A piece of multimode optical fiber with a low num er ical aperture (NA) is used as an inexpensive microlens to collimate the output r adiation of a laser diode bar in the high numerical aperture (NA) direction.The em...A piece of multimode optical fiber with a low num er ical aperture (NA) is used as an inexpensive microlens to collimate the output r adiation of a laser diode bar in the high numerical aperture (NA) direction.The emissions of the laser diode bar are coupled into multimode fiber array.The radi ation from individual ones of emitter regions is optically coupled into individu al ones of fiber array.Total coupling efficiency and fiber output power are 75% and 15W,respectively.展开更多
The coupling efficiency of the beam combination and the fiber-coupled module is limited due to the large vertical divergent angle of conventional semiconductor laser diodes. We present a high coupling efficiency modul...The coupling efficiency of the beam combination and the fiber-coupled module is limited due to the large vertical divergent angle of conventional semiconductor laser diodes. We present a high coupling efficiency module using photonic-band-crystal （PBC） laser diodes with narrow vertical divergent angles. Three PBC single-emitter laser diodes are combined into a fiber with core diameter of 105μm and numerical aperture of 0.22. A high coupling efficiency of 94.4% is achieved and the brightness is calculated to be 1.T MW/（cm2.sr） with the injection current of 8A.展开更多
A 1.60μm laser diode and electroabsorption modulator monolithically integrated with a novel dual-waveguide spot-size converter output for low-loss coupling to a cleaved single-mode optical fiber are demonstrated.The ...A 1.60μm laser diode and electroabsorption modulator monolithically integrated with a novel dual-waveguide spot-size converter output for low-loss coupling to a cleaved single-mode optical fiber are demonstrated.The devices emit in a single transverse and quasi single longitudinal mode with an SMSR of 25.6dB.These devices exhibit a 3dB modulation bandwidth of 15.0GHz,and modulator DC extinction ratios of 16.2dB.The output beam divergence angles of the spot-size converter in the horizontal and vertical directions are as small as 7.3°×18.0°,respectively,resulting in a 3.0dB coupling loss with a cleaved single-mode optical fiber.展开更多
Beam shaping is required for semiconductor lasers to achieve high optical fiber coupling efficiency in many applications.But the positioning errors on optics may reduce beam shaping effects,and then lead to low optica...Beam shaping is required for semiconductor lasers to achieve high optical fiber coupling efficiency in many applications.But the positioning errors on optics may reduce beam shaping effects,and then lead to low optical fiber coupling efficiency.In this work,the positioning errors models for the single emitter laser diode beam shaping system are established.Moreover,the relationships between the errors and the beam shaping effect of each shapers are analysed.Subsequently,the relationship between the errors and the optical fiber coupling efficiency is analysed.The result shows that position errors in the Z axis direction on the fast axis collimator have the greatest influence on the shaping effect,followed by the position errors in the Z axis direction on the converging lens,which should be strictly suppressed in actual operation.Besides,the position errors have a significant influence on the optical fiber coupling efficiency and need to be avoided.展开更多
Densities of Ar metastable states 1s5 and 1s3 are measured by using the tunable diode laser absorption spectroscopy（TDLAS） in Ar and Ar/O2 mixture dual-frequency capacitively coupled plasma（DF-CCP）. We investigate...Densities of Ar metastable states 1s5 and 1s3 are measured by using the tunable diode laser absorption spectroscopy（TDLAS） in Ar and Ar/O2 mixture dual-frequency capacitively coupled plasma（DF-CCP）. We investigate the effects of high-frequency（HF, 60 MHz） power, low-frequency（LF, 2 MHz） power, and working pressure on the density of Ar metastable states for three different gas components（0%, 5%, and 10% oxygen mixed in argon）. The dependence of Ar metastable state density on the oxygen content is also studied at different working pressures. It is found that densities of Ar metastable states in discharges with different gas components exhibit different behaviors as HF power increases. With the increase of HF power, the