Au80Sn20 alloy is a widely used solder for laser diode packaging.In this paper,the thermal resistance of Ga N-based blue laser diodes packaged in TO56 cans were measured by the forward voltage method.The microstructur...Au80Sn20 alloy is a widely used solder for laser diode packaging.In this paper,the thermal resistance of Ga N-based blue laser diodes packaged in TO56 cans were measured by the forward voltage method.The microstructures of Au80Sn20 solder were then investigated to understand the reason for the difference in thermal resistance.It was found that the microstructure with a higher content of Au-rich phase in the center of the solder and a lower content of(Au,Ni)Sn phase at the interface of the solder/heat sink resulted in lower thermal resistance.This is attributed to the lower thermal resistance of Au-rich phase and higher thermal resistance of(Au,Ni)Sn phase.展开更多
Using the finite-element method, the thermal resistances of GaN laser diode devices in a TO 56 package for both epi-up configuration and epi-down configuration are calculated. The effects of various parameters on the ...Using the finite-element method, the thermal resistances of GaN laser diode devices in a TO 56 package for both epi-up configuration and epi-down configuration are calculated. The effects of various parameters on the thermal characteristics are analysed, and the thicknesses of the AlN submount for both epi-up configuration and epi-down configuration are optimized. The obtained result provides a reference for the parameter selection of the package materials.展开更多
The influences of InGaN/GaN multiple quantum wells (MQWs) and AlGaN electron-blocking layers (EBL) on the performance of GaN-based violet laser diodes are investigated. Compared with the InGaN/GaN MQWs grown at two di...The influences of InGaN/GaN multiple quantum wells (MQWs) and AlGaN electron-blocking layers (EBL) on the performance of GaN-based violet laser diodes are investigated. Compared with the InGaN/GaN MQWs grown at two different temperatures, the same-temperature growth of InGaN well and GaN barrier layers has a positive effect on the threshold current and slope efficiency of laser diodes, indicating that the quality of MQWs is improved. In addition, the performance of GaN laser diodes could be further improved by increasing Al content in the AlGaN EBL due to the fact that the electron leakage current could be reduced by properly increasing the barrier height of AlGaN EBL. The violet laser diode with a peak output power of 20 W is obtained.展开更多
Due to the zero dispersion point at 1.3μm in optical fibres, 1.3-μm InGaAsP/InP laser diodes have become main light sources in fibre communication systems recently. Influences of quantum noises on direct-modulated p...Due to the zero dispersion point at 1.3μm in optical fibres, 1.3-μm InGaAsP/InP laser diodes have become main light sources in fibre communication systems recently. Influences of quantum noises on direct-modulated properties of single-mode 1.3-μm InGaAsP/InP laser diodes are investigated in this article. Considering the carrier and photon noises and the cross-correlation between the two noises, the power spectrum of the photon density and the signal-to-noise ratio (SNR) of the direct-modulated single-mode laser system are calculated using the linear approximation method. We find that the stochastic resonance (SR) always appears in the dependence of the SNR on the bias current density, and is strongly affected by the cross-correlation coefficient between the carrier and photon noises, the frequency of modulation signal, and the photon lifetime in the laser cavity. Hence, it is promising to use the SR mechanism to enhance the SNR of direct-modulated InGaAsP/InP laser diodes and improve the quality of optical fibre communication systems.展开更多
Catastrophic degradation of high power laser diodes is due to the generation of extended defects inside the active parts of the laser structure during the laser operation.The mechanism driving the degradation is stron...Catastrophic degradation of high power laser diodes is due to the generation of extended defects inside the active parts of the laser structure during the laser operation.The mechanism driving the degradation is strongly related to the existence of localized thermal stresses generated during the laser operation.These thermal stresses can overcome the yield strength of the materials forming the active part of the laser diode.Different factors contribute to reduce the laser power threshold for degradation.Among them the thermal transport across the laser structure constitutes a critical issue for the reliability of the device.展开更多
