Owing to the low p-type doping efficiency in the hole injection layers(HILs)of GaN-based ultra-violet(UV)vertical-cavity surface-emitting laser(VCSEL),effective hole injection in multi-quantum wells(MQW)is not achieve...Owing to the low p-type doping efficiency in the hole injection layers(HILs)of GaN-based ultra-violet(UV)vertical-cavity surface-emitting laser(VCSEL),effective hole injection in multi-quantum wells(MQW)is not achieved,significantly limiting the photoelectric performance of UV VCSELs.We developed a slope-shaped HIL and an EBL structure in AlGaN-based UV VCSELs.In this study,by improving hole in-jection efficiency,the hole concentration in the HIL is increased,and the hole barrier at the electron barrier layer(EBL)/HIL interface is decreased.This minimises the hindering effect of hole injection.A mathematic-al model of this structure was established using a commercial software,photonic integrated circuit simulator in three-dimension(PICS3D).We conducted simulations and theoretical analyses of the band structure and carrier concentration.Introducing polarisation doping through the Al composition gradient in the HIL en-hanced the hole concentration,thereby improving the hole injection efficiency.Furthermore,modifying the EBL eliminated the abrupt potential barrier for holes at the HIL/EBL interface,smoothing the valence band.This improved the stimulated radiative recombination rate in the MQW,increasing the laser power.There-fore,the sloped p-type layer can enhance the optoelectronic performance of UV VCSELs.展开更多
Pulsed anodic oxidation technique, a new way of forming current blocking layers, was successfully used in ridge-waveguide QW laser fabrication. This method was applied in 980 nm VCSELs fabrication to form a high-quali...Pulsed anodic oxidation technique, a new way of forming current blocking layers, was successfully used in ridge-waveguide QW laser fabrication. This method was applied in 980 nm VCSELs fabrication to form a high-quality native oxide current blocking layer, which simplifies the device process. A significant reduction of threshold current and a distinguished device performance are achieved. The 500 μm diameter device has a current threshold as low as 0.48 W. The maximum CW operation output power at room temperature is 1.48 W. The lateral divergence angle θ‖ and vertical divergence angle θ⊥ are as low as 15.3° and 13.8° without side-lobes at a current of 6 A.展开更多
We establish a novel method of controlling the transverse modes of vertical cavity surface emitting lasers （VCSELs） to achieve 1 mW single-fundamental-mode lasing. A dielectric mode filter is installed on top of the...We establish a novel method of controlling the transverse modes of vertical cavity surface emitting lasers （VCSELs） to achieve 1 mW single-fundamental-mode lasing. A dielectric mode filter is installed on top of the VCSEL. The dielectric layer （SiO2） is deposited and patterned to modify the mirror reflectivity across the oxide aperture via antiphase reflections. This mode selection is nondestructive and universally applicable for other structures under single transverse mode. Destructive etching techniques （dry/wet） or epitaxial regrowth are also not required. This method simplifies the preparation process and improves the repeatability of the device. Measurements show that under continuous-wave current injection, the side-mode suppression ratio exceeds 30 dB.展开更多
Vertical-cavity surface-emitting lasers(VCSELs)are essential in modern optoelectronic systems,driving applications in high-speed optical communications,3D sensing,and LiDAR.While significant progress has been made in ...Vertical-cavity surface-emitting lasers(VCSELs)are essential in modern optoelectronic systems,driving applications in high-speed optical communications,3D sensing,and LiDAR.While significant progress has been made in improving VCSEL performance,the role of cavity geometry in optimizing key optical characteristics remains insufficiently explored.This study systematically examines how distinct cavity geometries—circular,square,D-shaped,mushroom-shaped,and pentagonal—affect both the static and dynamic properties of broad-area VCSELs.We analyze their effects on optical power,multimode behavior,beam profile,spatial coherence,and polarization dynamics.Our results show that breaking the continuous rotational symmetry of the cavity effectively increases gain utilization and power,changes the multimode lasing characteristics,shapes the beam,and modifies the polarization.Notably,the pentagonal VCSEL exhibits more than twice the optical power density of its circular counterpart.It also supports the highest number of modes and the fastest mode dynamics,driven by strong mode interaction.These properties make it a strong candidate for high-speed entropy generation.Mushroom-shaped VCSELs demonstrate high power and low spatial coherence,making them ideal for speckle-free imaging and illumination applications.Meanwhile,D-shaped VCSELs provide the most stable polarization and controllable multimode behavior with high power,showcasing their potential for applications that require stable and low-coherence light sources.This study offers a comprehensive analysis of the impact of cavity geometry on VCSEL performance,which provides insights for optimizing VCSEL designs tailored to diverse applications that require distinct properties with broad applicability to advanced imaging,sensing,optical coherence tomography,high-speed communication,and other photonic technologies.展开更多
VCSEL Injection locking is demonstrated to increase laser bandwidth and reduce non-linearity and chirp. All these properties enhance analog and digital modulation performance.
