Pub Date : 2024-06-17DOI: 10.1109/JQE.2024.3415148
Avijit Koley;Saurabh Mani Tripathi
We propose and analyse a novel, birefringence free, wavelength filter based on counter-propagating cladding mode assisted integrated-optic Fabry-Pérot (FP) resonator. The FP cavity is formed by suitably designed counter-propagating cladding-mode exciting Bragg gratings in LiNbO3 ridge waveguide. Through rigorous vectorial modeling, we show that appropriate waveguide dimensions and crystal orientation enable birefringence-free operation for both the fundamental core mode as well as the excited cladding mode. We also show that the zero birefringence point of the filter remains unchanged regardless of the applied voltage across the crystal; the reasons behind this behaviour are also explained by the linear electro-optic effect of LiNbO3. Using this we demonstrate a linear electro-optic tuning of the individual Bragg grating spectrum as well as the FP resonances with a typical tuning coefficient of 4 pm/V. Our results may find application in designing high-speed tunable wavelength filters free from input polarization state with linear spectral tuning capabilities.
{"title":"Birefringence Free Spectral Tuning of Bragg Grating Based Fabry-Pérot Resonator in LiNbO₃ Waveguide Employing Counter- Propagating Cladding Modes","authors":"Avijit Koley;Saurabh Mani Tripathi","doi":"10.1109/JQE.2024.3415148","DOIUrl":"https://doi.org/10.1109/JQE.2024.3415148","url":null,"abstract":"We propose and analyse a novel, birefringence free, wavelength filter based on counter-propagating cladding mode assisted integrated-optic Fabry-Pérot (FP) resonator. The FP cavity is formed by suitably designed counter-propagating cladding-mode exciting Bragg gratings in LiNbO3 ridge waveguide. Through rigorous vectorial modeling, we show that appropriate waveguide dimensions and crystal orientation enable birefringence-free operation for both the fundamental core mode as well as the excited cladding mode. We also show that the zero birefringence point of the filter remains unchanged regardless of the applied voltage across the crystal; the reasons behind this behaviour are also explained by the linear electro-optic effect of LiNbO3. Using this we demonstrate a linear electro-optic tuning of the individual Bragg grating spectrum as well as the FP resonances with a typical tuning coefficient of 4 pm/V. Our results may find application in designing high-speed tunable wavelength filters free from input polarization state with linear spectral tuning capabilities.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 4","pages":"1-8"},"PeriodicalIF":2.2,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141560978","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}
Femtosecond laser has unique advantages in frequency conversion owing to broadband spectrum and ultra-high peak power. Here, the authors demonstrate the non-central phase matching second harmonic (SH) process by utilizing femtosecond ytterbium-doped fiber (YDF) laser. Numerical solution of the coupled wave equations for the process of femtosecond pulses SH indicates that the non-central phase matching is determined by the spectral broadening and frequency shift. Pumped by Watt-level 1040 nm femtosecond pluses, the period quasi-phase matching at the 1064 nm wavelength, the fundamental frequency (FF) spectrum broadened up to 34.7 nm width and red shifted about 6 nm, and the non-central phase matching SH with PPKTP crystal waveguide generates at around 523 nm. The experimental measurements confirm the theoretical predictions, and offer a deeper understanding of nonlinear optical effects. The non-central phase matching enables flexible frequency conversion with potential applications in ultrafast optics.
