circuit is about 26.9dB.A 50m V 10 MHz sine wave signal is amplified by the driving circuit,and then drives the MZM successfully.展开更多
Mobile robot global path planning in a static environment is an important problem. The paper proposes a method of global path planning based on neural network and genetic algorithm. We constructed the neural network m...Mobile robot global path planning in a static environment is an important problem. The paper proposes a method of global path planning based on neural network and genetic algorithm. We constructed the neural network model of environmental information in the workspace for a robot and used this model to establish the relationship between a collision avoidance path and the output of the model. Then the two-dimensional coding for the path via-points was converted to one-dimensional one and the fitness of both the collision avoidance path and the shortest distance are integrated into a fitness function. The simulation results showed that the proposed method is correct and effective.展开更多
The photocurrent effect in reverse biased p-n silicon waveguides at wavelength 1550 nm is experimentally investigated.The photocurrent,which is mainly related to surface-state absorption,defect-state absorption and/or...The photocurrent effect in reverse biased p-n silicon waveguides at wavelength 1550 nm is experimentally investigated.The photocurrent,which is mainly related to surface-state absorption,defect-state absorption and/or two-photon absorption,is more than 0.08µA/mm under 8 V reverse biasing and 0.75 mW irradiation.The responsivity of a silicon waveguide with length of 4500µm achieves 0.5 mA/W.Moreover,the enhancement of the photocurrent effect under the electric field is discussed.展开更多
A magneto-optical(MO)metal-sandwiched multilayered structure composed of metal,MO medium and dielectric buffer layers is presented and investigated by finite-element-method-based-mode solver and perturbation theory.Th...A magneto-optical(MO)metal-sandwiched multilayered structure composed of metal,MO medium and dielectric buffer layers is presented and investigated by finite-element-method-based-mode solver and perturbation theory.The results show that this structure exhibits large nonreciprocal phase shift,strong mode confinement in the narrow buffer layers as well as very low propagation loss.The propagation length with 1dB loss is much longer than the required length of𝜌π/2 nonreciprocal phase shifts in this structure.The modal area is smaller than half of the conventional MO waveguides.This phenomenon can be used to achieve a compact plasmonic isolator based on the Mach–Zehnder interferometer.展开更多
Variable supply voltage-clustered voltage scaling （VS-CVS） scheme can be very effective in reducing power consumption of CMOS circuits without degrading system performance. Level converting flip-flops （LCFFs） are ...Variable supply voltage-clustered voltage scaling （VS-CVS） scheme can be very effective in reducing power consumption of CMOS circuits without degrading system performance. Level converting flip-flops （LCFFs） are key elements in the CVS scheme. In this paper, a new explicit-pulsed double-edge triggered level converting flip-flop （nEP-DET-LCFF） is proposed, which employs double-edge triggering technique, dynamic structure, explicit pulse generator, conditional discharge technique and proper arrangement of stacked nMOS transistors to efficiently perform latching and level converting functions simultaneously. The proposed nEP-DET-LCFF combines merits of both conventional explicit-LCFFs and implicit-LCFFs. Simulation shows the proposed nEP-DET-LCFF has improvement of 19.2% -46% in delay, and 19.4% - 52.9% in power-delay product （PDP） as compared with the published LCFFs.展开更多
An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output d...An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output driving current. A better constant output current characteristic is achieved by using an amplifier to clamp the drain voltage of both the sampling MOSFET and power MOSFET to the same value with feedback control. Small signal equivalent circuit analysis shows that the small signal output resistance in the accurate proportional current sampling mode circuit is much larger than that in a traditional proportional current sampling mode circuit, and circuit stability could be assured. Circuit simulation and chip testing results show that when the LED driving current is 350 mA and the power supply is 6 V with ± 10% variation, the stability of the output constant current of the accurate proportional current sampling mode LED driving IC will show 41% improvement over that of a traditional proportional current sampling mode LED driving IC.展开更多
An eight-channel 400 GHz-spacing planar waveguide multi/demultiplexer employing etched diffraction grating is designed and fabricated on a silicon-on-insulator platform with a 220 nm thick top layer.The design paramet...An eight-channel 400 GHz-spacing planar waveguide multi/demultiplexer employing etched diffraction grating is designed and fabricated on a silicon-on-insulator platform with a 220 nm thick top layer.The design parameters are optimized by scalar diffraction simulation to obtain optimal performance with a small footprint of only 0.75 mm^(2).A bi-level adiabatic taper is used to connect the input/output waveguide and the slab waveguide so as to reduce the insertion loss and the broadening of the diffraction angle of the propagating light.The device is fabricated in a two-step process with E-beam lithography and dry etching,and the alignment accuracy is 10 nm or even better.Measurements show that the insertion loss is 7.35 dB and the crosstalk between adjacent channels is about-15 dB.Ways to improve the performance are also investigated in detail.展开更多
