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
CO2 laser rapid ablation mitigation(RAM)of fused silica has been used in high-power laser systems owing to its advantages of high efficiency,and ease of implementing batch and automated repairing.In order to study the...CO2 laser rapid ablation mitigation(RAM)of fused silica has been used in high-power laser systems owing to its advantages of high efficiency,and ease of implementing batch and automated repairing.In order to study the effect of repaired morphology of RAM on laser modulation and to improve laser damage threshold of optics,an finite element method(FEM)mathematical model of 351 nm laser irradiating fused silica optics is developed based on Maxwell electromagnetic field equations,to explore the 3D near-field light intensity distribution inside optics with repaired site on its surface.The influences of the cone angle and the size of the repaired site on incident laser modulation are studied as well.The results have shown that for the repaired site with a cone angle of 73.3°,the light intensity distribution has obvious three-dimensional characteristics.The relative light intensity on z-section has a circularly distribution,and the radius of the annular intensification zone increases with the decrease of z.While the distribution of maximum relative light intensity on y-section is parabolical with the increase of y.As the cone angle of the repaired site decreases,the effect of the repaired surface on light modulation becomes stronger,leading to a weak resistance to laser damage.Moreover,the large size repaired site would also reduce the laser damage threshold.Therefore,a repaired site with a larger cone angle and smaller size is preferred in practical CO2 laser repairing of surface damage.This work will provide theoretical guidance for the design of repaired surface topography,as well as the improvement of RAM process.展开更多
Two-dimensional(2D)nonlinear optical mediums with high and tunable light modulation capability can significantly stimulate the development of ultrathin,compact,and integrated optoelectronics devices and photonic eleme...Two-dimensional(2D)nonlinear optical mediums with high and tunable light modulation capability can significantly stimulate the development of ultrathin,compact,and integrated optoelectronics devices and photonic elements.2D carbides and nitrides of transition metals(MXenes)are a new class of 2D materials with excellent intrinsic and strong light-matter interaction characteristics.However,the current understanding of their photo-physical properties and strategies for improving optical performance is insufficient.To address this issue,we rationally designed and in situ synthesized a 2D Nb_(2)C/MoS_(2) heterostructure that outperforms pristine Nb2C in both linear and nonlinear optical performance.Excellent agreement between experimental and theoretical results demonstrated that the Nb_(2)C/MoS_(2) inherited the preponderance of Nb_(2)C and MoS_(2) in absorption at different wavelengths,resulting in the broadband enhanced optical absorption characteristics.In addition to linear optical modulation,we also achieved stronger near infrared nonlinear optical modulation,with a nonlinear absorption coefficient of Nb_(2)C/MoS_(2) being more than two times that of the pristine Nb_(2)C.These results were supported by the band alinement model which was determined by the X-ray photoelectron spectroscopy(XPS)experiment and first-principal theory calculation.The presented facile synthesis approach and robust light modulation strategy pave the way for broadband optoelectronic devices and optical modulators.展开更多
In order to decrease dispersion penalty and increase the optical bandwidth efficiency,an optical single-side-band modulation(SSBM) scheme in sub-carrier multiplexing(SCM) is proposed.The principle of the SSBM is analy...In order to decrease dispersion penalty and increase the optical bandwidth efficiency,an optical single-side-band modulation(SSBM) scheme in sub-carrier multiplexing(SCM) is proposed.The principle of the SSBM is analytically presented,and a configuration for generating optical SSB signal is proposed using a balanced Mach-Zehnder electro-optic modulator.展开更多
We demonstrate a new technique of measuring differential carrier lifetime and linewidth enhancement factor in a semiconductor optical amplifier. In our method, the optical responses and fiber transfer functions of a s...We demonstrate a new technique of measuring differential carrier lifetime and linewidth enhancement factor in a semiconductor optical amplifier. In our method, the optical responses and fiber transfer functions of a self-gain modulated SOA are measured and, from these, values of carrier lifetimes and linewidth enhancement factors are determined for various SOA input optical powers.展开更多
