Pub Date : 2024-09-26DOI: 10.1109/LPT.2024.3468647
Haoyun Zhang;Xuecheng Wu;Weiqi Jiang;Shining Zhu;Fengqiu Wang
Electro-optic frequency combs, generated by cascaded intensity and phase modulators, are known for their frequency agility. However, frequency detuning induced pulse distortion significantly hinders their applicability in asynchronous optical sampling. In this letter, we propose a scheme where a motor-driven optical delay line between the phase and intensity modulators serves as an effective pulse-duration compensation mechanism. A 10 GHz flat-topped optical frequency comb (OFC) at a central wavelength of 1552 nm is first optimized to output a 7.2 ps pulse. It is seen that the temporal pulses experience dramatic distortion and elongation (up to 130 ps) when frequency offset is present. Interestingly, the output pulse duration is periodically modulated by the frequency offset, and the associated period is inversely proportional to a system delay time ( $tau $ ) that is fundamentally linked to the phase retardation between the intensity and phase modulators. In this scheme, we derive an algorithm that can drive the optical delay line in a deterministic way to counter the effect of frequency detuning, and successfully demonstrate an OFC tunable across 8- 12 GHz, with a constant pulse duration ( $sim ~7$ ps). Our approach provides a practical solution for stabilizing pulse duration for repetition rate-tunable OFCs and can bring new capabilities in optical sensing and sampling.
{"title":"A Pulse-Duration Compensation Scheme for GHz Electro-Optic Frequency Comb","authors":"Haoyun Zhang;Xuecheng Wu;Weiqi Jiang;Shining Zhu;Fengqiu Wang","doi":"10.1109/LPT.2024.3468647","DOIUrl":"https://doi.org/10.1109/LPT.2024.3468647","url":null,"abstract":"Electro-optic frequency combs, generated by cascaded intensity and phase modulators, are known for their frequency agility. However, frequency detuning induced pulse distortion significantly hinders their applicability in asynchronous optical sampling. In this letter, we propose a scheme where a motor-driven optical delay line between the phase and intensity modulators serves as an effective pulse-duration compensation mechanism. A 10 GHz flat-topped optical frequency comb (OFC) at a central wavelength of 1552 nm is first optimized to output a 7.2 ps pulse. It is seen that the temporal pulses experience dramatic distortion and elongation (up to 130 ps) when frequency offset is present. Interestingly, the output pulse duration is periodically modulated by the frequency offset, and the associated period is inversely proportional to a system delay time (\u0000<inline-formula> <tex-math>$tau $ </tex-math></inline-formula>\u0000) that is fundamentally linked to the phase retardation between the intensity and phase modulators. In this scheme, we derive an algorithm that can drive the optical delay line in a deterministic way to counter the effect of frequency detuning, and successfully demonstrate an OFC tunable across 8- 12 GHz, with a constant pulse duration (\u0000<inline-formula> <tex-math>$sim ~7$ </tex-math></inline-formula>\u0000 ps). Our approach provides a practical solution for stabilizing pulse duration for repetition rate-tunable OFCs and can bring new capabilities in optical sensing and sampling.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 22","pages":"1325-1328"},"PeriodicalIF":2.3,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142397039","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/LPT.2024.3468389
Wang Xing;Cuiluan Wang;Zhenwu Liu;Fang Zhao;Lingni Zhu;Suping Liu;Xiaoyu Ma
Distributed Bragg Reflector laser diode (DBR-LD) plays a crucial role as pump sources due to its wavelength stability. This work firstly presents a $100~mu $ m wide $2^{mathrm {nd}}$ -order DBR-LD with surface etched grating. Based on scattering matrix method (SMM) and eigenmode expansion (EME) method, the $2^{mathrm {nd}}$ -order grating was designed as a period of 288.1 nm and a duty of cycle of 25%. Using ultra violet nanoimprint lithography (UV-NIL) and Inductively Coupled Plasma (ICP) dry etching technique, the grating was firstly fabricated with a depth of $1~mu $ m from surface. The laser diode achieved a maximum output power of 9.52 W with a full width at half-maximum (FWHM) spectral width of 0.4 nm in CW mode and an average wavelength drift coefficient of 0.0645 nm/°C over a wide temperature range from $- 10~^{circ }$ C to $100~^{circ }$ C in pulsed mode, expanded the operating temperature.