By taking the coupling between the non-neighbourhood waveguides into account, the coupling characteristic of three waveguide arrays is analysed. The strong coupling equation of three waveguides is dealt with Laplace t...By taking the coupling between the non-neighbourhood waveguides into account, the coupling characteristic of three waveguide arrays is analysed. The strong coupling equation of three waveguides is dealt with Laplace transform and LU decomposition. The general field evolution equation is obtained by inversion of the Laplace transform. The results show that the self-imaging conditions （Talbot effect） do not satisfy in general. The theoretical predictions are in good agreement with the BPM simulations.展开更多
Steering light into logic patterns with two-dimensional cascaded multimode waveguide is demonstrated. By employing the imaging properties of 2D multimode interference （MMI） and partial phase modulation method, the d...Steering light into logic patterns with two-dimensional cascaded multimode waveguide is demonstrated. By employing the imaging properties of 2D multimode interference （MMI） and partial phase modulation method, the design ideas and the implementing methods of the 2^（2×2） bits type spatial logic steering are discussed; therefore the structure of logical pattern is proposed. Numerical simulation is carried out to verify the design in detail by using the beam propagation method. It is expected to realize logic coders by using the integrated optical methods and exploit their potential applications in the field of optical logic.展开更多
A flexible-grid 1×(2×3)mode-and wavelength-selective switch which comprises counter-tapered couplers and silicon microring resonators has been proposed,optimized,and demonstrated experimentally in this work....A flexible-grid 1×(2×3)mode-and wavelength-selective switch which comprises counter-tapered couplers and silicon microring resonators has been proposed,optimized,and demonstrated experimentally in this work.By carefully thermally tuning phase shifters and silicon microring resonators,mode and wavelength signals can be independently and flexibly conveyed to any one of the output ports,and different bandwidths can be generated as desired.The particle swarm optimization algorithm and finite difference time-domain method are employed to optimize structural parameters of the twomode(de)multiplexer and crossing waveguide.The bandwidth-tunable wavelength-selective optical router composed of12 microring resonators is studied by taking advantage of the transfer matrix method.Measurement results show that,for the fabricated module,cross talk less than-10.18 dB,an extinction ratio larger than 17.41 d B,an in-band ripple lower than0.79 dB,and a 3-dB bandwidth changing from 0.38 to 1.05 nm are obtained,as the wavelength-channel spacing is 0.40 nm.The corresponding response time is measured to be 13.64μs.展开更多
Lead zirconium titanate(PZT)films(Zr/Ti=45:55)with a high dielectric constant are prepared successfully on the low-resistance Si substrate in sol–gel dip-coating process with PT film used as the buffer layer.The diel...Lead zirconium titanate(PZT)films(Zr/Ti=45:55)with a high dielectric constant are prepared successfully on the low-resistance Si substrate in sol–gel dip-coating process with PT film used as the buffer layer.The dielectric and ferroelectric properties of the films as well as the relationship between crystallization and preparing condition are studied.It is shown that the PZT ferroelectric thin films with a(110)preferred orientation and a wellcrystallized perovskite structure could be obtained after annealing at 800℃for 15 min.The particle size of the sample is about 14–25 nm.The P–E hysteresis loops are measured by means of the Sawyer–Tower test system with a compensation resistor at room temperature.The remanent polarization(Pr)and coercive electric field(Ec)of the measured PZT thin films are 47.7μC/cm2 and 18 kV/cm,respectively.The relative dielectric constantɛr and the dissipation factor tgδof the PZT thin films were measured with an LCR meter and were found to be 158 and 0.04–0.005,respectively.展开更多
As the transistor's feature scales down and the integration density of the monolithic circuit increases continuously,the traditional metal interconnects face significant performance limitation to meet the stringen...As the transistor's feature scales down and the integration density of the monolithic circuit increases continuously,the traditional metal interconnects face significant performance limitation to meet the stringent demands of high-speed,low-power and low-latency data transmission for on-and off-chip communications.Optical technology is poised to resolve these problems.Due to the complementary metal-oxide-semiconductor(CMOS) compatible process,silicon photonics is the leading candidate technology.Silicon photonic devices and networks have been improved dramatically in recent years,with a notable increase in bandwidth from the megahertz to the multi-gigahertz regime in just over half a decade.This paper reviews the recent developments in silicon photonics for optical interconnects and summarizes the work of our laboratory in this research field.展开更多
