Pub Date : 2024-09-27DOI: 10.1109/JQE.2024.3465253
{"title":"TechRxiv: Share Your Preprint Research with the World!","authors":"","doi":"10.1109/JQE.2024.3465253","DOIUrl":"https://doi.org/10.1109/JQE.2024.3465253","url":null,"abstract":"","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 5","pages":"1-1"},"PeriodicalIF":2.2,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10697332","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328390","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}
We employed 808 nm and 885 nm pumping sources for time-shared pumping of the compact Nd:YAG/Cr4+:YAG passively Q-switched laser by incorporating time and sequence modulation functions into the electrical modulation signals. Through adjusting the pumping peak powers and pulse widths of the two pump sources, various burst-mode lasers were realized. The repetition frequency and time intervals between pulse chain sequences, as well as the intervals between sub-pulses within a sequence, could be adjustable, addressing the challenge of precise timing control in burst-mode lasers. The time-shared pumping Q-switched laser displayed significantly better controllable pulse characteristic compared to the conventional single-pulse output mode of burst-mode lasers. In conclusion, this work has effectively expanded the application scope of burst-mode lasers, representing a novel contribution to the field.
{"title":"Burst-Mode Nd: YAG/Cr⁴⁺:YAG Laser With Tunable Pulse Chain Sequence and Intervals","authors":"Nihui Zhang;Di Xin;Zhenjiao Shan;Fengxin Dong;Xuyan Zhou;Hongbo Zhang;Wanhua Zheng","doi":"10.1109/JQE.2024.3468999","DOIUrl":"https://doi.org/10.1109/JQE.2024.3468999","url":null,"abstract":"We employed 808 nm and 885 nm pumping sources for time-shared pumping of the compact Nd:YAG/Cr4+:YAG passively Q-switched laser by incorporating time and sequence modulation functions into the electrical modulation signals. Through adjusting the pumping peak powers and pulse widths of the two pump sources, various burst-mode lasers were realized. The repetition frequency and time intervals between pulse chain sequences, as well as the intervals between sub-pulses within a sequence, could be adjustable, addressing the challenge of precise timing control in burst-mode lasers. The time-shared pumping Q-switched laser displayed significantly better controllable pulse characteristic compared to the conventional single-pulse output mode of burst-mode lasers. In conclusion, this work has effectively expanded the application scope of burst-mode lasers, representing a novel contribution to the field.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 6","pages":"1-7"},"PeriodicalIF":2.2,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142438567","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 : 2024-09-26DOI: 10.1109/JQE.2024.3468998
Xuanchen Guo;Yinyang Pei;Jianzhong Zhang
The spatial mode profile of distributed feedback (DFB) lasers is a unique characteristic that distinguishes them from lasers based on F-P cavities. It is utilized to achieve single-mode operation and improve relative intensity noise (RIN) performance. The effective cavity length method, as an approximate method for spatial mode profiling, is conveniently used for theoretical analysis. In this paper, the RIN of DFB fiber lasers was analyzed by considering their spatial mode profile without any approximations, and the results were compared with experimental findings. Additionally, numerical simulations of DFB fiber lasers with different structures were conducted to analyze their noise characteristics and the impact of spatial mode profile on the RIN of the lasers was discussed. The spatial mode profile was solved using the shooting method, with boundary conditions provided based on the erbium ion gain model. The spatial mode profile was then substituted into the RIN expression, yielding the RIN of DFB lasers influenced by spatial mode profile. This physical model is widely applicable and can be used to effectively analyze the dynamic characteristics of most DFB fiber laser structures.
