A compact electro-absorption modulator based on graphene photonic crystal fiber is proposed. To enhance the graphene–light interaction efficiency, the innermost six air-holes of photonic crystal fiber are replaced by...A compact electro-absorption modulator based on graphene photonic crystal fiber is proposed. To enhance the graphene–light interaction efficiency, the innermost six air-holes of photonic crystal fiber are replaced by two large semicircular holes, and monolayer graphene is deposited on the two large semicircular holes. By optimizing the structure parameters, a strong graphene–light interaction is obtained. Moreover, the switch on–off point of the modulator is unchangeable,which is only related to the frequency of the incident light. The influence factors of this composite structure have been analyzed. The proposed modulator is compared with other graphene-based modulators, and the results show that it is filled without dielectric spacer. There are some excellent performances, such as an extinction ratio 7 dB of y-polarization mode,3-dB modulation bandwidth of 70 GHz with small footprint of 205 μm, and a consumption of energy per bit 59 pJ/bit.展开更多
We report the simulation and experimental results of 1.3-μm InGaAsP/InP multiple quantum well (MQW) electro-absorption modulators (EAMs). In this work, the quantum confined Stark effect of the EAM is system- atic...We report the simulation and experimental results of 1.3-μm InGaAsP/InP multiple quantum well (MQW) electro-absorption modulators (EAMs). In this work, the quantum confined Stark effect of the EAM is system- atically analyzed through the finite element method. An optimized structure of the 1.3-μm InGaAsP/InP QW EAM is proposed for applications in 100 G ethernet. Then 1.3-μm InGaAsP/InP EAMs with f-3dB bandwidth of over 20 GHz and extinction ratio over 20 dB at 3 V bias voltage are demonstrated.展开更多
An electro-absorption(EA)modulator is one of key components for optical fiber communications due to the high speed,small size,low voltage and integration ability with other semiconductor devices.A 40 Gb/s InGaAsP/InP ...An electro-absorption(EA)modulator is one of key components for optical fiber communications due to the high speed,small size,low voltage and integration ability with other semiconductor devices.A 40 Gb/s InGaAsP/InP multiplequantum-well(MQW)EA modulator monolithically integrated with a semiconductor optical amplifier(SOA)was fabricated for digital communications.The modulator capacitance was reduced to obtain 40 GHz bandwidth,and the SOA section helped reduce the insertion loss from 18 dB to 3 dB.InGaAlAs/InP MQW EA modulators have also been fabricated and characterized for analog optical fiber communications.A low driving voltage of 2.7 V and high spurious free dynamic range of 107 dB·Hz2/3 were estimated by static and dynamic measurements.展开更多
A theoretical study on the red-shift of laser-induced electro-absorption is presented. It is found that laser-induced red-shift scales with the cube root of the pump laser intensity in the optical tunneling regime and...A theoretical study on the red-shift of laser-induced electro-absorption is presented. It is found that laser-induced red-shift scales with the cube root of the pump laser intensity in the optical tunneling regime and has an obvious deviation from this scale in the multi-photon regime. Our results show that in the optical tunneling regime, the laser-induced red shift has the same law as that in the direct current (DC) approximation. Though the scales are the same in the optical tunneling regime, the physical pictures in the two cases are quite different. The electro-absorption in the DC case is a tunneling-assisted transition process, while the laser-induced electro-absorption is a mixed multi-photon process.展开更多
The relationships between electrode absorptive capacity and solution temperature,concentration and electrode potential were investigated by theoretic analysis and experiments.The results show that the charge of electr...The relationships between electrode absorptive capacity and solution temperature,concentration and electrode potential were investigated by theoretic analysis and experiments.The results show that the charge of electric double-layer on electrode interface is very sensitive to temperature and electrode potential in the electroadsorption process.For the specific electrical adsorption device,the electrode potential must be controlled to avoid the electrolytic reaction.展开更多
