An all-fiber optical modulator, which is composed of a piece of no-core fiber spliced between two sections of singlemode fibers and uses magnetic fluid（MF） as the cladding of the no-core fiber section, is proposed a...An all-fiber optical modulator, which is composed of a piece of no-core fiber spliced between two sections of singlemode fibers and uses magnetic fluid（MF） as the cladding of the no-core fiber section, is proposed and investigated experimentally. Due to the tunable refractive index and absorption coefficient of MF, the output intensity can be modulated by controlling an applied magnetic field. The dependences of the modulator＇s temporal response on the working wavelength,the magnetic field strength（H）, and the MF＇s concentration are investigated experimentally. The results are explained qualitatively by the dynamic response process of MF under the action of a magnetic field. The findings are helpful for optimizing this kind of modulator.展开更多
In order to achieve a modulator with broad bandwidth and perfect impedance match,a novel electro-optical modulator based on GeO2-doped silica waveguides on silicon substrate is designed.The finite element model of the...In order to achieve a modulator with broad bandwidth and perfect impedance match,a novel electro-optical modulator based on GeO2-doped silica waveguides on silicon substrate is designed.The finite element model of the whole electro-optical modulator is established by means of ANSYS.With the finite element method analysis,the performance of the novel modulator is predicted.The simulation reveals that the designed modulator operates with a product of 3 dB optical bandwidth and modulating length of 226.59 GHz·cm,and a characteristic impedance of 51.6 Ω at 1 550 nm wavelength.Moreover,the calculated electrical reflected power of coplanar waveguide electrode is below-20 dB in the frequency ranging from 45 MHz to 65 GHz.Therefore,the designed modulator has wide modulation bandwidth and perfect impedance match.展开更多
A very simple scheme is presented for teleporting an unknown frequency state with the successful probability of 50%. Two acoustic-optical modulators and four narrow band photodetectors in the proposed scheme are used....A very simple scheme is presented for teleporting an unknown frequency state with the successful probability of 50%. Two acoustic-optical modulators and four narrow band photodetectors in the proposed scheme are used. One advantage of our scheme is that no Bell-state measurement is need and no any unitary transformation is performed.展开更多
Waveguide-integrated optical modulators are indispensable for on-chip optical interconnects and optical computing.To cope with the ever-increasing amount of data being generated and consumed,ultrafast waveguide-integr...Waveguide-integrated optical modulators are indispensable for on-chip optical interconnects and optical computing.To cope with the ever-increasing amount of data being generated and consumed,ultrafast waveguide-integrated optical modulators with low energy consumption are highly demanded.In recent years,two-dimensional(2D)materials have attracted a lot of attention and have provided tremendous opportunities for the development of high-performance waveguide-integrated optical modulators because of their extraordinary optoelectronic properties and versatile compatibility.This paper reviews the state-of-the-art waveguide-integrated optical modulators with 2D materials,providing researchers with the developing trends in the field and allowing them to identify existing challenges and promising potential solutions.First,the concept and fundamental mechanisms of optical modulation with 2D materials are summarized.Second,a review of waveguide-integrated optical modulators employing electro-optic,all-optic,and thermo-optic effects is provided.Finally,the challenges and perspectives of waveguide-integrated modulators with 2D materials are discussed.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
Saturable absorbers(SAs)covering wavelengths from near-infrared(NIR)to mid-infrared(MIR)band are required for mode-locking and Q-switching lasers in muti-band wavelengths.Here,broadband nonlinear optical property was ...Saturable absorbers(SAs)covering wavelengths from near-infrared(NIR)to mid-infrared(MIR)band are required for mode-locking and Q-switching lasers in muti-band wavelengths.Here,broadband nonlinear optical property was discovered in Cs_(x)WO_(3) nanorods(NRs),which as a novel non-stoichiometric SA for realizing ultrafast fiber lasers is first demonstrated.The Cs_(x)WO_(3) NRs based SA exhibited good mode-locking ability in three key wavelengths from NIR to MIR region,which is a key advantage over the most reported broadband SAs.The given Cs_(x)WO_(3) NRs showed a broadband optical absorption from 800 to 3,200 nm,and excellent SA properties at 1-μm,1.5-μm,and 2-μm optical bands.Employing such SA,the ultrashort pulse lasers with a pulse duration/repetition rate of 530 fs/37.42 MHz at 1,567 nm and 5.6 ps/41.50 MHz at 1,965 nm from Er-and Tm-doped fiber lasers(TDFL)were realized separately.In addition,a stable mode locked operation at 1,030 nm with a repetition rate of 48.80 MHz was also achieved from Yb-doped fiber laser(YDFL).This work not only offers a new and reliable broadband mode locker for ultrafast laser generation,but also broadens the application of Cs_(x)WO_(3) materials in the field of nonlinear fiber optics.展开更多