We propose an optical transmitter with reduced modulator driving voltage. This reduction is achieved through an on-off ratio improvement technique based on FWM. We confirmed the feasibility of the method in a 43-Gbit/...We propose an optical transmitter with reduced modulator driving voltage. This reduction is achieved through an on-off ratio improvement technique based on FWM. We confirmed the feasibility of the method in a 43-Gbit/s experiment.展开更多
An optical modulation format generation scheme based on spectral filtering and frequency-to-time mapping is experimentally demonstrated. Many modulation formats with continuously adjustable duty radio and bit rate can...An optical modulation format generation scheme based on spectral filtering and frequency-to-time mapping is experimentally demonstrated. Many modulation formats with continuously adjustable duty radio and bit rate can be formed by changing the dispersion of dispersion element and the bandwidth of shaped spectrum in this scheme. In the experiment, non-return-to-zero(NRZ) signal with bit rate of 29.41 Gbit/s and 1/2 duty ratio return-to-zero(RZ) signal with bit rate of 13.51 Gbit/s are obtained. The maximum bit rate of modulation format signal is also analyzed.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
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
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
We propose a novel optical signal regeneration system based on wavelength converters by use of cross gain modulation in cascaded semiconductor optical amplifiers. The nonlinearity in optical input/output characteristi...We propose a novel optical signal regeneration system based on wavelength converters by use of cross gain modulation in cascaded semiconductor optical amplifiers. The nonlinearity in optical input/output characteristics and eye opening using NRZ signal were archived.展开更多
A hybrid polarization division multiplexed-differential phase shift keying-multipulse pulse position modulation(PDM-DPSK-MPPM) scheme for multi-hop free-space optical(FSO) communication is investigated. The analytical...A hybrid polarization division multiplexed-differential phase shift keying-multipulse pulse position modulation(PDM-DPSK-MPPM) scheme for multi-hop free-space optical(FSO) communication is investigated. The analytical bit error rate(BER) of the proposed system in Gamma-Gamma turbulence channels is derived and verified using computer simulation. The results show that both multi-hop and hybrid modulation schemes are efficient techniques to improve the performance of FSO links. Compared with the traditional binary phase shift keying(BPSK) and MPPM, the hybrid scheme can improve the bandwidth-utilization efficiency and reliability of the system. Compared with the coherent demodulation of PDM-QPSK-MPPM, the system complexity is reduced at the cost of the degradation of BER performance, which can improve the practicality of hybrid modulation technology in FSO system.展开更多
The cross gain modulation, the cross phase modulation and their recovery time in the SOAs with the various lengths were experimentally investigated. It was found that these values strongly depended on the device length.
Noise and the resonance characteristics of the focal plane array(FPA)are the most important factors that affect the performance of the optical readout infrared(IR)FPA imaging system.This Letter presents a time-discret...Noise and the resonance characteristics of the focal plane array(FPA)are the most important factors that affect the performance of the optical readout infrared(IR)FPA imaging system.This Letter presents a time-discrete modulation technology that eliminates the background and restrain noise,which effectively improves the image quality of the optical readout IR FPA imaging system.The comparative experiments show that this technology can reduce the noise equivalent temperature difference greatly and make the images sharper.Moreover,when the imaging system is influenced by the environment vibration,the images obtained from the imaging system with time-discrete modulation restore twice as fast as without time-discrete modulation.展开更多
In this paper, we have evaluated a bidirectional wavelength division multiplexing passive optical network(WDM-PON) employing intensity modulated/direct detection optical orthogonal frequency division multiplexing(IM/D...In this paper, we have evaluated a bidirectional wavelength division multiplexing passive optical network(WDM-PON) employing intensity modulated/direct detection optical orthogonal frequency division multiplexing(IM/DD-OFDM). The proposed system employs 100 Gbit/s 16 quadrature amplitude modulation(16-QAM) downstream and 5 Gbit/s on-off keying(OOK) upstream wavelengths, respectively. The proposed system is considered low-cost as non-coherent IM/DD OFDM technology and a simple reflective semiconductor optical amplifier(RSOA) colorless transmitter are employed and no dispersion compensating fiber(DCF) is needed. Based on the bit error rate(BER) results of WDM signals, the proposed WDM-PON system can achieve up to 1.6 Tbit/s(100 Gbit/s/λ × 16 wavelengths) downstream transmission over a 30 km single mode fiber(SMF).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