分布式反馈（DFB）激光器的空间模式轮廓是其区别于基于 F-P 腔的激光器的独特特征。利用它可以实现单模运行并改善相对强度噪声（RIN）性能。有效腔长方法作为空间模式剖析的近似方法，可方便地用于理论分析。本文通过不考虑任何近似值的空间模式剖面分析了 DFB 光纤激光器的 RIN，并将结果与实验结果进行了比较。此外，还对不同结构的 DFB 光纤激光器进行了数值模拟，以分析其噪声特性，并讨论了空间模式剖面对激光器 RIN 的影响。空间模式轮廓采用射击法求解，并根据铒离子增益模型提供了边界条件。然后将空间模式剖面代入 RIN 表达式，得出受空间模式剖面影响的 DFB 激光器 RIN。该物理模型具有广泛的适用性，可用于有效分析大多数 DFB 光纤激光器结构的动态特性。
{"title":"Numerical Analysis of Relative Intensity Noise of Distributed-Feedback Fiber Lasers Considering Spatial Mode Profile","authors":"Xuanchen Guo;Yinyang Pei;Jianzhong Zhang","doi":"10.1109/JQE.2024.3468998","DOIUrl":"https://doi.org/10.1109/JQE.2024.3468998","url":null,"abstract":"The spatial mode profile of distributed feedback (DFB) lasers is a unique characteristic that distinguishes them from lasers based on F-P cavities. It is utilized to achieve single-mode operation and improve relative intensity noise (RIN) performance. The effective cavity length method, as an approximate method for spatial mode profiling, is conveniently used for theoretical analysis. In this paper, the RIN of DFB fiber lasers was analyzed by considering their spatial mode profile without any approximations, and the results were compared with experimental findings. Additionally, numerical simulations of DFB fiber lasers with different structures were conducted to analyze their noise characteristics and the impact of spatial mode profile on the RIN of the lasers was discussed. The spatial mode profile was solved using the shooting method, with boundary conditions provided based on the erbium ion gain model. The spatial mode profile was then substituted into the RIN expression, yielding the RIN of DFB lasers influenced by spatial mode profile. This physical model is widely applicable and can be used to effectively analyze the dynamic characteristics of most DFB fiber laser structures.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 6","pages":"1-10"},"PeriodicalIF":2.2,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142377142","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 : 2024-09-26DOI: 10.1109/JQE.2024.3468994
Yuko Kono;Shigeyuki Takagi
We have developed an experimental method for estimating the thermal lens effect of a Nd:YAG rod during laser oscillation in a high-power pulsed laser. By combining a stability analysis by cavity simulation with the change in the focal length of the rod and the beam quality according to the input, we were able to correct the reduction of the thermal effect on the rod due to laser oscillation. The proposed method makes it possible to design a resonator that appropriately considers the stability of the resonator that changes in accordance with the input power.
{"title":"Laser Cavity Analysis Method Considering Dynamic Change of Thermal Lens Effect","authors":"Yuko Kono;Shigeyuki Takagi","doi":"10.1109/JQE.2024.3468994","DOIUrl":"https://doi.org/10.1109/JQE.2024.3468994","url":null,"abstract":"We have developed an experimental method for estimating the thermal lens effect of a Nd:YAG rod during laser oscillation in a high-power pulsed laser. By combining a stability analysis by cavity simulation with the change in the focal length of the rod and the beam quality according to the input, we were able to correct the reduction of the thermal effect on the rod due to laser oscillation. The proposed method makes it possible to design a resonator that appropriately considers the stability of the resonator that changes in accordance with the input power.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 6","pages":"1-7"},"PeriodicalIF":2.2,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595046","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 : 2024-09-18DOI: 10.1109/JQE.2024.3462950
Jinye Li;Dechen Li;Peng Wang;Jinming Tao;Run Li;Qianqian Jia;Jianguo Liu
Broadband, compact electro-optic modulator is one of the key components in optical communication networks and microwave photonic systems. Here, this paper reports a thin-film lithium niobate electro-optic modulator with a 3 dB electro-optic bandwidth greater than 50 GHz after encapsulation, and discusses the electro-optic response and thermo-optic phase-shifting performance of the device. The modulator chip has a 3 dB electro-optic bandwidth greater than 67 GHz, and the fully encapsulated device has a small size (31 mm $times 10$ mm $times 5.3$ mm) while having a high electro-optic bandwidth of up to 51 GHz and an excellent half-wave voltage length product as low as 2.5 V $cdot$ cm. The DC bias is thermally shifted with a 2.3V half-wave voltage for reliable and stable bias characteristics.