Single-mode, long-wavelength vertical-cavity surface-emitting lasers （VCSELs） in the near- to mid-infrared covering the wavelength range from 1.3 to 2.3 μm are presented. This wide spectral emission range opens app...Single-mode, long-wavelength vertical-cavity surface-emitting lasers （VCSELs） in the near- to mid-infrared covering the wavelength range from 1.3 to 2.3 μm are presented. This wide spectral emission range opens applications in gas sensing and optical interconnects. All these lasers are monolithically grown in the InGaAlAs-InP material system utilizing a buried tunnel junction （BTJ） as current aperture. Fabricated with a novel high-speed design with reduced parasitics, bandwidths in excess of 10 GHz at 1.3 and 1.55 μm have been achieved. Therefore, the coarse wavelength division multiplexing （CWDM） wavelength range of 1.3 to 1.6 μm at 10 Gb/s can be accomplished with one technology. Error-free data-transmission at 10 Gb/s over a fiber link of 20 km is demonstrated. One-dimensional arrays have been fabricated with emission wavelengths addressable by current tuning. Micro-electro-mechanical system （MEMS） tunable devices provide an extended tuning range in excess of 50 nm with high spectral purity. All these devices feature continuous-wave （CW） operation with typical single-mode output powers exceeding 1 mW. The operation voltage is around 1 - 1.5 V and power consumption is as low as 10 - 20 mW. Furthermore, we have also developed VCSELs based on GaSb, targeting functionality of tunable diode laser spectroscopy （TDLS） applying a 1.84-μm VCSEL. at the wavelength range from 2.3 to 3.0 μm. The systems is shown by presenting a laser hygrometer展开更多
Based on spin-flip model （SFM）, the nonlinear dynamics of 1550nm vertical-cavity surface-emitting lasers （VCSELs） subject to polarization-preserved optical feedback （PPOF） and orthogonal optical injection （OOI...Based on spin-flip model （SFM）, the nonlinear dynamics of 1550nm vertical-cavity surface-emitting lasers （VCSELs） subject to polarization-preserved optical feedback （PPOF） and orthogonal optical injection （OOI） are theoretically investigated. The results show that two linear polarization （LP） modes can be simultaneously stimulated and polarization switching （PS） can be observed, which is different from the case that only y LP mode exists in a VCSEL with PPOF. Under the joint action of PPOF and OOI, the two LP modes will exhibit rich dynamical states, such as period one, period two, multi- period and chaos oscillation. Different evolution routes to chaos can be also observed. Moreover, frequency detuning Af（Af=fm fs, wherefn andfs are the center frequencies of free-running master VCSEL and slave VCSEL, respectively） has an obvious influence on the PS. With the increase of the positive frequency detuning PS points shift toward larger injection strengths; meanwhile, a suitable negative frequency demning value makes the injection strength for PS be the lowest.展开更多
We propose the transverse-mode control of vertical-cavity surface-emitting lasers (VCSELs) with a convex mirror. A possibility of improvements on single-mode output power and higher-order mode suppression is presented...We propose the transverse-mode control of vertical-cavity surface-emitting lasers (VCSELs) with a convex mirror. A possibility of improvements on single-mode output power and higher-order mode suppression is presented by optimizing a convex mirror.展开更多