The extinction ratio （ER） ofa Mach-Zehnder-interference （MZI） based silicon optical modulator can be strongly influenced by carrier absorption. Moreover, different doping positions can induce different distributio...The extinction ratio （ER） ofa Mach-Zehnder-interference （MZI） based silicon optical modulator can be strongly influenced by carrier absorption. Moreover, different doping positions can induce different distributions of injected carriers, leading to different ERs. This effect has been experimentally investigated based on the devices fabricated on silicon-on-insulator （SOl） by using a 0.18μm CMOS process. Our experiments indicate that a device with a doping position of about 0.5μm away from the edge of the rib waveguide has optimal ER.展开更多
A polarization-insensitive mode-order converting power splitter using a pixelated region is presented and investigated in this paper.As TE_(0)and TM_(0)modes are injected into the input port,they are converted into TE...A polarization-insensitive mode-order converting power splitter using a pixelated region is presented and investigated in this paper.As TE_(0)and TM_(0)modes are injected into the input port,they are converted into TE_(1)and TM_(1)modes,which evenly come out from the two output ports.The finite-difference time-domain method and direct-binary-search optimization algorithm are utilized to optimize structural parameters of the pixelated region to attain small insertion loss,low crosstalk,wide bandwidth,excellent power uniformity,polarization-insensitive property,and compact size.Experimental results reveal that the insertion loss,crosstalk,and power uniformity of the fabricated device at 1550 nm are 0.57,-19.67,and 0.094 d B in the case of TE polarization,while in the TM polarization,the relevant insertion loss,crosstalk,and power uniformity are 0.57,-19.40,and 0.11 d B.Within a wavelength range from 1520 to 1600 nm,for the fabricated device working at TE polarization,the insertion loss,crosstalk,and power uniformity are lower than 1.39,-17.64,and 0.14 dB.In the case of TM polarization,we achieved an insertion loss,crosstalk,and power uniformity less than 1.23,-17.62,and 0.14 dB.展开更多
In this Letter, we study the characteristics of a selectively buried glass waveguide that is fabricated by the backside masking method. The results show that the surface region appears when the width of the backside m...In this Letter, we study the characteristics of a selectively buried glass waveguide that is fabricated by the backside masking method. The results show that the surface region appears when the width of the backside mask is larger than 7 mm. Here, the glass substrate is 1.5 mm thick. It is also found that the buried depth evolution of the transition region remains almost unchanged and is independent of the width of the backside mask. The loss of the transition region is only 0.28 d B at the wavelength of 1.55 μm if the surface condition is good enough.展开更多
Graphene has shown promising perspectives in optical active components due to the large active-control of its permittivity-variation. This paper systematically reviews the recent developments ofgraphene-based optical ...Graphene has shown promising perspectives in optical active components due to the large active-control of its permittivity-variation. This paper systematically reviews the recent developments ofgraphene-based optical modulators, including material property, different integration schemes, single-layer graphene-based modulator, multi-layer and few-layer graphene-based modulators, corresponding figure-of-merits, wavelength/temperature tolerance, and graphene-based fiber-optic modulator. The different treatments for graphene＇s isotropic and aniso- tropic property were also discussed. The results showed graphene is an excellent material for enhancing silicon＇s weak modulation capability after it is integrated into the silicon platform, and has great potentials for complemen- tary metal oxide semiconductor （CMOS） compatible optical devices, showing significant influence on optical interconnects in future integrated optoelectronic circuits.展开更多
The photocurrent effect in pin silicon waveguides at 1550 nm wavelength is experimentally investigated. The photocurrent is mainly attributed to surface-state absorption,defect-state absorption and/or two-photon absor...The photocurrent effect in pin silicon waveguides at 1550 nm wavelength is experimentally investigated. The photocurrent is mainly attributed to surface-state absorption,defect-state absorption and/or two-photon absorption.Experimental results show that the photocurrent is enhanced by the avalanche effect.A pin silicon waveguide with an intrinsic region width of 3.4μm and a length of 2000μm achieves a responsivity of 4.6 mA/W and an avalanche multiplication factor of about five.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 50172042.
