In this study, we develop advanced numerical models to comprehensively investigate the static and dynamic performances for GaN-based vertical cavity surface emitting lasers (VCSELs) with optimized current injection efficiency. We propose using indium tin oxide (ITO) instead of SiO2 as the current confinement layer. The ITO/p-GaN forms a resistive junction, which improves hole injection efficiency and suppresses the hole leakage out of the aperture for GaN-based VCSELs. The ITO/p-GaN design eliminates the capacitance arising from the SiO2, and the VCSELs can be stabilized within a reduced time upon being turned on. We have also found that the defects on the recessed p-GaN region have significant impact on the static and dynamic characteristics for the proposed VCSELs, such that the surface defects generate charging/discharging processes. This may cause very significant laser power oscillation before the device is stabilized. As a result, we investigate the impact of defect density and defect energy levels on the device performances. We find that, besides decreasing the defect density, defects with shallow energy level may also have strong impact on delaying the device stabilization process. In order to suppress the defect-induced capturing effect for injected holes, we then design u-AlGaN/p-GaN/u-AlGaN/p-GaN so that the hetero-junctions can spread the current into the aperture center. This favors the hole to be apart from the surface defects, which enables the increased hole injection. Therefore, the designed VCSELs will reduce the oscillation duration before reaching the stabilized on-state.
{"title":"Enhanced Static and Dynamic Performance for GaN-Based VCSELs With ITO/p-GaN Resistive Current Injection Structure","authors":"Kangkai Tian;Jingyu Tang;Chunshuang Chu;Fuping Huang;Yonghui Zhang;Xiao Wei Sun;Zi-Hui Zhang","doi":"10.1109/JQE.2025.3574120","DOIUrl":"https://doi.org/10.1109/JQE.2025.3574120","url":null,"abstract":"In this study, we develop advanced numerical models to comprehensively investigate the static and dynamic performances for GaN-based vertical cavity surface emitting lasers (VCSELs) with optimized current injection efficiency. We propose using indium tin oxide (ITO) instead of SiO2 as the current confinement layer. The ITO/p-GaN forms a resistive junction, which improves hole injection efficiency and suppresses the hole leakage out of the aperture for GaN-based VCSELs. The ITO/p-GaN design eliminates the capacitance arising from the SiO2, and the VCSELs can be stabilized within a reduced time upon being turned on. We have also found that the defects on the recessed p-GaN region have significant impact on the static and dynamic characteristics for the proposed VCSELs, such that the surface defects generate charging/discharging processes. This may cause very significant laser power oscillation before the device is stabilized. As a result, we investigate the impact of defect density and defect energy levels on the device performances. We find that, besides decreasing the defect density, defects with shallow energy level may also have strong impact on delaying the device stabilization process. In order to suppress the defect-induced capturing effect for injected holes, we then design u-AlGaN/p-GaN/u-AlGaN/p-GaN so that the hetero-junctions can spread the current into the aperture center. This favors the hole to be apart from the surface defects, which enables the increased hole injection. Therefore, the designed VCSELs will reduce the oscillation duration before reaching the stabilized on-state.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"61 3","pages":"1-8"},"PeriodicalIF":2.2,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144536684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-26DOI: 10.1109/JQE.2025.3554459
Tu-Lu Liang;Wei Shao;Zi-Ye Xiao;Mei Yu;Lingyan Zhang;Wei Zhang;Jin Shi
In this study, optimization methods for the design of the compact and broadband adiabatic couplers are presented. Two definitions of an uncoupled waveguide system are introduced: the first involves connecting one of the two silicon waveguides to a boundary, directing its eigenmodes to the boundary, while the second removes one of the waveguides, resulting in eigenmodes confined to the remaining waveguide. The efficient design of adiabatic couplers is achieved by correcting and fitting the refractive indices of the even and odd eigenmodes in these uncoupled systems. The length of the adiabatic coupler designed by the proposed optimization method can be substantially reduced compared to the conventional linear adiabatic coupler. Calculations for the operating bandwidth of the designed adiabatic coupler show that the proposed optimization method can indeed achieve a paramount wide range of operating bandwidths (power transmission efficiencies of more than 90% are achieved for wavelengths from 1406 nm to 3775 nm). A comparison with other design methods demonstrates that the proposed optimization approach yields a coupler with higher efficiency than previous methods. These findings highlight the potential of this optimization strategy for designing high-performance adiabatic couplers with complex geometries in integrated optics.
