Article
Instruments & Instrumentation
Bing Han, Shisheng Dong, Yang Liu, Zinan Wang
Summary: In this study, the impacts of ytterbium-doped random fiber laser (YRFL) on the spectral and relative intensity noise (RIN) properties of cascaded random Raman fiber lasers (CRRFLs) are experimentally investigated. It is found that the bandwidth of the point reflector in YRFL determines the bandwidth and temporal stability of YRFL. By increasing the bandwidth of the point reflector, CRRFL with higher spectral purity and lower RIN can be achieved.
Article
Materials Science, Multidisciplinary
Zhuo-Hang Wei, Xiang Zhang, Chang-Shui Chen
Summary: Shortcuts to adiabaticity (STA) are emerging channels in atomic research that can quickly and accurately prepare desired quantum states. This study proposes a frequency conversion technique based on stimulated Raman shortcut-to-adiabatic passage (STIRSAP) that operates through a non-adiabatic route while maintaining the same energy distribution as adiabatic evolution. Numerical simulations demonstrate the efficiency and robustness of this conversion method, offering a novel scenario for frequency conversion and relaxing strict limitations on system parameters in adiabatic frequency conversion.
RESULTS IN PHYSICS
(2022)
Article
Optics
Pragati Aashna, K. Thyagarajan
Summary: A study on nonlinear stimulated Raman adiabatic passage (STIRAP) demonstrates the complete conversion of pump light to signal and idler with a large bandwidth using a nonlinear dark state similar to atomic population transfers.
Article
Engineering, Electrical & Electronic
Pawan Agarwal, Mohammad Chahardori, Deukhyoun Heo
Summary: A new boosted active-capacitor (BAC) architecture utilizing LC-tuned active-impedance-conversion is proposed for designing a wide tuning range voltage-controlled oscillator (VCO). The BAC, designed in a 65 nm bulk CMOS process, achieves a capacitance tuning ratio of 7.8 with high quality factor across VCO's tuning range, and the prototype VCO has a tuning range of 8.3-14.3 GHz with low power consumption and high FoMT.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2021)
Article
Optics
Yanlu Wang, Zhiping Yang, Mingyu Li, Jian-Jun He, Qiushun Li
Summary: A sensor based on cascaded double ring resonator (CDRR) with a micro-heater for thermal tuning is proposed in this paper. The refractive index change of the sample is converted into the change of electrical power, resulting in a higher sensitivity of the sensor.
CHINESE OPTICS LETTERS
(2022)
Article
Automation & Control Systems
Abraham Marquez, Vito Giuseppe Monopoli, Anatolii Tcai, Jose I. Leon, Giampaolo Buticchi, Sergio Vazquez, Marco Liserre, Leopoldo Garcia Franquelo
Summary: The cascaded H-bridge converter (CHB) is a suitable solution for various applications, but the discontinuous pulsewidth modulation (DPWM) used in this article to reduce switching losses leads to high harmonic distortion in the output voltage. The method proposed in this article cleverly groups the cells to mitigate basebands harmonic distortion and applies a variable-angle PS-PWM technique to reduce sidebands harmonics content, demonstrating good performance in experimental results.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2021)
Article
Optics
Haiyan Zhao, Jibo Yu, Ke Tian, Xin Wang, Shunbin Wang, Dejun Liu, Gerald Farrell, Pengfei Wang
Summary: This study presents the cascaded dual-wavelength lasing at 0.85 μm and 1.55 μm from an Er3+-doped ZBYA fluorozirconate glass microsphere for the first time. The effects of Er3+ concentration and microsphere diameter on the up-conversion and down-conversion lasers are investigated.