We report broadband all-fiber optical phase modulation based on the photo-thermal effect in a gas-filled hollow-core fiber.The phase modulation dynamics are studied by multi-physics simulation.A phase modulator is fab...We report broadband all-fiber optical phase modulation based on the photo-thermal effect in a gas-filled hollow-core fiber.The phase modulation dynamics are studied by multi-physics simulation.A phase modulator is fabricated using a 5.6-cm-long anti-resonant hollow-core fiber with pure acetylene filling.It has a half-wave optical power of 289 mW at 100 kHz and an average insertion loss 0.6 dB over a broad wavelength range from 1450 to 1650 nm.The rise and fall time constants are 3.5 and 3.7μs,respectively,2–3 orders of magnitude better than the previously reported microfiber-based photo-thermal phase modulators.The gas-filled hollow-core waveguide configuration is promising for optical phase modulation from ultraviolet to mid-infrared which is challenging to achieve with solid optical fibers.展开更多
A high-speed silicon modulator with broad optical bandwidth is proposed based on a symmetrically configured Mach- Zehnder interferometer. Careful phase bias control and traveling-wave design are used to improve the hi...A high-speed silicon modulator with broad optical bandwidth is proposed based on a symmetrically configured Mach- Zehnder interferometer. Careful phase bias control and traveling-wave design are used to improve the high-speed perfor- mance. Over a broadband wavelength range, high-speed operation up to 30 Gbit/s with a 4.5 dB-5.5 dB extinction ratio is experimentally demonstrated with a low driving voltage of 3 V.展开更多
The five -layer asymmetric coupled quantum well ( FACQW) , which is one of the potential -tailored quantum wells, is expected to show very large electrorefrac live index cha nge in a wideband transpar ency region far ...The five -layer asymmetric coupled quantum well ( FACQW) , which is one of the potential -tailored quantum wells, is expected to show very large electrorefrac live index cha nge in a wideband transpar ency region far from the absorption edge. Characteristics of the FACQW and its application to compact, ultrafast , low voltage optical modul ators and switches are dis cussed.展开更多
1 IntroductionLiNbO3 optical modulators have become essential transmission devices for current and future wideband fibre-optic communications for both military and telecommunications applications. For many telecommuni...1 IntroductionLiNbO3 optical modulators have become essential transmission devices for current and future wideband fibre-optic communications for both military and telecommunications applications. For many telecommunications applications, only a narrow bandwidth is required and thus resonantly enhancedMach-Zehndermodulators(RE-MZMs)have been developed to improve modulation efficiency at the expense of bandwidth.展开更多
We propose a novel silicon optical phase shifter structure based on heterogeneous strip-loaded waveguides on a photonic silicon on insulator(SOI) platform. The features of an etchless SOI layer and loaded strip would ...We propose a novel silicon optical phase shifter structure based on heterogeneous strip-loaded waveguides on a photonic silicon on insulator(SOI) platform. The features of an etchless SOI layer and loaded strip would enhance the performance and uniformity of silicon optical modulators on a large-scale wafer. We implemented the phase shifter by loading an amorphous silicon strip onto an SOI layer with a vertical PN diode structure. Compared to the conventional lateral PN phase shifter based on half-etched rib waveguides, this phase shifter shows a >1.5 times enhancement of modulation efficiency and provides >20 GHz high-speed operation.展开更多
We demonstrate a 12.5 Gb/s carrier-injection silicon Mach-Zehnder optical modulator.Under a nonreturn -zero（NRZ） pre-emphasized electrical drive signal with voltage swing of 6.3 V and forward bias of 0.7 V, the eye ...We demonstrate a 12.5 Gb/s carrier-injection silicon Mach-Zehnder optical modulator.Under a nonreturn -zero（NRZ） pre-emphasized electrical drive signal with voltage swing of 6.3 V and forward bias of 0.7 V, the eye is clearly opened with an extinction ratio of 8.4 dB.The device exhibits high modulation efficiency,with a figure of merit V_πL of 0.036 V·mm.展开更多