{"title":"Optimization Methods for the Design of Compact and Broadband Adiabatic Couplers","authors":"Tu-Lu Liang;Wei Shao;Zi-Ye Xiao;Mei Yu;Lingyan Zhang;Wei Zhang;Jin Shi","doi":"10.1109/JQE.2025.3554459","DOIUrl":"https://doi.org/10.1109/JQE.2025.3554459","url":null,"abstract":"In this study, optimization methods for the design of the compact and broadband adiabatic couplers are presented. Two definitions of an uncoupled waveguide system are introduced: the first involves connecting one of the two silicon waveguides to a boundary, directing its eigenmodes to the boundary, while the second removes one of the waveguides, resulting in eigenmodes confined to the remaining waveguide. The efficient design of adiabatic couplers is achieved by correcting and fitting the refractive indices of the even and odd eigenmodes in these uncoupled systems. The length of the adiabatic coupler designed by the proposed optimization method can be substantially reduced compared to the conventional linear adiabatic coupler. Calculations for the operating bandwidth of the designed adiabatic coupler show that the proposed optimization method can indeed achieve a paramount wide range of operating bandwidths (power transmission efficiencies of more than 90% are achieved for wavelengths from 1406 nm to 3775 nm). A comparison with other design methods demonstrates that the proposed optimization approach yields a coupler with higher efficiency than previous methods. These findings highlight the potential of this optimization strategy for designing high-performance adiabatic couplers with complex geometries in integrated optics.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"61 2","pages":"1-9"},"PeriodicalIF":2.2,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-22DOI: 10.1109/JQE.2025.3572831
Yue Zhang;Zhenxing Sun;Rulei Xiao;Xiangfei Chen
We propose and demonstrate a 150-channel multi-wavelength distributed feedback (DFB) laser array for dense wavelength division multiplexing (DWDM) systems. The proposed multi-wavelength laser array with wavelength spacing at 0.8 nm (100 GHz) meets the ITU-T specifications. Using the reconstructed equivalent chirp (REC) technique, an equivalent $pi $ phase shift is introduced at the center of the laser cavity to guarantee stable single longitudinal mode operation. Besides, the grating fabrication is simplified and the precision of the wavelength spacing is enhanced by the proposed REC technique. In addition, the asymmetric multiple-quantum-well (AMQW) technique is used to broaden the modal gain spectral, thus providing enough gain for all the wavelengths of interest. As a result, a 150-channel multi-wavelength DFB laser array is experimentally demonstrated. At the bias current of 120 mA, the side mode suppression ratios (SMSRs) of all the channels are above 45 dB. The lasing wavelengths are then linearly fitted and the fitted results indicate that the average channel spacing is 0.81 nm, which is only ±0.01 nm deviated from our design. All the 150 lasers operate with low threshold currents of 25 to 65 mA, which is owing to the broad wavelength range of gain provided by the AMQW structure. The output power of all the 150 lasers is over 10 mW at the bias current of200mA. The proposed laser array has a far-field divergence angle of $32^{circ } times 26^{circ }$ and Lorentzian fitted linewidth of 3.35 MHz. To the best of our knowledge, the 150-channel multi-wavelength DFB laser array reported in this paper represents the highest number of channels for a DFB laser array reported to date. The superior properties of the proposed laser array such as stable single-mode operation, precise wavelength control, and high channel count are advantageous for its application in the DWDM systems to enhance the transmission capacity.