{"title":"Non-Central Phase Matching Second Harmonic Generation by Using High Power Femtosecond Ytterbium-Doped Fiber Laser","authors":"Yu Liu;Shuanggen Zhang;Yangbo Bai;Wei Yan;Bochi Guo;Hui Zhou","doi":"10.1109/JQE.2024.3412091","DOIUrl":"https://doi.org/10.1109/JQE.2024.3412091","url":null,"abstract":"Femtosecond laser has unique advantages in frequency conversion owing to broadband spectrum and ultra-high peak power. Here, the authors demonstrate the non-central phase matching second harmonic (SH) process by utilizing femtosecond ytterbium-doped fiber (YDF) laser. Numerical solution of the coupled wave equations for the process of femtosecond pulses SH indicates that the non-central phase matching is determined by the spectral broadening and frequency shift. Pumped by Watt-level 1040 nm femtosecond pluses, the period quasi-phase matching at the 1064 nm wavelength, the fundamental frequency (FF) spectrum broadened up to 34.7 nm width and red shifted about 6 nm, and the non-central phase matching SH with PPKTP crystal waveguide generates at around 523 nm. The experimental measurements confirm the theoretical predictions, and offer a deeper understanding of nonlinear optical effects. The non-central phase matching enables flexible frequency conversion with potential applications in ultrafast optics.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 4","pages":"1-5"},"PeriodicalIF":2.2,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141560996","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}
Complex coupled distributed feedback (DFB) lasers and sampled grating distributed Bragg reflector (SGDBR) lasers under optical injection locking are investigated to determine lowest noise operation. A noise reduction (frequency and intensity combined) of up to 15 dB was measured utilizing detuned optical injection locking at the relaxation oscillation frequency. Furthermore, 4 dB improvement in frequency noise at 10 kHz offset for higher coupling coefficient DFBs under injection locking was measured. The DFB lasers show more sensitivity to injection locking and have a lower need of injection power while exhibiting better signal to noise ratio compared to an SGDBR.
{"title":"Minimizing Noise in Distributed Reflector Laser Types Under Optical Injection Locking","authors":"Arbnor Berisha;Hendrik Boerma;Ronald Kaiser;Patrick Runge;Martin Schell","doi":"10.1109/JQE.2024.3412088","DOIUrl":"https://doi.org/10.1109/JQE.2024.3412088","url":null,"abstract":"Complex coupled distributed feedback (DFB) lasers and sampled grating distributed Bragg reflector (SGDBR) lasers under optical injection locking are investigated to determine lowest noise operation. A noise reduction (frequency and intensity combined) of up to 15 dB was measured utilizing detuned optical injection locking at the relaxation oscillation frequency. Furthermore, 4 dB improvement in frequency noise at 10 kHz offset for higher coupling coefficient DFBs under injection locking was measured. The DFB lasers show more sensitivity to injection locking and have a lower need of injection power while exhibiting better signal to noise ratio compared to an SGDBR.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 4","pages":"1-6"},"PeriodicalIF":2.2,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10552750","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448036","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}
Pub Date : 2024-06-05DOI: 10.1109/JQE.2024.3410234
Zhang Meng;Naruya Mochizuki;Shiryu Oiwa;Hua Zhao;Peng Wang;Hongpu Li
A band-selectable and bandwidth-enhanced flat-top rejection filter is proposed and demonstrated both theoretically and experimentally, which is realized by using single-mode fiber (SMF)-based helical long-period fiber gratings (HLPGs) precisely operated at dispersion turning points (DTPs) of the same azimuthal order cladding mode but with different radial indices. As an important application of such HLPGs, the orbital angular momentum (OAM) mode converters enabling to have either a flat-top bandwidth of ~116 nm@-16 dB but centered at wavelength of ~1530 nm, or a flat-top bandwidth ~130 nm @-16 dB but centered at wavelength of ~1650 nm, have been successfully demonstrated. This is the first report for the experimental demonstration of such high-performance band-rejection filters with bands fully matching the C-L bands of the fiber communication. The proposed HLPGs may find potential applications to OAM mode converters, OAM tweezers, and OAM sensors.