文摘SiOxNy films are deposited by reactive sputtering from a Si target in Ar/O2/N2 atmospheres. In order to achieve the control of film composition and to keep a high deposition rate at the same time, a new sputtering model based on Berg＇s work is provided for the condition of double reactive gases. Analysis based on this model shows that the deposition process can easily enter the target-poisoning mode when the preset gas flow （N2 in this work） is too high, and the film composition will change from nitrogen-rich to SiO2-like with the increase of oxygen supply while keeping the N2 supply constant. The modelling results are confirmed in the deposition process of SiOxNy. Target self-bias voltages during sputtering are measured to characterize the different sputtering modes. FTIR-spectra and dielectric measurements are used to testify the model prediction of composition. Finally, an optimized sputtering condition is selected with the O2/N2 flow ratio varying from 0 to I and N2 supply fixed at I sccm. Average deposition rate of 17nm/min is obtained under this selected condition, which has suggested the model validity and potential for industry applications.
基金Supported by the Natural Basic Research Program of China(No 2007CB613405)the Natural Science Foundation of China(No 6177055).
文摘A monolithic optoelectronic integrated circuit chip on a silicon-on-insulator is designed and fabricated based on complementary metal oxide semiconductor compatible technology.The chip integrates an optical Mach-Zehnder modulator (MZM) and a CMOS driving circuit with the amplification function.Test results show that the extinction ratio of the MZM is close to 20dB and the small-signal gain of the CMOS driving circuit is about 26.9dB.A 50m V 10 MHz sine wave signal is amplified by the driving circuit,and then drives the MZM successfully.
基金Project supported by the National Natural Science Foundation of China (No. 60105003) and the Natural Science Foundation of Zhejiang Province (No. 600025), China
文摘Mobile robot global path planning in a static environment is an important problem. The paper proposes a method of global path planning based on neural network and genetic algorithm. We constructed the neural network model of environmental information in the workspace for a robot and used this model to establish the relationship between a collision avoidance path and the output of the model. Then the two-dimensional coding for the path via-points was converted to one-dimensional one and the fitness of both the collision avoidance path and the shortest distance are integrated into a fitness function. The simulation results showed that the proposed method is correct and effective.
基金by the Natural Basic Research Program of China under Grant No 2007CB613405the National Natural Science Foundation of China under Grant Nos 60977043 and 60808035.
文摘The photocurrent effect in reverse biased p-n silicon waveguides at wavelength 1550 nm is experimentally investigated.The photocurrent,which is mainly related to surface-state absorption,defect-state absorption and/or two-photon absorption,is more than 0.08µA/mm under 8 V reverse biasing and 0.75 mW irradiation.The responsivity of a silicon waveguide with length of 4500µm achieves 0.5 mA/W.Moreover,the enhancement of the photocurrent effect under the electric field is discussed.
基金Supported by the National Natural Science Foundation of China(No 61177055)the National Basic Research Program of China(No 2013CB632105)the Fujian-Provincial Education Department Foundation of China(JK2013053).