Graphene is a 2D material which has attracted tremendous interest from academia and industry,due to its attractive electrical and optical properties.By integrating graphene onto silicon photonics platform,various high...Graphene is a 2D material which has attracted tremendous interest from academia and industry,due to its attractive electrical and optical properties.By integrating graphene onto silicon photonics platform,various high-performance electrooptic and thermo-optic modulators have been demonstrated.In this paper,such graphene-based optical modulators are reviewed.The concept and principle of optical modulations are firstly analyzed and then an overview of the developing trends of optical modulators is presented.Meanwhile,the performances of graphene-based optical modulators,including power consumptions and speeds of electro-optic modulators as well as tuning efficiencies of thermo-optic modulators,are then evaluated and discussed in detail.All these optical modulators would play important roles in a wide range of applications including telecom,interconnects,computing,quantum information processing,and beam steering.展开更多
An in-line,all-optical fiber modulator based on a stereo graphene–microfiber structure(GMF)utilizing the lab-on-rod technique was demonstrated in this study.Owing to its unique spring-like geometry,an ultra-long GMF ...An in-line,all-optical fiber modulator based on a stereo graphene–microfiber structure(GMF)utilizing the lab-on-rod technique was demonstrated in this study.Owing to its unique spring-like geometry,an ultra-long GMF interaction can be achieved,and a modulation depth of,7.5 dB(,2.5 dB)and a modulation efficiency of,0.2 dB mW^(-1)(,0.07 dB mW^(-1))were demonstrated for two polarization states.The modulation depth and modulation efficiency are more than one order of magnitude larger than those of other graphene–microfiber hybrid all-optical modulators,although at the cost of a higher insertion loss.By further optimizing the transferring and cleaning process,the upper limit of the modulation depth is mainly determined by the loss from the intrinsic absorption,which depends on the light–graphene interaction.Then,the modulator can quickly switch between the on-state and the off-state with a theoretically maximized modulation depth of tens of decibels.This modulator is compatible with the current fiber-optic communication systems and may be applied in the near future to meet the impending need for ultrafast optical signal processing.展开更多
We report all-optical mid-infrared phase and intensity modulators based on the photo-thermal effect in an acetylene-filled anti-resonant hollow-core fiber.Optical absorption of the control beam promotes the gas molecu...We report all-optical mid-infrared phase and intensity modulators based on the photo-thermal effect in an acetylene-filled anti-resonant hollow-core fiber.Optical absorption of the control beam promotes the gas molecules to a higher energy level,which induces localized heating through non-radiative relaxation and modulates the refractive index of the gas material and hence the accumulated phase of the signal beam propagating through the hollow-core fiber.By modulating the intensity of the control beam,the phase of the signal beam is modulated accordingly.By use of a 1.53μm near-infrared control beam,all-optical phase modulation up to 2.2πrad is experimentally demonstrated at the signal wavelength of 3.35μm.With the phase modulator placed in one arm of a Mach-Zehnder interferometer,intensity modulation with on-off ratio of 25 dB is achieved.The gas-filled hollow-core-fiber modulators could operate over an ultra-broad wavelength band from near-to mid-infrared and have promising application in mid-infrared photonic systems.展开更多
In this work,a hybrid integrated optical transmitter module was designed and fabricated.A proton-exchanged Mach–Zehnder lithium niobate(LiNbO_(3))modulator chip was chosen to enhance the output extinction ratio.A fib...In this work,a hybrid integrated optical transmitter module was designed and fabricated.A proton-exchanged Mach–Zehnder lithium niobate(LiNbO_(3))modulator chip was chosen to enhance the output extinction ratio.A fiber was used to adjust the rotation of the polarization direction caused by the optical isolator.The whole optical path structure,including the laser chip,lens,fiber,and modulator chip,was simulated to achieve high optical output efficiency.After a series of process improvements,a module with an output extinction ratio of 34 dB and a bandwidth of 20.5 GHz(from 2 GHz)was obtained.The optical output efficiency of the whole module reached approximately 21%.The link performance of the module was also measured.展开更多
A wideband tunable frequency-doubling optoelectronic oscillator （FD-OEO） is proposed and experimentally demonstrated based on a polarization modulator and an optical bandpass filter （OBPF）. The central frequency o...A wideband tunable frequency-doubling optoelectronic oscillator （FD-OEO） is proposed and experimentally demonstrated based on a polarization modulator and an optical bandpass filter （OBPF）. The central frequency of the correspondingly fundamental OEO could be adjusted by tuning the bandwidth and central frequency of the OBPF, which could also be regarded as a photonic-assisted tunable microwave filter. The frequency tuning range of the FD-OEO covers from 9.5 to 32.8？GHz, and the single sideband phase noise of the fundamental signal is lower than -100dBc/Hz at an offset of 10？kHz. Moreover, the frequency stability of the generated signal is investigated by measuring its Allan deviation. The Allan deviation of the generated fundamental signal at 10？GHz is 2.39×10^-9.展开更多