Electroluminescence (EL) and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes (LDs) before lasing. Based on the ABC ...Electroluminescence (EL) and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes (LDs) before lasing. Based on the ABC mode, the EL result demonstrates that non-radiative recombination rates of LDs with threshold current densities of 4 and 6kA/cm2 are similar, while LD with threshold current density of 4kA/cm2 exhibits a smaller auger- like recombination rate compared with the one of 6kA/cm2. The internal quantum efficiency droop is more serious for LD with higher threshold current density. temperature-dependent photoluminescence is consistent The internal quantum efficiency value estimated from with EL measurements.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
Performances of blue and green laser diodes(LDs) with different u-InGaN upper waveguides(UWGs) are investigated theoretically by using LASTIP. It is found that the slope efficiency(SE) of blue LD decreases due t...Performances of blue and green laser diodes(LDs) with different u-InGaN upper waveguides(UWGs) are investigated theoretically by using LASTIP. It is found that the slope efficiency(SE) of blue LD decreases due to great optical loss when the indium content of u-InGaN UWG is more than 0.02, although its leakage current decreases obviously. Meanwhile the SE of the green LD increases when the indium content of u-InGaN UWG is varied from 0 to 0.05, which is attributed to the reduction of leakage current and the small increase of optical loss. Therefore, a new blue LD structure with In(0.05) Ga(0.95)N lower waveguide(LWG) is designed to reduce the optical loss, and its slope efficiency is improved significantly.展开更多
This paper reports that a long delay between the beginning of pumping current pulse and the onset of optical pulse is observed in InGaN laser diodes. The delay time decreases as the pumping current increases, and the ...This paper reports that a long delay between the beginning of pumping current pulse and the onset of optical pulse is observed in InGaN laser diodes. The delay time decreases as the pumping current increases, and the speed of the delay time reduction becomes slower as the current amplitude increases further. Such delay phenomena are remarkably less serious in laser diodes grown on GaN substrate than those on sapphire. It attributes the delay to the traps which cause a large optical loss by saturable absorption and retard the laser action. The traps can be bleached by capturing injected carriers. The effect of GaAs laser irradiation on InGaN laser action demonstrates that the traps responsible for the delay are deep centres which can be filled by the photo-assisted processes.展开更多
Usually GaAs/AlGaAs is utilized as an active layer material in laser diodes operating in the spectral range of 800- 850 nm. In this work, in addition to a traditional unstrained GaAs/AlGaAs distributed feedback (DFB...Usually GaAs/AlGaAs is utilized as an active layer material in laser diodes operating in the spectral range of 800- 850 nm. In this work, in addition to a traditional unstrained GaAs/AlGaAs distributed feedback (DFB) laser diode, a compressively strained InGaAlAs/AlGaAs DFB laser diode is numerically investigated in characteristic. The simulation results show that the compressively strained DFB laser diode has a lower transparency carrier density, higher gain, lower Auger recombination rate, and higher stimulated recombination rate, which lead to better a device performance, than the traditional unstrained GaAs/AlGaAs DFB laser diode.展开更多
A violet laser diode (LD) structure is grown on a free-standing c-plane GaN substrate and 4 μm×800μm ridge waveguide LDs are fabricated. The electrical and the optical characteristics of LDs under different f...A violet laser diode (LD) structure is grown on a free-standing c-plane GaN substrate and 4 μm×800μm ridge waveguide LDs are fabricated. The electrical and the optical characteristics of LDs under different facet-coating and chip-mounting conditions are investigated under pulse mode operation. The active region temperatures of p-side up and p-side down mounted LDs are calculated with different injection currents. The calculated thermal resistances of p-side up and p-side down mounted LDs are 4.6 K/W and 3 K/W, respectively. The threshold current of the p-side down mounted LD is much lower than that of the p-side up mounted LD. The blue shift of the emission wavelength with increasing injection current is observed only for the LD with p-side down mounting configuration, due to the more efficient heat dissipation.展开更多
