Self-accelerating beams have the unusual ability to remain diffraction-free while undergo the transverse shift during the free-space propagation.We theoretically identify that the transverse optical field distribution...Self-accelerating beams have the unusual ability to remain diffraction-free while undergo the transverse shift during the free-space propagation.We theoretically identify that the transverse optical field distribution of 2D self-accelerating beam is determined by the selection of the transverse Cartesian coordinates,when the caustic method is utilized for its trajectory design.Based on the coordinate-rotation method,we experimentally demonstrate a scheme to flexibly manipulate the rotation of transverse optical field for 2D self-accelerating beams under the condition of a designated trajectory.With this scheme,the transverse optical field can be rotated within a range of 90 degrees,especially when the trajectory of 2D self-accelerating beams needs to be maintained for free-space photonic interconnection.展开更多
The dynamic gain of a few-mode erbium-doped fiber amplifier(FM-EDFA)is vital for the long-haul mode division multiplexing(MDM)transmission.Here,we investigate the mode-dependent dynamic gain of an FM-EDFA under variou...The dynamic gain of a few-mode erbium-doped fiber amplifier(FM-EDFA)is vital for the long-haul mode division multiplexing(MDM)transmission.Here,we investigate the mode-dependent dynamic gain of an FM-EDFA under various manipulations of the pump mode.First,we numerically calculate the gain variation with respect to the input signal power,where a modedependent saturation input power occurs under different pump modes.Even under the fixed intensity profile of the pump laser,the saturation input power of each spatial mode is different.Moreover,high-order mode pumping leads to a compression of the linear amplification region,even though it is beneficial for the mitigation of the differential modal gain(DMG)arising in all guided modes.Then,we develop an all-fiber 3-mode EDFA,where the fundamental mode of the pump laser can be efficiently converted to the LP_(11)mode using the all-fiber mode-selective coupler(MSC).In comparison with the traditional LP_(01)pumping scheme,the DMG at 1550 nm can be mitigated from 1.61 dB to 0.97 dB under the LP_(11)mode pumping,while both an average gain of 19.93 dB and a DMG of less than 1 dB can be achieved from 1530 nm to 1560 nm.However,the corresponding signal input saturation powers are reduced by 0.3 dB for the LP_(01)mode and 1.6 dB for the LP_(11)mode,respectively.Both theoretical and experimental results indicate that a trade-off occurs between the DMG mitigation and the extension of the linear amplification range when the intensity profile of pump laser is manipulated.展开更多
Secure distribution of high-speed digital encryption/decryption keys over a classical fiber channel is strongly pursued for realizing perfect secrecy communication systems.However,it is still challenging to achieve a ...Secure distribution of high-speed digital encryption/decryption keys over a classical fiber channel is strongly pursued for realizing perfect secrecy communication systems.However,it is still challenging to achieve a secret key rate in the order of tens of gigabits per second to be comparable with the bit rate of commercial fiber-optic systems.In this paper,we propose and experimentally demonstrate a novel solution for high-speed secure key distribution based on temporal steganography and private chaotic phase scrambling in the classical physical layer.The encryption key is temporally concealed into the background noise in the time domain and randomly phase scrambled bit-by-bit by a private chaotic signal,which provides two layers of enhanced security to guarantee the privacy of key distribution while providing a high secret key rate.We experimentally achieved a record classical secret key rate of 10 Gb/s with a bit error rate lower than the hard-decision forward error correction(HD-FEC)over a 40 km standard single mode fiber.The proposed solution holds great promise for achieving high-speed key distribution in the classical fiber channel by combining steganographic transmission and chaotic scrambling.展开更多
The mode-division multiplexing technique combined with a few-mode erbium-doped fiber amplifier(FM-EDFA)demonstrates significant potential for solving the capacity limitation of standard single-mode fiber(SSMF)transmis...The mode-division multiplexing technique combined with a few-mode erbium-doped fiber amplifier(FM-EDFA)demonstrates significant potential for solving the capacity limitation of standard single-mode fiber(SSMF)transmission systems.However,the differential mode gain(DMG)arising in the FM-EDFA fundamentally limits its transmission capacity and length.Herein,an innovative DMG equalization strategy using femtosecond laser micromachining to adjust the refractive index(RI)is presented.Variable mode-dependent attenuations can be achieved according to the DMG profile of the FM-EDFA,enabling DMG equalization.To validate the proposed strategy,DMG equalization of the commonly used FM-EDFA configuration was investigated.Simulation results revealed that by optimizing both the length and RI modulation depth of the femtosecond laser-tailoring area,the maximum DMG(DMGmax)among the 3 linear-polarized(LP)mode-group was mitigated from 10 dB to 1.52 dB,whereas the average DMG(DMGave)over the C-band was reduced from 8.95 dB to 0.78 dB.Finally,a 2-LP mode-group DMG equalizer was experimentally demonstrated,resulting in a reduction of the DMGmax from 2.09 dB to 0.46 dB,and a reduction of DMGave over the C band from 1.64 dB to 0.26 dB,with only a 1.8 dB insertion loss.Moreover,a maximum range of variable DMG equalization was achieved with 5.4 dB,satisfying the requirements of the most commonly used 2-LP mode-group amplification scenarios.展开更多