Graphene-doped polymer nanofibers are fabricated by taper drawing of solvated polyvinyl alcohol doped with liquid-phase exfoliated graphene flakes.Nanofibers drawn this way typically have diameters measured in hundred...Graphene-doped polymer nanofibers are fabricated by taper drawing of solvated polyvinyl alcohol doped with liquid-phase exfoliated graphene flakes.Nanofibers drawn this way typically have diameters measured in hundreds of nanometers and lengths in tens of millimeters;they show excellent uniformity and surface smoothness for optical waveguiding.Owing to their tightly confined waveguiding behavior,light–matter interaction in these subwavelength-diameter nanofibers is significantly enhanced.Using approximately 1350-nm-wavelength femto-second pulses,we demonstrate saturable absorption behavior in these nanofibers with a saturation threshold down to 0.25 pJ pulse^(-1)(peak power,1.3 W).Additionally,using 1064-nm-wavelength nanosecond pulses as switching light,we show all-optical modulation of a 1550-nm-wavelength signal light guided along a single nanofiber with a switching peak power of,3.2 W.展开更多
Rhenium disulfide(ReS_2), a member of group Ⅶ transition metal dichalcogenides(TMDs), has attracted increasing attention because of its unique distorted 1T structure and electronic and optical properties, which are m...Rhenium disulfide(ReS_2), a member of group Ⅶ transition metal dichalcogenides(TMDs), has attracted increasing attention because of its unique distorted 1T structure and electronic and optical properties, which are much different from those of group Ⅵ TMDs(MoS_2, WS_2, MoSe_2, WSe_2, etc.). It has been proved that bulk ReS_2 behaves as a stack of electronically and vibrationally decoupled monolayers, which offers remarkable possibilities to prepare a monolayer ReS_2 facilely and offers a novel platform to study photonic properties of TMDs. However,due to the large and layer-independent bandgap, the nonlinear optical properties of ReS_2 from the visible to midinfrared spectral range have not yet been investigated. Here, the band structure of ReS_2 with the introduction of defects is simulated by the ab initio method, and the results indicate that the bandgap can be reduced from 1.38 to 0.54 eV with the introduction of defects in a suitable range. In the experiment, using a bulk ReS_2 with suitable defects as the raw material, a few-layered broadband ReS_2 saturable absorber(SA) is prepared by the liquid phase exfoliation method. Using the as-prepared ReS_2 SA, passively Q-switched solid-state lasers at wavelengths of 0.64,1.064, and 1.991 μm are investigated systematically. Moreover, with cavity design, a femtosecond passively modelocked laser at 1.06 μm is successfully realized based on the as-prepared ReS_2 SA for the first time. The results present a promising alternative for a rare broadband optical modulator and indicate the potential of ReS_2 in generating Q-switched and mode-locked pulsed lasers. It is further anticipated that this work may be helpful for the design of 2D optoelectronic devices with variable bandgaps.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
In this paper,we propose an effective method to compensate for the performance degradation of optically addressed spatial light modulators(OASLMs).The thermal deposition problem usually leads to the on-off ratio reduc...In this paper,we propose an effective method to compensate for the performance degradation of optically addressed spatial light modulators(OASLMs).The thermal deposition problem usually leads to the on-off ratio reduction of amplitude OASLM,so it is difficult to achieve better results in high-power laser systems.Through the analysis of the laser-induced temperature rise model and the liquid crystal layer voltage model,it is found that reducing the driving voltage of the liquid crystal light valve and increasing the driving current of the optical writing module can compensate for the decrease of on-off ratio caused by temperature rise.This is the result of effectively utilizing the photoconductive effect of Bi_(12)SiO_(20)(BSO)crystal.The experimental results verify the feasibility of the proposed method and increase the laser withstand power of amplitude-only OASLM by about a factor of 2.5.展开更多
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.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51775147 and 51705105)the Science Challenge Project of China(Grant No.TZ2016006-0503-01)+2 种基金the Young Elite Scientists Sponsorship Program by CAST(Grant No.2018QNRC001)the China Postdoctoral Science Foundation funded project(Grant Nos.2018T110288 and 2017M621260)the Self-Planned Task of State Key Laboratory of Robotics and System(HIT)(Grant Nos.SKLRS201718A and SKLRS201803B).