The accelerating burn in and screening method of processing 1 310 nm InGaAsP of laser diodes (LDs) is introduced. It is confirmed that the theory of burn in and screening is based on the second derivative minimum of...The accelerating burn in and screening method of processing 1 310 nm InGaAsP of laser diodes (LDs) is introduced. It is confirmed that the theory of burn in and screening is based on the second derivative minimum of burn-in curve, and the new testing method has been given, that is automatic current control (ACC) burn-in and automatic power control (APC) testing. This avoidably bring the errors of testing in only ACC or APC method, which need to monitor and control or test LDs power change by photo-detector (PD) at high temperature, and LDs or PDs must be into the same environment (PD will be burn-in at the same time). Through the experiment, the accelerating burn-in and screening condition of the devices has been confirmed: ACC, 200 mA, 100 ℃, 8 h. This raise work efficiency 12 times than Bellcore standard and save testing fee.展开更多
The 975 nm multimode diode lasers with high-order surface Bragg diffraction gratings have been simulated and calcu-lated using the 2D finite difference time domain(FDTD)algorithm and the scattering matrix method(SMM)....The 975 nm multimode diode lasers with high-order surface Bragg diffraction gratings have been simulated and calcu-lated using the 2D finite difference time domain(FDTD)algorithm and the scattering matrix method(SMM).The periods and etch depth of the grating parameters have been optimized.A board area laser diode(BA-LD)with high-order diffraction grat-ings has been designed and fabricated.At output powers up to 10.5 W,the measured spectral width of full width at half maxi-mum(FWHM)is less than 0.5 nm.The results demonstrate that the designed high-order surface gratings can effectively nar-row the spectral width of multimode semiconductor lasers at high output power.展开更多
Two kinds of continuous-wave GaN-based ultraviolet laser diodes(LDs) operated at room temperature and with different emission wavelengths are demonstrated.The LDs epitaxial layers are grown on GaN substrate by metal...Two kinds of continuous-wave GaN-based ultraviolet laser diodes(LDs) operated at room temperature and with different emission wavelengths are demonstrated.The LDs epitaxial layers are grown on GaN substrate by metalorganic chemical vapor deposition,with a 10 × 600 μm^2 ridge waveguide structure.The electrical and optical characteristics of the ultraviolet LDs are investigated under direct-current injection at room temperature.The stimulated emission peak wavelength of first LD is 392.9 nm,the threshold current density and voltage is 1.5kA/cm^2 and 5.0 V,respectively.The output light power is 80 mW under the 4.0 kA/cm^2 injection current density.The stimulated emission peak wavelength of second LD is 381.9 nm,the threshold current density the voltage is2.8 kA/cm^2 and 5.5 V,respectively.The output light power is 14 mW under a 4.0 kA/cm^2 injection current density.展开更多
Electron leakage in GaAs-based separately confined heterostructure 808 nm laser diodes (SCH LDs) has a serious influence on device performance. Here, in order to reduce the energy of electrons injected into the quan...Electron leakage in GaAs-based separately confined heterostructure 808 nm laser diodes (SCH LDs) has a serious influence on device performance. Here, in order to reduce the energy of electrons injected into the quantum well (QW), an A1GaAs interlayer with a smaller A1 component is added between the active region and the n-side waveguide. Numerical device simulation reveals that when the Al-composition of the A1GaAs interlayer and its thickness are properly elected, the electron leakage is remarkably depressed and the characteristics of LDs are improved, owing to the reduction of injected electron energy and the improvement of QW capture efficiency.展开更多
Organic semiconductor is one of the most promising luminescent and lasing materials that can be chemically synthesized with a controllable performance and possess high cross-section of stimulated emission[1].Organic s...Organic semiconductor is one of the most promising luminescent and lasing materials that can be chemically synthesized with a controllable performance and possess high cross-section of stimulated emission[1].Organic semiconductor laser diodes(OSLDs)can be prepared by simple processing technologies and integrated easily with other optoelectronic devices.As a result,OSLDs would展开更多