A theoretical study for femtosecond laser-induced ultrafast electro-absorption of bulk solids is presented.Our numerical results show that,in the case of low intensity of the pump laser where the interaction between t...A theoretical study for femtosecond laser-induced ultrafast electro-absorption of bulk solids is presented.Our numerical results show that,in the case of low intensity of the pump laser where the interaction between the pump laser and solids is in the multi-photon regime,the energy band of solids can be approximately taken as a parabolic band and electro-absorption spectrums from the parabolic band and real band are nearly the same.While,in the case of high intensity where the interaction is in the tunneling regime,spectrums from the parabolic band and real band are quite different.The physical mechanism for the difference in the tunneling regime is found.We find that the non-parabolic parts of the real energy band and Bragger scattering of electrons near the first Brillouin zone boundaries,which are neglected in previous studies,strongly influence the electro-absorption spectrum in the tunneling regime.These two physical processes cause the difference of spectrums.Our theoretical results are in accordance with the experiment result.展开更多
Integrated electro-absorption-modulated distributed feedback laser diodes(EMLs)are attracting much interest in optical communications for the advantages of a compact structure,low power consumption,and high-speed modu...Integrated electro-absorption-modulated distributed feedback laser diodes(EMLs)are attracting much interest in optical communications for the advantages of a compact structure,low power consumption,and high-speed modulation.In integrated EML,the microwave interaction between the distributed feedback laser diode(DFB-LD)and the electro-absorption modulator(EAM)has a nonnegligible influence on the modulation performance,especially at the high-frequency region.In this paper,integrated EML was investigated as a three-port network with two electrical inputs and a single optical output,where the scattering matrix of the integrated device was theoretically deduced and experimentally measured.Based on the theoretical model and the measured data,the microwave equivalent circuit model of the integrated device was established,from which the microwave interaction between DFB-LD and EAM was successfully extracted.The results reveal that the microwave interaction within integrated EML contains both the electrical isolation and optical coupling.The electrical isolation is bidirectional while the optical coupling is directional,which aggravates the microwave interaction in the direction from DFB-LD to EAM.展开更多
This paper reports on the design,fabrication,and performance of an integrated electro-absorptive modulated laser based on butt-joint configuration for 10Gbit/s application.This paper mainly aims at two aspects.One is ...This paper reports on the design,fabrication,and performance of an integrated electro-absorptive modulated laser based on butt-joint configuration for 10Gbit/s application.This paper mainly aims at two aspects.One is to improve the optical coupling between the laser and modulator;another is to increase the bandwidth of such devices by reducing the capacitance parameter of the modulator.The integrated devices exhibit high static and dynamic characteristics. Typical threshold current is 15mA,with some value as low as 8mA.Output power at 100mA is more than 10mW.The extinction characteristics,modulation bandwidth,and electrical return loss are measured.3dB bandwidth more than 10GHz is monitored.展开更多
This paper presents a novel scheme to monolithically integrate an evanescently-coupled uni-travelling carrier photodiode with a planar short multimode waveguide structure and a large optical cavity electroabsorption m...This paper presents a novel scheme to monolithically integrate an evanescently-coupled uni-travelling carrier photodiode with a planar short multimode waveguide structure and a large optical cavity electroabsorption modulator based on a multimode waveguide structure. By simulation, both electroabsorption modulator and photodiode show excellent optical performances. The device can be fabricated with conventional photolithography, reactive ion etching, and chemical wet etching.展开更多
A theoretical model of the refractive index changes of the TE and TM modes in an electro-absorption modulator (EAM) is deduced. The photon absorption and refractive index changes are analyzed numerically. The influe...A theoretical model of the refractive index changes of the TE and TM modes in an electro-absorption modulator (EAM) is deduced. The photon absorption and refractive index changes are analyzed numerically. The influence of pump intensity on the phase difference between the TE and TM modes is studied. The polarization rotation effect is obtained in the EAM, and a novel all-optical fiber loop buffer is designed.展开更多