JOURNAL OF LUMINESCENCE
(2023)
Article
Nanoscience & Nanotechnology
Manohar Reddy Busireddy, Tsung-Wei Chen, Sheng-Ci Huang, Hebing Nie, Yi-Jia Su, Chih-Ting Chuang, Pei-Jung Kuo, Jiun-Tai Chen, Chain-Shu Hsu
Summary: This study explores the effect of blend film morphology on the performance of organic photovoltaic devices by modifying the molecular design of wide-bandgap conjugated polymer donors (WB-CPDs). The results show that the blend film with methyl groups exhibits stronger aggregation behavior and pi-pi stacking, which enhances phase separation, charge transport, and fill factor (FF). However, the incorporation of methyl groups reduces the absorption coefficient of the blend film, resulting in a decrease in short-circuit current density (J(SC)). Ultimately, the optimized blend film achieves higher power conversion efficiency.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Yuanhongliu Gao, Xiaoyu Chen, Tonglei Cheng, Fang Wang, Xin Yan
Summary: This study demonstrates all-optical wavelength conversion using cascaded four-wave mixing (FWM) phenomena with graphene oxide (GO) and a highly nonlinear fiber (HNLF) device. The experimental results show that GO, with its strong third-order nonlinear effect, is an excellent material for nonlinear optical wavelength conversion. The amplification of HNLF and GO, along with the group velocity matching of pump and signal, promotes the cascaded nonlinear frequency mixing process. The maximum spacing between signal and pump is found to be 21 nm, and the order of cascaded FWM light increases as GO increases, leading to a maximum first-order FWM conversion efficiency of -14.5 dB. This is the first investigation of cascaded FWM-based all-optical wavelength conversion in HNLF-GO with wide wavelength selectivity, providing a new approach for fabricating high-performance nonlinear optical devices.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2024)
Article
Chemistry, Multidisciplinary
Jochen Vanderspikken, Quan Liu, Zhen Liu, Tom Vandermeeren, Tom Cardeynaels, Sam Gielen, Bruno Van Mele, Niko Van den Brande, Benoit Champagne, Koen Vandewal, Wouter Maes
Summary: This research explores the enhancement of charge transfer absorption by altering the side chains of organic semiconductor donor polymers, thereby increasing the interfacial area between the polymer and fullerene. This improvement extends the detection range and performance of organic narrow-band photodetectors.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Multidisciplinary Sciences
Maissa Daoud, Mohamed Ghorbel, Hassene Mnif
Summary: This paper presents the design of an Ultra-Wide Band (UWB) Low Noise cascaded Amplifier (LNA) used for biomedical applications, which utilizes inductances minimization technique to reduce LNA surface area while maintaining low power consumption, low noise, high stability, linearity, and gain. The designed LNA demonstrates good performance in simulations.
SCIENTIFIC REPORTS
(2021)
Article
Optics
Peipei Zheng, Duanduan Wu, Shixun Dai
Summary: A new wavelength tunable Raman fiber laser has been successfully demonstrated experimentally and theoretically at the 1.6 mu m waveband using the Raman gain spectrum control method. The laser is a two-end-pumped structure with a gain spectrum formed by the superposition of two stimulated Raman scattering gain curves generated by the two pump lasers. By varying the power ratios of the pump lasers, the Raman gain peak can be controlled, allowing for easy tuning of the laser wavelength. The experimental and theoretical results confirm the feasibility of this technique for practical and low-cost wavelength tunable Raman lasers in the special wavelength region.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Handa Zhang, Xiang Zhang, Ting Wan, Dong Cheng, Fujie Li, Zhonghao Zhang, Changshui Chen
Summary: This paper presents a novel domain inversion crystal structure for studying cascaded three-wave mixing process. The scheme achieves efficient wavelength conversion and enhances flexibility in structure design. Compared with conventional methods, it enables a broader conversion wavelength range, providing a theoretical basis for obtaining mid-infrared laser sources.
