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few mode fiber

Qi-Qi Yang, Rui-Tong Liu, Chao Huang, Yi-Fan Huang, Lin-Feng Gao, Bing Sun, Zhi-Peng Huang, Lei Zhang, Chen-Xia Hu, Ze-Qi Zhang, Chun-Lin Sun, Qiang Wang, Yu-Long Tang, Hao-Li Zhang
The rediscovery of black phosphorus (BP) has expanded the 2D family into Group 15 (Nitrogen Group) elements, among which bismuthene is the latest member with extraordinary opto-electronic, catalytic and biocompatible properties and potential as a 2D topological insulator. However, bulk Bi is not easily mechanically exfoliated as its counterpart of BP. Thus, to date, the reports on 2D Bi fabrication are rare, and investigations on its nonlinear optical properties are even less. Herein, we rationally designed a new strategy combining acid-interaction and liquid exfoliation to successfully transform metal bulk Bi into few-layer semiconductor, which resulted in unseen opto-electronic properties, such as tunable nonlinear responses all the way to the near-infrared (NIR) region...
October 16, 2018: Nanoscale
Jesper Lægsgaard, Federica Poli, Annamaria Cucinotta, Stefano Selleri
A coupled-mode theory for nonlinear mode coupling by the thermo-optic effect, originally developed for single-core fiber amplifiers, is applied to the case of dual-core amplifiers. It is shown that a non-phase-matched coupling term, which is usually irrelevant in single-core amplifiers, can strongly affect the mode stability when the coupling length between supermodes exceeds a few centimeters. The phase-mismatched coupling can lead to a strongly reduced instability threshold and static deformation effects for a range of intermediate coupling lengths...
October 1, 2018: Optics Letters
Pablo Eugui, Antonia Lichtenegger, Marco Augustin, Danielle J Harper, Martina Muck, Thomas Roetzer, Andreas Wartak, Thomas Konegger, Georg Widhalm, Christoph K Hitzenberger, Adelheid Woehrer, Bernhard Baumann
Optical coherence tomography (OCT) is a powerful technology for rapid volumetric imaging in biomedicine. The bright field imaging approach of conventional OCT systems is based on the detection of directly backscattered light, thereby waiving the wealth of information contained in the angular scattering distribution. Here we demonstrate that the unique features of few-mode fibers (FMF) enable simultaneous bright and dark field (BRAD) imaging for OCT. As backscattered light is picked up by the different modes of a FMF depending upon the angular scattering pattern, we obtain access to the directional scattering signatures of different tissues by decoupling illumination and detection paths...
June 1, 2018: Biomedical Optics Express
Gabriela Croitoru Salamu, Nicolaie Pavel
We report on laser performances obtained in Q-switch mode operation from buried depressed-cladding waveguides of circular shape (100 μm diameter) that were inscribed in Nd:YAG and Nd:YVO₄ media by direct writing with a femtosecond laser beam. The Q-switch operation was realized with a Cr4+ :YAG saturable absorber, aiming to obtain laser pulses of moderate (few μJ) energy at high (tens to hundreds kHz) repetition rate. An average power of 0.52 W at 1.06 μm consisting of a train of pulses of 7.79 μJ energy at 67 kHz repetition rate, was obtained from a waveguide realized in a 4...
September 12, 2018: Materials
Jiaxiong Li, Lulu Wang, Jiangbing Du, Shoulin Jiang, Lin Ma, Chengkun Cai, Long Zhu, Andong Wang, Ming-Jun Li, Hao Chen, Jian Wang, Zuyuan He
We design and experimentally demonstrate a few-mode Raman amplifier over the C+L band with a flat on-off gain of ∼4  dB, for the first time, to the best of our knowledge. A state-of-the-art gain bandwidth of 75 nm (1530-1605 nm) is achieved. The wavelength-dependent gain for both LP01 and LP11 modes is about 0.6 dB, and the maximum mode-dependent gain is less than 0.3 dB. Mode-division multiplexed optical transmissions are performed over 75 km few-mode fiber assisted by the proposed Raman amplifier...
September 15, 2018: Optics Letters
Jun Zhao, Jingchao Liang, Liusheng Chu, Fuqiang Shen
Many researchers have performed experimental and theoretical studies on the shear behavior of steel fiber reinforced concrete (SFRC) beams with conventional reinforcement; few studies involve the shear behavior of SFRC beams with high-strength reinforcement. In this paper, the shear test of eleven beams with high-strength reinforcement was carried out, including eight SFRC beams and three reinforced concrete (RC) beams. The load-deflection curve, concrete strain, stirrup strain, diagonal crack width, failure mode and shear bearing capacity of the beams were investigated...