Thin film p-side up vertical-cavity surface-emitting lasers(VCSELs)with 940 nm wavelength on a composite metal(Copper/Invar/Copper;CIC)substrate has been demonstrated by twice-bonding transfer and substrate removing t...Thin film p-side up vertical-cavity surface-emitting lasers(VCSELs)with 940 nm wavelength on a composite metal(Copper/Invar/Copper;CIC)substrate has been demonstrated by twice-bonding transfer and substrate removing techniques.The CIC substrate is a sandwich structure with a 10µm thick Copper(Cu)layer/30µm thick Invar layer/10µm thick Cu layer.The Invar layer was composed of Iron(Fe)and Nickel(Ni)with a proportion of 70:30.The thermal expansion coefcient of the composite CIC metal can match that of the GaAs substrate.It results that the VCSEL layers can be successfully transferred to CIC metal substrate without cracking.At 1 mA current,the top-emitting VCSEL/GaAs and thin-flm VCSEL/CIC had a voltage of 1.39 and 1.37 V,respectively.The optical output powers of VCSEL/GaAs and VCSEL/CIC were 21.91 and 24.40 mW,respectively.The 50µm thick CIC substrate can play a good heat dissipation function,which results in improving the electrical and optical characteristics of thin flm VCSELs/CIC.The VCSEL/CIC exhibited a superior thermal management capability as compared with VCSEL/GaAs.The obtained data suggested that VCSELs on a composite metal substrate not only afected signifcantly the characteristics of thin film VCSEL,but also improved considerably the device thermal performance.展开更多
文摘Owing to the low p-type doping efficiency in the hole injection layers(HILs)of GaN-based ultra-violet(UV)vertical-cavity surface-emitting laser(VCSEL),effective hole injection in multi-quantum wells(MQW)is not achieved,significantly limiting the photoelectric performance of UV VCSELs.We developed a slope-shaped HIL and an EBL structure in AlGaN-based UV VCSELs.In this study,by improving hole in-jection efficiency,the hole concentration in the HIL is increased,and the hole barrier at the electron barrier layer(EBL)/HIL interface is decreased.This minimises the hindering effect of hole injection.A mathematic-al model of this structure was established using a commercial software,photonic integrated circuit simulator in three-dimension(PICS3D).We conducted simulations and theoretical analyses of the band structure and carrier concentration.Introducing polarisation doping through the Al composition gradient in the HIL en-hanced the hole concentration,thereby improving the hole injection efficiency.Furthermore,modifying the EBL eliminated the abrupt potential barrier for holes at the HIL/EBL interface,smoothing the valence band.This improved the stimulated radiative recombination rate in the MQW,increasing the laser power.There-fore,the sloped p-type layer can enhance the optoelectronic performance of UV VCSELs.
文摘Pulsed anodic oxidation technique, a new way of forming current blocking layers, was successfully used in ridge-waveguide QW laser fabrication. This method was applied in 980 nm VCSELs fabrication to form a high-quality native oxide current blocking layer, which simplifies the device process. A significant reduction of threshold current and a distinguished device performance are achieved. The 500 μm diameter device has a current threshold as low as 0.48 W. The maximum CW operation output power at room temperature is 1.48 W. The lateral divergence angle θ‖ and vertical divergence angle θ⊥ are as low as 15.3° and 13.8° without side-lobes at a current of 6 A.