metastable density increases rapidly at the initial stage, and then tends to be saturated at a higher HF power. With a small fraction（5% or 10%） of oxygen added in argon plasma, a similar change of the Ar metastable density with HF power can be observed, but the metastable density is saturated at a higher HF power than in the pure argon discharge. In the DF-CCP, the metastable density is found to be higher than in a single frequency discharge, and has weak dependence on LF power. As working pressure increases, the metastable state density first increases and then decreases,and the pressure value, at which the density maximum occurs, decreases with oxygen content increasing. Besides, adding a small fraction of oxygen into argon plasma will significantly dwindle the metastable state density as a result of quenching loss by oxygen molecules.展开更多
A novel 1 55μm laser diode with spot size converter is designed and fabricated using conventional photolithography and chemical wet etching process.For the laser diode,a ridge double core structure is employed.For...A novel 1 55μm laser diode with spot size converter is designed and fabricated using conventional photolithography and chemical wet etching process.For the laser diode,a ridge double core structure is employed.For the spot size converter,a buried ridge double core structure is incorporated.The laterally tapered active core is designed and optically combined with the thin and wide passive core to control the size of mode.The laser diode threshold current is measured to be 40mA together with high slop efficiency of 0 35W/A.The beam divergence angles in the horizontal and vertical directions are as small as 14 89°×18 18°,respectively,resulting in low coupling losses with a cleaved optical fiber (3dB loss).展开更多
A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere,and the output of every bar is specially off-axis compressed to realize high coupling effic...A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere,and the output of every bar is specially off-axis compressed to realize high coupling efficiency.The output beam of this semiconductor laser diode stack is shaped by a hollow duct to the laser active medium.The efficiency of the hollow light pipe,which is used for semiconductor laser diode stack coupling,is analyzed by geometric optics and ray tracing.Geometric optics analysis diagnoses the reasons for coupling loss and guides the design of the structure.Ray tracing analyzes the relation between the structural parameters and the output characteristics of this pumping system,and guides parameter optimization.Simulation and analysis results show that putting the semiconductor laser diode arrays on a spherical surface can increase coupling efficiency, reduce the optimum duct length and improve the output energy field distribution.展开更多
Near-infrared(NIR)phosphor-converted light-emitting diodes/laser diodes(LEDs/LDs)are prospective lighting sources for NIR spectroscopy.However,developing NIR phosphor materials with desired thermal robustness and high...Near-infrared(NIR)phosphor-converted light-emitting diodes/laser diodes(LEDs/LDs)are prospective lighting sources for NIR spectroscopy.However,developing NIR phosphor materials with desired thermal robustness and high photoelectric efficiency is a crucial challenge for their applications.In this work,based on the cationic radius matching effect,a series of(Lu,Y)_(3)(Al,Sc,Cr)_(2)Al_(3)O_(12)NIR phosphor ceramics(LuYScCr NIR-PCs)were fabricated by vacuum sintering.Excellent thermal stability(95%@150℃)was obtained in the prepared NIR-PCs,owing to their weak electron-phonon coupling effect(small Huang-Rhys factor).Being excited at 460 nm,NIR-PCs realized a broadband emission(650-850 nm)with internal quantum efficiency(IQE)of 60.68%.Combining NIR-PCs with LED/LD chips,the maximum output power of the encapsulated LED prototype was 447 mW@300 mA with photoelectric efficiency of as high as 18.6%@180 mA,and the maximum output power of the LD prototype was 814 mW@2.5 A.The working temperatures of NIR-PCs were 70.8℃@300 mA(LED)and 102.8℃@3 A(LD).Finally,the prepared NIR-PCs applied in food detection were verified in this study,demonstrating their anticipated application prospects in the future.展开更多
A compact optical flip-flop with a directional coupler has been designed and analyzed. Using a narrow gap directional coupler, we have predicted the device length could be reduced down to 500μm from 1300μm.