文摘A magneto-optical(MO)metal-sandwiched multilayered structure composed of metal,MO medium and dielectric buffer layers is presented and investigated by finite-element-method-based-mode solver and perturbation theory.The results show that this structure exhibits large nonreciprocal phase shift,strong mode confinement in the narrow buffer layers as well as very low propagation loss.The propagation length with 1dB loss is much longer than the required length of𝜌π/2 nonreciprocal phase shifts in this structure.The modal area is smaller than half of the conventional MO waveguides.This phenomenon can be used to achieve a compact plasmonic isolator based on the Mach–Zehnder interferometer.
基金Supported by the National Natural Science Foundation of China （No.60503027） Acknowledgements： The authors are grateful to Prof. Zhao PeiYi of Chapman University, Orange, USA, for beneficial discussions.
文摘Variable supply voltage-clustered voltage scaling （VS-CVS） scheme can be very effective in reducing power consumption of CMOS circuits without degrading system performance. Level converting flip-flops （LCFFs） are key elements in the CVS scheme. In this paper, a new explicit-pulsed double-edge triggered level converting flip-flop （nEP-DET-LCFF） is proposed, which employs double-edge triggering technique, dynamic structure, explicit pulse generator, conditional discharge technique and proper arrangement of stacked nMOS transistors to efficiently perform latching and level converting functions simultaneously. The proposed nEP-DET-LCFF combines merits of both conventional explicit-LCFFs and implicit-LCFFs. Simulation shows the proposed nEP-DET-LCFF has improvement of 19.2% -46% in delay, and 19.4% - 52.9% in power-delay product （PDP） as compared with the published LCFFs.
基金supported by the High Efficacy Energy-Saving Project of Zhejiang Province China(No.2006C11007).
文摘An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output driving current. A better constant output current characteristic is achieved by using an amplifier to clamp the drain voltage of both the sampling MOSFET and power MOSFET to the same value with feedback control. Small signal equivalent circuit analysis shows that the small signal output resistance in the accurate proportional current sampling mode circuit is much larger than that in a traditional proportional current sampling mode circuit, and circuit stability could be assured. Circuit simulation and chip testing results show that when the LED driving current is 350 mA and the power supply is 6 V with ± 10% variation, the stability of the output constant current of the accurate proportional current sampling mode LED driving IC will show 41% improvement over that of a traditional proportional current sampling mode LED driving IC.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61007063 and 61228501the National HighTechnology Research and Development Program of China under Grant No 2012AA012203the Doctoral Discipline Foundation of Ministry of Education under Grant No 20120101110054,and Tang Zhongyin Fund.
文摘An eight-channel 400 GHz-spacing planar waveguide multi/demultiplexer employing etched diffraction grating is designed and fabricated on a silicon-on-insulator platform with a 220 nm thick top layer.The design parameters are optimized by scalar diffraction simulation to obtain optimal performance with a small footprint of only 0.75 mm^(2).A bi-level adiabatic taper is used to connect the input/output waveguide and the slab waveguide so as to reduce the insertion loss and the broadening of the diffraction angle of the propagating light.The device is fabricated in a two-step process with E-beam lithography and dry etching,and the alignment accuracy is 10 nm or even better.Measurements show that the insertion loss is 7.35 dB and the crosstalk between adjacent channels is about-15 dB.Ways to improve the performance are also investigated in detail.
基金Supported by the National Basic Research Programme of China under Grant No 2007CB613405, and the National Natural Science Foundation of China under Grant No 60777015.
文摘By taking the coupling between the non-neighbourhood waveguides into account, the coupling characteristic of three waveguide arrays is analysed. The strong coupling equation of three waveguides is dealt with Laplace transform and LU decomposition. The general field evolution equation is obtained by inversion of the Laplace transform. The results show that the self-imaging conditions （Talbot effect） do not satisfy in general. The theoretical predictions are in good agreement with the BPM simulations.
基金Project supported by the National Natural Science Foundation of China （Grant No 60477018） and the Major Program of the National Natural Science Foundation of China （Grant No 60436020）.