In this paper,we proposed a novel ultra・flat broadband microwave frequency comb(MFC)generation based on optical frequency comb(OFC)with a multiplequantum-well electroabsorption modulator(MQW-EAM)in critical state.The ...In this paper,we proposed a novel ultra・flat broadband microwave frequency comb(MFC)generation based on optical frequency comb(OFC)with a multiplequantum-well electroabsorption modulator(MQW-EAM)in critical state.The scheme is simple and easy to adjust.The performance of the MFC generation scheme is investigated using software Optisystem.The results show that the comb spacing of MFC can be adjusted from 5 to 20 GHz by changing RF signafs frequency and the MFC is almost independent on the linewidth of the tunable laser diode.The performance of the MFC can be improved by reasonably increasing the voltage of the RF,the smallsignal gain of the Erbium-doped fiber amplifier(EDFA)and the responsivity of the photodetector.The MFC generated by this scheme has 300 GHz effective bandwidth with 15 comb lines,whose power variation is 0.02 dB,when the components9 parameters in the Optisystem are set as follows:the power of tunable laser diode(TLD)is 0 dBm,the wavelength is 1552.52 nm,and linewidth is 1 MHz;RF signaPs frequency is 20 GHz and the voltage is 10 V;the reverse bias voltage of MQW-EAM is 6.92 V;the small-signal gain of the EDFA is 40 dB;the responsivity of the photodetector(PD)is 1 A/W.展开更多
The demultiplexing experiment from a 40 Gb/s optical time-division multiplexing signal is completed by using electro- absorption sampling window based on electronic phase-locked loop circuit for clock recovery. Error-...The demultiplexing experiment from a 40 Gb/s optical time-division multiplexing signal is completed by using electro- absorption sampling window based on electronic phase-locked loop circuit for clock recovery. Error-free demultiplexing is achieved when the launched optical power into electro-absorption sampling window reaches 5.5 dBm without optical filter following the EDFA.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
Broadband optical frequency comb(OFC)generation based on a single electro-absorption modulator(EAM)is proposed.The EAM is driven by a radio frequency(RF)multi-frequency signal generated by a multiplication coupler com...Broadband optical frequency comb(OFC)generation based on a single electro-absorption modulator(EAM)is proposed.The EAM is driven by a radio frequency(RF)multi-frequency signal generated by a multiplication coupler composed of an electrical power splitter and an arithmetic circuit.Thus the number of comb-lines of the generated OFC can be increased.A complete theoretical model of OFC generation by an EAM driven by nth power of the RF source is established,and the performance of the OFC is analyzed by using OptiSystem software.The results show that,the number of comb-lines of the OFC is positively correlated with the number of multiplication of the RF source signal.The frequency spacing of the comb-lines is twice the frequency of the RF source signal and is tunable by adjusting the frequency of the RF source signal.Increasing chirp factor and modulation index of EAM could increase the number of comb-lines of the generated OFC.The amplitude of the RF source signal had little impact on the fatness of the OFC and the average OFC power.The scheme developed is not only simple and low-cost,but also can produce a large number of comb-lines.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61575170 and 61675176)the Key Basic Research Program of Hebei Province,China(Grant No.16961701D)the“Xin Rui Gong Cheng”Talent Project of Yanshan University。
文摘A compact electro-absorption modulator based on graphene photonic crystal fiber is proposed. To enhance the graphene–light interaction efficiency, the innermost six air-holes of photonic crystal fiber are replaced by two large semicircular holes, and monolayer graphene is deposited on the two large semicircular holes. By optimizing the structure parameters, a strong graphene–light interaction is obtained. Moreover, the switch on–off point of the modulator is unchangeable,which is only related to the frequency of the incident light. The influence factors of this composite structure have been analyzed. The proposed modulator is compared with other graphene-based modulators, and the results show that it is filled without dielectric spacer. There are some excellent performances, such as an extinction ratio 7 dB of y-polarization mode,3-dB modulation bandwidth of 70 GHz with small footprint of 205 μm, and a consumption of energy per bit 59 pJ/bit.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61274046,61474111 and 61321063the National High-Technology Research and Development Program of China under Grant No 2013AA014202
文摘We report the simulation and experimental results of 1.3-μm InGaAsP/InP multiple quantum well (MQW) electro-absorption modulators (EAMs). In this work, the quantum confined Stark effect of the EAM is system- atically analyzed through the finite element method. An optimized structure of the 1.3-μm InGaAsP/InP QW EAM is proposed for applications in 100 G ethernet. Then 1.3-μm InGaAsP/InP EAMs with f-3dB bandwidth of over 20 GHz and extinction ratio over 20 dB at 3 V bias voltage are demonstrated.