{"title":"Experimental Demonstration of 150-Channel REC-DFB Laser Array Based on Asymmetric Multiple-Quantum-Well","authors":"Yue Zhang;Zhenxing Sun;Rulei Xiao;Xiangfei Chen","doi":"10.1109/JQE.2025.3572831","DOIUrl":"https://doi.org/10.1109/JQE.2025.3572831","url":null,"abstract":"We propose and demonstrate a 150-channel multi-wavelength distributed feedback (DFB) laser array for dense wavelength division multiplexing (DWDM) systems. The proposed multi-wavelength laser array with wavelength spacing at 0.8 nm (100 GHz) meets the ITU-T specifications. Using the reconstructed equivalent chirp (REC) technique, an equivalent <inline-formula> <tex-math>$pi $ </tex-math></inline-formula> phase shift is introduced at the center of the laser cavity to guarantee stable single longitudinal mode operation. Besides, the grating fabrication is simplified and the precision of the wavelength spacing is enhanced by the proposed REC technique. In addition, the asymmetric multiple-quantum-well (AMQW) technique is used to broaden the modal gain spectral, thus providing enough gain for all the wavelengths of interest. As a result, a 150-channel multi-wavelength DFB laser array is experimentally demonstrated. At the bias current of 120 mA, the side mode suppression ratios (SMSRs) of all the channels are above 45 dB. The lasing wavelengths are then linearly fitted and the fitted results indicate that the average channel spacing is 0.81 nm, which is only ±0.01 nm deviated from our design. All the 150 lasers operate with low threshold currents of 25 to 65 mA, which is owing to the broad wavelength range of gain provided by the AMQW structure. The output power of all the 150 lasers is over 10 mW at the bias current of200mA. The proposed laser array has a far-field divergence angle of <inline-formula> <tex-math>$32^{circ } times 26^{circ }$ </tex-math></inline-formula> and Lorentzian fitted linewidth of 3.35 MHz. To the best of our knowledge, the 150-channel multi-wavelength DFB laser array reported in this paper represents the highest number of channels for a DFB laser array reported to date. The superior properties of the proposed laser array such as stable single-mode operation, precise wavelength control, and high channel count are advantageous for its application in the DWDM systems to enhance the transmission capacity.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"61 3","pages":"1-7"},"PeriodicalIF":2.2,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-22DOI: 10.1109/JQE.2025.3572859
Sebastian W. Schaefer;Ras-Jeevan K. Obhi;D. Paige Wilson;Philip J. Poole;Jiaren R. Liu;Christopher E. Valdivia;Trevor Hall;Zhenguo Lu;Karin Hinzer
Monolithic mode-locked diode lasers based on InAs/InP quantum dashes offer an inexpensive and efficient platform for spectral comb generation. These combs are used in dense wavelength division multiplexing schemes within optical fiber interconnects and frequency references in metrology. Depending on the application, integration can require operation at elevated temperatures, reducing light conversion efficiency. The lasers studied in this work are monolithic $1.55~mu $ m InAs/InP quantum dash cleave/cleave ridge waveguide lasers. We demonstrate performance over temperature and show numerical optoelectronic modelling of said device using Crosslight PICS3D. We discuss the limitations that arise when using an established industry modelling tool to simulate novel devices with complex physics. While the model has potential to predict of a narrow set of properties tied predominantly to carrier transport, its limitations point towards using more bespoke models to capture the complex physics of mode-locking.
{"title":"Numerical Modeling of InAs/InP Quantum Dash Ridge Lasers as a Function of Temperature","authors":"Sebastian W. Schaefer;Ras-Jeevan K. Obhi;D. Paige Wilson;Philip J. Poole;Jiaren R. Liu;Christopher E. Valdivia;Trevor Hall;Zhenguo Lu;Karin Hinzer","doi":"10.1109/JQE.2025.3572859","DOIUrl":"https://doi.org/10.1109/JQE.2025.3572859","url":null,"abstract":"Monolithic mode-locked diode lasers based on InAs/InP quantum dashes offer an inexpensive and efficient platform for spectral comb generation. These combs are used in dense wavelength division multiplexing schemes within optical fiber interconnects and frequency references in metrology. Depending on the application, integration can require operation at elevated temperatures, reducing light conversion efficiency. The lasers studied in this work are monolithic <inline-formula> <tex-math>$1.55~mu $ </tex-math></inline-formula>m InAs/InP quantum dash cleave/cleave ridge waveguide lasers. We demonstrate performance over temperature and show numerical optoelectronic modelling of said device using Crosslight PICS3D. We discuss the limitations that arise when using an established industry modelling tool to simulate novel devices with complex physics. While the model has potential to predict of a narrow set of properties tied predominantly to carrier transport, its limitations point towards using more bespoke models to capture the complex physics of mode-locking.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"61 3","pages":"1-8"},"PeriodicalIF":2.2,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11009133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we theoretically investigate the nonlinear dynamics of a passively Q-switched Nd:YAG/Cr:YAG laser under the triangular wave pump modulation. The influence of the key parameters of the modulation frequency, modulation amplitude, and unmodulated pump rate on the nonlinear dynamics are analyzed. Meanwhile, the nonlinear dynamic evolution routes of the pulse peak and pulse frequency are also determined. The results show that the passively Q-switched Nd:YAG/Cr:YAG laser can exhibit rich nonlinear dynamics, such as period-one (P1), period-two (P2), multi-period (MP), and chaotic pulsation (CP) under some suitable parameters. Furthermore, the nonlinear dynamic evolution routes of pulse peak and pulse frequency exhibit similar trends, but their intensity changes follow opposite directions.
