{"title":"Carrier density dynamics and frequency shift in optically injected VCSELs","authors":"Sami S. Alharthi, Najm Al-Hosiny","doi":"10.1016/j.optcom.2024.131227","DOIUrl":"10.1016/j.optcom.2024.131227","url":null,"abstract":"<div><div>We theoretically and systematically study the dynamics of carrier density in optically injected VCSELs and correlate it to the observed frequency shift outside the locking region. We also show the dependence of carrier dynamics on all major parameters including frequency detuning, injection level and the linewidth enhancement factor (LEF).</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Weak-value amplification in fast and slow light in a ring resonator","authors":"Keigo Nakamura , Kazuki Bando , Takahiro Matsumoto , Makoto Tomita","doi":"10.1016/j.optcom.2024.131209","DOIUrl":"10.1016/j.optcom.2024.131209","url":null,"abstract":"<div><div>We analyzed fast and slow light in a fiber-ring resonator in a framework of weak-value measurements, obtaining the explicit form of the interaction Hamiltonian. Here, we fully utilized the advantage of the fiber-ring resonator in experiments and directly observed the time delay of the circulating pulse inside the ring, as well as the delays of the total output pulses that traversed the system under different pre- and post-selection states. The mean arrival time of the total output pulse can be expressed as the delay time of the circulating pulse amplified by a factor that reflects the weak value, thus both fast and slow light in the fiber-ring resonator system are quantitatively described using the framework of weak-value amplification.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pouria Amiri , Saifollah Rasouli , Davud Hebri , Sergey A. Ponomarenko
{"title":"Talbot-effect-based multiplication of Laguerre–Gaussian beams with non-zero radial indices: From theory to experimental realization","authors":"Pouria Amiri , Saifollah Rasouli , Davud Hebri , Sergey A. Ponomarenko","doi":"10.1016/j.optcom.2024.131203","DOIUrl":"10.1016/j.optcom.2024.131203","url":null,"abstract":"<div><div>We present a Talbot self-imaging inspired method for multiplying Laguerre–Gaussian (LG) beams of non-zero radial indices. We explore theoretically and experimentally the LG beam diffraction from two-dimensional (2D) periodic structures. In particular, we determine near-field LG beam diffraction patterns from a 2D binary grating of a small opening ratio (OR). We demonstrate that incident LG beam intensity patterns are reproduced as images of individual square apertures of the grating in certain Talbot planes. We also investigate the impact of the number of fractional-Talbot and Talbot planes on the quality of the generated 2D array of multiplexed LG modes. Our theoretical predictions are in good agreement with our experiments. Our method can find applications in optical communication, optical tweezing, multi-particle trapping, screening, and micro-manipulation.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vitaly P. Panov , Doyeon Lee , V.V. Kotlyar , A.A. Kovalev , P.A.N.S. Priyadharshana , Keumcheol Kwak , L.K. Migara , Jang-Kun Song
{"title":"Topological charge of a Gaussian beam with an off-axis optical vortex","authors":"Vitaly P. Panov , Doyeon Lee , V.V. Kotlyar , A.A. Kovalev , P.A.N.S. Priyadharshana , Keumcheol Kwak , L.K. Migara , Jang-Kun Song","doi":"10.1016/j.optcom.2024.131220","DOIUrl":"10.1016/j.optcom.2024.131220","url":null,"abstract":"<div><div>We show that when an optical vortex with a topological charge <em>n</em> shifts from the optical axis of a Gaussian beam, the orbital angular momentum decreases, whereas the topological charge remains unchanged. We experimentally confirmed this phenomenon with the aid of a <em>q</em>-plate array generated in a liquid crystal cell filled with a frustrated chiral nematic. We also theoretically proved that the topological charge of an optical vortex is conserved when the optical vortex is displaced from the axis.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hao Liu , Chen Jiang , Shuaicheng Liu , Jihong Ye , Hao Zhai , Jian Li , Jun Wang , Qi Wang , Xin Wei , Xiaomin Ren