基金supported by National ScienceFoundation Programs(60536020,60723002)"973"State Key Basic Research Programs(2006CB302800,2006CB921106)
文摘An electro-absorption(EA)modulator is one of key components for optical fiber communications due to the high speed,small size,low voltage and integration ability with other semiconductor devices.A 40 Gb/s InGaAsP/InP multiplequantum-well(MQW)EA modulator monolithically integrated with a semiconductor optical amplifier(SOA)was fabricated for digital communications.The modulator capacitance was reduced to obtain 40 GHz bandwidth,and the SOA section helped reduce the insertion loss from 18 dB to 3 dB.InGaAlAs/InP MQW EA modulators have also been fabricated and characterized for analog optical fiber communications.A low driving voltage of 2.7 V and high spurious free dynamic range of 107 dB·Hz2/3 were estimated by static and dynamic measurements.
基金Project supported by the Fundamental Research Funds for the Central Universities,China (Grant No.A735496)the National Natural Science Foundation of China (Grant No.61178018)the Ph.D. Funding Support Program of the Education Ministry of China (Grant No.20110185110007)
文摘A theoretical study on the red-shift of laser-induced electro-absorption is presented. It is found that laser-induced red-shift scales with the cube root of the pump laser intensity in the optical tunneling regime and has an obvious deviation from this scale in the multi-photon regime. Our results show that in the optical tunneling regime, the laser-induced red shift has the same law as that in the direct current (DC) approximation. Though the scales are the same in the optical tunneling regime, the physical pictures in the two cases are quite different. The electro-absorption in the DC case is a tunneling-assisted transition process, while the laser-induced electro-absorption is a mixed multi-photon process.
基金Sponsored by the International Science and Technology Cooperation of China (Grant No. 2008DFR60340 )Scientific Technological Project of Weihai(Grant No. 2008087)+1 种基金China Postdoctoral Science Foundation (Grant No. 20100471038)Fundamental Research Funds for the Central Universities(Grant No. HIT. NSRIF. 2009156)
文摘The relationships between electrode absorptive capacity and solution temperature,concentration and electrode potential were investigated by theoretic analysis and experiments.The results show that the charge of electric double-layer on electrode interface is very sensitive to temperature and electrode potential in the electroadsorption process.For the specific electrical adsorption device,the electrode potential must be controlled to avoid the electrolytic reaction.
基金Project supported by the National Natural Science Foundation of China(Grant No.61505023)
文摘A theoretical study for femtosecond laser-induced ultrafast electro-absorption of bulk solids is presented.Our numerical results show that,in the case of low intensity of the pump laser where the interaction between the pump laser and solids is in the multi-photon regime,the energy band of solids can be approximately taken as a parabolic band and electro-absorption spectrums from the parabolic band and real band are nearly the same.While,in the case of high intensity where the interaction is in the tunneling regime,spectrums from the parabolic band and real band are quite different.The physical mechanism for the difference in the tunneling regime is found.We find that the non-parabolic parts of the real energy band and Bragger scattering of electrons near the first Brillouin zone boundaries,which are neglected in previous studies,strongly influence the electro-absorption spectrum in the tunneling regime.These two physical processes cause the difference of spectrums.Our theoretical results are in accordance with the experiment result.
基金This work was supported by the National Key Research and Development Program of China under Grant No.2018YFE0201900the National Natural Science Foundation of China under Grants No.61927821 and No.61875240the Joint Research Fund of Ministry of Education of China under Grant No.6141A02022436.
文摘Integrated electro-absorption-modulated distributed feedback laser diodes(EMLs)are attracting much interest in optical communications for the advantages of a compact structure,low power consumption,and high-speed modulation.In integrated EML,the microwave interaction between the distributed feedback laser diode(DFB-LD)and the electro-absorption modulator(EAM)has a nonnegligible influence on the modulation performance,especially at the high-frequency region.In this paper,integrated EML was investigated as a three-port network with two electrical inputs and a single optical output,where the scattering matrix of the integrated device was theoretically deduced and experimentally measured.Based on the theoretical model and the measured data,the microwave equivalent circuit model of the integrated device was established,from which the microwave interaction between DFB-LD and EAM was successfully extracted.The results reveal that the microwave interaction within integrated EML contains both the electrical isolation and optical coupling.The electrical isolation is bidirectional while the optical coupling is directional,which aggravates the microwave interaction in the direction from DFB-LD to EAM.
