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1550 nm

Ran Gao, Danfeng Lu, Jin Cheng, Zhi-Mei Qi
A real-time all-fiber anemometer based on laser-heated few-layer graphene in aligned graded-index fibers has been proposed and experimentally demonstrated. The proposed fiber-optic anemometer was composed of a pair of all-fiber collimators by using aligned graded-index fibers that was coated with the few-layer graphene. The few-layer graphene was heated through a heating light from a 532-nm laser, which changed the optical transmittance of signal light with the wavelength of 1550 nm. The wind speed can be measured through the transmission power of the signal light based on the wind cooling effects on the heated few-layer graphene, acting as a "hot-wire" anemometer...
July 15, 2017: Optics Letters
Ming-Sheng Lai, Chia-Chien Huang
We propose a polarization beam splitter (PBS) with a footprint of only 600 × 790 nm(2) operating at a wavelength of λ = 1550 nm, which is the smallest PBS ever demonstrated. This device uses CMOS-compatible materials, namely, silicon and silica. The present PBS comprises two Si waveguides with different geometrical aspect ratios adjoined side-by-side, which separates the transverse-electric (TE) and transverse-magnetic (TM) modes without relying on an additional coupling region. The designed PBS achieves a polarization extinction ratio of approximately 25 dB for both modes and insertion losses of approximately 0...
July 3, 2017: Scientific Reports
Hilal Gokalp
BACKGROUND: Striae distensae (SD) are a type of dermal scarring that is quite common and difficult to treat. Two forms are known: striae rubrae (SR) and striae albae (SA). OBJECTIVE: We evaluated and compared the long-term clinical effectiveness of SR and SA treatment using a 1550-nm non-ablative fractional laser (NAFL). MATERIALS AND METHODS: We included 16 female patients (8 with SR and 8 with SA) who had developed abdominal SD during pregnancy...
June 30, 2017: Journal of Cosmetic and Laser Therapy: Official Publication of the European Society for Laser Dermatology
Hongxin Zhang, Tianqing Jia, Long Chen, Yuchan Zhang, Shian Zhang, Donghai Feng, Zhenrong Sun, Jianrong Qiu
We report optical depletion of upconversion luminescence (UCL) in NaYF4:Yb(3+),Tm(3+) nanoparticles excited simultaneously by 980 nm and 1550 nm lasers. The UCL intensity is greatly depleted, while the downshifted emission at 1210 nm is obviously enhanced. The disturbances of 1550 nm photons on energy transfer between Yb(3+) and Tm(3+), cross relaxation (CR), the thermal effect and the stimulated emission depletion (STED) process are qualitatively evaluated. Our investigations verify that the unexpected depletion phenomena are governed by the STED process...
July 21, 2017: Physical Chemistry Chemical Physics: PCCP
Chao Mei, Feng Li, Jinhui Yuan, Zhe Kang, Xianting Zhang, Binbin Yan, Xinzhu Sang, Qiang Wu, Xian Zhou, Kangping Zhong, Liang Wang, Kuiru Wang, Chongxiu Yu, P K A Wai
Parabolic pulses have important applications in both basic and applied sciences, such as high power optical amplification, optical communications, all-optical signal processing, etc. The generation of parabolic similaritons in tapered hydrogenated amorphous silicon photonic wires at telecom (λ ~ 1550 nm) and mid-IR (λ ≥ 2100 nm) wavelengths is demonstrated and analyzed. The self-similar theory of parabolic pulse generation in passive waveguides with increasing nonlinearity is presented. A generalized nonlinear Schrödinger equation is used to describe the coupled dynamics of optical field in the tapered hydrogenated amorphous silicon photonic wires with either decreasing dispersion or increasing nonlinearity...
June 19, 2017: Scientific Reports
Hyeongrak Choi, Mikkel Heuck, Dirk Englund
We propose a photonic crystal nanocavity design with self-similar electromagnetic boundary conditions, achieving ultrasmall mode volume (V_{eff}). The electric energy density of a cavity mode can be maximized in the air or dielectric region, depending on the choice of boundary conditions. We illustrate the design concept with a silicon-air one-dimensional photon crystal cavity that reaches an ultrasmall mode volume of V_{eff}∼7.01×10^{-5}λ^{3} at λ∼1550  nm. We show that the extreme light concentration in our design can enable ultrastrong Kerr nonlinearities, even at the single-photon level...
