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photonic crystal fiber

Takeshi Fujisawa, Kunimasa Saitoh
The transmission characteristics of helically twisted photonic crystal fibers (PCFs) having off-axis cores are theoretically investigated for the first time, to the best of our knowledge. Due to the modified equivalent permittivity and permeability tensors induced by helical twisting, the transmission characteristics of helically twisted PCFs depend on the core position. A beam propagation method developed for helically twisted waveguides, which qualitatively and quantitatively explained the reported transmission spectra of helically twisted PCFs, is used for the analysis...
October 15, 2018: Optics Letters
Sigang Yang, Yi Yang, Jinyan Li, Siming Ding, Hongwei Chen, Minghua Chen, Shizhong Xie
An opto-electronic oscillator based on guided acoustic wave Brillouin scattering in a photonic crystal fiber (PCF) stimulated by a light wave in 1 μm band is proposed and demonstrated. A short length of a homemade PCF stimulated by relatively low pump power leads to strong coupling between the pump and probe waves. The oscillation is realized in a feedback loop, in which the acoustic wave bridges the pump and probe. Oscillation is achieved at 1.237 GHz, which matches the resonance of the acoustic mode, in a single-longitudinal-mode operation of the hybrid cavity...
October 15, 2018: Optics Letters
Xin Yan, Bin Li, Tonglei Cheng, Shuguang Li
A photonic crystal fiber (PCF) sensor based on gold nanowires able to detect changes in surface plasmon resonance (SPR) was proposed and numerically investigated through the finite element method. To facilitate real-time detection, the analyte in this sensor was located outside the optical fiber. The effects of diameters of both air hole and gold wires on the sensing characteristics of the sensor were discussed. The sensor was designed to detect liquids with refractive indexes ranging between 1.33 and 1.36...
September 3, 2018: Sensors
A'Lester C Allen, Jaione Romero-Mangado, Staci Adams, Michael Flynn, Bin Chen, Jin Z Zhang
The Synthetic Biological Membrane (SBM) project at NASA Ames developed a portable, self-repairing wastewater purification system. The self-repair process relies upon secreted fatty acids from a genetically engineered organism. However, solubilized fatty acids are difficult to detect using conventional methods. Surface-enhanced Raman scattering (SERS) was used to successfully detect solubilized fatty acids with the following limits of detection: 10-9 , 10-8 , 10-9 , and 10-6 M for decanoic acid, myristic acid, palmitic acid, and stearic acid, respectively...
September 6, 2018: Journal of Physical Chemistry. B
S Upendar, I Allayarov, M A Schmidt, T Weiss
We adapt the resonant state expansion to optical fibers such as capillary and photonic crystal fibers. As a key requirement of the resonant state expansion and any related perturbative approach, we derive the correct analytical normalization for all modes of these fiber structures, including leaky modes that radiate energy perpendicular to the direction of propagation and have fields that grow with distance from the fiber core. Based on the normalized fiber modes, an eigenvalue equation is derived that allows for calculating the influence of small and large perturbations such as structural disorder on the guiding properties...
August 20, 2018: Optics Express
Tao Wu, Kun Chen, Huijie Zhao, Weipeng Zhang, Yan Li, Haoyun Wei
Though dual soliton is used as the Stokes source in coherent anti-Stokes Raman scattering (CARS) experiments, the mechanism behind it is still not fully investigated. In this paper, dual-soliton pulses generation with a highly birefringent photonic crystal fiber (PCF) is numerically explored and experimentally verified. The simulated pulse exhibits various characteristics in the temporal and spectral domains with respect to the input linear polarization angle, and can be classified into four regions based on distances in the temporal and spectral domain of the soliton pair...
August 20, 2018: Optics Express
Tomasz Stefaniuk, Grzegorz Stępniewski, Dariusz Pysz, Ryszard Stępień, Ryszard Buczyński
We report on modeling, development, and optical characterization of fused silica photonic crystal fiber with germanium doped microinclusion placed in the middle of the core. The fiber is designed to efficiently couple and guide LP02 mode. It offers high optical density in the center region, large mode separation, low losses, and small dispersion with relatively flat profile for both LP01 and LP02 modes in 1-1.6 µm wavelength range. We demonstrate that by changing geometrical and material parameters of the inclusion partially independent tuning of propagation constants of individual modes is possible, what might be found is a variety of potential applications, e...
August 20, 2018: Optics Express
Michał Nikodem, Karol Krzempek, Grzegorz Dudzik, Krzysztof Abramski
A laser-based spectrometer exploiting a novel Kagome-type hollow core photonic crystal fiber, which serves as a gas cell is demonstrated. Low attenuation of this silica-based fiber in the 3.4 µm wavelength region enables accessing strong, fundamental transitions of methane, which was used as a target analyte in the presented experiment. With an all-fiber differential frequency generation source combined with wavelength modulation spectroscopy technique detection limit at single parts-per-million by volume level was obtained...