文摘This paper reports on the design,fabrication,and performance of an integrated electro-absorptive modulated laser based on butt-joint configuration for 10Gbit/s application.This paper mainly aims at two aspects.One is to improve the optical coupling between the laser and modulator;another is to increase the bandwidth of such devices by reducing the capacitance parameter of the modulator.The integrated devices exhibit high static and dynamic characteristics. Typical threshold current is 15mA,with some value as low as 8mA.Output power at 100mA is more than 10mW.The extinction characteristics,modulation bandwidth,and electrical return loss are measured.3dB bandwidth more than 10GHz is monitored.
基金supported by the National Natural Science Foundation of China (Grant No 90401025)the National 973 project (Grant No 2006CB604901)
文摘This paper presents a novel scheme to monolithically integrate an evanescently-coupled uni-travelling carrier photodiode with a planar short multimode waveguide structure and a large optical cavity electroabsorption modulator based on a multimode waveguide structure. By simulation, both electroabsorption modulator and photodiode show excellent optical performances. The device can be fabricated with conventional photolithography, reactive ion etching, and chemical wet etching.
基金supported by the National Natural Science Foundation of China(Grant No.61077014)the National Basic Research Program of China(Grant No.2010CB327601)
文摘A theoretical model of the refractive index changes of the TE and TM modes in an electro-absorption modulator (EAM) is deduced. The photon absorption and refractive index changes are analyzed numerically. The influence of pump intensity on the phase difference between the TE and TM modes is studied. The polarization rotation effect is obtained in the EAM, and a novel all-optical fiber loop buffer is designed.
基金Related studies were supported by the National Natural Science Foundation of China(Grant No.61275067).
文摘In this paper,we proposed a novel ultra・flat broadband microwave frequency comb(MFC)generation based on optical frequency comb(OFC)with a multiplequantum-well electroabsorption modulator(MQW-EAM)in critical state.The scheme is simple and easy to adjust.The performance of the MFC generation scheme is investigated using software Optisystem.The results show that the comb spacing of MFC can be adjusted from 5 to 20 GHz by changing RF signafs frequency and the MFC is almost independent on the linewidth of the tunable laser diode.The performance of the MFC can be improved by reasonably increasing the voltage of the RF,the smallsignal gain of the Erbium-doped fiber amplifier(EDFA)and the responsivity of the photodetector.The MFC generated by this scheme has 300 GHz effective bandwidth with 15 comb lines,whose power variation is 0.02 dB,when the components9 parameters in the Optisystem are set as follows:the power of tunable laser diode(TLD)is 0 dBm,the wavelength is 1552.52 nm,and linewidth is 1 MHz;RF signaPs frequency is 20 GHz and the voltage is 10 V;the reverse bias voltage of MQW-EAM is 6.92 V;the small-signal gain of the EDFA is 40 dB;the responsivity of the photodetector(PD)is 1 A/W.
基金supported by National 863 High TechnologyProjects of China (No. 2007AA01Z258, 2008AA01Z15)National Natural Science Foundation of China (No.60577034, 60747002,60877042)Science Foundation of Beijing(No.4062027).
文摘The demultiplexing experiment from a 40 Gb/s optical time-division multiplexing signal is completed by using electro- absorption sampling window based on electronic phase-locked loop circuit for clock recovery. Error-free demultiplexing is achieved when the launched optical power into electro-absorption sampling window reaches 5.5 dBm without optical filter following the EDFA.
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 National Natural Science Foundation of China(Grant No.61571237).
文摘Broadband optical frequency comb(OFC)generation based on a single electro-absorption modulator(EAM)is proposed.The EAM is driven by a radio frequency(RF)multi-frequency signal generated by a multiplication coupler composed of an electrical power splitter and an arithmetic circuit.Thus the number of comb-lines of the generated OFC can be increased.A complete theoretical model of OFC generation by an EAM driven by nth power of the RF source is established,and the performance of the OFC is analyzed by using OptiSystem software.The results show that,the number of comb-lines of the OFC is positively correlated with the number of multiplication of the RF source signal.The frequency spacing of the comb-lines is twice the frequency of the RF source signal and is tunable by adjusting the frequency of the RF source signal.Increasing chirp factor and modulation index of EAM could increase the number of comb-lines of the generated OFC.The amplitude of the RF source signal had little impact on the fatness of the OFC and the average OFC power.The scheme developed is not only simple and low-cost,but also can produce a large number of comb-lines.