June 2, 2017: Physical Review Letters
Krishna C Balram, Marcelo I Davanço, B Robert Ilic, Ji-Hoon Kyhm, Jin Dong Song, Kartik Srinivasan
Acoustic wave devices provide a promising chip-scale platform for efficiently coupling radio frequency (RF) and optical fields. Here, we use an integrated piezo-optomechanical circuit platform that exploits both the piezoelectric and photoelastic coupling mechanisms to link 2.4 GHz RF waves to 194 THz (1550 nm) optical waves, through coupling to propagating and localized 2.4 GHz acoustic waves. We demonstrate acousto-optic modulation, resonant in both the optical and mechanical domains, in which waveforms encoded on the RF carrier are mapped to the optical field...
February 2017: Physical Review Applied
Hidetaka Terasawa, Freddy Tan, Okihiro Sugihara, Akari Kawasaki, Daisuke Inoue, Tatsuya Yamashita, Manabu Kagami, Olivier Maury, Yann Bretonnière, Chantal Andraud
Light-induced self-written (LISW) optical waveguides were fabricated for the first time, to the best of our knowledge, using a photopolymerizable resin system formed by 1550 nm pulse laser light. A two-photon absorption (TPA) chromophore with a TPA cross section of several hundred Goeppert-Mayer (GM) at 1550 nm was used. Furthermore, the optical interconnection between a single-mode fiber and a fiber Bragg grating was demonstrated by the present technique, using one-way irradiation of 1550 nm laser light through the single-mode fiber...
June 1, 2017: Optics Letters
Florian Denis-le Coarer, Ana Quirce, Ángel Valle, Luis Pesquera, Marc Sciamanna, Hugo Thienpont, Krassimir Panajotov
We report an experimental study of the polarization nonlinear dynamics in a 1550 nm single-mode vertical-cavity surface-emitting laser (VCSEL) subject to parallel optical injection. Experimentally measured stability maps identifying regions of different nonlinear dynamics for various values of bias current are reported. We show that VCSELs with more than a 35 dB polarization mode suppression ratio can have rich nonlinear dynamics in both linear polarizations, including periodic and chaotic behaviors appearing simultaneously in both polarization modes...
June 1, 2017: Optics Letters
Parinaz Aleahmad, Mercedeh Khajavikhan, Demetrios Christodoulides, Patrick LiKamWa
On-chip photonic networks hold great promise for enabling next-generation high speed computation and communication systems. It is currently envisioned that future integrated photonic networks will be capable of processing dense digital information on a single monolithic platform by involving a multitude of optical components ranging from lasers to modulators, to routers, interconnects and detectors. Among the possible functionalities to be incorporated in such arrangements is the ability to route information in a unidirectional way among N-ports - a capability typically afforded through the use of optical circulators...
May 18, 2017: Scientific Reports
Reza Khazaeinezhad, Meena Siddiqui, Benjamin J Vakoc
We demonstrate a novel high-speed and broadband laser architecture based on stretched pulse active mode locking that provides a wavelength-swept and wavelength-stepped output. The laser utilizes a single intracavity 8.3 meter chirped fiber Bragg grating to generate positive and negative dispersion, and can be operated with or without an intracavity fixed Fabry-Perot etalon to generate wavelength-swept and wavelength-stepped (frequency comb) outputs, respectively. Using a four-path delay line at the output, we achieved 16...
May 15, 2017: Optics Letters
Honghui Sun, Tian Jiang, Yunyi Zang, Xin Zheng, Yan Gong, Yong Yan, Zhongjie Xu, Yu Liu, Liang Fang, Xiang'ai Cheng, Ke He
Topological insulators (TIs) are new states of quantum matter in which the spin-momentum-locked surface states reside in the bulk insulating gap and have triggered extensive investigations on fundamental properties and potential applications. Herein, we report scalable, broadband photovoltaic detectors based on the topological insulator Sb2Te3/strontium titanate (STO) heterostructure. Large-scale (2 mm × 5 mm), high crystalline quality p-type Sb2Te3 films were fabricated on an n-type STO substrate by the molecular beam epitaxy (MBE) method...
July 13, 2017: Nanoscale
Lijun Huang, Hai Yan, Xiaochuan Xu, Swapnajit Chakravarty, Naimei Tang, Huiping Tian, Ray T Chen
Compared to the conventional strip waveguide microring resonators, subwavelength grating (SWG) waveguide microring resonators have better sensitivity and lower detection limit due to the enhanced photon-analyte interaction. As sensors, especially biosensors, are usually used in absorptive ambient environment, it is very challenging to further improve the detection limit of the SWG ring resonator by simply increasing the sensitivity. The high sensitivity resulted from larger mode-analyte overlap also brings significant absorption loss, which deteriorates the quality factor of the resonator...