宽带、紧凑型电光调制器是光通信网络和微波光子系统的关键部件之一。本文报告了一种薄膜铌酸锂电光调制器，其封装后的 3 dB 电光带宽大于 50 GHz，并讨论了该器件的电光响应和热光移相性能。该调制器芯片的3 dB电光带宽大于67 GHz，完全封装后的器件体积小（31 mm×10 mm×5.3 mm），电光带宽高达51 GHz，半波电压长度积低至2.5 V cm。直流偏压采用 2.3V 半波电压热偏移，具有可靠稳定的偏压特性。
{"title":"Ultra-Compact, Fully Packaged Broadband Thin-Film Lithium Niobate Modulator for Microwave Photonics","authors":"Jinye Li;Dechen Li;Peng Wang;Jinming Tao;Run Li;Qianqian Jia;Jianguo Liu","doi":"10.1109/JQE.2024.3462950","DOIUrl":"10.1109/JQE.2024.3462950","url":null,"abstract":"Broadband, compact electro-optic modulator is one of the key components in optical communication networks and microwave photonic systems. Here, this paper reports a thin-film lithium niobate electro-optic modulator with a 3 dB electro-optic bandwidth greater than 50 GHz after encapsulation, and discusses the electro-optic response and thermo-optic phase-shifting performance of the device. The modulator chip has a 3 dB electro-optic bandwidth greater than 67 GHz, and the fully encapsulated device has a small size (31 mm \u0000<inline-formula> <tex-math>$times 10$ </tex-math></inline-formula>\u0000 mm \u0000<inline-formula> <tex-math>$times 5.3$ </tex-math></inline-formula>\u0000 mm) while having a high electro-optic bandwidth of up to 51 GHz and an excellent half-wave voltage length product as low as 2.5 V\u0000<inline-formula> <tex-math>$cdot$ </tex-math></inline-formula>\u0000 cm. The DC bias is thermally shifted with a 2.3V half-wave voltage for reliable and stable bias characteristics.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 6","pages":"1-9"},"PeriodicalIF":2.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255945","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 : 2024-09-18DOI: 10.1109/JQE.2024.3462953
Faramarz Alihosseini;Hesam Zandi
We introduce a high-performance terahertz detector based on the photo-thermoelectric effect (PTE) in graphene. Our study outlines a novel approach to enhance terahertz detection through a photodetector that employs a hybrid structure. This structure combines the localized surface plasmon resonance of dual grating gates with the resonant modes of a Fabry-Perot cavity configuration, facilitating a strong interaction between terahertz light and the active graphene layer, thereby improving light absorption. Our numerical investigation reveals frequency selectivity within the terahertz absorptance spectrum for incident waves with transverse magnetic polarization, leading to near-perfect absorptance of graphene. This substantial absorption creates an amplified thermal gradient across the graphene channel due to localized heat generation from terahertz wave absorption. The detector’s absorption characteristics can be adjusted by altering geometrical parameters and tuning two gate voltages. Furthermore, incorporating dual grating gates to create a pn-junction leads to a non-uniform Seebeck coefficient along the channel, enhancing the generated voltage. At a resonant frequency of 1.6 THz, the detector demonstrates a responsivity of 1.26 V/W and a noise-equivalent power (NEP) of $5.2 mathrm {nW}/sqrt {mathrm {Hz}}$ at room temperature, under biasing the two grating gates with the low voltages of ±0.2 V.