基金Project supported by the National Key Research and Development Project,China(Grant No.2017YFB0503200)the National Natural Science Foundation of China(Grant Nos.61434005,61474118,11774343,and 11674314)+1 种基金the Science and Technology Program of Jilin Province,China(Grant No.20160203013GX)the Youth Innovation Promotion Association,China(Grant No.2017260)
文摘We establish a novel method of controlling the transverse modes of vertical cavity surface emitting lasers （VCSELs） to achieve 1 mW single-fundamental-mode lasing. A dielectric mode filter is installed on top of the VCSEL. The dielectric layer （SiO2） is deposited and patterned to modify the mirror reflectivity across the oxide aperture via antiphase reflections. This mode selection is nondestructive and universally applicable for other structures under single transverse mode. Destructive etching techniques （dry/wet） or epitaxial regrowth are also not required. This method simplifies the preparation process and improves the repeatability of the device. Measurements show that under continuous-wave current injection, the side-mode suppression ratio exceeds 30 dB.
基金supported by the King Abdullah University of Science and Technology(KAUST)under the Grant of Transition Award in Semiconductors:Grant No.FCC/1/5939,the KAUST Center of Excellence for Renewable Energy and Storage Technologies(CREST):Grant No.FCC/1/5937,and the KAUST Grant Nos.RFS-OFP2023-5534,BAS/1/1614-01-01,ORA-2022-5313,and ORFS-2022-CRG11-5079.The authors acknowledge the use of the KAUST Nanofabrication Core Lab and the KAUST Imaging and Characterization Core Lab facilities.
文摘Vertical-cavity surface-emitting lasers(VCSELs)are essential in modern optoelectronic systems,driving applications in high-speed optical communications,3D sensing,and LiDAR.While significant progress has been made in improving VCSEL performance,the role of cavity geometry in optimizing key optical characteristics remains insufficiently explored.This study systematically examines how distinct cavity geometries—circular,square,D-shaped,mushroom-shaped,and pentagonal—affect both the static and dynamic properties of broad-area VCSELs.We analyze their effects on optical power,multimode behavior,beam profile,spatial coherence,and polarization dynamics.Our results show that breaking the continuous rotational symmetry of the cavity effectively increases gain utilization and power,changes the multimode lasing characteristics,shapes the beam,and modifies the polarization.Notably,the pentagonal VCSEL exhibits more than twice the optical power density of its circular counterpart.It also supports the highest number of modes and the fastest mode dynamics,driven by strong mode interaction.These properties make it a strong candidate for high-speed entropy generation.Mushroom-shaped VCSELs demonstrate high power and low spatial coherence,making them ideal for speckle-free imaging and illumination applications.Meanwhile,D-shaped VCSELs provide the most stable polarization and controllable multimode behavior with high power,showcasing their potential for applications that require stable and low-coherence light sources.This study offers a comprehensive analysis of the impact of cavity geometry on VCSEL performance,which provides insights for optimizing VCSEL designs tailored to diverse applications that require distinct properties with broad applicability to advanced imaging,sensing,optical coherence tomography,high-speed communication,and other photonic technologies.
文摘VCSEL Injection locking is demonstrated to increase laser bandwidth and reduce non-linearity and chirp. All these properties enhance analog and digital modulation performance.
基金the German Research Council(DFG)the National Natural Science Foundation of China(No.60510173 and 60506006)+1 种基金the European Union via NEMIS(No.FP6-2005-IST-5-031845)the German Federal Ministry of Education and Research via NOSE(No.13N8772).