Realizing high-fidelity optical information transmission through a scattering medium is of vital importance in both science and applications,such as short-range fiber communication and optical encryption.Theoretically...Realizing high-fidelity optical information transmission through a scattering medium is of vital importance in both science and applications,such as short-range fiber communication and optical encryption.Theoretically,an input wavefront can be reconstructed by inverting the transmission matrix of the scattering medium.However,this deterministic method for retrieving light field information encoded in the wavefront has not yet been experimentally demonstrated.Herein,we demonstrate light field information transmission through different scattering media with near-unity fidelity.Multi-dimensional optical information can be delivered through either a multimode fiber or a ground glass without relying on any averaging or approximation,where their Pearson correlation coefficients can be up to 99%.展开更多
The carrier-free phase-retrieval(CF-PR)receiver can reconstruct the optical field information only from two de-correlated intensity measurements without the involvement of a continuous-wave optical carrier.Here,we pro...The carrier-free phase-retrieval(CF-PR)receiver can reconstruct the optical field information only from two de-correlated intensity measurements without the involvement of a continuous-wave optical carrier.Here,we propose a digital subcarrier multiplexing(DSM)-enabled CF-PR receiver with hardware-efficient and modulation format-transparent merits.By numerically retrieving the optical field information of 56 GBaud DSM signals with QPSK/16QAM/32QAM modulation after 80-km standard single-mode fiber(SSMF)transmission,we identify that the DSM enabled CF-PR receiver is beneficial in reducing the implementation complexity of the CF-PR process,in comparison with the traditional single-carrier counterpart,because the lower symbol rate of each subcarrier is helpful in reducing the implementation complexity of multiple chromatic dispersion compensations and emulations during the PR iteration.Moreover,the DSM-enabled CF-PR receiver is verified to be robust toward various transmission imperfections,including transmitter-side laser linewidth and its wavelength drift,receiver-side time skew,and amplitude imbalance between two intensity tributaries.Finally,the superiority of the DSM-enabled CF-PR receiver is experimentally verified by recovering the optical field information of 25 GBaud 16QAM signals,after 40-km SSMF transmission for the first time.Thus,the DSM-enabled CF-PR receiver is promising for high-capacity photonic interconnection with direct detection.展开更多
High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky opti...High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky optical components that are slow to respond,cumbersome to use,and sometimes with high drive voltages.Here,we overcome these limitations by harnessing photonic integrated circuits based on thin-film lithium niobate platform.We successfully realize a portfolio of thin-film lithium niobate devices for essential polarization management functionalities,including arbitrary polarization generation,fast polarization measurement,polarization scrambling,and automatic polarization control.The present devices feature ultra-fast control speeds,low drive voltages,low optical losses and compact footprints.Using these devices,we achieve high fidelity polarization generation with a polarization extinction ratio up to 41.9 dB and fast polarization scrambling with a scrambling rate up to 65 Mrad s−1,both of which are best results in integrated optics.We also demonstrate the endless polarization state tracking operation in our devices.The demonstrated devices unlock a drastically new level of performance and scales in polarization management devices,leading to a paradigm shift in polarization management.展开更多
We propose a novel waveguide design of polarization-maintaining few mode fiber(PM-FMF) supporting ≥10non-degenerate modes, utilizing a central circular air hole and a circumjacent elliptical-ring core. The structure ...We propose a novel waveguide design of polarization-maintaining few mode fiber(PM-FMF) supporting ≥10non-degenerate modes, utilizing a central circular air hole and a circumjacent elliptical-ring core. The structure endows a new degree of freedom to adjust the birefringence of all the guided modes, including the fundamental polarization mode. Numerical simulations demonstrate that, by optimizing the air hole and elliptical-ring core,a PM-FMF supporting 10 distinctive polarization modes has been achieved, and the effective index difference Δn_(eff) between the adjacent guided modes could be kept larger than 1.32 × 10^(-4) over the whole C +L band. The proposed fiber structure can flexibly tailored to support an even larger number of modes in PM-FMF(14-mode PM-FMF has been demonstrated as an example), which can be readily applicable to a scalable mode division multiplexing system.展开更多