September 11, 2018: Materials
Bo Guo, Shi-Hao Wang, Zhi-Xin Wu, Ze-Xin Wang, Da-He Wang, Hao Huang, Feng Zhang, Yan-Qi Ge, Han Zhang
Few-layer bismuthene is an emerging two-dimensional material in the fields of physics, chemistry, and material science. However, its nonlinear optical property and the related photonics device have been seldom studied so far. Here, we demonstrate a sub-200 fs soliton mode-locked erbium-doped fiber laser (EDFL) using a microfiber-based bismuthene saturable absorber for the first time, to the best of our knowledge. The bismuthene nanosheets are synthesized by the sonochemical exfoliation method and transferred onto the taper region of a microfiber by the optical deposition method...
September 3, 2018: Optics Express
Shoulin Jiang, Lin Ma, Shuai Wang, Xinyu Fan, Zuyuan He
We investigated the fiber fuse propagation speed in different kinds of few-mode fibers (FMFs) by combining heterodyne detection and time-frequency analysis. The periodic speed oscillation due to mode interference was observed, and we confirm that the characteristic length Lc (defined as the optical discharge propagation distance within a period of speed oscillation) is independent of the launched power, which is different from that observed in single-mode fibers. Moreover, we believe that the optical field modulation with enough intensity led to the variation of the optical discharge center position...
September 1, 2018: Optics Letters
Xiaobo Heng, Jiulin Gan, Zhishen Zhang, Jiong Li, Muqiao Li, Hua Zhao, Qi Qian, Shanhui Xu, Zhongmin Yang
A transverse mode switchable all-fiber Brillouin laser architecture is proposed. This laser architecture consists mainly of an optical switch, a set of cascaded mode selection couplers (MSCs), and a few-mode fiber ring cavity. By switching the output signal of the optical switch, specific transverse modes generated by MSCs can be coupled into the ring cavity to excite the corresponding Brillouin scattering light. Based on the Brillouin nonlinear effect, the desired mode resonant amplification is guaranteed, and a transverse mode switchable laser beam is obtained...
September 1, 2018: Optics Letters
Chen Yang, Meng Wang, Ming Tang, Hao Wu, Can Zhao, Tongqing Liu, Songnian Fu, Weijun Tong
A link optimized few-mode fiber-based Raman distributed temperature sensor is proposed to enhance the temperature resolution of the long-distance sensing system. Comprehensive theoretical analysis and experimental validation in contrast with the traditional single-mode fiber-based sensing link have been conducted to reveal the benefits provided by the optimization scheme. The temperature resolutions are about 3.8°C for the proposed fiber link at 20 km distance, leading to about 6.2°C improvement compared with the single-mode fiber (SMF) link...
August 20, 2018: Applied Optics
Xiaobo Heng, Jiulin Gan, Zhishen Zhang, Jiong Li, Muqiao Li, Hua Zhao, Qi Qian, Shanhui Xu, Zhongmin Yang
An all-fiber scheme for stable orbital angular momentum (OAM) beam generation and propagation is proposed and demonstrated. This scheme is based on a self-designed and manufactured graded-index few mode fiber (GI-FMF) and compatible mode selection coupler (MSC). The MSC, which consists of a conventional single mode fiber (SMF) and the GI-FMF, can effectively couple the fundamental mode in the SMF to the desired OAM mode in the GI-FMF based on phase matching condition. Meanwhile, the GI-FMF breaks the degeneracy between the desired eigenmodes and neighboring vector modes, thereby allowing the preservation and propagation of the selectively excited OAM modes...
June 25, 2018: Optics Express
Yinping Liu, Lin Ma, Chen Yang, Weijun Tong, Zuyuan He
We designed and fabricated a graded-index few-mode fiber (GI-FMF) with large effective mode area and low intermodal dispersion for Raman distributed temperature sensor (RDTS) to simultaneously achieve high spatial and temperature resolution over long distance. In experiment, we measured the spatial and temperature resolution of the RDTS using different types of fibers under different launch conditions based on a commercially available RDTS system. By using the GI-FMF under the overfilled launch condition, we achieved a 1 °C temperature resolution with a spatial resolution of 1...
August 6, 2018: Optics Express
Xiaojun Liang, Wei-Ling Li, William A Wood, John D Downie, Jason E Hurley, Anthony Ng'oma
Evolution of next generation wireless networks brings challenges to efficiently transmit a large amount of data from a base station to a remote antenna unit. We investigate a space division multiplexing technique that employs few mode fibers (FMFs) to transmit 3 × 3 MIMO wireless signals, aiming to employ a common digital signal processing (DSP) unit to equalize both the fiber and wireless channel. We optimize system parameters and obtain above 28 dB and 23 dB signal-to-interference and noise ratio (SINR) for 3 meters wireless systems with 500 m and 2 km FMF, which correspond to the transmission capacity of 578 Mb/s and 468 Mb/s using a 20 MHz bandwidth, respectively...
