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few mode fiber

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
María Del Rayo Jiménez Vivanco, Godofredo García, Rafael Doti, Jocelyn Faubert, Jesus Eduardo Lugo Arce
In this work, we have followed ethanol evaporation at two different concentrations using a fiber optic spectrometer and a screen capture application with a resolving capacity of 10 ms. The transmission spectra are measured in the visible-near-infrared range with a resolution of 0.5 nm. Porous Silicon microcavities were fabricated by electrochemistry etching of crystalline silicon. The microcavities were designed to have a localized mode at 472 nm (blue band). Ethanol infiltration produces a redshift of approximately 17 nm...
May 26, 2018: Materials
Jian Yuan, Haoran Mu, Lei Li, Yao Chen, Wenzhi Yu, Kai Zhang, Baoquan Sun, Shenghuang Lin, Shaojuan Li, Qiaoliang Bao
A multilayer platinum diselenide (PtSe2 ) film was experimentally demonstrated as a new type of saturable absorber with the capability to deliver robust dissipative solitons in a passively mode-locked fiber laser. The PtSe2 film synthesized by chemical vapor deposition was placed onto the ferule of a single mode optical fiber through a typical dry transfer process. The nonlinear optical measurements reveal efficient saturable absorption characteristics in terms of a large modulation depth (26%) and low saturable intensity (0...
June 27, 2018: ACS Applied Materials & Interfaces
C Hari Krishna, Sourabh Roy
We have demonstrated a method for the generation of spiral vector beams using a few-mode optical fiber. The beams are generated due to the combination of orthogonal linearly polarized modes with a tilted polarization vector in the few-mode optical fiber. The excitation of these modes is controlled by the incident state of polarization and coupling conditions at the input end of the fiber. The beams with clockwise and counterclockwise nature of spiral polarization are generated, and switching between them is demonstrated...
May 10, 2018: Applied Optics
Teng Wang, Fan Shi, Yiping Huang, Jianxiang Wen, Zhengqian Luo, Fufei Pang, Tingyun Wang, Xianglong Zeng
Generation of high-order modes with high quality is important for the application of cylindrical vector beams in fibers. We experimentally demonstrated high-order LP11 mode generation and amplification with a broad bandwidth in an all few-mode fiber laser. A wavelength-division-multiplexing (WDM) mode selective coupler (MSC) is proposed to achieve efficient mode conversion from LP01 mode to LP11 mode, but also combine high-order LP11 modes at the wavelengths of 980/1550 nm. To the best of our knowledge, this is the first report on the high-order mode oscillation in an all few-mode fiber laser...
April 30, 2018: Optics Express
Tetsuya Hayashi, Yoshiaki Tamura, Takuji Nagashima, Kazuhiro Yonezawa, Toshiki Taru, Koji Igarashi, Daiki Soma, Yuta Wakayama, Takehiro Tsuritani
We report on a measurement method for the effective area of the few-mode fiber. We derived a transform equation between a near-field pattern and a far-field pattern generalized for circularly-asymmetric higher-order modes of a cylindrical core, and enabled effective area measurement of the higher-order modes using high-dynamic-range far-field scan technique and low-crosstalk mode multiplexer. The measured effective area values agreed well with the values that were numerically predicted using a finite-element method from the refractive index profile, when the modal crosstalk was suppressed...
April 30, 2018: Optics Express
Mohamed Morsy-Osman, Mohammed Sowailem, Eslam El-Fiky, Tristan Goodwill, Thang Hoang, Stephane Lessard, David V Plant
We propose a DSP-free coherent-lite system that requires neither high-speed DSP nor high-resolution signal converters for deployment inside datacenters over single mode fiber links with reaches of 10 km and less. The removal of converters and DSP, in which some subsystems are fundamental for successful coherent detection, is enabled by either replacing DSP subsystems with optics having equivalent functions or by re-engineering the system. We validate in a proof-of-concept experiment the proposed DSP-free system using 50 Gbaud DP-16QAM delivering 400 Gb/s over 10 km of single mode fiber (SMF) below the KP4 forward error correction (FEC) threshold of 2...
April 2, 2018: Optics Express
Tao Hu, Juhao Li, Dawei Ge, Zhongying Wu, Yu Tian, Lei Shen, Yaping Liu, Su Chen, Zhengbin Li, Yongqi He, Zhangyuan Chen
Weakly coupled-mode division multiplexing (MDM) over few-mode fibers (FMF) for short-reach transmission has attracted great interest, which can avoid multiple-input-multiple-output digital signal processing (MIMO-DSP) by greatly suppressing modal crosstalk. In this paper, step-index FMF supporting 4 linearity polarization (LP) modes for MIMO-free transmission is designed and fabricated for the first time, to our knowledge. Modal crosstalk of the fiber is suppressed by increasing the mode effective refractive index differences...
April 2, 2018: Optics Express
Varun Kelkar, Smaranika Swain, Deepa Venkitesh
We propose and experimentally demonstrate a method for measuring the differential modal group delay (DMGD) of a few-mode fiber using a Fourier domain mode-locked laser (FDML). We use the fast frequency-swept, wavelength-tunable output of the FDML in order to perform time domain measurements of interference of the modes, which is further postprocessed to extract the DMGD. We demonstrate the measurement of DMGD for a commercial two-mode fiber over the C-band. This method is not limited by the magnitude of DMGD or the number of modes and is minimally affected by time-dependent polarization and mode fluctuations, environmental noise, and spectral resolution of instruments...