Distributed optical fiber Brillouin sensors detect the temperature and strain along a fiber according to the local Brillouin frequency shift(BFS),which is usually calculated by the measured Brillouin spectrum using Lo...Distributed optical fiber Brillouin sensors detect the temperature and strain along a fiber according to the local Brillouin frequency shift(BFS),which is usually calculated by the measured Brillouin spectrum using Lorentzian curve fitting.In addition,cross-correlation,principal component analysis,and machine learning methods have been proposed for the more efficient extraction of BFS.However,existing methods only process the Brillouin spectrum individually,ignoring the correlation in the time domain,indicating that there is still room for improvement.Here,we propose and experimentally demonstrate a BFS extraction convolutional neural network(BFSCNN)to retrieve the distributed BFS directly from the measured two-dimensional data.Simulated ideal Brillouin spectra with various parameters are used to train the BFSCNN.Both the simulation and experimental results show that the extraction accuracy of the BFSCNN is better than that of the traditional curve fitting algorithm with a much shorter processing time.The BFSCNN has good universality and robustness and can effectively improve the performances of existing Brillouin sensors.展开更多
Ultra-high-speed, ultra-large-capacity and ultra-long-haul （3U） are the forever pursuit of optical communication. As a new mode of optical communication, 3U transmission can greatly promote next generation optical i...Ultra-high-speed, ultra-large-capacity and ultra-long-haul （3U） are the forever pursuit of optical communication. As a new mode of optical communication, 3U transmission can greatly promote next generation optical internet and broadband mobile communication network development and technological progress, therefore it has become the focus of international high-tech intellectual property competition ground. This paper introduces the scientific problems, key technologies and important achievements in 3U transmission research.展开更多
Negative refraction might occur at the interface between a two-dimensional photonic crystal(Ph C)slab and a homogeneous medium,where the guiding of the electromagnetic wave along the third dimension is governed by tot...Negative refraction might occur at the interface between a two-dimensional photonic crystal(Ph C)slab and a homogeneous medium,where the guiding of the electromagnetic wave along the third dimension is governed by total internal reflection.Herein,we report on the observation of negative refraction in the Ph C slab where the vertical guiding is enabled by a bound state in the continuum and essentially beyond the light cone.Such abnormal refraction and guiding mechanism are based on the synchronous crafting of spatial dispersion and the radiative lifetime of Bloch modes within the radiative continuum.Microwave experiments are provided to further validate the numerical proposal in an all-dielectric Ph C platform.It is envisioned that the negative refraction observed beyond the light cone might facilitate the development of optical devices in integrated optics,such as couplers,multiplexers,and demultiplexers.展开更多
A theoretical and experimental study on curvature sensing using a Brillouin optical time-domain analyzer based on the ring-core fiber(RCF)is reported.The Brillouin gain spectrum of the RCF is investigated,and the Bril...A theoretical and experimental study on curvature sensing using a Brillouin optical time-domain analyzer based on the ring-core fiber(RCF)is reported.The Brillouin gain spectrum of the RCF is investigated,and the Brillouin frequency shift(BFS)dependence on temperature and strain is calibrated.We theoretically analyze the fiber bending-induced BFS and peak Brillouin gain variation for the RCF through a numerical simulation method,and the RCF is revealed to have a high curvature sensitivity.Distributed curvature sensing is successfully demonstrated,with the bending radius ranging from 0.5 to 1.5 cm,corresponding to a BFS variation from 32.90 to7.81 MHz.The RCF takes advantage of great bending loss resistance,and the maximum macrobending loss at the extreme bending radius of 0.5 cm is less than 0.01 d B/turn.Besides,the peak Brillouin gain of the RCF is discovered to vary significantly in response to fiber bending,which is expected to be another parameter for distributed curvature determination.The results imply that the RCF is a promising candidate for highly sensitive distributed curvature measurement,especially in sharp bending circumstances.展开更多