{"title":"High Power Narrow Spectrum Second-Order DBR Laser Diode Operating Over a Wide Temperature Range","authors":"Wang Xing;Cuiluan Wang;Zhenwu Liu;Fang Zhao;Lingni Zhu;Suping Liu;Xiaoyu Ma","doi":"10.1109/LPT.2024.3468389","DOIUrl":"https://doi.org/10.1109/LPT.2024.3468389","url":null,"abstract":"Distributed Bragg Reflector laser diode (DBR-LD) plays a crucial role as pump sources due to its wavelength stability. This work firstly presents a \u0000<inline-formula> <tex-math>$100~mu $ </tex-math></inline-formula>\u0000 m wide \u0000<inline-formula> <tex-math>$2^{mathrm {nd}}$ </tex-math></inline-formula>\u0000-order DBR-LD with surface etched grating. Based on scattering matrix method (SMM) and eigenmode expansion (EME) method, the \u0000<inline-formula> <tex-math>$2^{mathrm {nd}}$ </tex-math></inline-formula>\u0000-order grating was designed as a period of 288.1 nm and a duty of cycle of 25%. Using ultra violet nanoimprint lithography (UV-NIL) and Inductively Coupled Plasma (ICP) dry etching technique, the grating was firstly fabricated with a depth of \u0000<inline-formula> <tex-math>$1~mu $ </tex-math></inline-formula>\u0000 m from surface. The laser diode achieved a maximum output power of 9.52 W with a full width at half-maximum (FWHM) spectral width of 0.4 nm in CW mode and an average wavelength drift coefficient of 0.0645 nm/°C over a wide temperature range from \u0000<inline-formula> <tex-math>$- 10~^{circ }$ </tex-math></inline-formula>\u0000 C to \u0000<inline-formula> <tex-math>$100~^{circ }$ </tex-math></inline-formula>\u0000 C in pulsed mode, expanded the operating temperature.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 23","pages":"1365-1368"},"PeriodicalIF":2.3,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142451005","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}
This work demonstrated a self-powered Ga2O3-based metal–semiconductor–metal solar-blind ultraviolet photodetector using the following asymmetric electrodes at varying size ratios: a Schottky interdigitated electrode with wide fingers and an ohmic interdigitated electrode with narrow fingers. At a bias of 0 V, the responsivity of the device featuring Schottky electrode to ohmic electrode size ratios of 8:1 is 3.64 mA/W. Thus, increasing electrode size ratios led to significant enhancements in device self-powered performance. Leveraging the energy band structure theory, we elucidated the rationale behind the improved self-powered performance of the devices, attributing it to the broadening of the depletion region at the metal–semiconductor interface, which facilitated photogenerated carrier transport. The device exhibited a high responsivity of 495 A/W under a forward bias of 10 V while still maintaining a considerable responsivity of 16.7 A/W under a reverse bias of 10 V. Additionally, the device realizes UV optical communication adopting international Morse code.
这项研究展示了一种基于 Ga2O3 的自供电金属半导体-金属日光盲紫外线光电探测器，该探测器采用了以下不同尺寸比的不对称电极：宽指肖特基互斥电极和窄指欧姆互斥电极。偏压为 0 V 时，肖特基电极与欧姆电极尺寸比为 8:1 的器件的响应率为 3.64 mA/W。因此，增加电极尺寸比能显著提高器件的自供电性能。利用能带结构理论，我们阐明了器件自供电性能提高的原因，即金属-半导体界面耗尽区的扩大促进了光生载流子的传输。该器件在 10 V 的正向偏压下实现了 495 A/W 的高响应率，而在 10 V 的反向偏压下仍保持了 16.7 A/W 的可观响应率。此外，该器件还实现了采用国际摩尔斯电码的紫外光通信。
{"title":"Self-Powered Ga₂O₃ MSM Solar-Blind UV PDs With Asymmetric Electrodes for Optical Communications","authors":"Biao Gong;Shiting Dai;Xiao Wang;Bingjie Ye;Irina Nikolaevna Parkhomenko;Fadei Fadeevich Komarov;Junjun Xue;Yu Liu;Weiying Qian;Mei Ge;Guofeng Yang","doi":"10.1109/LPT.2024.3466948","DOIUrl":"https://doi.org/10.1109/LPT.2024.3466948","url":null,"abstract":"This work demonstrated a self-powered Ga2O3-based metal–semiconductor–metal solar-blind ultraviolet photodetector using the following asymmetric electrodes at varying size ratios: a Schottky interdigitated electrode with wide fingers and an ohmic interdigitated electrode with narrow fingers. At a bias of 0 V, the responsivity of the device featuring Schottky electrode to ohmic electrode size ratios of 8:1 is 3.64 mA/W. Thus, increasing electrode size ratios led to significant enhancements in device self-powered performance. Leveraging the energy band structure theory, we elucidated the rationale behind the improved self-powered performance of the devices, attributing it to the broadening of the depletion region at the metal–semiconductor interface, which facilitated photogenerated carrier transport. The device exhibited a high responsivity of 495 A/W under a forward bias of 10 V while still maintaining a considerable responsivity of 16.7 A/W under a reverse bias of 10 V. Additionally, the device realizes UV optical communication adopting international Morse code.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 22","pages":"1305-1308"},"PeriodicalIF":2.3,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142376845","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}