Microwave magneto-optic （MO） modulators can directly transform radio frequency （RF） signals into optical data through the Bragg diffraction of guided optical waves （GOWs） induced by microwave magneto-static wav...Microwave magneto-optic （MO） modulators can directly transform radio frequency （RF） signals into optical data through the Bragg diffraction of guided optical waves （GOWs） induced by microwave magneto-static waves （MSWs）. According to the MO coupled-mode theory, the modulation of continuous GOWs by a rectangular magneto-static-forwardvolume-wave （MSFVW） pulse in MO film waveguide is studied in the small signal case and the modulated optical pulse at the output is analyzed by means of an analytical form, which is dependent on the instantaneous diffraction intensity determined by the overlap of rectangular MSFVW pulse and light beam aperture. On the basis of it, the characteristics of MSFVW-based MO modulators can be explained well for the case of rectangular pulse modulation. It is also shown that the line codes of optical data generated by MO Bragg modulators can be controlled by adjusting the duty factor of modulating pulse signals.展开更多
Efficient coupling from the silicon waveguide to the GeSi layer is the key to success in the GeSi electro-absorption （EA） modulator based on evanescent coupling. A lateral taper in the upper GeSi layer has room for ...Efficient coupling from the silicon waveguide to the GeSi layer is the key to success in the GeSi electro-absorption （EA） modulator based on evanescent coupling. A lateral taper in the upper GeSi layer has room for increasing the modulating efficiency and alleviating the sensitivity of the extinction ratio （ER） and insertion loss （IL） to the length of the active region. The light behavior and the effect of the taper are explored in detail using the beam propagation method （BPM）. After optimization, the light can nearly be totally confined in the GeSi layer without any oscillation. The modulator with the designed taper can achieve low IL and high ER.展开更多
Exploring materials with high electrochemical activity is of keen interest for electrochemistry-controlled optical and energy storage devices.However,it remains a great challenge for transition metal oxides to meet th...Exploring materials with high electrochemical activity is of keen interest for electrochemistry-controlled optical and energy storage devices.However,it remains a great challenge for transition metal oxides to meet this feature due to their low electron conductivity and insufficient reaction sites.Here,we propose a type of transition metal phosphate(NiHPO_(4)·3H_(2)O,NHP)by a facile and scalable electrodeposition method,which can achieve the capability of efficient ion accommodation and injection/extraction for electrochromic energy storage applications.Specifically,the NHP film with an ultra-high transmittance(approach to 100%)achieves a large optical modulation(90.8%at 500 nm),high coloration efficiency(75.4 cm^(2)C^(-1)at 500 nm),and a high specific capacity of 47.8 mAh g^(-1)at 0.4 A g^(-1).Furthermore,the transformation mechanism of NHP upon electrochemical reaction is systematically elucidated using in situ and ex situ techniques.Ultimately,a large-area electrochromic smart window with 100 cm^(2)is constructed based on the NHP electrode,displaying superior electrochromic energy storage performance in regulating natural light and storing electrical charges.Our findings may open up new strategies for developing advanced electrochromic energy storage materials and smart windows.展开更多
基金Project supported by the Natural Science Foundation of Tianjin City,China(Grant No.13JCYBJC16100)the National Natural Science Foundation of China(Grant No.61107035)+1 种基金the National Key Scientific Instrument and Equipment Development Project of China(Grant No.2013YQ03091502)the National Basic Research Program of China(Grant Nos.2010CB327802 and 2010CB327806)
文摘An all-fiber optical modulator, which is composed of a piece of no-core fiber spliced between two sections of singlemode fibers and uses magnetic fluid（MF） as the cladding of the no-core fiber section, is proposed and investigated experimentally. Due to the tunable refractive index and absorption coefficient of MF, the output intensity can be modulated by controlling an applied magnetic field. The dependences of the modulator＇s temporal response on the working wavelength,the magnetic field strength（H）, and the MF＇s concentration are investigated experimentally. The results are explained qualitatively by the dynamic response process of MF under the action of a magnetic field. The findings are helpful for optimizing this kind of modulator.