With the rapidly increasing bandwidth requirements of optical communication networks, compact and low-cost large-scale optical switches become necessary. Silicon pbotonics is a promising technology due to its small fo...With the rapidly increasing bandwidth requirements of optical communication networks, compact and low-cost large-scale optical switches become necessary. Silicon pbotonics is a promising technology due to its small footprint, cost competitiveness, and high bandwidth density. In this paper, we demonstrate a 12 × 12 silicon wavelength routing switch employing cascaded arrayed waveguide interconnection network on a the switch＇s footprint. We single chip. We optimize develop an algorithm based gratings （AWGs） connected by a silicon waveguide the connecting strategy of the crossing structure to reduce on minimum standard deviation to minimize the port-to- port insertion loss （IL） fluctuation of the switch globally. The simulated port-to-port IL fluctuation decreases by about 3 dB compared with that of the conventional one. The average measured port-to-port IL is 13.03 dB, with a standard deviation of 0.78 dB and a fluctuation of 2.39 dB. The device can be used for wide applications in core networks and data centers.展开更多
Fiber lasers are a paradigm of dissipative systems,which distinguish themselves from a Hamilton system where energy is conservative.Consequently,pulses generated in a fiber laser are always accompanied by the continuo...Fiber lasers are a paradigm of dissipative systems,which distinguish themselves from a Hamilton system where energy is conservative.Consequently,pulses generated in a fiber laser are always accompanied by the continuous wave(CW).Under certain hypothesis,pulses generated in a fiber laser can be considered as a soliton,a product of a Hamilton system.Therefore,all the descriptions of solitons of a fiber laser are approximate.Coexistence of solitons and the CW from a fiber laser prevents unveiling of real nonlinear dynamics in fiber lasers,such as soliton interactions.Pulse behavior in a fiber laser can be represented by the state of single pulse,the state of period doubling of single pulse,the states of two pulses either tightly bound or loosely distributed,the states of three pulses,and various combinations of the above-mentioned states.Recently,soliton distillation was proposed and numerically demonstrated based on the nonlinear Fourier transform(NFT)[J.Lightwave Technol.39,2542(2021)].Solitons can be separated from the coherent CW background.Therefore,it is feasible to isolate solitons from CW background in a fiber laser.Here,we applied the NFT to various pulses generated in a fiber laser,including single pulse,single pulse in period doubling,different double pulses,and multiple pulses.Furthermore,with the approach of soliton distillation,the corresponding pure solitons of those pulses are reconstructed.Simulation results suggest that the NFT can be used to identify soliton dynamics excluding CW influence in a fiber laser,which paves a new way for uncovering real soliton interaction in nonlinear systems.展开更多
We present the design, fabrication, and characterization of a highly nonlinear few-mode fiber(HNL-FMF) with an intermodal nonlinear coefficient of 2.8 W · km-1, which to the best of our knowledge is the highest r...We present the design, fabrication, and characterization of a highly nonlinear few-mode fiber(HNL-FMF) with an intermodal nonlinear coefficient of 2.8 W · km-1, which to the best of our knowledge is the highest reported to date. The graded-index circular core fiber supports two mode groups(MGs) with six eigenmodes and is highly doped with germanium. This breaks the mode degeneracy within the higher-order MG, leading to different group velocities among corresponding eigenmodes. Thus, the HNL-FMF can support multiple intermodal four-wave mixing processes between the two MGs at the same time. In a proof-of-concept experiment, we demonstrate simultaneous intermodal wavelength conversions among three eigenmodes of the HNL-FMF over the C band.展开更多
This paper investigated the impact of Rayleigh backscattering （RB） noise in the proposed wavelength- division-multiplexed （WDM） single-fiber loopback access network. RB noise＇s impacts on the downstream and upstr...This paper investigated the impact of Rayleigh backscattering （RB） noise in the proposed wavelength- division-multiplexed （WDM） single-fiber loopback access network. RB noise＇s impacts on the downstream and upstream service were discussed in details. It was found that the receiver sensitivity was less sensitive when the seeding-light power was below - 12.6 dBm. And for the uplink RB noise, a higher reflective semiconductor optical amplifier （RSOA）＇s bias current results in lower receiver sensitivity.展开更多
基金supports from National Key R&D Program of China(Grant No.2018YFB1801001)the National Natural Science Foundation of China(Grant No.61875061)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams.
文摘Self-accelerating beams have the unusual ability to remain diffraction-free while undergo the transverse shift during the free-space propagation.We theoretically identify that the transverse optical field distribution of 2D self-accelerating beam is determined by the selection of the transverse Cartesian coordinates,when the caustic method is utilized for its trajectory design.Based on the coordinate-rotation method,we experimentally demonstrate a scheme to flexibly manipulate the rotation of transverse optical field for 2D self-accelerating beams under the condition of a designated trajectory.With this scheme,the transverse optical field can be rotated within a range of 90 degrees,especially when the trajectory of 2D self-accelerating beams needs to be maintained for free-space photonic interconnection.