In order to improve the output power and increase the lifetime of laser diodes,expansion-matched submounts were investigated by finite element analysis.The submount was designed as sandwiched structure.By varying the ...In order to improve the output power and increase the lifetime of laser diodes,expansion-matched submounts were investigated by finite element analysis.The submount was designed as sandwiched structure.By varying the vertical structure and material of the middle layer,the thermal expansion behavior on the mounting surface was simulated to obtain the expansion-matched design.In addition,the thermal performance of laser diodes packaged by different submounts was compared.The numerical results showed that,changing the thickness ratio of surface copper to middle layer will lead the stress and junction temperature to the opposite direction.Thus compromise needs to be made in the design of the vertical structure.In addition,the silicon carbide(SiC) is the most promising material candidate for the middle layer among the materials discussed in this paper.The simulated results were aimed at providing guidance for the optimal design of sandwich-structure submounts.展开更多
Semiconductor diode lasers are widely used in a variety of applications, such as pumping, telecommunication, laser display, industrial manufacturing, and medical treatments because of their high wall-plug efficiency,
c-plane GaN-based blue laser diodes(LDs) were fabricated with Al-free cladding layers(CLs) and deepened etching depth of mesa structure, so the aspect ratio of the far-field pattern(FFP) of the laser beam can be...c-plane GaN-based blue laser diodes(LDs) were fabricated with Al-free cladding layers(CLs) and deepened etching depth of mesa structure, so the aspect ratio of the far-field pattern(FFP) of the laser beam can be reduced to as low as 1.7, which is nearly the same as conventional AlGa In P-based red LDs. By using GaN CLs,the radiation angle of the laser beam θ⊥ is only 10.1° in the direction perpendicular to the junction plane. After forming a deeply etched mesa, the beam divergence angle parallel to the junction plane of FFP, θ;, increases from4.9° to 5.8°. After using the modified structure, the operation voltage of LD is effectively reduced by 2 V at an injection current of 50 mA, but the threshold current value increases. The etching damage may be one of the main reasons responsible for the increase of the threshold current.展开更多
The thermal characteristics of 808 nm Al Ga As/Ga As laser diodes(LDs) are analyzed via electrical transient measurements and infrared thermography. The temperature rise and thermal resistance are measured at variou...The thermal characteristics of 808 nm Al Ga As/Ga As laser diodes(LDs) are analyzed via electrical transient measurements and infrared thermography. The temperature rise and thermal resistance are measured at various input currents and powers. From the electrical transient measurements, it is found that there is a significant reduction in thermal resistance with increasing power because of the device power conversion efficiency. The component thermal resistance that was obtained from the structure function showed that the total thermal resistance is mainly composed of the thermal resistance of the sub-mount rather than that of the LD chip, and the thermal resistance of the sub-mount decreases with increasing current. The temperature rise values are also measured by infrared thermography and are calibrated based on a reference image, with results that are lower than those determined by electrical transient measurements. The difference in the results is caused by the limited spatial resolution of the measurements and by the signal being captured from the facet rather than from the junction of the laser diode.展开更多
基金supported by the National Key Research and Development Program of China(Grant Nos.2016YFB0401803,2017YFE0131500,2017YFB0405000)National Natural Science Foundation of China(Grant Nos.61834008,61574160,61804164,and 61704184)+1 种基金Natural Science Foundation of Jiangsu province(BK20180254)China Postdoctoral Science Foundation(2018M630619)。
文摘Au80Sn20 alloy is a widely used solder for laser diode packaging.In this paper,the thermal resistance of Ga N-based blue laser diodes packaged in TO56 cans were measured by the forward voltage method.The microstructures of Au80Sn20 solder were then investigated to understand the reason for the difference in thermal resistance.It was found that the microstructure with a higher content of Au-rich phase in the center of the solder and a lower content of(Au,Ni)Sn phase at the interface of the solder/heat sink resulted in lower thermal resistance.This is attributed to the lower thermal resistance of Au-rich phase and higher thermal resistance of(Au,Ni)Sn phase.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60506001,60976045,60836003,60776047,and 61076119)the National Basic Research Program of China (Grant No. 2007CB936700)the Funds for Outstanding Yong Researchers from the National Natural Science Foundation of China (Grant No. 60925017)