Integrated optics hold great potential to accelerate deep learning tasks with high clock rates, parallelism and low-loss data transmission. Silicon photonic integrated circuits can perform large-scale and low-power-consuming optical linear operations by using weighting mechanism through linear optics. However, on-chip light attenuation and nonlinear activation functions are still huge challenges for large-scale optical neural networks. Here, we demonstrate a high-speed electro-absorption modulator (EAM) monolithically integrated with a distributed feedback (DFB) laser that can deliver high output lasing power for larger scale expansion while acting as a nonlinear activation function unit. With the use of the obtained nonlinear activation function, a convolutional neural network (CNN) is simulated to perform a handwritten digit classification benchmark task with high accuracy. Thanks to its compactness, high response speed and laser integration, the demonstrated nonlinear unit has the potential to be used in heterogeneously integrated large-scale photonic neural networks.
{"title":"Photonic Neural Activation Function Based on High-Speed Electro-Absorption Modulated Laser","authors":"Qi Tian;Yunlong Li;Qihui Zhou;Yu Han;Ruigang Zhang;Kaiyuan Wang;Deming Liu;Shuang Zheng;Minming Zhang","doi":"10.1109/LPT.2024.3466888","DOIUrl":"https://doi.org/10.1109/LPT.2024.3466888","url":null,"abstract":"Integrated optics hold great potential to accelerate deep learning tasks with high clock rates, parallelism and low-loss data transmission. Silicon photonic integrated circuits can perform large-scale and low-power-consuming optical linear operations by using weighting mechanism through linear optics. However, on-chip light attenuation and nonlinear activation functions are still huge challenges for large-scale optical neural networks. Here, we demonstrate a high-speed electro-absorption modulator (EAM) monolithically integrated with a distributed feedback (DFB) laser that can deliver high output lasing power for larger scale expansion while acting as a nonlinear activation function unit. With the use of the obtained nonlinear activation function, a convolutional neural network (CNN) is simulated to perform a handwritten digit classification benchmark task with high accuracy. Thanks to its compactness, high response speed and laser integration, the demonstrated nonlinear unit has the potential to be used in heterogeneously integrated large-scale photonic neural networks.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 22","pages":"1317-1320"},"PeriodicalIF":2.3,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142397079","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 : 2024-09-23DOI: 10.1109/LPT.2024.3466120
J. Castrellon-Uribe;J. J. Medina-Cabrera;M. C. Soto-Robles;J. A. Sandoval-Espino;R. E. Nuñez-Gómez
A fiber optic curvature sensor based on a tapered single-mode optical fiber coated with a polyester polymer (T-SMF-CPP) is proposed and experimentally demonstrated. Fabrication of the tapered optical fibers was realized by heating and stretching by a flame, and an airbrush was used to coat the surface of the tapered fiber with the polymer. The operating principle of the sensor was based on the interaction of the evanescent wave with the polyester polymer deposited on the tapered fiber. By adopting intensity demodulation in experiments, average sensitivities of -5.017 dB/m-1 and 5.862 dB/m-1 in the curvature ranges from 1.23 to 4.44 m-1 and from 4.64 to 7.54 m-1, respectively, were obtained for a fixed wavelength of $lambda =1572.45$ nm. The curvature of the sensor did not show a temperature dependence in the range [24-90 °C].
