Phase is an intrinsic property of light,and thus a crucial parameter across numerous applications in modern optics.Various methods exist for measuring the phase of light,each presenting challenges and limitationsfrom ...Phase is an intrinsic property of light,and thus a crucial parameter across numerous applications in modern optics.Various methods exist for measuring the phase of light,each presenting challenges and limitationsfrom the mechanical stability requirements of free-space interferometers to the computational complexity usually associated with methods based on spatial light modulators.Here,we utilize a passive photonic integrated circuit to spatially probe phase and intensity distributions of free-space light beams.Phase information is encoded into intensity through a set of passive on-chip interferometers,allowing conventional detectors to retrieve the phase profile of light through single-shot intensity measurements.Furthermore,we use silicon nitride as a material platform for the waveguide architecture,facilitating multi-spectral utilization in the visible spectral range.Our approach for fast,multi-spectral,and spatially resolved measurement of intensity and phase enables a wide variety of potential applications,ranging from microscopy to free-space optical communication.展开更多
Spatial modes have received substantial attention over the last decades and are used in optical communication applications.In fiber-optic communications,the employed linearly polarized modes and phase vortex modes car...Spatial modes have received substantial attention over the last decades and are used in optical communication applications.In fiber-optic communications,the employed linearly polarized modes and phase vortex modes carrying orbital angular momentum can be synthesized by fiber vector eigenmodes.To improve the transmission capacity and miniaturize the communication system,straightforward fiber vector eigenmode multiplexing and generation of fiber-eigenmode-like polarization vortices(vector vortex modes)using photonic integrated devices are of substantial interest.Here,we propose and demonstrate direct fiber vector eigenmode multiplexing transmission seeded by integrated optical vortex emitters.By exploiting vector vortex modes(radially and azimuthally polarized beams)generated from silicon microring resonators etched with angular gratings,we report data-carrying fiber vector eigenmode multiplexing transmission through a 2-km large-core fiber,showing low-level mode crosstalk and favorable link performance.These demonstrations may open up added capacity scaling opportunities by directly accessing multiple vector eigenmodes in the fiber and provide compact solutions to replace bulky diffractive optical elements for generating various optical vector beams.展开更多
Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially wit...Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially with atmospheric turbulence or other scattering or aberrations, the arriving beam shapes may not even be known in advance. We show that such beams can be still separated in the optical domain, and simultaneously detected with negligible cross-talk, even if they share the same wavelength and polarization, and even with unknown arriving beam shapes. The kernel of the adaptive multibeam receiver presented in this work is a programmable integrated photonic processor that is coupled to free-space beams through a two-dimensional array of optical antennas. We demonstrate separation of beam pairs arriving from different directions, with overlapping spatial modes in the same direction, and even with mixing between the beams deliberately added in the path. With the circuit’s optical bandwidth of more than 40 nm, this approach offers an enabling technology for the evolution of FSO from single-beam to multibeam space-division multiplexed systems in a perturbed environment, which has been a game-changing transition in fiber-optic systems.展开更多
High-quality integrated diamond photonic devices have previously been demonstrated in applications from nonlinear photonics to on-chip quantum optics.However,the small sample sizes of single crystal material available...High-quality integrated diamond photonic devices have previously been demonstrated in applications from nonlinear photonics to on-chip quantum optics.However,the small sample sizes of single crystal material available,and the difficulty in tuning its optical properties,are barriers to the scaling of these technologies.Both of these issues can be addressed by integrating micrometer-scale diamond devices onto host photonic integrated circuits using a highly accurate micro-assembly method.In this work a diamond micro-disk resonator is integrated with a standard single-mode silicon-on-insulator waveguide,exhibiting an average loaded Q-factor of 3.1×10^4 across a range of spatial modes,with a maximum loaded Q-factor of 1.05×10^5.The micrometer-scale device size and high thermal impedance of the silica interface layer allow for significant thermal loading and continuous resonant wavelength tuning across a 450 pm range using a milliwatt-level optical pump.This diamond-on-demand integration technique paves the way for tunable devices coupled across large-scale photonic circuits.展开更多