文摘Using the finite-element method, the thermal resistances of GaN laser diode devices in a TO 56 package for both epi-up configuration and epi-down configuration are calculated. The effects of various parameters on the thermal characteristics are analysed, and the thicknesses of the AlN submount for both epi-up configuration and epi-down configuration are optimized. The obtained result provides a reference for the parameter selection of the package materials.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFB0401801the National Natural Science Foundation of China under Grant Nos 61574135,61574134,61474142,61474110,61377020,61376089,and 61223005the One Hundred Person Project of the Chinese Academy of Sciences
文摘The influences of InGaN/GaN multiple quantum wells (MQWs) and AlGaN electron-blocking layers (EBL) on the performance of GaN-based violet laser diodes are investigated. Compared with the InGaN/GaN MQWs grown at two different temperatures, the same-temperature growth of InGaN well and GaN barrier layers has a positive effect on the threshold current and slope efficiency of laser diodes, indicating that the quality of MQWs is improved. In addition, the performance of GaN laser diodes could be further improved by increasing Al content in the AlGaN EBL due to the fact that the electron leakage current could be reduced by properly increasing the barrier height of AlGaN EBL. The violet laser diode with a peak output power of 20 W is obtained.
基金Project supported by the National Natural Science Foundation of China (Grant No 10275025).
文摘Due to the zero dispersion point at 1.3μm in optical fibres, 1.3-μm InGaAsP/InP laser diodes have become main light sources in fibre communication systems recently. Influences of quantum noises on direct-modulated properties of single-mode 1.3-μm InGaAsP/InP laser diodes are investigated in this article. Considering the carrier and photon noises and the cross-correlation between the two noises, the power spectrum of the photon density and the signal-to-noise ratio (SNR) of the direct-modulated single-mode laser system are calculated using the linear approximation method. We find that the stochastic resonance (SR) always appears in the dependence of the SNR on the bias current density, and is strongly affected by the cross-correlation coefficient between the carrier and photon noises, the frequency of modulation signal, and the photon lifetime in the laser cavity. Hence, it is promising to use the SR mechanism to enhance the SNR of direct-modulated InGaAsP/InP laser diodes and improve the quality of optical fibre communication systems.
基金funded by the Spanish Government(MAT-2010-20441-C02)
文摘Catastrophic degradation of high power laser diodes is due to the generation of extended defects inside the active parts of the laser structure during the laser operation.The mechanism driving the degradation is strongly related to the existence of localized thermal stresses generated during the laser operation.These thermal stresses can overcome the yield strength of the materials forming the active part of the laser diode.Different factors contribute to reduce the laser power threshold for degradation.Among them the thermal transport across the laser structure constitutes a critical issue for the reliability of the device.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0401803 and 2016YFB0402002the National Natural Science Foundation of China under Grant Nos 61574160 and 61334005+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDA09020401the Visiting Professorship for Senior International Scientists of the Chinese Academy of Sciences under Grant No 2013T2J0048
文摘Electroluminescence (EL) and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes (LDs) before lasing. Based on the ABC mode, the EL result demonstrates that non-radiative recombination rates of LDs with threshold current densities of 4 and 6kA/cm2 are similar, while LD with threshold current density of 4kA/cm2 exhibits a smaller auger- like recombination rate compared with the one of 6kA/cm2. The internal quantum efficiency droop is more serious for LD with higher threshold current density. temperature-dependent photoluminescence is consistent The internal quantum efficiency value estimated from with EL measurements.