文摘CO2 laser rapid ablation mitigation(RAM)of fused silica has been used in high-power laser systems owing to its advantages of high efficiency,and ease of implementing batch and automated repairing.In order to study the effect of repaired morphology of RAM on laser modulation and to improve laser damage threshold of optics,an finite element method(FEM)mathematical model of 351 nm laser irradiating fused silica optics is developed based on Maxwell electromagnetic field equations,to explore the 3D near-field light intensity distribution inside optics with repaired site on its surface.The influences of the cone angle and the size of the repaired site on incident laser modulation are studied as well.The results have shown that for the repaired site with a cone angle of 73.3°,the light intensity distribution has obvious three-dimensional characteristics.The relative light intensity on z-section has a circularly distribution,and the radius of the annular intensification zone increases with the decrease of z.While the distribution of maximum relative light intensity on y-section is parabolical with the increase of y.As the cone angle of the repaired site decreases,the effect of the repaired surface on light modulation becomes stronger,leading to a weak resistance to laser damage.Moreover,the large size repaired site would also reduce the laser damage threshold.Therefore,a repaired site with a larger cone angle and smaller size is preferred in practical CO2 laser repairing of surface damage.This work will provide theoretical guidance for the design of repaired surface topography,as well as the improvement of RAM process.
基金financial support from the National Natural Science Foundation of China(Nos.61874141,11904239)Natural Science Foundation of Hunan Province(Grant Nos.2021JJ40709,2021JJ20080,2022JJ20080)+2 种基金Postgraduate Innovative Project of Central South University(Grant No.2021zzts0056)Open Sharing Found for the Large-scale Instruments and Equipment of Central South Universitysupported in part by the High Performance Computing Center of Central South University。
文摘Two-dimensional(2D)nonlinear optical mediums with high and tunable light modulation capability can significantly stimulate the development of ultrathin,compact,and integrated optoelectronics devices and photonic elements.2D carbides and nitrides of transition metals(MXenes)are a new class of 2D materials with excellent intrinsic and strong light-matter interaction characteristics.However,the current understanding of their photo-physical properties and strategies for improving optical performance is insufficient.To address this issue,we rationally designed and in situ synthesized a 2D Nb_(2)C/MoS_(2) heterostructure that outperforms pristine Nb2C in both linear and nonlinear optical performance.Excellent agreement between experimental and theoretical results demonstrated that the Nb_(2)C/MoS_(2) inherited the preponderance of Nb_(2)C and MoS_(2) in absorption at different wavelengths,resulting in the broadband enhanced optical absorption characteristics.In addition to linear optical modulation,we also achieved stronger near infrared nonlinear optical modulation,with a nonlinear absorption coefficient of Nb_(2)C/MoS_(2) being more than two times that of the pristine Nb_(2)C.These results were supported by the band alinement model which was determined by the X-ray photoelectron spectroscopy(XPS)experiment and first-principal theory calculation.The presented facile synthesis approach and robust light modulation strategy pave the way for broadband optoelectronic devices and optical modulators.
基金supported by Science Foundation for Youthful Teachers of Anhui University (Grant No.2007jql104)
文摘In order to decrease dispersion penalty and increase the optical bandwidth efficiency,an optical single-side-band modulation(SSBM) scheme in sub-carrier multiplexing(SCM) is proposed.The principle of the SSBM is analytically presented,and a configuration for generating optical SSB signal is proposed using a balanced Mach-Zehnder electro-optic modulator.