文摘A piece of multimode optical fiber with a low num er ical aperture (NA) is used as an inexpensive microlens to collimate the output r adiation of a laser diode bar in the high numerical aperture (NA) direction.The emissions of the laser diode bar are coupled into multimode fiber array.The radi ation from individual ones of emitter regions is optically coupled into individu al ones of fiber array.Total coupling efficiency and fiber output power are 75% and 15W,respectively.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61535013,61321063 and 61404133the National Key Research and Development Program of China under Grant Nos 2016YFB0402203,2016YFB0401804 and2016YFA0301102the Youth Innovation Promotion Association of Chinese Academy of Sciences under Grant No 2014096
文摘The coupling efficiency of the beam combination and the fiber-coupled module is limited due to the large vertical divergent angle of conventional semiconductor laser diodes. We present a high coupling efficiency module using photonic-band-crystal （PBC） laser diodes with narrow vertical divergent angles. Three PBC single-emitter laser diodes are combined into a fiber with core diameter of 105μm and numerical aperture of 0.22. A high coupling efficiency of 94.4% is achieved and the brightness is calculated to be 1.T MW/（cm2.sr） with the injection current of 8A.
文摘A 1.60μm laser diode and electroabsorption modulator monolithically integrated with a novel dual-waveguide spot-size converter output for low-loss coupling to a cleaved single-mode optical fiber are demonstrated.The devices emit in a single transverse and quasi single longitudinal mode with an SMSR of 25.6dB.These devices exhibit a 3dB modulation bandwidth of 15.0GHz,and modulator DC extinction ratios of 16.2dB.The output beam divergence angles of the spot-size converter in the horizontal and vertical directions are as small as 7.3°×18.0°,respectively,resulting in a 3.0dB coupling loss with a cleaved single-mode optical fiber.
基金Project(51475479) supported by the National Natural Science Foundation of ChinaProject(2017YFB1104800) supported by the National Key Research and Development Program of China+2 种基金Project(2016GK2098) supported by the Key Research and Development Program of Hunan Province,ChinaProject(ZZYJKT2017-07) supported by the State Key Laboratory of High Performance Complex Manufacturing,Central South University,ChinaProject(JMTZ201804) supported by the Key Laboratory for Precision&Non-traditional Machining of Ministry of Education,Dalian University of Technology,China
文摘Beam shaping is required for semiconductor lasers to achieve high optical fiber coupling efficiency in many applications.But the positioning errors on optics may reduce beam shaping effects,and then lead to low optical fiber coupling efficiency.In this work,the positioning errors models for the single emitter laser diode beam shaping system are established.Moreover,the relationships between the errors and the beam shaping effect of each shapers are analysed.Subsequently,the relationship between the errors and the optical fiber coupling efficiency is analysed.The result shows that position errors in the Z axis direction on the fast axis collimator have the greatest influence on the shaping effect,followed by the position errors in the Z axis direction on the converging lens,which should be strictly suppressed in actual operation.Besides,the position errors have a significant influence on the optical fiber coupling efficiency and need to be avoided.
基金supported by the National Natural Science Foundation of China(Grant Nos.11335004,11722541,11675039,and 11747153)the Important National Science and Technology Specific Project,China(Grant No.2011ZX02403-001)
文摘Densities of Ar metastable states 1s5 and 1s3 are measured by using the tunable diode laser absorption spectroscopy（TDLAS） in Ar and Ar/O2 mixture dual-frequency capacitively coupled plasma（DF-CCP）. We investigate the effects of high-frequency（HF, 60 MHz） power, low-frequency（LF, 2 MHz） power, and working pressure on the density of Ar metastable states for three different gas components（0%, 5%, and 10% oxygen mixed in argon）. The dependence of Ar metastable state density on the oxygen content is also studied at different working pressures. It is found that densities of Ar metastable states in discharges with different gas components exhibit different behaviors as HF power increases. With the increase of HF power, the metastable density increases rapidly at the initial stage, and then tends to be saturated at a higher HF power. With a small fraction（5% or 10%） of oxygen added in argon plasma, a similar change of the Ar metastable density with HF power can be observed, but the metastable density is saturated at a higher HF power than in the pure argon discharge. In the DF-CCP, the metastable density is found to be higher than in a single frequency discharge, and has weak dependence on LF power. As working pressure increases, the metastable state density first increases and then decreases,and the pressure value, at which the density maximum occurs, decreases with oxygen content increasing. Besides, adding a small fraction of oxygen into argon plasma will significantly dwindle the metastable state density as a result of quenching loss by oxygen molecules.