May 1, 2017: Optics Express
Shen Xiang, Hu Xiongwei, Yang Luyun, Dai Nengli, Wu Jianjun, Zhang Fangfang, Peng Jingang, Li Haiqing, Li Jinyan
We have demonstrated a helical long-period grating (HLPG) manufactured from multicore fiber (MCF) combined with twist and CO<sub>2</sub>-laser heating technology. The MCF we used behaves as a kind of single mode fiber. The nineteen cores of MCF are distributed hexagonally which make the helical structure only exist in core area after heating and twisting. There are several strong couplings between the core and cladding modes at different wavelengths when the grating pitch was 900 µm. The extinction ratio of the main coupling reached 20 dB at 1550 nm...
May 1, 2017: Optics Express
Christoph A Riedel, Kai Sun, Otto L Muskens, C H de Groot
The interest in plasmonic electro-optical modulators with nanoscale footprint and ultrafast low-energy performance has generated a demand for precise multiphysics modeling of the electrical and optical properties of plasmonic nanostructures. We perform combined simulations that account for the interaction of highly confined nearfields with charge accumulation and depletion on the nanoscale. Validation of our numerical model is done by comparison to a recently published reflective meta-absorber. The simulations show excellent agreement to the experimental mid-infrared data...
May 1, 2017: Optics Express
Riccardo Marchetti, Valerio Vitali, Cosimo Lacava, Ilaria Cristiani, Benoit Charbonnier, Viviane Muffato, Maryse Fournier, Paolo Minzioni
We report on the experimental characterization, in the telecom C-band, of group-velocity dispersion (D) in 100-nm high rectangular strip waveguides realized by silicon-on-insulator technology. We compare the experimental results with numerical predictions, showing that 100-nm high waveguides exhibit normal dispersion and that the absolute value of the dispersion coefficient D decreases as the waveguide width is increased. D at 1550 nm varies from -8130 to -3900 ps/(nm·km) by increasing the waveguide width from 500 to 800 nm...
May 1, 2017: Optics Express
Yongsoo Lee, Wooram Kim
The application of laser treatments beginning on the day of stitch removal has been demonstrated to improve scar quality. However, there are few guidelines for the treatment of immature scars (ISs), which are defined as "scars whose features are not yet expressed." The purpose of this study was to extract information about early combination laser treatment (CLT) beyond what is currently known by analyzing 33 pairs of pre-treatment and post-treatment photographs of ISs. Two hundred fifty medical records of patients with scars were reviewed, and 33 scars were included in the study...
May 2, 2017: Lasers in Medical Science
O A Lukianova, V Yu Novikov, A A Parkhomenko, V V Sirota, V V Krasilnikov
The microstructure and phase composition of the high-content Al2O3-Y2O3-doped spark plasma-sintered silicon nitride were investigated. Fully dense silicon nitride ceramics with a typical α-Si3N4 equiaxed structure with average grain size from 200 to 530 nm, high elastic modulus of 288 GPa, and high hardness of 2038 HV were spark plasma sintered (SPSed) at 1550 °C. Silicon nitride with elongated β-Si3N4 grains, higher hardness of 1800 HV, density of 3.25 g/cm(3), and Young's modulus 300 GPa SPSed at 1650 °C was also reviewed...
December 2017: Nanoscale Research Letters
M A Eftekhar, L G Wright, M S Mills, M Kolesik, R Amezcua Correa, F W Wise, D N Christodoulides
We demonstrate that the pump's spatial input profile can provide additional degrees of freedom in tailoring at will the nonlinear dynamics and the ensuing spectral content of supercontinuum generation in highly multimoded optical fibers. Experiments and simulations carried out at 1550 nm indicate that the modal composition of the input beam can substantially alter the soliton fission process as well as the resulting Raman and dispersive wave generation that eventually lead to supercontinuum in such a multimode environment...
April 17, 2017: Optics Express
Kazuki Yasuhara, Feng Yu, Takaaki Ishigure
We fabricate low-loss single-mode (SM) polymer optical waveguides using a photomask-free simple technique named the Mosquito method. The insertion losses of a 5-cm long SM polymer waveguide fabricated are 2.52 dB and 4.03 dB at 1310- and 1550-nm wavelengths, respectively. The coupling loss between a single-mode fiber and the waveguide is as low as 0.5 dB including the Fresnel reflection. The 0.5-dB misalignment tolerance in the radial direction is ± 2.0 μm at 1550 nm. The Mosquito method is promising for fabricating SM polymer optical waveguides compatible with silicon photonics chips...
April 17, 2017: Optics Express
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