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.
基金Project supported by the National Key R&D Program of China(Grant Nos.2016YFB0400803 and 2016YFB0401801)the National Natural Science Foundation of China(Grant Nos.61674138,61674139,61604145,61574135,61574134,61474142,61474110,61377020,and 61376089)+1 种基金the Science Challenge Project,China(Grant No.TZ2016003)the Beijing Municipal Science and Technology Project,China(Grant No.Z161100002116037)
文摘Performances of blue and green laser diodes(LDs) with different u-InGaN upper waveguides(UWGs) are investigated theoretically by using LASTIP. It is found that the slope efficiency(SE) of blue LD decreases due to great optical loss when the indium content of u-InGaN UWG is more than 0.02, although its leakage current decreases obviously. Meanwhile the SE of the green LD increases when the indium content of u-InGaN UWG is varied from 0 to 0.05, which is attributed to the reduction of leakage current and the small increase of optical loss. Therefore, a new blue LD structure with In(0.05) Ga(0.95)N lower waveguide(LWG) is designed to reduce the optical loss, and its slope efficiency is improved significantly.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60976045,60506001,60836003 and 60776047)the National Basic Research Program of China (Grant No. 2007CB936700)the National Natural Science Foundation for Distinguished Young Scholars of China (Grant No. 60925017)
文摘This paper reports that a long delay between the beginning of pumping current pulse and the onset of optical pulse is observed in InGaN laser diodes. The delay time decreases as the pumping current increases, and the speed of the delay time reduction becomes slower as the current amplitude increases further. Such delay phenomena are remarkably less serious in laser diodes grown on GaN substrate than those on sapphire. It attributes the delay to the traps which cause a large optical loss by saturable absorption and retard the laser action. The traps can be bleached by capturing injected carriers. The effect of GaAs laser irradiation on InGaN laser action demonstrates that the traps responsible for the delay are deep centres which can be filled by the photo-assisted processes.
基金Project supported by the National Natural Science Foundation of China (Grant No 10374085). Acknowledgment The authors would like to thank the members of the nano-opotoelectronics laboratory for helpful discussion.
文摘Usually GaAs/AlGaAs is utilized as an active layer material in laser diodes operating in the spectral range of 800- 850 nm. In this work, in addition to a traditional unstrained GaAs/AlGaAs distributed feedback (DFB) laser diode, a compressively strained InGaAlAs/AlGaAs DFB laser diode is numerically investigated in characteristic. The simulation results show that the compressively strained DFB laser diode has a lower transparency carrier density, higher gain, lower Auger recombination rate, and higher stimulated recombination rate, which lead to better a device performance, than the traditional unstrained GaAs/AlGaAs DFB laser diode.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60506001,60776047,60476021,60576003 and 60836003)the National Basic Research Programme of China (Grant No 2007CB936700)
文摘A violet laser diode (LD) structure is grown on a free-standing c-plane GaN substrate and 4 μm×800μm ridge waveguide LDs are fabricated. The electrical and the optical characteristics of LDs under different facet-coating and chip-mounting conditions are investigated under pulse mode operation. The active region temperatures of p-side up and p-side down mounted LDs are calculated with different injection currents. The calculated thermal resistances of p-side up and p-side down mounted LDs are 4.6 K/W and 3 K/W, respectively. The threshold current of the p-side down mounted LD is much lower than that of the p-side up mounted LD. The blue shift of the emission wavelength with increasing injection current is observed only for the LD with p-side down mounting configuration, due to the more efficient heat dissipation.