{"title":"Reducing dislocations for room-temperature continuous-wave InGaAs/AlGaAs multiple quantum well lasers monolithically grown on Si","authors":"Hao Liu , Chen Jiang , Shuaicheng Liu , Jihong Ye , Hao Zhai , Jian Li , Jun Wang , Qi Wang , Xin Wei , Xiaomin Ren","doi":"10.1016/j.optcom.2024.131214","DOIUrl":"10.1016/j.optcom.2024.131214","url":null,"abstract":"<div><div>As dislocation-sensitive light-emitting devices, quantum well lasers monolithically grown on Si substrates operate poorly compared to their counterparts on native ones. In this work, a GaAs/Si virtual substrate with a low threading dislocation density of 8.9 × 10<sup>6</sup>/cm<sup>2</sup> was achieved by using a combined dislocation-reducing method. Meanwhile, by using two In-containing strained layer separately inserted into upper and lower AlGaAs cladding layers, the active region was virtually free of gliding dislocations. With the reduced dislocations in the active region, the fabricated Si-based broad-stripe ridged lasers exhibited continuous-wave lasing at room temperature, and a low threshold current density of 1015 A/cm<sup>2</sup>, high operation temperature of 90 °C as well as a device lifetime of over 87.25 h were achieved. These results demonstrate an experimentally feasible way to optimize a Si-based InGaAs/AlGaAs quantum well laser and further promote the research on monolithic integration.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shiwen Song , Qinghua Tian , Xiao Zhang , Xiangjun Xin , Fu Wang , Dandan Sun , Xiongyan Tang , Lei Zhu , Feng Tian , Sitong Zhou , Qi Zhang
{"title":"A bandwidth allocation scheme based on GRU traffic prediction in passive optical networks","authors":"Shiwen Song , Qinghua Tian , Xiao Zhang , Xiangjun Xin , Fu Wang , Dandan Sun , Xiongyan Tang , Lei Zhu , Feng Tian , Sitong Zhou , Qi Zhang","doi":"10.1016/j.optcom.2024.131222","DOIUrl":"10.1016/j.optcom.2024.131222","url":null,"abstract":"<div><div>With the advancement of information technology, network slicing technology has emerged as a viable solution for ensuring Quality of Service (QoS) in optical access networks. Current research is increasingly focusing on the integration of optical access networks with network slicing technologies. This paper proposes a bandwidth allocation scheme based on traffic prediction, specifically designed for resource management in optical network slicing scenarios. The scheme employs a Gated Recurrent Unit (GRU) neural network model to forecast future traffic, and combines bandwidth and latency factors to allocate bandwidth to each slice based on predicted values, thereby meeting the QoS requirements of various services. Simulation results indicate that, compared to the baseline algorithm, the proposed scheme achieved a 35.42% increase in Explaining Variance Score (EVS) and a 38.16% improvement in R2 score for factory slicing prediction. Similarly, for data center slicing prediction, the EVS score increased by 32.29% and the R2 score improved by 41.96%. In terms of performance metrics such as latency, packet loss rate, and throughput, the proposed algorithm outperforms both traditional prediction algorithms and the baseline algorithm.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuqi Sun , Yuanzhu Zhou , Yuezhang Hou , Yangmei Liu , Ting Luo , Zhili Li , Baoqun Li , Tianshu Wang , Xinjian Pan
{"title":"41.6nm/44 fs Mamyshev Yb-doped fiber laser with bound-state solitons and multiple harmonics","authors":"Yuqi Sun , Yuanzhu Zhou , Yuezhang Hou , Yangmei Liu , Ting Luo , Zhili Li , Baoqun Li , Tianshu Wang , Xinjian Pan","doi":"10.1016/j.optcom.2024.131221","DOIUrl":"10.1016/j.optcom.2024.131221","url":null,"abstract":"<div><div>A circular Mamyshev Yb-doped fiber laser was experimentally designed, and multiple pulse modes, including single-pulse, bound-state pulse, and harmonic mode-locked pulse, were observed by modulating the seed source and pump power. Single-pulse mode-locking with a single-pulse energy of 68.6 nJ was demonstrated at a repetition frequency of 12.1 MHz with a spectral half-height width of 41.6 nm and a compressed pulse duration of 44 fs. Results were also obtained for bound-state and harmonic mode-locked pulses, both with post-compression pulse durations of less than 100 fs. The experiments provide validation of the dynamics of a wide range of pulses in Mamyshev lasers. These findings have implications for the further exploration and understanding of pulse dynamics within the optical domain.