RESULTS IN PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Bo Wei Xu, Shao Yong Zheng, Yuanxin Li, Wenquan Che
Summary: This article proposes a coupler with simultaneously tunable power division ratio and phase difference based on a multivector summation method. The proposed tunable coupler utilizes varactor diodes on a cross-shaped quarter-wavelength coupled lines to control the power division ratio and phase. A highly tunable coupler operating at 1.8 GHz is designed, fabricated, and measured, showing the ability to tune the power division ratio from -7 to 1 dB with a 90° phase difference and the phase difference from 10° to 165° with equal power division. The coupler also exhibits good return loss and isolation.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Optics
Arnab De, Anupam Mishra, Dipak Kumar Khatua, Vivek Dwij, Vasant Sathe, Satyam Jena, Rajeev Ranjan
Summary: A novel approach to thermometric material design based on temperature tuning of emission was proposed. A model ferroelectric phosphor demonstrated high thermal sensitivity and good signal discriminability, providing a promising alternative route for developing self-referencing optical thermometers with high sensitivity.
Article
Engineering, Electrical & Electronic
Fufei Pang, Haoqiang Zheng, Huanhuan Liu, Junfeng Yang, Na Chen, Yana Shang, Siddharth Ramachandran, Tingyun Wang
IEEE PHOTONICS TECHNOLOGY LETTERS
(2019)
Article
Optics
Lars Rishoj, Fengyuan Deng, Boyin Tai, Ji-Xin Cheng, Siddharth Ramachandran
Article
Optics
X. Liu, E. N. Christensen, K. Rottwitt, S. Ramachandran
Article
Multidisciplinary Sciences
Aaron P. Greenberg, Gautam Prabhakar, Siddharth Ramachandran
NATURE COMMUNICATIONS
(2020)
Review
Nanoscience & Nanotechnology
Zelin Ma, Siddharth Ramachandran
Summary: Multimode fibers have attracted renewed attention due to the spatial diversity they offer, with circularly polarized orbital angular momentum modes being identified as the most stable eigenbasis for light propagation in suitably designed fibers. By manipulating light's path memory effects, a controllable means of tailoring light's phase is demonstrated, which has implications for using higher-order modes in optical fiber applications.
Article
Engineering, Electrical & Electronic
V. Balaswamy, V. R. Supradeepa
Summary: This study demonstrates the versatility of a recently developed technique called Stimulated Raman Scattering, which allows for simultaneous wavelength conversion and power combining of multiple Ytterbium-doped fiber lasers. Experimental results show that the technique works effectively with different wavelength spacing and can be applied to the combination of more than two lasers.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2022)
Article
Optics
Rashmita Deheri, Sarthak Dash, V. R. Supradeepa, V Balaswamy
Summary: Researchers have achieved low-intensity noise cascaded Raman fiber lasers (CRFLs) with high spectral purity by using a low-intensity noise, narrow linewidth Yb-fiber amplifier as a pump source.
Proceedings Paper
Engineering, Electrical & Electronic
Aaron P. Greenberg, Gautam Prabhakar, Siddharth Ramachandran
2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
Aku Antikainen, Havva Begum Kabagoz, Siddharth Ramachandran
2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
Lars Rishoj, Ivan Coto Hernandez, Nate Jowett, Siddharth Ramachandran
2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
Zelin Ma, Poul Kristensen, Siddharth Ramachandran
2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
Robert Lindberg, Xiao Liu, Siddharth Ramachandran, Valdas Pasiskevicius
2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
Xiao Liu, Aku Antikainen, Zelin Ma, Poul Kristensen, Siddharth Ramachandran
2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
Havva Begum Kabagoz, Siyuan Zhang, Lars Rishoj, Aku Antikainen, Siddharth Ramachandran
2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2020)
Proceedings Paper
Optics
V Balaswamy, Roopa Prakash, Vishal Choudhury, Santosh Aparanji, B. S. Vikram, V. R. Supradeepa
NONLINEAR FREQUENCY GENERATION AND CONVERSION: MATERIALS AND DEVICES XVIII
(2019)