{"title":"Helical Long-Period Fiber Grating-Based Band- Selectable and Bandwidth-Enhanced Flat-Top Filter and Its Application to Wideband OAM Mode Converter","authors":"Zhang Meng;Naruya Mochizuki;Shiryu Oiwa;Hua Zhao;Peng Wang;Hongpu Li","doi":"10.1109/JQE.2024.3410234","DOIUrl":"https://doi.org/10.1109/JQE.2024.3410234","url":null,"abstract":"A band-selectable and bandwidth-enhanced flat-top rejection filter is proposed and demonstrated both theoretically and experimentally, which is realized by using single-mode fiber (SMF)-based helical long-period fiber gratings (HLPGs) precisely operated at dispersion turning points (DTPs) of the same azimuthal order cladding mode but with different radial indices. As an important application of such HLPGs, the orbital angular momentum (OAM) mode converters enabling to have either a flat-top bandwidth of ~116 nm@-16 dB but centered at wavelength of ~1530 nm, or a flat-top bandwidth ~130 nm @-16 dB but centered at wavelength of ~1650 nm, have been successfully demonstrated. This is the first report for the experimental demonstration of such high-performance band-rejection filters with bands fully matching the C-L bands of the fiber communication. The proposed HLPGs may find potential applications to OAM mode converters, OAM tweezers, and OAM sensors.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 4","pages":"1-8"},"PeriodicalIF":2.2,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448008","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 : 2024-04-29DOI: 10.1109/JQE.2024.3395127
Yun Chen;Jiahe Yu;Wentao Zhang;Wei Huang
In this study, we demonstrate the relationship between the absorbing frequency and the quasi-bound states in the continuum (quasi-BIC) frequency by employing the coupled-mode theory (CMT) and interference theory. The structure consists of a symmetric-protected BIC metal structure layer, a polyimide spacer layer, and a silicon substrate. The top layer contains two similar metal structures, which make the structure asymmetric by varying one of them slightly, thus producing a symmetrical broken quasi-BIC. When a metal reflecting plate is added to the bottom of the dielectric spacer layer, a quasi-BIC absorber is formed. This is the first theoretical calculation using the coupled mode equation to analyze the relationship between the absorption frequency of a quasi-BIC absorber and the quasi-BIC resonance frequency, which is related to the resonance frequency of a single structure in a unit cell. According to the relationship between the coupling strength and distance between the structures within a unit cell combined with the resonant frequency of quasi-BIC, the geometric parameters of the absorber within a frequency range can be inverse design.
{"title":"Inverse Design of Quasi-Bound States in the Continuum Absorber","authors":"Yun Chen;Jiahe Yu;Wentao Zhang;Wei Huang","doi":"10.1109/JQE.2024.3395127","DOIUrl":"https://doi.org/10.1109/JQE.2024.3395127","url":null,"abstract":"In this study, we demonstrate the relationship between the absorbing frequency and the quasi-bound states in the continuum (quasi-BIC) frequency by employing the coupled-mode theory (CMT) and interference theory. The structure consists of a symmetric-protected BIC metal structure layer, a polyimide spacer layer, and a silicon substrate. The top layer contains two similar metal structures, which make the structure asymmetric by varying one of them slightly, thus producing a symmetrical broken quasi-BIC. When a metal reflecting plate is added to the bottom of the dielectric spacer layer, a quasi-BIC absorber is formed. This is the first theoretical calculation using the coupled mode equation to analyze the relationship between the absorption frequency of a quasi-BIC absorber and the quasi-BIC resonance frequency, which is related to the resonance frequency of a single structure in a unit cell. According to the relationship between the coupling strength and distance between the structures within a unit cell combined with the resonant frequency of quasi-BIC, the geometric parameters of the absorber within a frequency range can be inverse design.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 3","pages":"1-11"},"PeriodicalIF":2.5,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140820418","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}
Objective: Nephrolithiasis is a common urological disease that can lead to renal failure. Oxidative stress has been shown to be a contributing factor for nephrolithiasis and many agents have been studied to prevent and treat oxidative stress-related nephrolithiasis and renal damage. Myrtus communis (MC) extract has been shown to be an important antioxidant in different animal models. In this study, MC extract was administered preventively or therapeutically to rats with kidney stones, and its effectiveness was investigated.