基金supported by the National Key R&D Program of China(No.2018YFB1800903)the National Natural Science Foundation of China(No.U22A2087)+1 种基金the Guangdong Introducing Innovative and Entrepreneurial Teams of the Pearl River Talent Recruitment Program(No.2021ZT09X044)the Guangdong Provincial Key Laboratory of Photonics Information Technology(No.2020B121201011)。
文摘The dynamic gain of a few-mode erbium-doped fiber amplifier(FM-EDFA)is vital for the long-haul mode division multiplexing(MDM)transmission.Here,we investigate the mode-dependent dynamic gain of an FM-EDFA under various manipulations of the pump mode.First,we numerically calculate the gain variation with respect to the input signal power,where a modedependent saturation input power occurs under different pump modes.Even under the fixed intensity profile of the pump laser,the saturation input power of each spatial mode is different.Moreover,high-order mode pumping leads to a compression of the linear amplification region,even though it is beneficial for the mitigation of the differential modal gain(DMG)arising in all guided modes.Then,we develop an all-fiber 3-mode EDFA,where the fundamental mode of the pump laser can be efficiently converted to the LP_(11)mode using the all-fiber mode-selective coupler(MSC).In comparison with the traditional LP_(01)pumping scheme,the DMG at 1550 nm can be mitigated from 1.61 dB to 0.97 dB under the LP_(11)mode pumping,while both an average gain of 19.93 dB and a DMG of less than 1 dB can be achieved from 1530 nm to 1560 nm.However,the corresponding signal input saturation powers are reduced by 0.3 dB for the LP_(01)mode and 1.6 dB for the LP_(11)mode,respectively.Both theoretical and experimental results indicate that a trade-off occurs between the DMG mitigation and the extension of the linear amplification range when the intensity profile of pump laser is manipulated.
基金National Key Research and Development Program of China(2023YFB2906000)National Natural Science Foundation of China(62004047,62375055,U2001601,U22A2087)+1 种基金Guangdong Basic and Applied Basic Research Foundation(2023B1515020088)Guangdong Introducing Innovative and Entrepreneurial Teams of“The Pearl River Talent Recruitment Program”(2019ZT08X340)。
文摘Secure distribution of high-speed digital encryption/decryption keys over a classical fiber channel is strongly pursued for realizing perfect secrecy communication systems.However,it is still challenging to achieve a secret key rate in the order of tens of gigabits per second to be comparable with the bit rate of commercial fiber-optic systems.In this paper,we propose and experimentally demonstrate a novel solution for high-speed secure key distribution based on temporal steganography and private chaotic phase scrambling in the classical physical layer.The encryption key is temporally concealed into the background noise in the time domain and randomly phase scrambled bit-by-bit by a private chaotic signal,which provides two layers of enhanced security to guarantee the privacy of key distribution while providing a high secret key rate.We experimentally achieved a record classical secret key rate of 10 Gb/s with a bit error rate lower than the hard-decision forward error correction(HD-FEC)over a 40 km standard single mode fiber.The proposed solution holds great promise for achieving high-speed key distribution in the classical fiber channel by combining steganographic transmission and chaotic scrambling.
基金supported by the National Natural Science Foundation of China(62305071)China Postdoctoral Science Foundation(2023M740747)Guangdong Introducing Innovative and Entrepreneurial Teams of“The Pearl River Talent Recruitment Program”(2021ZT09X044).
文摘The mode-division multiplexing technique combined with a few-mode erbium-doped fiber amplifier(FM-EDFA)demonstrates significant potential for solving the capacity limitation of standard single-mode fiber(SSMF)transmission systems.However,the differential mode gain(DMG)arising in the FM-EDFA fundamentally limits its transmission capacity and length.Herein,an innovative DMG equalization strategy using femtosecond laser micromachining to adjust the refractive index(RI)is presented.Variable mode-dependent attenuations can be achieved according to the DMG profile of the FM-EDFA,enabling DMG equalization.To validate the proposed strategy,DMG equalization of the commonly used FM-EDFA configuration was investigated.Simulation results revealed that by optimizing both the length and RI modulation depth of the femtosecond laser-tailoring area,the maximum DMG(DMGmax)among the 3 linear-polarized(LP)mode-group was mitigated from 10 dB to 1.52 dB,whereas the average DMG(DMGave)over the C-band was reduced from 8.95 dB to 0.78 dB.Finally,a 2-LP mode-group DMG equalizer was experimentally demonstrated,resulting in a reduction of the DMGmax from 2.09 dB to 0.46 dB,and a reduction of DMGave over the C band from 1.64 dB to 0.26 dB,with only a 1.8 dB insertion loss.Moreover,a maximum range of variable DMG equalization was achieved with 5.4 dB,satisfying the requirements of the most commonly used 2-LP mode-group amplification scenarios.