基金Supported by National Natural Science Foundation of China (No.60577023)Key Laboratory of Opto-Electronics Information and Technical Science of Ministry of Education,China
文摘In order to achieve a modulator with broad bandwidth and perfect impedance match,a novel electro-optical modulator based on GeO2-doped silica waveguides on silicon substrate is designed.The finite element model of the whole electro-optical modulator is established by means of ANSYS.With the finite element method analysis,the performance of the novel modulator is predicted.The simulation reveals that the designed modulator operates with a product of 3 dB optical bandwidth and modulating length of 226.59 GHz·cm,and a characteristic impedance of 51.6 Ω at 1 550 nm wavelength.Moreover,the calculated electrical reflected power of coplanar waveguide electrode is below-20 dB in the frequency ranging from 45 MHz to 65 GHz.Therefore,the designed modulator has wide modulation bandwidth and perfect impedance match.
文摘A very simple scheme is presented for teleporting an unknown frequency state with the successful probability of 50%. Two acoustic-optical modulators and four narrow band photodetectors in the proposed scheme are used. One advantage of our scheme is that no Bell-state measurement is need and no any unitary transformation is performed.
基金funding support from the National Major Research and Development Program(2019YFB2203603)the National Science Fund for Distinguished Young Scholars(61725503)+2 种基金the National Natural Science Foundation of China(NSFC)(62275273,11804387,and 91950205)the China Postdoctoral Science Foundation(2020M681847)the Zhejiang Provincial Natural Science Foundation(LZ18F050001).
文摘Waveguide-integrated optical modulators are indispensable for on-chip optical interconnects and optical computing.To cope with the ever-increasing amount of data being generated and consumed,ultrafast waveguide-integrated optical modulators with low energy consumption are highly demanded.In recent years,two-dimensional(2D)materials have attracted a lot of attention and have provided tremendous opportunities for the development of high-performance waveguide-integrated optical modulators because of their extraordinary optoelectronic properties and versatile compatibility.This paper reviews the state-of-the-art waveguide-integrated optical modulators with 2D materials,providing researchers with the developing trends in the field and allowing them to identify existing challenges and promising potential solutions.First,the concept and fundamental mechanisms of optical modulation with 2D materials are summarized.Second,a review of waveguide-integrated optical modulators employing electro-optic,all-optic,and thermo-optic effects is provided.Finally,the challenges and perspectives of waveguide-integrated modulators with 2D materials are discussed.