August 6, 2018: Optics Express
Jun Liu, Shimao Li, Yunhong Ding, Shi Chen, Cheng Du, Qi Mo, Toshio Morioka, Kresten Yvind, Leif Katsuo Oxenløwe, Siyuan Yu, Xinlun Cai, Jian Wang
We experimentally demonstrate orbital angular momentum (OAM) modes emission from a high emission efficiency OAM emitter for 20-Gbit/s quadrature phase-shift keying (QPSK) carrying data transmission in few-mode fiber (FMF). The device is capable of emitting vector optical vortices carrying well-defined OAM efficiently with the efficiency of the device >37%. Seven modes propagate through a 2-km two-mode and a 3.6-km three-mode FMF with measured optical signal-to-noise ratio (OSNR) penalties less than 4 dB at a bit-error rate (BER) of 2 × 10-3 ...
June 11, 2018: Optics Express
Xuan Zhan, Yinping Liu, Ming Tang, Lin Ma, Ruoxu Wang, Li Duan, Lin Gan, Chen Yang, Weijun Tong, Songnian Fu, Deming Liu, Zuyuan He
We proposed and experimentally demonstrated paralleled Mach-Zehnder interferometers (MZIs) in few-mode multicore fiber (FM-MCF) for temperature and strain discriminative sensing. A section of FM-MCF is sandwich-spliced between two single-mode multicore fiber (SM-MCF) with a rotational offset. The arbitrarily controlled angular misalignment generates intentional intermodal interferences in outer cores of the FM-MCF thus multiple MZI structures are implemented. Experimental results show that the temperature sensitivities are 105...
June 11, 2018: Optics Express
Jianping Li, Jianbo Zhang, Fan Li, Xincheng Huang, Shecheng Gao, Zhaohui Li
The fiber vector eigenmode based mode division multiplexing (VMDM) transmission over few-mode fiber (FMF) with the 1st-order cylinder vector beams (CVBs) has been demonstrated. The performances of generated CVB using q-plate (QP) have been characterized before and after transmission over the FMF respectively based on the high-order Poincaré sphere model and polarization grating (PG). The measured minimum mode isolations between the two CVBs (TM01 and TE01 modes) of the used 4-mode FMF are about 16.8 dB after transmitting over 5 m and 12...
July 9, 2018: Optics Express
Zhiqun Yang, Jian Zhao, Neng Bai, Ezra Ip, Ting Wang, Zhihong Li, Guifang Li
We experimentally demonstrate adaptive variable-forgetting-factor (VFF) recursive-least-square frequency-domain equalization (RLS-FDE) for mode-division multiplexing. The VFF-RLS-FDE algorithm improves convergence speed as transmission distance increases. For MDM transmission over a 1,000-km few-mode fiber, the convergence speed was increased by 18.7 times in comparison with LMS-FDE. In the meantime, the convergence error performance of VFF-RLS is also much superior to LMS while fixed-forgetting-factor RLS has a 0...
July 9, 2018: Optics Express
Haojie Zhang, Noel Healy, Antoine F J Runge, Chung Che Huang, Daniel W Hewak, Anna C Peacock
Few-layer molybdenum disulfide (MoS2 ) has an electronic band structure that is dependent on the number of layers and, therefore, is a very promising material for an array of optoelectronic, photonic, and lasing applications. In this Letter, we make use of a side-polished optical fiber platform to gain access to the nonlinear optical properties of the MoS2 material. We show that the nonlinear response can be significantly enhanced via resonant coupling to the thin film material, allowing for the observation of optical modulation and spectral broadening in the telecom band...
July 1, 2018: Optics Letters
Ayoub Ladaci, Sylvain Girard, Luciano Mescia, Arnaud Laurent, Carine Ranger, David Kermen, Thierry Robin, Benoit Cadier, Mathieu Boutillier, Baidy Sane, Emmanuel Marin, Adriana Morana, Youcef Ouerdane, Aziz Boukenter
The radiation responses of different high-power erbium/ytterbium-codoped fiber amplifiers (HP-EYDFA) have been investigated up to 100 krad (SiO2 ) dose levels. These devices are able to deliver 20 W of signal output power at 1565 nm by pumping at 915 nm (43 W) radiation tolerant (Er/Yb) or radiation hardened (ErYbCe) active few mode fibers; these performances are needed for free-space communications between low-orbit satellites and ground transceivers. X-ray irradiation results show that, thanks to a positive influence of the photo- and thermal-bleaching phenomena associated with such high-power operating conditions, the gain degradation levels of HP-EYDFA based on radiation hardened fibers remain below 6% after 100 krad at an accelerated dose rate of 3...
July 1, 2018: Optics Letters
Yunhe Zhao, Haoshuo Chen, Nicolas K Fontaine, Jiaxiong Li, Roland Ryf, Yunqi Liu
We demonstrate broadband and low-loss three-mode and six-mode scramblers employing CO2 -laser inscribed long-period gratings (LPGs) for space-division multiplexing. Step-index (SI) few-mode fibers are used to avoid mode coupling to the cladding modes. We characterize the mode scramblers using a swept-wavelength interferometer. Mode-dependent loss (MDL) and modal transfer matrices over the C+L band are presented. Demonstrated LPGs with negligible MDL and low insertion loss contributed to high-performance CO2 -laser inscription...
June 15, 2018: Optics Letters
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