文摘The accelerating burn in and screening method of processing 1 310 nm InGaAsP of laser diodes (LDs) is introduced. It is confirmed that the theory of burn in and screening is based on the second derivative minimum of burn-in curve, and the new testing method has been given, that is automatic current control (ACC) burn-in and automatic power control (APC) testing. This avoidably bring the errors of testing in only ACC or APC method, which need to monitor and control or test LDs power change by photo-detector (PD) at high temperature, and LDs or PDs must be into the same environment (PD will be burn-in at the same time). Through the experiment, the accelerating burn-in and screening condition of the devices has been confirmed: ACC, 200 mA, 100 ℃, 8 h. This raise work efficiency 12 times than Bellcore standard and save testing fee.
基金supported by the National Key R&D Program of China,No.2022YFB4601201.
文摘The 975 nm multimode diode lasers with high-order surface Bragg diffraction gratings have been simulated and calcu-lated using the 2D finite difference time domain(FDTD)algorithm and the scattering matrix method(SMM).The periods and etch depth of the grating parameters have been optimized.A board area laser diode(BA-LD)with high-order diffraction grat-ings has been designed and fabricated.At output powers up to 10.5 W,the measured spectral width of full width at half maxi-mum(FWHM)is less than 0.5 nm.The results demonstrate that the designed high-order surface gratings can effectively nar-row the spectral width of multimode semiconductor lasers at high output power.
基金Projects the supported by the National Key R&D Program of China(Nos.2016YFB0401801,2016YFB0400803)the National Natural Science Foundation of China(Nos.61674138,61674139,61604145,61574135,61574134,61474142,61474110,61377020,61376089)+1 种基金the Science Challenge Project(No.JCKY2016212A503)the One Hundred Person Project of the Chinese Academy of Sciences
文摘Two kinds of continuous-wave GaN-based ultraviolet laser diodes(LDs) operated at room temperature and with different emission wavelengths are demonstrated.The LDs epitaxial layers are grown on GaN substrate by metalorganic chemical vapor deposition,with a 10 × 600 μm^2 ridge waveguide structure.The electrical and optical characteristics of the ultraviolet LDs are investigated under direct-current injection at room temperature.The stimulated emission peak wavelength of first LD is 392.9 nm,the threshold current density and voltage is 1.5kA/cm^2 and 5.0 V,respectively.The output light power is 80 mW under the 4.0 kA/cm^2 injection current density.The stimulated emission peak wavelength of second LD is 381.9 nm,the threshold current density the voltage is2.8 kA/cm^2 and 5.5 V,respectively.The output light power is 14 mW under a 4.0 kA/cm^2 injection current density.
基金supported by the National Natural Science Foundation of China(Nos.61377020,61376089,61223005,61176126)the National Science Fund for Distinguished Young Scholars(No.60925017)
文摘Electron leakage in GaAs-based separately confined heterostructure 808 nm laser diodes (SCH LDs) has a serious influence on device performance. Here, in order to reduce the energy of electrons injected into the quantum well (QW), an A1GaAs interlayer with a smaller A1 component is added between the active region and the n-side waveguide. Numerical device simulation reveals that when the Al-composition of the A1GaAs interlayer and its thickness are properly elected, the electron leakage is remarkably depressed and the characteristics of LDs are improved, owing to the reduction of injected electron energy and the improvement of QW capture efficiency.
基金supported by the CAS Innovation Program, the National Natural Science Foundation of China (51503196, 61775211, 61704170, 61405195 and 61774154)the financial support from the State Key Laboratory of Luminescence and Applications
文摘Organic semiconductor is one of the most promising luminescent and lasing materials that can be chemically synthesized with a controllable performance and possess high cross-section of stimulated emission[1].Organic semiconductor laser diodes(OSLDs)can be prepared by simple processing technologies and integrated easily with other optoelectronic devices.As a result,OSLDs would
文摘In order to improve the output power and increase the lifetime of laser diodes,expansion-matched submounts were investigated by finite element analysis.The submount was designed as sandwiched structure.By varying the vertical structure and material of the middle layer,the thermal expansion behavior on the mounting surface was simulated to obtain the expansion-matched design.In addition,the thermal performance of laser diodes packaged by different submounts was compared.The numerical results showed that,changing the thickness ratio of surface copper to middle layer will lead the stress and junction temperature to the opposite direction.Thus compromise needs to be made in the design of the vertical structure.In addition,the silicon carbide(SiC) is the most promising material candidate for the middle layer among the materials discussed in this paper.The simulated results were aimed at providing guidance for the optimal design of sandwich-structure submounts.