文摘Single-mode, long-wavelength vertical-cavity surface-emitting lasers （VCSELs） in the near- to mid-infrared covering the wavelength range from 1.3 to 2.3 μm are presented. This wide spectral emission range opens applications in gas sensing and optical interconnects. All these lasers are monolithically grown in the InGaAlAs-InP material system utilizing a buried tunnel junction （BTJ） as current aperture. Fabricated with a novel high-speed design with reduced parasitics, bandwidths in excess of 10 GHz at 1.3 and 1.55 μm have been achieved. Therefore, the coarse wavelength division multiplexing （CWDM） wavelength range of 1.3 to 1.6 μm at 10 Gb/s can be accomplished with one technology. Error-free data-transmission at 10 Gb/s over a fiber link of 20 km is demonstrated. One-dimensional arrays have been fabricated with emission wavelengths addressable by current tuning. Micro-electro-mechanical system （MEMS） tunable devices provide an extended tuning range in excess of 50 nm with high spectral purity. All these devices feature continuous-wave （CW） operation with typical single-mode output powers exceeding 1 mW. The operation voltage is around 1 - 1.5 V and power consumption is as low as 10 - 20 mW. Furthermore, we have also developed VCSELs based on GaSb, targeting functionality of tunable diode laser spectroscopy （TDLS） applying a 1.84-μm VCSEL. at the wavelength range from 2.3 to 3.0 μm. The systems is shown by presenting a laser hygrometer
文摘Based on spin-flip model （SFM）, the nonlinear dynamics of 1550nm vertical-cavity surface-emitting lasers （VCSELs） subject to polarization-preserved optical feedback （PPOF） and orthogonal optical injection （OOI） are theoretically investigated. The results show that two linear polarization （LP） modes can be simultaneously stimulated and polarization switching （PS） can be observed, which is different from the case that only y LP mode exists in a VCSEL with PPOF. Under the joint action of PPOF and OOI, the two LP modes will exhibit rich dynamical states, such as period one, period two, multi- period and chaos oscillation. Different evolution routes to chaos can be also observed. Moreover, frequency detuning Af（Af=fm fs, wherefn andfs are the center frequencies of free-running master VCSEL and slave VCSEL, respectively） has an obvious influence on the PS. With the increase of the positive frequency detuning PS points shift toward larger injection strengths; meanwhile, a suitable negative frequency demning value makes the injection strength for PS be the lowest.
文摘We propose the transverse-mode control of vertical-cavity surface-emitting lasers (VCSELs) with a convex mirror. A possibility of improvements on single-mode output power and higher-order mode suppression is presented by optimizing a convex mirror.
基金supported by the Science and Technology Council,Taiwan,China under the grants NSTC 109-2634-F-009-028,110-2224-E-A49-003,111-2634-F-A49-007,and 111-2218-E-A49-019-MBK,Ingentec Corp.and the Center for Emergent Functional Matter Science of Yang Ming Chiao Tung University from the Featured Areas Research Center Program within the framework of the Higher Education Sprout Project(Taiwan,China)funding and material measurement support(grant number:2022-T-018)and we thank Taiwan Semiconductor Research Institute for facilities supporting.
文摘Thin film p-side up vertical-cavity surface-emitting lasers(VCSELs)with 940 nm wavelength on a composite metal(Copper/Invar/Copper;CIC)substrate has been demonstrated by twice-bonding transfer and substrate removing techniques.The CIC substrate is a sandwich structure with a 10µm thick Copper(Cu)layer/30µm thick Invar layer/10µm thick Cu layer.The Invar layer was composed of Iron(Fe)and Nickel(Ni)with a proportion of 70:30.The thermal expansion coefcient of the composite CIC metal can match that of the GaAs substrate.It results that the VCSEL layers can be successfully transferred to CIC metal substrate without cracking.At 1 mA current,the top-emitting VCSEL/GaAs and thin-flm VCSEL/CIC had a voltage of 1.39 and 1.37 V,respectively.The optical output powers of VCSEL/GaAs and VCSEL/CIC were 21.91 and 24.40 mW,respectively.The 50µm thick CIC substrate can play a good heat dissipation function,which results in improving the electrical and optical characteristics of thin flm VCSELs/CIC.The VCSEL/CIC exhibited a superior thermal management capability as compared with VCSEL/GaAs.The obtained data suggested that VCSELs on a composite metal substrate not only afected signifcantly the characteristics of thin film VCSEL,but also improved considerably the device thermal performance.