文摘We demonstrate a new technique of measuring differential carrier lifetime and linewidth enhancement factor in a semiconductor optical amplifier. In our method, the optical responses and fiber transfer functions of a self-gain modulated SOA are measured and, from these, values of carrier lifetimes and linewidth enhancement factors are determined for various SOA input optical powers.
文摘We propose an optical transmitter with reduced modulator driving voltage. This reduction is achieved through an on-off ratio improvement technique based on FWM. We confirmed the feasibility of the method in a 43-Gbit/s experiment.
基金supported by the National Natural Science Foundation of China(No.61377075)the Tianjin Natural Science Foundation(No.17JCYBJC16600)
文摘An optical modulation format generation scheme based on spectral filtering and frequency-to-time mapping is experimentally demonstrated. Many modulation formats with continuously adjustable duty radio and bit rate can be formed by changing the dispersion of dispersion element and the bandwidth of shaped spectrum in this scheme. In the experiment, non-return-to-zero(NRZ) signal with bit rate of 29.41 Gbit/s and 1/2 duty ratio return-to-zero(RZ) signal with bit rate of 13.51 Gbit/s are obtained. The maximum bit rate of modulation format signal is also analyzed.
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.
文摘We propose a novel optical signal regeneration system based on wavelength converters by use of cross gain modulation in cascaded semiconductor optical amplifiers. The nonlinearity in optical input/output characteristics and eye opening using NRZ signal were archived.
基金supported by the National Natural Science Foundation of China(No.61373124)
文摘A hybrid polarization division multiplexed-differential phase shift keying-multipulse pulse position modulation(PDM-DPSK-MPPM) scheme for multi-hop free-space optical(FSO) communication is investigated. The analytical bit error rate(BER) of the proposed system in Gamma-Gamma turbulence channels is derived and verified using computer simulation. The results show that both multi-hop and hybrid modulation schemes are efficient techniques to improve the performance of FSO links. Compared with the traditional binary phase shift keying(BPSK) and MPPM, the hybrid scheme can improve the bandwidth-utilization efficiency and reliability of the system. Compared with the coherent demodulation of PDM-QPSK-MPPM, the system complexity is reduced at the cost of the degradation of BER performance, which can improve the practicality of hybrid modulation technology in FSO system.
文摘The cross gain modulation, the cross phase modulation and their recovery time in the SOAs with the various lengths were experimentally investigated. It was found that these values strongly depended on the device length.
基金supported by the National Natural Science Foundation of China under Grant Nos.61377109 and 61301190
文摘Noise and the resonance characteristics of the focal plane array(FPA)are the most important factors that affect the performance of the optical readout infrared(IR)FPA imaging system.This Letter presents a time-discrete modulation technology that eliminates the background and restrain noise,which effectively improves the image quality of the optical readout IR FPA imaging system.The comparative experiments show that this technology can reduce the noise equivalent temperature difference greatly and make the images sharper.Moreover,when the imaging system is influenced by the environment vibration,the images obtained from the imaging system with time-discrete modulation restore twice as fast as without time-discrete modulation.
基金supported by the Erciyes University Scientific Research Projects Coordination Unit (No.FDK-2019-8750)。
文摘In this paper, we have evaluated a bidirectional wavelength division multiplexing passive optical network(WDM-PON) employing intensity modulated/direct detection optical orthogonal frequency division multiplexing(IM/DD-OFDM). The proposed system employs 100 Gbit/s 16 quadrature amplitude modulation(16-QAM) downstream and 5 Gbit/s on-off keying(OOK) upstream wavelengths, respectively. The proposed system is considered low-cost as non-coherent IM/DD OFDM technology and a simple reflective semiconductor optical amplifier(RSOA) colorless transmitter are employed and no dispersion compensating fiber(DCF) is needed. Based on the bit error rate(BER) results of WDM signals, the proposed WDM-PON system can achieve up to 1.6 Tbit/s(100 Gbit/s/λ × 16 wavelengths) downstream transmission over a 30 km single mode fiber(SMF).