{"title":"Tapered Optical Fiber Coated With a Polyester Polymer as a Curvature Sensor","authors":"J. Castrellon-Uribe;J. J. Medina-Cabrera;M. C. Soto-Robles;J. A. Sandoval-Espino;R. E. Nuñez-Gómez","doi":"10.1109/LPT.2024.3466120","DOIUrl":"https://doi.org/10.1109/LPT.2024.3466120","url":null,"abstract":"A fiber optic curvature sensor based on a tapered single-mode optical fiber coated with a polyester polymer (T-SMF-CPP) is proposed and experimentally demonstrated. Fabrication of the tapered optical fibers was realized by heating and stretching by a flame, and an airbrush was used to coat the surface of the tapered fiber with the polymer. The operating principle of the sensor was based on the interaction of the evanescent wave with the polyester polymer deposited on the tapered fiber. By adopting intensity demodulation in experiments, average sensitivities of -5.017 dB/m-1 and 5.862 dB/m-1 in the curvature ranges from 1.23 to 4.44 m-1 and from 4.64 to 7.54 m-1, respectively, were obtained for a fixed wavelength of \u0000<inline-formula> <tex-math>$lambda =1572.45$ </tex-math></inline-formula>\u0000 nm. The curvature of the sensor did not show a temperature dependence in the range [24-90 °C].","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 21","pages":"1281-1284"},"PeriodicalIF":2.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142368215","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 : 2024-09-23DOI: 10.1109/LPT.2024.3465501
Yi Huang;Xiaofeng Chen;Wei Shen;Ziyi Wei;Chengyong Hu;Chuanlu Deng;Lisen Wang;Qi Zhang;Wei Chen;Xiaobei Zhang;Lin Chen;Wei Jin;Jianming Tang;Tingyun Wang
Although pulse compression optical time domain reflectometry (PC-OTDR) exhibits high performance in spatial resolution and dynamic range, it inevitably introduces auto-correlation sidelobes, potentially impacting measurement accuracy. In this letter, an improved CLEAN algorithm is proposed to efficiently suppress sidelobes and enhance the peak-to-sidelobe ratio (PSLR) of signals in PC-OTDR. The proposed method introduces an adaptive step factor instead of the traditional fixed factor to reduce the number of iterations. Compared to the traditional method, the proposed method achieves a 2.87 dB improvement of PSLR from a 10 km sensing fiber. In addition, the computation time cost is significantly reduced, which is 1.92 s less than that of the traditional CLEAN algorithm.
{"title":"Sidelobe Suppression Method with Improved CLEAN Algorithm for Pulse Compression OTDR","authors":"Yi Huang;Xiaofeng Chen;Wei Shen;Ziyi Wei;Chengyong Hu;Chuanlu Deng;Lisen Wang;Qi Zhang;Wei Chen;Xiaobei Zhang;Lin Chen;Wei Jin;Jianming Tang;Tingyun Wang","doi":"10.1109/LPT.2024.3465501","DOIUrl":"https://doi.org/10.1109/LPT.2024.3465501","url":null,"abstract":"Although pulse compression optical time domain reflectometry (PC-OTDR) exhibits high performance in spatial resolution and dynamic range, it inevitably introduces auto-correlation sidelobes, potentially impacting measurement accuracy. In this letter, an improved CLEAN algorithm is proposed to efficiently suppress sidelobes and enhance the peak-to-sidelobe ratio (PSLR) of signals in PC-OTDR. The proposed method introduces an adaptive step factor instead of the traditional fixed factor to reduce the number of iterations. Compared to the traditional method, the proposed method achieves a 2.87 dB improvement of PSLR from a 10 km sensing fiber. In addition, the computation time cost is significantly reduced, which is 1.92 s less than that of the traditional CLEAN algorithm.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 22","pages":"1321-1324"},"PeriodicalIF":2.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142397080","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 : 2024-09-20DOI: 10.1109/LPT.2024.3465224
Maciej Wojtkiewicz;Bruce Rae;Robert K. Henderson
This letter presents a compact pixel frontend utilizing thin-oxide-only transistors paired with RC-coupled SPAD manufactured in a 3D-stacked technology. The frontend employs an optimized CMOS inverter operated close to its threshold to improve the sensitivity to low-amplitude SPAD pulses observed in a high light conditions close to device paralysis. This allows to achieve a dynamic range of 126dB and a maximum count rate of 117 Mcps ideal for automotive LiDAR or other ToF applications requiring tolerance to high background irradiance levels.