Emerging applications based on optical beams carrying orbital angular momentum （OAM） will likely require photonic integrated devices and circuits for miniaturization, improved performance and enhanced functionality....Emerging applications based on optical beams carrying orbital angular momentum （OAM） will likely require photonic integrated devices and circuits for miniaturization, improved performance and enhanced functionality. This paper reviews the state-of-the art in the field of OAM of light, reports recent developments in silicon integrated OAM emitters, and discusses the applications potentials and challenges in silicon integrated OAM devices which can be used in future OAM based optical communications systems.展开更多
Optical vortices （OVs） refer to a class of cylindrical optical modes with azimuthally varying phase terms arising either from polarization rotation or from the angular projection of the wave vector that at the quant...Optical vortices （OVs） refer to a class of cylindrical optical modes with azimuthally varying phase terms arising either from polarization rotation or from the angular projection of the wave vector that at the quantum level corresponds to photon spin or orbital angular momenta. OVs have attracted the attention of researchers in many areas of optics and photonics, as their potential applications range from optical communications, optical manipulation, imaging, sensing, to quantum information. In recent years, integrated photonics has becomes an effective method of manipulating OVs. In this paper, the theoretical framework and experimental progress of integrated photonics for the manipulation of OVs were reviewed.展开更多
Passive mode-locking in semiconductor lasers in a Fabry–Perot configuration with a bandgap blueshift applied to the saturable absorber(SA)section has been experimentally characterized.For the first time a fully post-...Passive mode-locking in semiconductor lasers in a Fabry–Perot configuration with a bandgap blueshift applied to the saturable absorber(SA)section has been experimentally characterized.For the first time a fully post-growth technique,quantum well intermixing,was adopted to modify the material bandgap in the SA section.The measurements showed not only an expected narrowing of the pulse width but also a significant expansion of the range of bias conditions generating a stable train of optical pulses.Moreover,the pulses from lasers with bandgap shifted absorbers presented reduced chirp and increased peak power with respect to the nonshifted case.展开更多
基金Bundesministerium fur Arbeit und Wirtschaft(CDL-SMBS)Osterreichische Nationalstiftung fir Forschung,Technologie und Entwicklung(CDL-SMBS)Christian Doppler Forschungsgesellschaft(CDL-SMBS).
文摘Phase is an intrinsic property of light,and thus a crucial parameter across numerous applications in modern optics.Various methods exist for measuring the phase of light,each presenting challenges and limitationsfrom the mechanical stability requirements of free-space interferometers to the computational complexity usually associated with methods based on spatial light modulators.Here,we utilize a passive photonic integrated circuit to spatially probe phase and intensity distributions of free-space light beams.Phase information is encoded into intensity through a set of passive on-chip interferometers,allowing conventional detectors to retrieve the phase profile of light through single-shot intensity measurements.Furthermore,we use silicon nitride as a material platform for the waveguide architecture,facilitating multi-spectral utilization in the visible spectral range.Our approach for fast,multi-spectral,and spatially resolved measurement of intensity and phase enables a wide variety of potential applications,ranging from microscopy to free-space optical communication.
基金supported by the National Basic Research Program of China(973 Program)under grants 2014CB340004,2014CB340001 and 2014CB340003the National Natural Science Foundation of China(NSFC)under grants 11690031,61761130082,11574001,11774116,11274131,61222502,61575224 and 61622510+4 种基金the Royal Society-Newton Advanced Fellowshipthe National Program for Support of Top-notch Young Professionalsthe Program for New Century Excellent Talents in University(NCET-11-0182)the Program for HUST Academic Frontier Youth Team,the Project ROAM(H2020-ICT-2014-1—Contract Number:645361)the Project Cornerstone(EPSRC-EP/L021129/1)。
文摘Spatial modes have received substantial attention over the last decades and are used in optical communication applications.In fiber-optic communications,the employed linearly polarized modes and phase vortex modes carrying orbital angular momentum can be synthesized by fiber vector eigenmodes.To improve the transmission capacity and miniaturize the communication system,straightforward fiber vector eigenmode multiplexing and generation of fiber-eigenmode-like polarization vortices(vector vortex modes)using photonic integrated devices are of substantial interest.Here,we propose and demonstrate direct fiber vector eigenmode multiplexing transmission seeded by integrated optical vortex emitters.By exploiting vector vortex modes(radially and azimuthally polarized beams)generated from silicon microring resonators etched with angular gratings,we report data-carrying fiber vector eigenmode multiplexing transmission through a 2-km large-core fiber,showing low-level mode crosstalk and favorable link performance.These demonstrations may open up added capacity scaling opportunities by directly accessing multiple vector eigenmodes in the fiber and provide compact solutions to replace bulky diffractive optical elements for generating various optical vector beams.