Methods: Wistar albino rats were divided into four groups (n=8); control (C), ethylene glycol (EG), EG+preventive MC, and EG+curative MC groups. The nephrolithiasis model was created by adding 0.75% EG to drinking water for 8 weeks. Ultimately, 24-hour urine was collected to measure calcium, citrate, and creatinine levels. After decapitation, kidney tissues were harvested for histological analyses, measurement of osteopontin and 8-hydroxydeoxyguanosine (8-OHdG) levels, and N-acetyl-β-glucosaminidase (NAG), myeloperoxidase (MPO) and caspase-3 activities.
Results: In 24-hour urine samples, calcium, citrate and creatinine levels were decreased in the EG group, while oxalate levels were increased and in treatment groups these parameters returned to control levels. MPO, 8-OHdG, caspase-3 and NAG activity were significantly increased in tissue and these changes were reversed in both MC groups. Histological findings also supported the biochemical parameters.
Conclusion: MC can reduce oxidative stress and histopathological changes in kidney tissues in rat nephrolithiasis model when used as either a preventive or therapeutic agent. If supported with further clinical trials, MC might have clinical implications in preventing oxidative renal cell injury and ultimately kidney stone formation.
{"title":"The effect of <i>Myrtus communis</i> L. extract on nephrolithiasis model in rats.","authors":"Busra Ertas, Dogancan Dorucu, Oznur Gulerturk, Ali Sen, Ozge Cevik, Sule Cetinel, Pinar Eker, Asuman Akgun, Emre Tarik Sener, Goksel Sener","doi":"10.14744/nci.2023.09068","DOIUrl":"10.14744/nci.2023.09068","url":null,"abstract":"<p><strong>Objective: </strong>Nephrolithiasis is a common urological disease that can lead to renal failure. Oxidative stress has been shown to be a contributing factor for nephrolithiasis and many agents have been studied to prevent and treat oxidative stress-related nephrolithiasis and renal damage. <i>Myrtus communis</i> (MC) extract has been shown to be an important antioxidant in different animal models. In this study, MC extract was administered preventively or therapeutically to rats with kidney stones, and its effectiveness was investigated.</p><p><strong>Methods: </strong>Wistar albino rats were divided into four groups (n=8); control (C), ethylene glycol (EG), EG+preventive MC, and EG+curative MC groups. The nephrolithiasis model was created by adding 0.75% EG to drinking water for 8 weeks. Ultimately, 24-hour urine was collected to measure calcium, citrate, and creatinine levels. After decapitation, kidney tissues were harvested for histological analyses, measurement of osteopontin and 8-hydroxydeoxyguanosine (8-OHdG) levels, and N-acetyl-β-glucosaminidase (NAG), myeloperoxidase (MPO) and caspase-3 activities.</p><p><strong>Results: </strong>In 24-hour urine samples, calcium, citrate and creatinine levels were decreased in the EG group, while oxalate levels were increased and in treatment groups these parameters returned to control levels. MPO, 8-OHdG, caspase-3 and NAG activity were significantly increased in tissue and these changes were reversed in both MC groups. Histological findings also supported the biochemical parameters.</p><p><strong>Conclusion: </strong>MC can reduce oxidative stress and histopathological changes in kidney tissues in rat nephrolithiasis model when used as either a preventive or therapeutic agent. If supported with further clinical trials, MC might have clinical implications in preventing oxidative renal cell injury and ultimately kidney stone formation.</p>","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"44 1","pages":"91-98"},"PeriodicalIF":1.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11095334/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84293637","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}
Pub Date : 2024-04-15DOI: 10.1109/JQE.2024.3389043
Tianwen Xia;Le Wang;Enguo Chen;Zhonghang Huang;Chunli Yan;Dalei Wu;Q. Frank Yan;Jie Sun
Earlier researchers have designed nanostructures such as stripe gratings (SG) or photonic crystals array (PhCA) to improve the light extraction efficiency (LEE) of light-emitting diodes (LEDs) by the diffraction mechanism. However, through k-domain method and simulation analysis, this letter finds that although SG perform well in 2D simulation, their effect drops sharply in 3D space, a phenomenon being overlooked in the community. This letter explains the diffraction mechanism of LEDs with nanostructure in 2D and 3D space through K-domain analysis, and reveals the inaccuracy of simulating LED with SG in 2D space. Unlike SG, PhCA offers diffraction in two directions and may be more suitable for LEDs.