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This work was supported by the Specialized Fund for the Doctoral Research of Jilin Engineering Normal University under(No.BSKJ201920)the Science and Technology Research Project of Jilin Province's Education Department(No.JJKH20210175KJ)the Project of Science and Technology Plan of Jilin Province(No.YDZJ202101ZYTS178)。
文摘Saturable absorbers(SAs)covering wavelengths from near-infrared(NIR)to mid-infrared(MIR)band are required for mode-locking and Q-switching lasers in muti-band wavelengths.Here,broadband nonlinear optical property was discovered in Cs_(x)WO_(3) nanorods(NRs),which as a novel non-stoichiometric SA for realizing ultrafast fiber lasers is first demonstrated.The Cs_(x)WO_(3) NRs based SA exhibited good mode-locking ability in three key wavelengths from NIR to MIR region,which is a key advantage over the most reported broadband SAs.The given Cs_(x)WO_(3) NRs showed a broadband optical absorption from 800 to 3,200 nm,and excellent SA properties at 1-μm,1.5-μm,and 2-μm optical bands.Employing such SA,the ultrashort pulse lasers with a pulse duration/repetition rate of 530 fs/37.42 MHz at 1,567 nm and 5.6 ps/41.50 MHz at 1,965 nm from Er-and Tm-doped fiber lasers(TDFL)were realized separately.In addition,a stable mode locked operation at 1,030 nm with a repetition rate of 48.80 MHz was also achieved from Yb-doped fiber laser(YDFL).This work not only offers a new and reliable broadband mode locker for ultrafast laser generation,but also broadens the application of Cs_(x)WO_(3) materials in the field of nonlinear fiber optics.
基金We are grateful for financial supports from the National Key Research and Development Program of China(2019YFB2203904)the National Natural Science Foundation of China(U21A20506,62105122,61827820,62005233)+1 种基金the Shenzhen STIC Funding(RCBS20200714114819032)the Local Innovative and Research Teams Project of Guangdong Pear River Talents Program(2019BT02X105).
文摘We report broadband all-fiber optical phase modulation based on the photo-thermal effect in a gas-filled hollow-core fiber.The phase modulation dynamics are studied by multi-physics simulation.A phase modulator is fabricated using a 5.6-cm-long anti-resonant hollow-core fiber with pure acetylene filling.It has a half-wave optical power of 289 mW at 100 kHz and an average insertion loss 0.6 dB over a broad wavelength range from 1450 to 1650 nm.The rise and fall time constants are 3.5 and 3.7μs,respectively,2–3 orders of magnitude better than the previously reported microfiber-based photo-thermal phase modulators.The gas-filled hollow-core waveguide configuration is promising for optical phase modulation from ultraviolet to mid-infrared which is challenging to achieve with solid optical fibers.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2012AA012202)the National Basic Research Program of China(Grant No.2011CB301701)+1 种基金the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KGCX2-EW-102)the National Natural Science Foundation of China(Grant Nos.61107048 and 61275065)
文摘A high-speed silicon modulator with broad optical bandwidth is proposed based on a symmetrically configured Mach- Zehnder interferometer. Careful phase bias control and traveling-wave design are used to improve the high-speed perfor- mance. Over a broadband wavelength range, high-speed operation up to 30 Gbit/s with a 4.5 dB-5.5 dB extinction ratio is experimentally demonstrated with a low driving voltage of 3 V.
文摘The five -layer asymmetric coupled quantum well ( FACQW) , which is one of the potential -tailored quantum wells, is expected to show very large electrorefrac live index cha nge in a wideband transpar ency region far from the absorption edge. Characteristics of the FACQW and its application to compact, ultrafast , low voltage optical modul ators and switches are dis cussed.
文摘1 IntroductionLiNbO3 optical modulators have become essential transmission devices for current and future wideband fibre-optic communications for both military and telecommunications applications. For many telecommunications applications, only a narrow bandwidth is required and thus resonantly enhancedMach-Zehndermodulators(RE-MZMs)have been developed to improve modulation efficiency at the expense of bandwidth.
文摘We propose a novel silicon optical phase shifter structure based on heterogeneous strip-loaded waveguides on a photonic silicon on insulator(SOI) platform. The features of an etchless SOI layer and loaded strip would enhance the performance and uniformity of silicon optical modulators on a large-scale wafer. We implemented the phase shifter by loading an amorphous silicon strip onto an SOI layer with a vertical PN diode structure. Compared to the conventional lateral PN phase shifter based on half-etched rib waveguides, this phase shifter shows a >1.5 times enhancement of modulation efficiency and provides >20 GHz high-speed operation.