{"title":"126 dB High Dynamic Range SPAD Frontend for Time of Flight Applications","authors":"Maciej Wojtkiewicz;Bruce Rae;Robert K. Henderson","doi":"10.1109/LPT.2024.3465224","DOIUrl":"https://doi.org/10.1109/LPT.2024.3465224","url":null,"abstract":"This letter presents a compact pixel frontend utilizing thin-oxide-only transistors paired with RC-coupled SPAD manufactured in a 3D-stacked technology. The frontend employs an optimized CMOS inverter operated close to its threshold to improve the sensitivity to low-amplitude SPAD pulses observed in a high light conditions close to device paralysis. This allows to achieve a dynamic range of 126dB and a maximum count rate of 117 Mcps ideal for automotive LiDAR or other ToF applications requiring tolerance to high background irradiance levels.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 21","pages":"1293-1296"},"PeriodicalIF":2.3,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142368525","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 : 2024-09-20DOI: 10.1109/LPT.2024.3464865
Wei He;Zhongjun Jiang;Liang Wang
Photodiodes serve as pivotal components in optical data links, where minimized dark current and junction capacitance is vital for improving the detection sensitivity and response speed of the devices. This study experimentally and theoretically demonstrates that the one-side junction photodiode (OSJ-PD) exhibits reduced dark current and diminished junction capacitance. Notably, the device has a capacitance density of $2.2 times 10^{-4} mathrm {pF} / mu mathrm {m}^{2}$ and a dark current density of $2.4 times 10^{-5} mathrm {nA} / mu mathrm {m}^{2}$ at −5 V bias. Numerical simulations of current-voltage characteristics reveal that Shockley-Read-Hall (SRH) and trap-assisted tunneling (TAT) currents dominate dark current at low reverse bias from 0 V to −14 V, while band-to-band tunneling (BBT) current prevails at higher reverse bias from −14 V to −20 V. This study, for the first time, explains the trend of the variation in the dark current curve with bias voltage based on the generation mechanisms of dark current. Furthermore, we have theoretically demonstrated that the dark current of the OSJ-PD is insensitive to defect density at low voltages, and attributed the low junction capacitance to the wide depletion layer nature of the OSJ-PDs. These findings provide a comprehensive understanding of carrier transport and give a demonstration to analyze the current variation within diverse photodiodes.
光电二极管是光数据链路中的关键元件，最大限度地降低暗电流和结电容对提高器件的检测灵敏度和响应速度至关重要。这项研究从实验和理论上证明，单面结光电二极管（OSJ-PD）可降低暗电流和结电容。值得注意的是，该器件的电容密度为 2.2 times 10^{-4}mathrm {pF} / mu mu {pF} 。/ mu mathrm {m}^{2}$，暗电流密度为 2.4 times 10^{-5}mathrm {nA}。/ mu mathrm {m}^{2}$ ，偏压为 -5 V。电流-电压特性的数值模拟显示，在 0 V 至 -14 V 的低反向偏压下，肖克利-雷德-霍尔（SRH）电流和阱辅助隧穿（TAT）电流在暗电流中占主导地位，而在 -14 V 至 -20 V 的较高反向偏压下，带对带隧穿（BBT）电流占主导地位。此外，我们还从理论上证明了 OSJ-PD 的暗电流在低电压下对缺陷密度不敏感，并将低结电容归因于 OSJ-PD 的宽耗尽层性质。这些发现提供了对载流子传输的全面理解，并为分析各种光电二极管内部的电流变化提供了示范。
{"title":"Dark Current Transport and Junction Capacitance Mechanism in InP One-Side Junction Photodiodes","authors":"Wei He;Zhongjun Jiang;Liang Wang","doi":"10.1109/LPT.2024.3464865","DOIUrl":"https://doi.org/10.1109/LPT.2024.3464865","url":null,"abstract":"Photodiodes serve as pivotal components in optical data links, where minimized dark current and junction capacitance is vital for improving the detection sensitivity and response speed of the devices. This study experimentally and theoretically demonstrates that the one-side junction photodiode (OSJ-PD) exhibits reduced dark current and diminished junction capacitance. Notably, the device has a capacitance density of \u0000<inline-formula> <tex-math>$2.2 times 10^{-4} mathrm {pF} / mu mathrm {m}^{2}$ </tex-math></inline-formula>\u0000 and a dark current density of \u0000<inline-formula> <tex-math>$2.4 times 10^{-5} mathrm {nA} / mu mathrm {m}^{2}$ </tex-math></inline-formula>\u0000 at −5 V bias. Numerical simulations of current-voltage characteristics reveal that Shockley-Read-Hall (SRH) and trap-assisted tunneling (TAT) currents dominate dark current at low reverse bias from 0 V to −14 V, while band-to-band tunneling (BBT) current prevails at higher reverse bias from −14 V to −20 V. This study, for the first time, explains the trend of the variation in the dark current curve with bias voltage based on the generation mechanisms of dark current. Furthermore, we have theoretically demonstrated that the dark current of the OSJ-PD is insensitive to defect density at low voltages, and attributed the low junction capacitance to the wide depletion layer nature of the OSJ-PDs. These findings provide a comprehensive understanding of carrier transport and give a demonstration to analyze the current variation within diverse photodiodes.