文摘A novel 1 55μm laser diode with spot size converter is designed and fabricated using conventional photolithography and chemical wet etching process.For the laser diode,a ridge double core structure is employed.For the spot size converter,a buried ridge double core structure is incorporated.The laterally tapered active core is designed and optically combined with the thin and wide passive core to control the size of mode.The laser diode threshold current is measured to be 40mA together with high slop efficiency of 0 35W/A.The beam divergence angles in the horizontal and vertical directions are as small as 14 89°×18 18°,respectively,resulting in low coupling losses with a cleaved optical fiber (3dB loss).
基金Project supported by the National High Technology Research and Development Program of China(No.2009AA034701)
文摘A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere,and the output of every bar is specially off-axis compressed to realize high coupling efficiency.The output beam of this semiconductor laser diode stack is shaped by a hollow duct to the laser active medium.The efficiency of the hollow light pipe,which is used for semiconductor laser diode stack coupling,is analyzed by geometric optics and ray tracing.Geometric optics analysis diagnoses the reasons for coupling loss and guides the design of the structure.Ray tracing analyzes the relation between the structural parameters and the output characteristics of this pumping system,and guides parameter optimization.Simulation and analysis results show that putting the semiconductor laser diode arrays on a spherical surface can increase coupling efficiency, reduce the optimum duct length and improve the output energy field distribution.
基金The authors acknowledge the generous financial support from the National Natural Science Foundation of China(Nos.52302139,61973103,52272141,and 51972060)Doctoral Foundation Project of Henan University of Technology(No.2021BS069)+3 种基金Natural Science Foundation of Henan Province Youth Fund(No.222300420039)the Key Science and Technology Program of Henan Province(Nos.222102210023 and 232102211074)Project of Songshan Laboratory(No.YYJC072022020)Key Specialized Research of Zhengzhou Science and Technology Innovation Cooperation(No.21ZZXTCX01).
文摘Near-infrared(NIR)phosphor-converted light-emitting diodes/laser diodes(LEDs/LDs)are prospective lighting sources for NIR spectroscopy.However,developing NIR phosphor materials with desired thermal robustness and high photoelectric efficiency is a crucial challenge for their applications.In this work,based on the cationic radius matching effect,a series of(Lu,Y)_(3)(Al,Sc,Cr)_(2)Al_(3)O_(12)NIR phosphor ceramics(LuYScCr NIR-PCs)were fabricated by vacuum sintering.Excellent thermal stability(95%@150℃)was obtained in the prepared NIR-PCs,owing to their weak electron-phonon coupling effect(small Huang-Rhys factor).Being excited at 460 nm,NIR-PCs realized a broadband emission(650-850 nm)with internal quantum efficiency(IQE)of 60.68%.Combining NIR-PCs with LED/LD chips,the maximum output power of the encapsulated LED prototype was 447 mW@300 mA with photoelectric efficiency of as high as 18.6%@180 mA,and the maximum output power of the LD prototype was 814 mW@2.5 A.The working temperatures of NIR-PCs were 70.8℃@300 mA(LED)and 102.8℃@3 A(LD).Finally,the prepared NIR-PCs applied in food detection were verified in this study,demonstrating their anticipated application prospects in the future.
文摘A compact optical flip-flop with a directional coupler has been designed and analyzed. Using a narrow gap directional coupler, we have predicted the device length could be reduced down to 500μm from 1300μm.