文摘Steering light into logic patterns with two-dimensional cascaded multimode waveguide is demonstrated. By employing the imaging properties of 2D multimode interference （MMI） and partial phase modulation method, the design ideas and the implementing methods of the 2^（2×2） bits type spatial logic steering are discussed; therefore the structure of logical pattern is proposed. Numerical simulation is carried out to verify the design in detail by using the beam propagation method. It is expected to realize logic coders by using the integrated optical methods and exploit their potential applications in the field of optical logic.
基金supported by the National Natural Science Foundation of China(Nos.62275134,62234008,61875098,and 61874078)the Zhejiang Provincial Natural Science Foundation(Nos.LY20F050003 and LY20F050001)+2 种基金the Natural Science Foundation of Ningbo(Nos.2022J099 and 202003N4159)the Youth Science and Technology Innovation Leading Talent Project of Ningbo(No.2023QL003)the K.C.Wong Magna Fund at Ningbo University。
文摘A flexible-grid 1×(2×3)mode-and wavelength-selective switch which comprises counter-tapered couplers and silicon microring resonators has been proposed,optimized,and demonstrated experimentally in this work.By carefully thermally tuning phase shifters and silicon microring resonators,mode and wavelength signals can be independently and flexibly conveyed to any one of the output ports,and different bandwidths can be generated as desired.The particle swarm optimization algorithm and finite difference time-domain method are employed to optimize structural parameters of the twomode(de)multiplexer and crossing waveguide.The bandwidth-tunable wavelength-selective optical router composed of12 microring resonators is studied by taking advantage of the transfer matrix method.Measurement results show that,for the fabricated module,cross talk less than-10.18 dB,an extinction ratio larger than 17.41 d B,an in-band ripple lower than0.79 dB,and a 3-dB bandwidth changing from 0.38 to 1.05 nm are obtained,as the wavelength-channel spacing is 0.40 nm.The corresponding response time is measured to be 13.64μs.
基金supported by the National Natural Science Foundation of China (No.50177027 and No.50072018).
文摘Lead zirconium titanate(PZT)films(Zr/Ti=45:55)with a high dielectric constant are prepared successfully on the low-resistance Si substrate in sol–gel dip-coating process with PT film used as the buffer layer.The dielectric and ferroelectric properties of the films as well as the relationship between crystallization and preparing condition are studied.It is shown that the PZT ferroelectric thin films with a(110)preferred orientation and a wellcrystallized perovskite structure could be obtained after annealing at 800℃for 15 min.The particle size of the sample is about 14–25 nm.The P–E hysteresis loops are measured by means of the Sawyer–Tower test system with a compensation resistor at room temperature.The remanent polarization(Pr)and coercive electric field(Ec)of the measured PZT thin films are 47.7μC/cm2 and 18 kV/cm,respectively.The relative dielectric constantɛr and the dissipation factor tgδof the PZT thin films were measured with an LCR meter and were found to be 158 and 0.04–0.005,respectively.
基金supported by the National Natural Science Foundation of China (Grants Nos. 60977043,61007063 and 61228501)National High-Tech Research & Development Program of China ("863" Project)(Grant No. 2012AA012203)+1 种基金Tang Zhongyin Fundthe Scholarship Award for Excellent Doctoral Student granted by the Ministry of Educationof China
文摘As the transistor's feature scales down and the integration density of the monolithic circuit increases continuously,the traditional metal interconnects face significant performance limitation to meet the stringent demands of high-speed,low-power and low-latency data transmission for on-and off-chip communications.Optical technology is poised to resolve these problems.Due to the complementary metal-oxide-semiconductor(CMOS) compatible process,silicon photonics is the leading candidate technology.Silicon photonic devices and networks have been improved dramatically in recent years,with a notable increase in bandwidth from the megahertz to the multi-gigahertz regime in just over half a decade.This paper reviews the recent developments in silicon photonics for optical interconnects and summarizes the work of our laboratory in this research field.
基金Project Supported by the Natural Basic Research Program of China(No.2007CB6I3405)the NationaI Natural Science Foundation of China(Nos.60977043,60808035)
文摘The extinction ratio （ER） ofa Mach-Zehnder-interference （MZI） based silicon optical modulator can be strongly influenced by carrier absorption. Moreover, different doping positions can induce different distributions of injected carriers, leading to different ERs. This effect has been experimentally investigated based on the devices fabricated on silicon-on-insulator （SOl） by using a 0.18μm CMOS process. Our experiments indicate that a device with a doping position of about 0.5μm away from the edge of the rib waveguide has optimal ER.