{"title":"Enhanced Spectrally Selective Terahertz Detection in a Photo-Thermoelectric Graphene Detector With Dual Nano-Grating Gates","authors":"Faramarz Alihosseini;Hesam Zandi","doi":"10.1109/JQE.2024.3462953","DOIUrl":"10.1109/JQE.2024.3462953","url":null,"abstract":"We introduce a high-performance terahertz detector based on the photo-thermoelectric effect (PTE) in graphene. Our study outlines a novel approach to enhance terahertz detection through a photodetector that employs a hybrid structure. This structure combines the localized surface plasmon resonance of dual grating gates with the resonant modes of a Fabry-Perot cavity configuration, facilitating a strong interaction between terahertz light and the active graphene layer, thereby improving light absorption. Our numerical investigation reveals frequency selectivity within the terahertz absorptance spectrum for incident waves with transverse magnetic polarization, leading to near-perfect absorptance of graphene. This substantial absorption creates an amplified thermal gradient across the graphene channel due to localized heat generation from terahertz wave absorption. The detector’s absorption characteristics can be adjusted by altering geometrical parameters and tuning two gate voltages. Furthermore, incorporating dual grating gates to create a pn-junction leads to a non-uniform Seebeck coefficient along the channel, enhancing the generated voltage. At a resonant frequency of 1.6 THz, the detector demonstrates a responsivity of 1.26 V/W and a noise-equivalent power (NEP) of \u0000<inline-formula> <tex-math>$5.2 mathrm {nW}/sqrt {mathrm {Hz}}$ </tex-math></inline-formula>\u0000 at room temperature, under biasing the two grating gates with the low voltages of ±0.2 V.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 6","pages":"1-8"},"PeriodicalIF":2.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255946","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 : 2024-09-09DOI: 10.1109/JQE.2024.3456073
H. Ahmad;K. Kamaruzzaman;M. Z. Samion
This work demonstrates mode-locking and Q-switching in a holmium-doped fiber laser (HDFL) using topological insulator (TI) antimony telluride (Sb2Te3) as the saturable absorber (SA). The TI was drop-casted on an arc-shaped fiber to generate mode-locked pulses and used in thin-film form to generate Q-switched pulses. The mode-locked pulses obtained were centered at 2081.1 nm with a repetition rate of 13.4 MHz, signal-to-noise ratio of 42 dB, and 1.85 ps pulse width. The Q-switched pulses were generated at the center wavelength of 2086.3 nm within the pump power of 1.55 W until 1.80 W. Within this range, the repetition rate peaked at 50.76 kHz and the pulse width dropped to a minimum value of $2.64~mu $ s. To the best of the author’s knowledge, this is the first work to use a topological insulator in an HDFL to generate both mode-locked and Q-switched pulses.
{"title":"Mode-Locking and Q-Switching in Holmium Doped Fiber Laser Using Topological Insulator (Sb₂Te₃) as Saturable Absorber","authors":"H. Ahmad;K. Kamaruzzaman;M. Z. Samion","doi":"10.1109/JQE.2024.3456073","DOIUrl":"10.1109/JQE.2024.3456073","url":null,"abstract":"This work demonstrates mode-locking and Q-switching in a holmium-doped fiber laser (HDFL) using topological insulator (TI) antimony telluride (Sb2Te3) as the saturable absorber (SA). The TI was drop-casted on an arc-shaped fiber to generate mode-locked pulses and used in thin-film form to generate Q-switched pulses. The mode-locked pulses obtained were centered at 2081.1 nm with a repetition rate of 13.4 MHz, signal-to-noise ratio of 42 dB, and 1.85 ps pulse width. The Q-switched pulses were generated at the center wavelength of 2086.3 nm within the pump power of 1.55 W until 1.80 W. Within this range, the repetition rate peaked at 50.76 kHz and the pulse width dropped to a minimum value of \u0000<inline-formula> <tex-math>$2.64~mu $ </tex-math></inline-formula>\u0000s. To the best of the author’s knowledge, this is the first work to use a topological insulator in an HDFL to generate both mode-locked and Q-switched pulses.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 6","pages":"1-8"},"PeriodicalIF":2.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191334","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 : 2024-09-05DOI: 10.1109/JQE.2024.3454604