基金supported by the National Key R&D Program of China(No.2018YFB1801001)the National Natural Science Foundation of China(No.62222505)the Guangdong Introducing Innovative Entrepreneurial Teams of the Pearl River Talent Recruitment Program(Nos.2019ZT08X340 and 2021ZT09X044).
文摘Realizing high-fidelity optical information transmission through a scattering medium is of vital importance in both science and applications,such as short-range fiber communication and optical encryption.Theoretically,an input wavefront can be reconstructed by inverting the transmission matrix of the scattering medium.However,this deterministic method for retrieving light field information encoded in the wavefront has not yet been experimentally demonstrated.Herein,we demonstrate light field information transmission through different scattering media with near-unity fidelity.Multi-dimensional optical information can be delivered through either a multimode fiber or a ground glass without relying on any averaging or approximation,where their Pearson correlation coefficients can be up to 99%.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB2900702)the National Natural Science Foundation of China(Grant No.U21A20506)the Guangdong Introducing Innovative and Entrepreneurial Teams of“The Pearl River Talent Recruitment Program”(Grant No.2021ZT09X044).
文摘The carrier-free phase-retrieval(CF-PR)receiver can reconstruct the optical field information only from two de-correlated intensity measurements without the involvement of a continuous-wave optical carrier.Here,we propose a digital subcarrier multiplexing(DSM)-enabled CF-PR receiver with hardware-efficient and modulation format-transparent merits.By numerically retrieving the optical field information of 56 GBaud DSM signals with QPSK/16QAM/32QAM modulation after 80-km standard single-mode fiber(SSMF)transmission,we identify that the DSM enabled CF-PR receiver is beneficial in reducing the implementation complexity of the CF-PR process,in comparison with the traditional single-carrier counterpart,because the lower symbol rate of each subcarrier is helpful in reducing the implementation complexity of multiple chromatic dispersion compensations and emulations during the PR iteration.Moreover,the DSM-enabled CF-PR receiver is verified to be robust toward various transmission imperfections,including transmitter-side laser linewidth and its wavelength drift,receiver-side time skew,and amplitude imbalance between two intensity tributaries.Finally,the superiority of the DSM-enabled CF-PR receiver is experimentally verified by recovering the optical field information of 25 GBaud 16QAM signals,after 40-km SSMF transmission for the first time.Thus,the DSM-enabled CF-PR receiver is promising for high-capacity photonic interconnection with direct detection.
基金supported by the National Key Research and Development Program of China(2019YFB1803900 and 2019YFA0705000)National Natural Science Foundation of China(11690031 and 11761131001)+2 种基金Key R&D Program of Guangdong Province(2018B030329001)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X121)Key-Area Research and Development Program of Guangdong Province(2019B121204003).
文摘High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky optical components that are slow to respond,cumbersome to use,and sometimes with high drive voltages.Here,we overcome these limitations by harnessing photonic integrated circuits based on thin-film lithium niobate platform.We successfully realize a portfolio of thin-film lithium niobate devices for essential polarization management functionalities,including arbitrary polarization generation,fast polarization measurement,polarization scrambling,and automatic polarization control.The present devices feature ultra-fast control speeds,low drive voltages,low optical losses and compact footprints.Using these devices,we achieve high fidelity polarization generation with a polarization extinction ratio up to 41.9 dB and fast polarization scrambling with a scrambling rate up to 65 Mrad s−1,both of which are best results in integrated optics.We also demonstrate the endless polarization state tracking operation in our devices.The demonstrated devices unlock a drastically new level of performance and scales in polarization management devices,leading to a paradigm shift in polarization management.