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Photonic reservoir computing for parallel task processing based on a feedback-free spin-polarized VCSEL","authors":"Yigong Yang, Yu Huang, Pei Zhou, Nianqiang Li","doi":"10.1016/j.optcom.2024.131225","DOIUrl":"10.1016/j.optcom.2024.131225","url":null,"abstract":"<div><div>Time delayed reservoir computing (RC) is a novel artificial neural network that is easy to implement in hardware due to its extremely simple structure. Because of its time-division multiplexed information processing, laser-based photonic time-delayed RCs usually realize parallel processing with polarization/wavelength multiplexing. However, the performance of two different tasks is difficult to regulate separately and simultaneously in the time delayed RC system, especially for the chip-scale configuration. Here, we propose a feedback-free RC system based on a spin-polarized vertical-cavity surface-emitting semiconductor laser (VCSEL), which simplifies the whole system structure and can process time series prediction and waveform recognition tasks in parallel, with employing the input and output coding to provide the effect from past states. By separately setting the number of past states introduced by the coding for the two tasks, the performance of the two tasks can be adjusted respectively. Furthermore, by appropriately tuning the pump polarization ellipticity which is the unique feature for the spin-polarized VCSEL, the computational ability of the proposed RC can be focused on one of the two parallel tasks. Therefore, the proposed RC system is capable of dealing with different tasks with high performance, and also expected to provide a viable solution for integrated neuromorphic computing systems due to its compact, feedback-free structure.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ultrasensitive strain sensor of dual parallel FPIs utilizing femtosecond laser processing and Vernier effect","authors":"Changli Dong, Changning Liu","doi":"10.1016/j.optcom.2024.131210","DOIUrl":"10.1016/j.optcom.2024.131210","url":null,"abstract":"<div><div>This study proposes and develops a highly sensitive fiber optic strain sensor utilizing femtosecond laser processing and the Vernier effect. The sensor features two parallel Fabry-Pérot interferometers (FPI), with each FPI consisting of an air bubble and a tapered fiber optic cascade. FPI 2 serves as the sensing cavity, while FPI 1 acts as the reference cavity. The strain sensing capability of a single FPI 2 is measured at 6.67 p.m./με, while the parallel configuration of FPI 2 with FPI 1 achieves a sensitivity of 68.3 p.m./με, resulting in an amplification of 10.24. Furthermore, the proposed sensor demonstrates excellent repeatability, low-temperature cross-sensitivity, simple fabrication, and cost-effectiveness, making it a promising tool for strain measurement applications.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lei Zhang, Xin Dai, Weihua Zhang, Wenqing Wang, Xiaochen Liu, Wenbo Li
{"title":"A TDLAS gas detection method based on digital signal modulation","authors":"Lei Zhang, Xin Dai, Weihua Zhang, Wenqing Wang, Xiaochen Liu, Wenbo Li","doi":"10.1016/j.optcom.2024.131211","DOIUrl":"10.1016/j.optcom.2024.131211","url":null,"abstract":"<div><div>This research presents a novel TDLAS gas concentration detection method based on digital modulation. The method inherits the advantage of a simple system structure from Direct Absorption Spectroscopy, as well as the excellent sensitivity of Wavelength Modulation Spectroscopy. A low-frequency sawtooth wave is employed to drive the laser, resulting in a digital direct absorption spectrum signal. By constructing a cosine modulation sequence in the time domain and performing linear interpolation on the direct absorption spectrum, it successfully converts to a wavelength-modulated absorption spectrum and simultaneously generates a digital reference signal at double the frequency. Ultimately, phase-locked amplification technology can be used to calculate the amplitude of the second harmonic. Since both the modulation and reference signals are generated digitally, they ensure a strict frequency-doubling relationship and phase correlation, which not only reduces the complexity of the hardware system but also effectively minimizes system errors. Because digital technology generates both the modulation and reference signals, it ensures that they have the same phase and a strict frequency-doubling relationship. Experimental results demonstrate that, when fitted by a cubic polynomial, the second harmonic amplitude and the gas concentration have a correlation coefficient (R<sup>2</sup>) as high as 0.99999 and a root mean square error as low as 0.0011. This proves the method's great accuracy and reliability in practical applications.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}