Yuchen Jiang;Miao Hu;Mengmeng Xu;Haozhen Li;Xuefang Zhou;Meihua Bi;Sunqiang Pan;Chong Liu
The linearity of the laser frequency modulation is a crucial factor that affects the performance of the frequency-modulated continuous wave (FMCW) LiDAR ranging. Nonlinearity can influence ranging resolution and introduce errors. This paper proposes a method for correcting frequency modulation nonlinearity based on waveform preprocessing for the modulation signal of the laser. After correction, the residual nonlinearity (1-r2) of the laser is reduced to $1.85times 10^{-4}$ for the up-sweeping and $8.47times 10^{-4}$ for the down-sweeping using the modulation signal with the repetition frequency of 50 kHz. The full-width at half of the maximum (FWHM) of the spectrum decreases by 86% compared to pre-correction, resulting in the ranging error of 0.37% at the distance of 38 cm. With distances of 0.90 m, 1.80 m, 2.89 m, and 4.13 m, respectively, the ranging error stabilizes at 0.2%, and the minimum deflection of distance can reach $8~mathrm {mu m}$ .
{"title":"Frequency Modulation Nonlinear Correction and Ranging in FMCW LiDAR","authors":"Yuchen Jiang;Miao Hu;Mengmeng Xu;Haozhen Li;Xuefang Zhou;Meihua Bi;Sunqiang Pan;Chong Liu","doi":"10.1109/JQE.2024.3454604","DOIUrl":"10.1109/JQE.2024.3454604","url":null,"abstract":"The linearity of the laser frequency modulation is a crucial factor that affects the performance of the frequency-modulated continuous wave (FMCW) LiDAR ranging. Nonlinearity can influence ranging resolution and introduce errors. This paper proposes a method for correcting frequency modulation nonlinearity based on waveform preprocessing for the modulation signal of the laser. After correction, the residual nonlinearity (1-r2) of the laser is reduced to \u0000<inline-formula> <tex-math>$1.85times 10^{-4}$ </tex-math></inline-formula>\u0000 for the up-sweeping and \u0000<inline-formula> <tex-math>$8.47times 10^{-4}$ </tex-math></inline-formula>\u0000 for the down-sweeping using the modulation signal with the repetition frequency of 50 kHz. The full-width at half of the maximum (FWHM) of the spectrum decreases by 86% compared to pre-correction, resulting in the ranging error of 0.37% at the distance of 38 cm. With distances of 0.90 m, 1.80 m, 2.89 m, and 4.13 m, respectively, the ranging error stabilizes at 0.2%, and the minimum deflection of distance can reach \u0000<inline-formula> <tex-math>$8~mathrm {mu m}$ </tex-math></inline-formula>\u0000.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 6","pages":"1-7"},"PeriodicalIF":2.2,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191335","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 : 2024-09-02DOI: 10.1109/JQE.2024.3453281
Thomas B. Simpson;Joseph S. Suelzer;Nicholas G. Usechak
Gain switching of semiconductor lasers by strong sinusoidal current modulation can generate Period Two (P2) and Period Three (P3) sub-harmonic pulse trains. It is known that these pulse trains can be interrupted by bursting events, for the P2 pulse train predominantly consisting of short segments of relatively weak pulses at the modulation frequency (a P1-like state) before the system returns to the dominant P2 state. Similarly, for systems operating in the P3 state, intermittent switching yields combinations of P1- and P2-like pulses. To better understand these experimental observations, we perform numerical simulations using a standard model coupling the circulating optical field to the carriers of the gain medium and then compare the results with our experimental measurements on a single-mode distributed feedback laser. The simulations show that low optical power events typically precede the interruptions of the dominant sub-harmonic pulse trains. During these events, stochastic sources, such as spontaneous emission noise, which interact with the circulating optical field are found to dominate the deterministic changes to the calculated trajectory. With output in either P2 or P3 dominant pulse trains, we numerically and experimentally demonstrate that the induced phase fluctuations follow the statistics of classical telegraph noise for the P2 state, and a three-state variant for the P3 state.