基金supported by the National Natural Science Foundation of China(No.60977037)
文摘We demonstrate a 12.5 Gb/s carrier-injection silicon Mach-Zehnder optical modulator.Under a nonreturn -zero（NRZ） pre-emphasized electrical drive signal with voltage swing of 6.3 V and forward bias of 0.7 V, the eye is clearly opened with an extinction ratio of 8.4 dB.The device exhibits high modulation efficiency,with a figure of merit V_πL of 0.036 V·mm.
基金supported by the National Key R&D Program of China(2019YFB2205204)the National Natural Science Foundation of China(61875120)the“Shuguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission.
文摘Graphene is a 2D material which has attracted tremendous interest from academia and industry,due to its attractive electrical and optical properties.By integrating graphene onto silicon photonics platform,various high-performance electrooptic and thermo-optic modulators have been demonstrated.In this paper,such graphene-based optical modulators are reviewed.The concept and principle of optical modulations are firstly analyzed and then an overview of the developing trends of optical modulators is presented.Meanwhile,the performances of graphene-based optical modulators,including power consumptions and speeds of electro-optic modulators as well as tuning efficiencies of thermo-optic modulators,are then evaluated and discussed in detail.All these optical modulators would play important roles in a wide range of applications including telecom,interconnects,computing,quantum information processing,and beam steering.
基金This work is sponsored by the National 973 program(2012CB921803 and 2011CBA00205)the National Science Fund of China under grants 61225026,61322503,61457069,61435008 and 61490714the Fundamental Research Funds for the Central Universities.
文摘An in-line,all-optical fiber modulator based on a stereo graphene–microfiber structure(GMF)utilizing the lab-on-rod technique was demonstrated in this study.Owing to its unique spring-like geometry,an ultra-long GMF interaction can be achieved,and a modulation depth of,7.5 dB(,2.5 dB)and a modulation efficiency of,0.2 dB mW^(-1)(,0.07 dB mW^(-1))were demonstrated for two polarization states.The modulation depth and modulation efficiency are more than one order of magnitude larger than those of other graphene–microfiber hybrid all-optical modulators,although at the cost of a higher insertion loss.By further optimizing the transferring and cleaning process,the upper limit of the modulation depth is mainly determined by the loss from the intrinsic absorption,which depends on the light–graphene interaction.Then,the modulator can quickly switch between the on-state and the off-state with a theoretically maximized modulation depth of tens of decibels.This modulator is compatible with the current fiber-optic communication systems and may be applied in the near future to meet the impending need for ultrafast optical signal processing.
基金supported by the National Key Research and Development Program of China(2019YFB2203904)National Natural Science Foundation of China(61827820,62005233)+1 种基金the Shenzhen STIC Funding(RCBS20200714114819032)the Local Innovative and Research Teams Project of Guangdong Pear River Talents Program(2019BT02X105).
文摘We report all-optical mid-infrared phase and intensity modulators based on the photo-thermal effect in an acetylene-filled anti-resonant hollow-core fiber.Optical absorption of the control beam promotes the gas molecules to a higher energy level,which induces localized heating through non-radiative relaxation and modulates the refractive index of the gas material and hence the accumulated phase of the signal beam propagating through the hollow-core fiber.By modulating the intensity of the control beam,the phase of the signal beam is modulated accordingly.By use of a 1.53μm near-infrared control beam,all-optical phase modulation up to 2.2πrad is experimentally demonstrated at the signal wavelength of 3.35μm.With the phase modulator placed in one arm of a Mach-Zehnder interferometer,intensity modulation with on-off ratio of 25 dB is achieved.The gas-filled hollow-core-fiber modulators could operate over an ultra-broad wavelength band from near-to mid-infrared and have promising application in mid-infrared photonic systems.
基金This work was supported by National Key Research and Development Program of China(2018YFB2201101)the Strategic Priority Research Program of Chinese Academy of Sciences,Grant No.XDB43000000Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park No.Z201100004020004。
文摘In this work,a hybrid integrated optical transmitter module was designed and fabricated.A proton-exchanged Mach–Zehnder lithium niobate(LiNbO_(3))modulator chip was chosen to enhance the output extinction ratio.A fiber was used to adjust the rotation of the polarization direction caused by the optical isolator.The whole optical path structure,including the laser chip,lens,fiber,and modulator chip,was simulated to achieve high optical output efficiency.After a series of process improvements,a module with an output extinction ratio of 34 dB and a bandwidth of 20.5 GHz(from 2 GHz)was obtained.The optical output efficiency of the whole module reached approximately 21%.The link performance of the module was also measured.