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 21","pages":"1297-1300"},"PeriodicalIF":2.3,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142368216","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 : 2024-09-19DOI: 10.1109/LPT.2024.3463879
Sunil Mohan;Nagendra Kumar
This letter demonstrates an optical fiber sensor employing chitosan-caped gold nanoparticle (Au-NPs) coated on etched FBG (EFBG) for the label-free detection of Hg2+ in an aqueous solution. The Bragg wavelength of proposed optical fiber is monitored at different Hg2+ concentrations in water for the experimental investigation of sensor characteristics. The sensor responds linearly over a range of 1–10 ppb mercury concentration, with a sensitivity of 101.7pm/ppb. The limit of detection (LOD) of the proposed sensor is 0.07 ppb, well within the World Health Organization’s (WHO) acceptable limit of 2 ppb for safe drinking water.
{"title":"Etched FBG-Based Optical Fiber Sensor for Hg²+ Ion Detection in Aqueous Solution","authors":"Sunil Mohan;Nagendra Kumar","doi":"10.1109/LPT.2024.3463879","DOIUrl":"https://doi.org/10.1109/LPT.2024.3463879","url":null,"abstract":"This letter demonstrates an optical fiber sensor employing chitosan-caped gold nanoparticle (Au-NPs) coated on etched FBG (EFBG) for the label-free detection of Hg2+ in an aqueous solution. The Bragg wavelength of proposed optical fiber is monitored at different Hg2+ concentrations in water for the experimental investigation of sensor characteristics. The sensor responds linearly over a range of 1–10 ppb mercury concentration, with a sensitivity of 101.7pm/ppb. The limit of detection (LOD) of the proposed sensor is 0.07 ppb, well within the World Health Organization’s (WHO) acceptable limit of 2 ppb for safe drinking water.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 21","pages":"1289-1292"},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142368463","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}
We demonstrate the generation of 350 fs pulse by post-compression of a neodymium (Nd)-doped picosecond laser within a single stage bulk multi-pass cell (MPC) device. By meticulous design and precise alignment of the optical path, a record-high number of 125 passes is implemented, resulting in a spectral broadening factor of 16 and a pulse compression factor of 27.1. To the best of our knowledge, this represents the first instance of a 300-fs class pulse width being emitted from a single-stage MPC post-compression Nd-doped picosecond laser device. It also has been proven to be applicable for laser processing.
{"title":"Sub-350 fs Pulse Generation via Nonlinear Compression With an Nd-Doped Picosecond Laser","authors":"Liya Shen;Jiajun Song;Yujie Peng;Junze Zhu;Yinfei Liu;Guanguang Gao;Yuchun Liu;Cong Chen;Yang Liao;Yuxin Leng","doi":"10.1109/LPT.2024.3464103","DOIUrl":"https://doi.org/10.1109/LPT.2024.3464103","url":null,"abstract":"We demonstrate the generation of 350 fs pulse by post-compression of a neodymium (Nd)-doped picosecond laser within a single stage bulk multi-pass cell (MPC) device. By meticulous design and precise alignment of the optical path, a record-high number of 125 passes is implemented, resulting in a spectral broadening factor of 16 and a pulse compression factor of 27.1. To the best of our knowledge, this represents the first instance of a 300-fs class pulse width being emitted from a single-stage MPC post-compression Nd-doped picosecond laser device. It also has been proven to be applicable for laser processing.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"36 21","pages":"1257-1260"},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328385","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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