{"title":"Phase Shifts in Gain-Switched Semiconductor Laser Subharmonic Pulse Trains","authors":"Thomas B. Simpson;Joseph S. Suelzer;Nicholas G. Usechak","doi":"10.1109/JQE.2024.3453281","DOIUrl":"10.1109/JQE.2024.3453281","url":null,"abstract":"Gain switching of semiconductor lasers by strong sinusoidal current modulation can generate Period Two (P2) and Period Three (P3) sub-harmonic pulse trains. It is known that these pulse trains can be interrupted by bursting events, for the P2 pulse train predominantly consisting of short segments of relatively weak pulses at the modulation frequency (a P1-like state) before the system returns to the dominant P2 state. Similarly, for systems operating in the P3 state, intermittent switching yields combinations of P1- and P2-like pulses. To better understand these experimental observations, we perform numerical simulations using a standard model coupling the circulating optical field to the carriers of the gain medium and then compare the results with our experimental measurements on a single-mode distributed feedback laser. The simulations show that low optical power events typically precede the interruptions of the dominant sub-harmonic pulse trains. During these events, stochastic sources, such as spontaneous emission noise, which interact with the circulating optical field are found to dominate the deterministic changes to the calculated trajectory. With output in either P2 or P3 dominant pulse trains, we numerically and experimentally demonstrate that the induced phase fluctuations follow the statistics of classical telegraph noise for the P2 state, and a three-state variant for the P3 state.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 6","pages":"1-12"},"PeriodicalIF":2.2,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191336","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 : 2024-08-26DOI: 10.1109/JQE.2024.3450371
Jing Shen;Yujuan Feng
By utilizing the principle of optical logic signal processing of periodically poled lithium niobate (PPLN) waveguide, this paper proposes schemes of all-optical general set-reset (RS) flip-flop and clocked RS flip-flop based on cascaded second-order nonlinearities of sum-frequency generation (SFG) and difference-frequency generation (DFG), and the principle is theoretically investigated. The waveforms, eye diagrams, extinction ratio (ER) and full width at half maximum (FWHM) of the light waves are calculated and simulated numerically. The results of static simulation demonstrate that the logic of general and clocked RS flip-flops are achieved well by these schemes; the timing sequential simulation demonstrate that the logic properties of flip-flops with a feedback loop can also be achieved well for timing sequential optical signals.
{"title":"All-Optical General RS Flip-Flop and Clocked RS Flip-Flop Based on Cascaded PPLN Waveguides","authors":"Jing Shen;Yujuan Feng","doi":"10.1109/JQE.2024.3450371","DOIUrl":"10.1109/JQE.2024.3450371","url":null,"abstract":"By utilizing the principle of optical logic signal processing of periodically poled lithium niobate (PPLN) waveguide, this paper proposes schemes of all-optical general set-reset (RS) flip-flop and clocked RS flip-flop based on cascaded second-order nonlinearities of sum-frequency generation (SFG) and difference-frequency generation (DFG), and the principle is theoretically investigated. The waveforms, eye diagrams, extinction ratio (ER) and full width at half maximum (FWHM) of the light waves are calculated and simulated numerically. The results of static simulation demonstrate that the logic of general and clocked RS flip-flops are achieved well by these schemes; the timing sequential simulation demonstrate that the logic properties of flip-flops with a feedback loop can also be achieved well for timing sequential optical signals.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 6","pages":"1-8"},"PeriodicalIF":2.2,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191337","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}
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