基金the European Commission,Horizon 2020 Programme(SuperPixels,grant no.829116)by the Air Force Office of Scientific Research(AFOSR,grant no.FA9550-17-1-0002).
文摘Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially with atmospheric turbulence or other scattering or aberrations, the arriving beam shapes may not even be known in advance. We show that such beams can be still separated in the optical domain, and simultaneously detected with negligible cross-talk, even if they share the same wavelength and polarization, and even with unknown arriving beam shapes. The kernel of the adaptive multibeam receiver presented in this work is a programmable integrated photonic processor that is coupled to free-space beams through a two-dimensional array of optical antennas. We demonstrate separation of beam pairs arriving from different directions, with overlapping spatial modes in the same direction, and even with mixing between the beams deliberately added in the path. With the circuit’s optical bandwidth of more than 40 nm, this approach offers an enabling technology for the evolution of FSO from single-beam to multibeam space-division multiplexed systems in a perturbed environment, which has been a game-changing transition in fiber-optic systems.
基金Engineering and Physical Sciences Research Council(EP/L015315/1,EP/L021129/1,EP/P013570/1,EP/P013597/1,EP/R03480X/1)The authors acknowledge the efforts of the staff of the James Watt Nanofabrication Centre at the University of Glasgow。
文摘High-quality integrated diamond photonic devices have previously been demonstrated in applications from nonlinear photonics to on-chip quantum optics.However,the small sample sizes of single crystal material available,and the difficulty in tuning its optical properties,are barriers to the scaling of these technologies.Both of these issues can be addressed by integrating micrometer-scale diamond devices onto host photonic integrated circuits using a highly accurate micro-assembly method.In this work a diamond micro-disk resonator is integrated with a standard single-mode silicon-on-insulator waveguide,exhibiting an average loaded Q-factor of 3.1×10^4 across a range of spatial modes,with a maximum loaded Q-factor of 1.05×10^5.The micrometer-scale device size and high thermal impedance of the silica interface layer allow for significant thermal loading and continuous resonant wavelength tuning across a 450 pm range using a milliwatt-level optical pump.This diamond-on-demand integration technique paves the way for tunable devices coupled across large-scale photonic circuits.
文摘Emerging applications based on optical beams carrying orbital angular momentum （OAM） will likely require photonic integrated devices and circuits for miniaturization, improved performance and enhanced functionality. This paper reviews the state-of-the art in the field of OAM of light, reports recent developments in silicon integrated OAM emitters, and discusses the applications potentials and challenges in silicon integrated OAM devices which can be used in future OAM based optical communications systems.
基金The authors wish to acknowledge support by the National Basic Research Program of China （No. 2014CB340000）, the National Natural Science Foundation of China-Key Research Project （Grant No. 61490715）, and the EU Horizon2020 program under project ROAM.
文摘Optical vortices （OVs） refer to a class of cylindrical optical modes with azimuthally varying phase terms arising either from polarization rotation or from the angular projection of the wave vector that at the quantum level corresponds to photon spin or orbital angular momenta. OVs have attracted the attention of researchers in many areas of optics and photonics, as their potential applications range from optical communications, optical manipulation, imaging, sensing, to quantum information. In recent years, integrated photonics has becomes an effective method of manipulating OVs. In this paper, the theoretical framework and experimental progress of integrated photonics for the manipulation of OVs were reviewed.
基金the technical staff of the James Watt Nanofabrication Centre at Glasgow University and discussions with Salvador Balle.V.Pusino acknowledges partial financial support from the GRPE program and EPSRC under grant agreement EP/P504937/1.
文摘Passive mode-locking in semiconductor lasers in a Fabry–Perot configuration with a bandgap blueshift applied to the saturable absorber(SA)section has been experimentally characterized.For the first time a fully post-growth technique,quantum well intermixing,was adopted to modify the material bandgap in the SA section.The measurements showed not only an expected narrowing of the pulse width but also a significant expansion of the range of bias conditions generating a stable train of optical pulses.Moreover,the pulses from lasers with bandgap shifted absorbers presented reduced chirp and increased peak power with respect to the nonshifted case.