早期研究人员设计了条纹光栅(SG)或光子晶体阵列(PhCA)等纳米结构,利用衍射机制提高发光二极管(LED)的光提取效率(LEE)。然而,通过 k 域方法和仿真分析,本文发现条纹光栅虽然在二维仿真中表现良好,但在三维空间中效果却急剧下降,而这一现象却被业界所忽视。本文通过 K 域分析解释了具有纳米结构的 LED 在二维和三维空间的衍射机制,并揭示了在二维空间使用 SG 模拟 LED 的不准确性。与 SG 不同,PhCA 提供两个方向的衍射,可能更适合 LED。
{"title":"Comparison of GaN LED Optical Simulation in 2D and 3D Space Based on k-Domain Analysis Method","authors":"Tianwen Xia;Le Wang;Enguo Chen;Zhonghang Huang;Chunli Yan;Dalei Wu;Q. Frank Yan;Jie Sun","doi":"10.1109/JQE.2024.3389043","DOIUrl":"10.1109/JQE.2024.3389043","url":null,"abstract":"Earlier researchers have designed nanostructures such as stripe gratings (SG) or photonic crystals array (PhCA) to improve the light extraction efficiency (LEE) of light-emitting diodes (LEDs) by the diffraction mechanism. However, through k-domain method and simulation analysis, this letter finds that although SG perform well in 2D simulation, their effect drops sharply in 3D space, a phenomenon being overlooked in the community. This letter explains the diffraction mechanism of LEDs with nanostructure in 2D and 3D space through K-domain analysis, and reveals the inaccuracy of simulating LED with SG in 2D space. Unlike SG, PhCA offers diffraction in two directions and may be more suitable for LEDs.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 3","pages":"1-6"},"PeriodicalIF":2.5,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140577945","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 : 2024-04-08DOI: 10.1109/JQE.2024.3386101
Zheng Zheng;Ward A. P. M. Hendriks;S. M. García-Blanco;Lantian Chang
We present a multiple microrings channel integrated chip and develop a signal processing method that enables parallel sensing with this chip. We utilize fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) to extract signals from different rings with different free spectra ranges (FSR). We verify this algorithm with temperature and solution sensing experiments. Compared with the conventional single-ring-single-resonance method, it shows improvements in up to 8 multi-channels capability and higher time resolution with the same experimental hardware.
{"title":"Parallel Sensing With Multiple Microrings on a Single Bus Waveguide","authors":"Zheng Zheng;Ward A. P. M. Hendriks;S. M. García-Blanco;Lantian Chang","doi":"10.1109/JQE.2024.3386101","DOIUrl":"10.1109/JQE.2024.3386101","url":null,"abstract":"We present a multiple microrings channel integrated chip and develop a signal processing method that enables parallel sensing with this chip. We utilize fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) to extract signals from different rings with different free spectra ranges (FSR). We verify this algorithm with temperature and solution sensing experiments. Compared with the conventional single-ring-single-resonance method, it shows improvements in up to 8 multi-channels capability and higher time resolution with the same experimental hardware.","PeriodicalId":13200,"journal":{"name":"IEEE Journal of Quantum Electronics","volume":"60 3","pages":"1-5"},"PeriodicalIF":2.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140577920","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}
High performance InGaAs photodetectors are highly desired for the ever-growing photoelectric industry. Despite maturity at the production level, the underlying causes of noise and dark current need clarification for further improvement. We studied the dark current and noise characteristics in PIN In0.53Ga0.47As photodiodes with different mesa sizes. The dark current noise exhibits a clear spectral 1/ $f$