基金National Natural Science Foundation of China(NSFC)(61331010,61205063)863 High Technology plan(2015AA016904)Program for New Century Excellent Talents in University(NCET)(NCET-13-0235)
文摘We propose a novel waveguide design of polarization-maintaining few mode fiber(PM-FMF) supporting ≥10non-degenerate modes, utilizing a central circular air hole and a circumjacent elliptical-ring core. The structure endows a new degree of freedom to adjust the birefringence of all the guided modes, including the fundamental polarization mode. Numerical simulations demonstrate that, by optimizing the air hole and elliptical-ring core,a PM-FMF supporting 10 distinctive polarization modes has been achieved, and the effective index difference Δn_(eff) between the adjacent guided modes could be kept larger than 1.32 × 10^(-4) over the whole C +L band. The proposed fiber structure can flexibly tailored to support an even larger number of modes in PM-FMF(14-mode PM-FMF has been demonstrated as an example), which can be readily applicable to a scalable mode division multiplexing system.
基金National Key Research and Development Program of China(2018YFB1801002)National Natural Science Foundation of China(61722108,61931010)Innovation Fund of WNLO。
文摘Distributed optical fiber Brillouin sensors detect the temperature and strain along a fiber according to the local Brillouin frequency shift(BFS),which is usually calculated by the measured Brillouin spectrum using Lorentzian curve fitting.In addition,cross-correlation,principal component analysis,and machine learning methods have been proposed for the more efficient extraction of BFS.However,existing methods only process the Brillouin spectrum individually,ignoring the correlation in the time domain,indicating that there is still room for improvement.Here,we propose and experimentally demonstrate a BFS extraction convolutional neural network(BFSCNN)to retrieve the distributed BFS directly from the measured two-dimensional data.Simulated ideal Brillouin spectra with various parameters are used to train the BFSCNN.Both the simulation and experimental results show that the extraction accuracy of the BFSCNN is better than that of the traditional curve fitting algorithm with a much shorter processing time.The BFSCNN has good universality and robustness and can effectively improve the performances of existing Brillouin sensors.
文摘Ultra-high-speed, ultra-large-capacity and ultra-long-haul （3U） are the forever pursuit of optical communication. As a new mode of optical communication, 3U transmission can greatly promote next generation optical internet and broadband mobile communication network development and technological progress, therefore it has become the focus of international high-tech intellectual property competition ground. This paper introduces the scientific problems, key technologies and important achievements in 3U transmission research.
基金National Key Research and Development Program of China(2018YFB1801001)National Natural Science Foundation of China(91750110)+2 种基金Guangdong Introducing Innovative and Entrepreneurial Teams of the Pearl River Talent Recruitment Program(2019ZT08X340)Research and Development Plan in Key Areas of Guangdong Province(2018B010114002)Pearl River Nova Program of Guangzhou(201806010040)。
文摘Negative refraction might occur at the interface between a two-dimensional photonic crystal(Ph C)slab and a homogeneous medium,where the guiding of the electromagnetic wave along the third dimension is governed by total internal reflection.Herein,we report on the observation of negative refraction in the Ph C slab where the vertical guiding is enabled by a bound state in the continuum and essentially beyond the light cone.Such abnormal refraction and guiding mechanism are based on the synchronous crafting of spatial dispersion and the radiative lifetime of Bloch modes within the radiative continuum.Microwave experiments are provided to further validate the numerical proposal in an all-dielectric Ph C platform.It is envisioned that the negative refraction observed beyond the light cone might facilitate the development of optical devices in integrated optics,such as couplers,multiplexers,and demultiplexers.
基金National Basic Research Program of China(973Program)(2018YFB1801002)National Natural Science Foundation of China(61722108+1 种基金61931010)Innovation Fund of WNLO。
文摘A theoretical and experimental study on curvature sensing using a Brillouin optical time-domain analyzer based on the ring-core fiber(RCF)is reported.The Brillouin gain spectrum of the RCF is investigated,and the Brillouin frequency shift(BFS)dependence on temperature and strain is calibrated.We theoretically analyze the fiber bending-induced BFS and peak Brillouin gain variation for the RCF through a numerical simulation method,and the RCF is revealed to have a high curvature sensitivity.Distributed curvature sensing is successfully demonstrated,with the bending radius ranging from 0.5 to 1.5 cm,corresponding to a BFS variation from 32.90 to7.81 MHz.The RCF takes advantage of great bending loss resistance,and the maximum macrobending loss at the extreme bending radius of 0.5 cm is less than 0.01 d B/turn.Besides,the peak Brillouin gain of the RCF is discovered to vary significantly in response to fiber bending,which is expected to be another parameter for distributed curvature determination.The results imply that the RCF is a promising candidate for highly sensitive distributed curvature measurement,especially in sharp bending circumstances.