基金Supported by the National Natural Science Foundation of China under Grant No 61675196the National Basic Research Program of China under Grant No 2014CB340102+1 种基金the National High-Tech Research and Development Program of China under Grant No 2015AA016903the Open Research of Beijing University of Posts and Telecommunications under Grant No IOOC2013A002
文摘A wideband tunable frequency-doubling optoelectronic oscillator （FD-OEO） is proposed and experimentally demonstrated based on a polarization modulator and an optical bandpass filter （OBPF）. The central frequency of the correspondingly fundamental OEO could be adjusted by tuning the bandwidth and central frequency of the OBPF, which could also be regarded as a photonic-assisted tunable microwave filter. The frequency tuning range of the FD-OEO covers from 9.5 to 32.8？GHz, and the single sideband phase noise of the fundamental signal is lower than -100dBc/Hz at an offset of 10？kHz. Moreover, the frequency stability of the generated signal is investigated by measuring its Allan deviation. The Allan deviation of the generated fundamental signal at 10？GHz is 2.39×10^-9.
基金supported by the National Natural Science Foundation of China under Grant No 60671027the Application Basis Research Foundation of Sichuan Province under Grant No 07JY029-089
文摘Microwave magneto-optic （MO） modulators can directly transform radio frequency （RF） signals into optical data through the Bragg diffraction of guided optical waves （GOWs） induced by microwave magneto-static waves （MSWs）. According to the MO coupled-mode theory, the modulation of continuous GOWs by a rectangular magneto-static-forwardvolume-wave （MSFVW） pulse in MO film waveguide is studied in the small signal case and the modulated optical pulse at the output is analyzed by means of an analytical form, which is dependent on the instantaneous diffraction intensity determined by the overlap of rectangular MSFVW pulse and light beam aperture. On the basis of it, the characteristics of MSFVW-based MO modulators can be explained well for the case of rectangular pulse modulation. It is also shown that the line codes of optical data generated by MO Bragg modulators can be controlled by adjusting the duty factor of modulating pulse signals.
文摘Efficient coupling from the silicon waveguide to the GeSi layer is the key to success in the GeSi electro-absorption （EA） modulator based on evanescent coupling. A lateral taper in the upper GeSi layer has room for increasing the modulating efficiency and alleviating the sensitivity of the extinction ratio （ER） and insertion loss （IL） to the length of the active region. The light behavior and the effect of the taper are explored in detail using the beam propagation method （BPM）. After optimization, the light can nearly be totally confined in the GeSi layer without any oscillation. The modulator with the designed taper can achieve low IL and high ER.
基金financially the National Natural Science Foundation of China(U2004175,51902086 and 62222402)China Postdoctoral Science Foundation(2022M711036)the Key Scientific Research Project plan of the University in Henan Province(22A430002)。
文摘Exploring materials with high electrochemical activity is of keen interest for electrochemistry-controlled optical and energy storage devices.However,it remains a great challenge for transition metal oxides to meet this feature due to their low electron conductivity and insufficient reaction sites.Here,we propose a type of transition metal phosphate(NiHPO_(4)·3H_(2)O,NHP)by a facile and scalable electrodeposition method,which can achieve the capability of efficient ion accommodation and injection/extraction for electrochromic energy storage applications.Specifically,the NHP film with an ultra-high transmittance(approach to 100%)achieves a large optical modulation(90.8%at 500 nm),high coloration efficiency(75.4 cm^(2)C^(-1)at 500 nm),and a high specific capacity of 47.8 mAh g^(-1)at 0.4 A g^(-1).Furthermore,the transformation mechanism of NHP upon electrochemical reaction is systematically elucidated using in situ and ex situ techniques.Ultimately,a large-area electrochromic smart window with 100 cm^(2)is constructed based on the NHP electrode,displaying superior electrochromic energy storage performance in regulating natural light and storing electrical charges.Our findings may open up new strategies for developing advanced electrochromic energy storage materials and smart windows.