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This work was supported by the National Natural Science Foundation of China(61475140)the National Basic Research Program of China(2013CB328703 and 2012CB921400)Y.Ron.Shen was supported by the Director,Office of Science,Office of Basic Energy Sciences,Materials Sciences and Engineering Division,of the U.S.Department of Energy(DEAC03-76SF00098).
文摘Graphene-doped polymer nanofibers are fabricated by taper drawing of solvated polyvinyl alcohol doped with liquid-phase exfoliated graphene flakes.Nanofibers drawn this way typically have diameters measured in hundreds of nanometers and lengths in tens of millimeters;they show excellent uniformity and surface smoothness for optical waveguiding.Owing to their tightly confined waveguiding behavior,light–matter interaction in these subwavelength-diameter nanofibers is significantly enhanced.Using approximately 1350-nm-wavelength femto-second pulses,we demonstrate saturable absorption behavior in these nanofibers with a saturation threshold down to 0.25 pJ pulse^(-1)(peak power,1.3 W).Additionally,using 1064-nm-wavelength nanosecond pulses as switching light,we show all-optical modulation of a 1550-nm-wavelength signal light guided along a single nanofiber with a switching peak power of,3.2 W.
基金National Natural Science Foundation of China(NSFC)(51321091,61505098,61575110,61675116)Young Scholars Program of Shandong University(SDU)(2017WLJH48)
文摘Rhenium disulfide(ReS_2), a member of group Ⅶ transition metal dichalcogenides(TMDs), has attracted increasing attention because of its unique distorted 1T structure and electronic and optical properties, which are much different from those of group Ⅵ TMDs(MoS_2, WS_2, MoSe_2, WSe_2, etc.). It has been proved that bulk ReS_2 behaves as a stack of electronically and vibrationally decoupled monolayers, which offers remarkable possibilities to prepare a monolayer ReS_2 facilely and offers a novel platform to study photonic properties of TMDs. However,due to the large and layer-independent bandgap, the nonlinear optical properties of ReS_2 from the visible to midinfrared spectral range have not yet been investigated. Here, the band structure of ReS_2 with the introduction of defects is simulated by the ab initio method, and the results indicate that the bandgap can be reduced from 1.38 to 0.54 eV with the introduction of defects in a suitable range. In the experiment, using a bulk ReS_2 with suitable defects as the raw material, a few-layered broadband ReS_2 saturable absorber(SA) is prepared by the liquid phase exfoliation method. Using the as-prepared ReS_2 SA, passively Q-switched solid-state lasers at wavelengths of 0.64,1.064, and 1.991 μm are investigated systematically. Moreover, with cavity design, a femtosecond passively modelocked laser at 1.06 μm is successfully realized based on the as-prepared ReS_2 SA for the first time. The results present a promising alternative for a rare broadband optical modulator and indicate the potential of ReS_2 in generating Q-switched and mode-locked pulsed lasers. It is further anticipated that this work may be helpful for the design of 2D optoelectronic devices with variable bandgaps.
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supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA25020303)the financial support of the Self Deployed Projects of Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences.
文摘In this paper,we propose an effective method to compensate for the performance degradation of optically addressed spatial light modulators(OASLMs).The thermal deposition problem usually leads to the on-off ratio reduction of amplitude OASLM,so it is difficult to achieve better results in high-power laser systems.Through the analysis of the laser-induced temperature rise model and the liquid crystal layer voltage model,it is found that reducing the driving voltage of the liquid crystal light valve and increasing the driving current of the optical writing module can compensate for the decrease of on-off ratio caused by temperature rise.This is the result of effectively utilizing the photoconductive effect of Bi_(12)SiO_(20)(BSO)crystal.The experimental results verify the feasibility of the proposed method and increase the laser withstand power of amplitude-only OASLM by about a factor of 2.5.