基金National Natural Science Foundation of China(NSFC)(61775069,61635004)National High Technology Research and Development Program of China,863 Program(2015AA015504)
文摘With the rapidly increasing bandwidth requirements of optical communication networks, compact and low-cost large-scale optical switches become necessary. Silicon pbotonics is a promising technology due to its small footprint, cost competitiveness, and high bandwidth density. In this paper, we demonstrate a 12 × 12 silicon wavelength routing switch employing cascaded arrayed waveguide interconnection network on a the switch＇s footprint. We single chip. We optimize develop an algorithm based gratings （AWGs） connected by a silicon waveguide the connecting strategy of the crossing structure to reduce on minimum standard deviation to minimize the port-to- port insertion loss （IL） fluctuation of the switch globally. The simulated port-to-port IL fluctuation decreases by about 3 dB compared with that of the conventional one. The average measured port-to-port IL is 13.03 dB, with a standard deviation of 0.78 dB and a fluctuation of 2.39 dB. The device can be used for wide applications in core networks and data centers.
基金National Key R&D Program of China(2018YFB1801001)Fundamental Research Funds for the Central Universities(HUST 2020kfy XJJS007)+4 种基金National Natural Science Foundation of China(61875061)Protocol of the 9th Session of China-Croatia Scientific and Technological Cooperation Committee(9-28)Protocol of the 38th Session of China-Poland Scientific and Technological Cooperation Committee(6)National Agency for Academic Exchange in Poland(PPN/BCN/2019/1/00068)Foundation for Polish Science First TEAM POIR(04.04.00-00-1D64/16)。
文摘Fiber lasers are a paradigm of dissipative systems,which distinguish themselves from a Hamilton system where energy is conservative.Consequently,pulses generated in a fiber laser are always accompanied by the continuous wave(CW).Under certain hypothesis,pulses generated in a fiber laser can be considered as a soliton,a product of a Hamilton system.Therefore,all the descriptions of solitons of a fiber laser are approximate.Coexistence of solitons and the CW from a fiber laser prevents unveiling of real nonlinear dynamics in fiber lasers,such as soliton interactions.Pulse behavior in a fiber laser can be represented by the state of single pulse,the state of period doubling of single pulse,the states of two pulses either tightly bound or loosely distributed,the states of three pulses,and various combinations of the above-mentioned states.Recently,soliton distillation was proposed and numerically demonstrated based on the nonlinear Fourier transform(NFT)[J.Lightwave Technol.39,2542(2021)].Solitons can be separated from the coherent CW background.Therefore,it is feasible to isolate solitons from CW background in a fiber laser.Here,we applied the NFT to various pulses generated in a fiber laser,including single pulse,single pulse in period doubling,different double pulses,and multiple pulses.Furthermore,with the approach of soliton distillation,the corresponding pure solitons of those pulses are reconstructed.Simulation results suggest that the NFT can be used to identify soliton dynamics excluding CW influence in a fiber laser,which paves a new way for uncovering real soliton interaction in nonlinear systems.
基金National Key R&D Program of China(2018YFB1801002)National Natural Science Foundation of China(61711530043)+2 种基金Fundamental Research Funds for the Central Universities(2018JYCXJJ024)Swedish Research Council(VR)(2015-00535,2017-05157)Swedish Foundation for International Cooperation in Research and Higher Education(STINT)(CH2016-6754)
文摘We present the design, fabrication, and characterization of a highly nonlinear few-mode fiber(HNL-FMF) with an intermodal nonlinear coefficient of 2.8 W · km-1, which to the best of our knowledge is the highest reported to date. The graded-index circular core fiber supports two mode groups(MGs) with six eigenmodes and is highly doped with germanium. This breaks the mode degeneracy within the higher-order MG, leading to different group velocities among corresponding eigenmodes. Thus, the HNL-FMF can support multiple intermodal four-wave mixing processes between the two MGs at the same time. In a proof-of-concept experiment, we demonstrate simultaneous intermodal wavelength conversions among three eigenmodes of the HNL-FMF over the C band.
文摘This paper investigated the impact of Rayleigh backscattering （RB） noise in the proposed wavelength- division-multiplexed （WDM） single-fiber loopback access network. RB noise＇s impacts on the downstream and upstream service were discussed in details. It was found that the receiver sensitivity was less sensitive when the seeding-light power was below - 12.6 dBm. And for the uplink RB noise, a higher reflective semiconductor optical amplifier （RSOA）＇s bias current results in lower receiver sensitivity.