基金supported by the National Natural Science Foundation of China(Nos.62275134,62234008,and 61875098)the Zhejiang Provincial Natural Science Foundation(Nos.LY20F050003 and LY20F050001)+2 种基金the Youth Science and Technology Innovation Leading Talent Project of Ningbo(No.2023QL003)the Natural Science Foundation of Ningbo(Nos.2022J099 and 202003N4159)the K.C.Wong Magna Fund in Ningbo University。
文摘A polarization-insensitive mode-order converting power splitter using a pixelated region is presented and investigated in this paper.As TE_(0)and TM_(0)modes are injected into the input port,they are converted into TE_(1)and TM_(1)modes,which evenly come out from the two output ports.The finite-difference time-domain method and direct-binary-search optimization algorithm are utilized to optimize structural parameters of the pixelated region to attain small insertion loss,low crosstalk,wide bandwidth,excellent power uniformity,polarization-insensitive property,and compact size.Experimental results reveal that the insertion loss,crosstalk,and power uniformity of the fabricated device at 1550 nm are 0.57,-19.67,and 0.094 d B in the case of TE polarization,while in the TM polarization,the relevant insertion loss,crosstalk,and power uniformity are 0.57,-19.40,and 0.11 d B.Within a wavelength range from 1520 to 1600 nm,for the fabricated device working at TE polarization,the insertion loss,crosstalk,and power uniformity are lower than 1.39,-17.64,and 0.14 dB.In the case of TM polarization,we achieved an insertion loss,crosstalk,and power uniformity less than 1.23,-17.62,and 0.14 dB.
基金supported by the Natural Science Foundation of China under Grant Nos.61228501 and 61475137the National 863 Project of China under Grant No.2012AA012203the Doctoral Discipline Foundation of Ministry of Education under Grant No.20120101110054
文摘In this Letter, we study the characteristics of a selectively buried glass waveguide that is fabricated by the backside masking method. The results show that the surface region appears when the width of the backside mask is larger than 7 mm. Here, the glass substrate is 1.5 mm thick. It is also found that the buried depth evolution of the transition region remains almost unchanged and is independent of the width of the backside mask. The loss of the transition region is only 0.28 d B at the wavelength of 1.55 μm if the surface condition is good enough.
基金Acknowledgements This work was supported by the National Basic Research Program of China （No. 2014CB340005）, the National Natural Science Foundation of China （Grant Nos. 61205054 and 61371029）,Zhejiang Provincial Natural Science Foundation of China （Nos. Z1110330 and LQ 12F05006）, the Excellent Young Faculty Awards Program （Zijin Plan） at ZhejiangUniversity.
文摘Graphene has shown promising perspectives in optical active components due to the large active-control of its permittivity-variation. This paper systematically reviews the recent developments ofgraphene-based optical modulators, including material property, different integration schemes, single-layer graphene-based modulator, multi-layer and few-layer graphene-based modulators, corresponding figure-of-merits, wavelength/temperature tolerance, and graphene-based fiber-optic modulator. The different treatments for graphene＇s isotropic and aniso- tropic property were also discussed. The results showed graphene is an excellent material for enhancing silicon＇s weak modulation capability after it is integrated into the silicon platform, and has great potentials for complemen- tary metal oxide semiconductor （CMOS） compatible optical devices, showing significant influence on optical interconnects in future integrated optoelectronic circuits.
基金supported by the Natural Basic Research Program of China(No.2013CB632105)the National Natural Science Foundation of China(No.61177055)
文摘The photocurrent effect in pin silicon waveguides at 1550 nm wavelength is experimentally investigated. The photocurrent is mainly attributed to surface-state absorption,defect-state absorption and/or two-photon absorption.Experimental results show that the photocurrent is enhanced by the avalanche effect.A pin silicon waveguide with an intrinsic region width of 3.4μm and a length of 2000μm achieves a responsivity of 4.6 mA/W and an avalanche multiplication factor of about five.