基金supported by the National Natural Science Foundation of China(Nos.61404138 and 61474119)the National Basic Research Program of China(No.2013CB933303)+3 种基金the International Science Technology Cooperation Program of the Chinese Academy of Sciences(No.181722KYSB20160005)the International Science Technology Cooperation Program of China(No.2013DFR00730)the Jilin Provincial Natural Science Foundation(Nos.20160101243JC and 20150520105JH)the Opened Fund of the State Key Laboratory on Integrated Optoelectronics(No.IOSKL2016KF15)
文摘Semiconductor diode lasers are widely used in a variety of applications, such as pumping, telecommunication, laser display, industrial manufacturing, and medical treatments because of their high wall-plug efficiency,
基金supported by the National Key R&D Program(Nos.2017YFB0403100,2017YFB0403101)the National Natural Science Foundation of China(Nos.61534007,61404156,61522407,61604168,61775230)+7 种基金the Key Frontier Scientific Research Program of the Chinese Academy of Sciences(No.QYZDB-SSW-JSC014)the Science and Technology Service Network Initiative of the Chinese Academy of Sciences,the Key R&D Program of Jiangsu Province(No.BE2017079)the Natural Science Foundation of Jiangsu Province(No.BK20160401)the China Postdoctoral Science Foundation(No.2016M591944)supported by the Open Fund of the State Key Laboratory of Luminescence and Applications(No.SKLA-2016-01)the Open Fund of the State Key Laboratory on Integrated Optoelectronics(Nos.IOSKL2016KF04,IOSKL2016KF07)the Seed Fund from SINANO,CAS(No.Y5AAQ51001)supported technically by Nano Fabrication Facility,Platform for Characterization&Test,Nano-X of SINANO,CAS
文摘c-plane GaN-based blue laser diodes(LDs) were fabricated with Al-free cladding layers(CLs) and deepened etching depth of mesa structure, so the aspect ratio of the far-field pattern(FFP) of the laser beam can be reduced to as low as 1.7, which is nearly the same as conventional AlGa In P-based red LDs. By using GaN CLs,the radiation angle of the laser beam θ⊥ is only 10.1° in the direction perpendicular to the junction plane. After forming a deeply etched mesa, the beam divergence angle parallel to the junction plane of FFP, θ;, increases from4.9° to 5.8°. After using the modified structure, the operation voltage of LD is effectively reduced by 2 V at an injection current of 50 mA, but the threshold current value increases. The etching damage may be one of the main reasons responsible for the increase of the threshold current.
基金Project supported by the National Natural Science Foundation of China(Nos.61376077,61201046,61204081)
文摘The thermal characteristics of 808 nm Al Ga As/Ga As laser diodes(LDs) are analyzed via electrical transient measurements and infrared thermography. The temperature rise and thermal resistance are measured at various input currents and powers. From the electrical transient measurements, it is found that there is a significant reduction in thermal resistance with increasing power because of the device power conversion efficiency. The component thermal resistance that was obtained from the structure function showed that the total thermal resistance is mainly composed of the thermal resistance of the sub-mount rather than that of the LD chip, and the thermal resistance of the sub-mount decreases with increasing current. The temperature rise values are also measured by infrared thermography and are calibrated based on a reference image, with results that are lower than those determined by electrical transient measurements. The difference in the results is caused by the limited spatial resolution of the measurements and by the signal being captured from the facet rather than from the junction of the laser diode.