{"title":"Nonlinear Dynamics of a Passively Q-Switched Nd:YAG/Cr:YAG Laser Under Triangular Wave Pump Modulation","authors":"Jiayi Bian;Zhaoqi Sun;Qiupin Wang;Tao Deng;Xiaodong Lin;Jianjun Chen;Ziye Gao","doi":"10.1109/JQE.2025.3572867","DOIUrl":"https://doi.org/10.1109/JQE.2025.3572867","url":null,"abstract":"In this work, we theoretically investigate the nonlinear dynamics of a passively Q-switched Nd:YAG/Cr:YAG laser under the triangular wave pump modulation. The influence of the key parameters of the modulation frequency, modulation amplitude, and unmodulated pump rate on the nonlinear dynamics are analyzed. Meanwhile, the nonlinear dynamic evolution routes of the pulse peak and pulse frequency are also determined. The results show that the passively Q-switched Nd:YAG/Cr:YAG laser can exhibit rich nonlinear dynamics, such as period-one (P1), period-two (P2), multi-period (MP), and chaotic pulsation (CP) under some suitable parameters. Furthermore, the nonlinear dynamic evolution routes of pulse peak and pulse frequency exhibit similar trends, but their intensity changes follow opposite directions.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"61 3","pages":"1-6"},"PeriodicalIF":2.2,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-22DOI: 10.1109/JQE.2025.3572864
Soumi Pal;Arpit Khandelwal;Nitin Bhatia
We show that the stable dual mode emission, characterized by different polarization of the modes, requires the buried heterostructure (BH) laser to operate in the linear gain region above the threshold; however, not reaching the saturation levels. Additionally, the laser must operate in the weak coupling regime where the self-gain saturation coefficient must be larger than that of the cross-gain coefficient. Furthermore, the method of reflectivity modification has been applied to achieve the dual mode emission at much lower pump current values. The dual mode output is targeted towards the generation of microwave signals using the optical heterodyning method. Various practical issues, such as the implementation mechanism of this method, the impact of spontaneous emission, and the corresponding phase noise performance of the resultant microwave signal, are also discussed.
{"title":"Stable Dual Wavelength Emission From the Buried Heterostructure Laser Using Reflectivity Modification Method for Microwave Generation","authors":"Soumi Pal;Arpit Khandelwal;Nitin Bhatia","doi":"10.1109/JQE.2025.3572864","DOIUrl":"https://doi.org/10.1109/JQE.2025.3572864","url":null,"abstract":"We show that the stable dual mode emission, characterized by different polarization of the modes, requires the buried heterostructure (BH) laser to operate in the linear gain region above the threshold; however, not reaching the saturation levels. Additionally, the laser must operate in the weak coupling regime where the self-gain saturation coefficient must be larger than that of the cross-gain coefficient. Furthermore, the method of reflectivity modification has been applied to achieve the dual mode emission at much lower pump current values. The dual mode output is targeted towards the generation of microwave signals using the optical heterodyning method. Various practical issues, such as the implementation mechanism of this method, the impact of spontaneous emission, and the corresponding phase noise performance of the resultant microwave signal, are also discussed.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"61 3","pages":"1-10"},"PeriodicalIF":2.2,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144536661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-20DOI: 10.1109/JQE.2025.3549251
{"title":"IEEE Journal of Quantum Electronics information for authors","authors":"","doi":"10.1109/JQE.2025.3549251","DOIUrl":"https://doi.org/10.1109/JQE.2025.3549251","url":null,"abstract":"","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"61 1","pages":"C3-C3"},"PeriodicalIF":2.2,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10935772","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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