May 1, 2018: Optics Letters
Jintao Wang, Hao Chen, Zike Jiang, Jinde Yin, Jinzhang Wang, Min Zhang, Tingchao He, Junzi Li, Peiguang Yan, Shuangchen Ruan
A passively mode-locked thulium-doped fiber (TDF) laser was realized by employing chemical vapor deposited few-layer molybdenum ditelluride (MoTe2 ) as a saturable absorber (SA). The few-layer MoTe2 film was transferred onto the waist of a microfiber and then incorporated into a TDF laser with a typical all-fiber ring cavity configuration. Stable soliton pulses emitting at 1930.22 nm were obtained with a 3 dB bandwidth of 4.45 nm, a pulse duration of 952 fs, and an average power of 36.7 mW.
May 1, 2018: Optics Letters
Sebastian Schlangen, Kort Bremer, Yulong Zheng, Sebastian Böhm, Michael Steinke, Felix Wellmann, Jörg Neumann, Bernhard Roth, Ludger Overmeyer
Long-period fiber gratings (LPGs) are well known for their sensitivity to external influences, which make them interesting for a large number of sensing applications. For these applications, fibers with a high numerical aperture (i.e., fibers with highly germanium (Ge)-doped fused silica fiber cores) are more attractive since they are intrinsically photosensitive, as well as less sensitive to bend- and microbend-induced light attenuations. In this work, we introduce a novel method to inscribe LPGs into highly Ge-doped, single-mode fibers...
April 27, 2018: Sensors
Manoj Kumar Dasa, Christos Markos, Michael Maria, Christian R Petersen, Peter M Moselund, Ole Bang
We propose a cost-effective high-pulse energy supercontinuum (SC) source based on a telecom range diode laser-based amplifier and a few meters of standard single-mode optical fiber, with a pulse energy density as high as ~25 nJ/nm in the 1650-1850 nm regime (factor >3 times higher than any SC source ever used in this wavelength range). We demonstrate how such an SC source combined with a tunable filter allows high-resolution spectroscopic photoacoustic imaging and the spectroscopy of lipids in the first overtone transition band of C-H bonds (1650-1850 nm)...
April 1, 2018: Biomedical Optics Express
Xuejun Zhang, Ze Wu, Fu Liu, Qiangqiang Fu, Xiaoyong Chen, Jian Xu, Zhaochuan Zhang, Yunyun Huang, Yong Tang, Tuan Guo, Jacques Albert
We propose and demonstrate hydrogen peroxide (H2 O2 ) and glucose concentration measurements using a plasmonic optical fiber sensor. The sensor utilizes a tilted fiber Bragg grating (TFBG) written in standard single mode communication fiber. The fiber is over coated with an nm-scale film of silver that supports surface plasmon resonances (SPRs). Such a tilted grating SPR structure provides a high density of narrow spectral resonances (Q-factor about 105 ) that overlap with the broader absorption band of the surface plasmon waves in the silver film, thereby providing an accurate tool to measure small shifts of the plasmon resonance frequencies...
April 1, 2018: Biomedical Optics Express
Long Zhu, Andong Wang, Shi Chen, Jun Liu, Jian Wang
Mode-division multiplexing (MDM), which employs the spatial modes of light as information carriers, has been widely investigated to increase the transmission capacity. Few-mode fibers (FMFs) and multi-mode fibers (MMFs) have been used for MDM fiber transmission. One of the MDM techniques known as twisted light multiplexing using orbital angular momentum (OAM) modes has recently attracted increasing interest. In this Letter, by splicing two FMFs together with a conventional OM3 MMF, we propose and demonstrate OAM-based MDM in a heterogeneous fiber-optic network, i...
April 15, 2018: Optics Letters
Zhenzhen Zhang, Cheng Guo, Liang Cui, Qi Mo, Ningbo Zhao, Cheng Du, Xiaoying Li, Guifang Li
We experimentally demonstrate a 12-mode group (21 spatial mode) cladding-pumped few-mode erbium-doped fiber amplifier. The differential modal gain (DMG) is dramatically reduced by using the double cladding erbium-doped fiber (DC-EDF) with a refractive index trench structure, which helps to tightly confine all 21 spatial modes in the core and to mitigate the bending loss. Our experimental results show that the DMG gain is about 3 dB when the average signal modal gain for all 12 mode groups is up to 15 dB across the C-band...
April 1, 2018: Optics Letters
Hailong Zhou, Qiuchi Zhu, Wenhai Liang, Guangze Zhu, Yanyun Xue, Su Chen, Lei Shen, Mian Liu, Jianji Dong, Xinliang Zhang
Since few-mode fibers (FMFs) have great potential as the new transmission media for optical communications, the ability to distinguish different fiber modes is essential. Most of the traditional schemes do not yield phase information, or are limited by beam size and mechanical requirements. Here, a method is presented to analyze the mode distribution of FMFs. The fiber modes are mapped to different frequencies by using dynamic spatial phase masks. The complex amplitudes at these frequencies indicate the amplitudes and phases of the fiber modes...
April 1, 2018: Optics Letters
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