August 20, 2018: Optics Express
Daquan Yang, Xin Chen, Xuan Zhang, Chuwen Lan, Ying Zhang
We present the design of simultaneous high-quality (Q)-factor and high-sensitivity (S) photonic crystal nanofiber cavities (PCNFCs) made of single silica nanofiber that have a low-index contrast (ratio=1.45). By using the three-dimensional finite-difference time-domain method, two different resonant modes, dielectric mode (DM) and air mode (AM), are designed and optimized to achieve an ultrahigh figure of merit (FOM), respectively. Numerical simulations are performed to study the Q-factors and sensitivities of the proposed PCNFCs...
August 20, 2018: Applied Optics
A'Lester C Allen, Jaione Romero-Mangado, Staci Adams, Michael Flynn, Bin Chen, Jin Z Zhang
The Synthetic Biological Membrane (SBM) project at NASA Ames developed a portable, self-repairing wastewater purification system. The self-repair process relies upon secreted fatty acids from a genetically engineered organism. However, solubilized fatty acids are difficult to detect using conventional methods. Surface-enhanced Raman scattering (SERS) was used to successfully detect solubilized fatty acids with the following limits of detection: 10-9 M, 10-8 M, 10-9 M, and 10-6 M for decanoic acid, myristic acid, palmitic acid, and stearic acid, respectively...
August 20, 2018: Journal of Physical Chemistry. A
Tianyu Yang, Can Ding, Richard W Ziolkowski, Y Jay Guo
-A novel photonic crystal fiber (PCF) design that yields very high birefringence is proposed and analyzed. Its significantly enhanced birefringence is achieved by filling selected air holes in the cladding with an epsilon-near-zero (ENZ) material. Extensive simulation results of this asymmetric material distribution in the lower THz range demonstrate that the reported PCF has a birefringence above 0.1 and a loss below 0.01 cm-1 over a wide band of frequencies. Moreover, it exhibits near zero dispersion at 0...
June 25, 2018: Optics Express
Benjamin G Ward
A finite element steady periodic scalar beam propagation method suited to treating mode instability in amplifiers incorporating fibers with complicated design features is presented and demonstrated on test cases. These incorporate large pitch photonic crystal fibers with confined and down-doped cores in co-pumped and counter-pumped configurations. Seed power fluctuations and slight launch misalignment are proposed and implemented as a noise source to seed the instability. Down doping the confined core by -7...
June 25, 2018: Optics Express
XingTao Zhao, Jirui Cheng, Qiang Xiong, Lu Hua, Guohui Jiang
To study the four-wave mixing (FWM) effect and wavelength conversion in a hollow core bandgap photonic crystal fiber filled with Ar, we conducted an experiment using a femtosecond laser with the pulse width of 120 fs, a repetition rate of 76 MHz, and tunable central wavelength from 760 to 980 nm. It is observed that new spectra are generated in both sides of the pump at a special wavelength, which can exactly satisfy the phase matching conditions of FWM. Combining experimental results with theoretical analysis, we find that the experimental phenomenon is mainly caused by FWM, and some other nonlinear phase effects, such as self-phase modulation, stimulated Raman scattering, and the soliton effect, have also occurred in this nonlinear process...
July 10, 2018: Applied Optics
Masatoshi Mitaki, Kazuhiko Sugiyama, Masao Kitano
We developed an optical frequency comb based on a Yb:KYW laser. Soft-aperture Kerr-lens mode-locking at the cavity transverse-mode degeneration enabled us to generate 360 mW from a 750 mW pump laser diode. This resulted in spectral broadening over one octave using just a photonic crystal fiber. We achieved a free-running linewidth of 15 kHz in the carrier-envelope offset frequency by optimizing the cavity group delay dispersion, crystal position, and pump laser power, which led to a residual phase noise of 0...
June 20, 2018: Applied Optics
Kun Zhao, Bo Zhang, Di Feng, Ningfang Song
A smooth end face is the critical factor for the application of photonic crystal fiber (PCF) to enhance coupling efficiency. A number of air holes distributed on the cladding make the surface a discontinuous structure. For the sake of acquiring a high-quality end surface of PCF, this paper proposes a detailed study first on dynamics simulation of the grinding process of PCF using a finite element model with a verification experiment later. To facilitate the calculation, the grinding is simplified as a single grain to cut the material on the location between two holes...
June 20, 2018: Applied Optics
Min Liu, Hongtao Yuan, Ping Shum, Cong Shao, Haonan Han, Lihua Chu
A novel photonic crystal fiber (PCF) with an elliptical tellurite core is proposed to realize high birefringence and high nonlinearity simultaneously as well as low confinement loss at the wavelength of 1.55 μm. The guiding properties, such as the birefringence, the nonlinearity, and the confinement loss, have been investigated by using the full vectorial finite element method. The results show that the birefringence and the nonlinear coefficient can be up to 7.57×10-2 and 188.39  W-1  Km-1 , respectively, and the confinement loss can be only 10-9   dB/m...
August 1, 2018: Applied Optics
Junjie Lu, Yan Li, Yanhua Han, Yi Liu, Jianmin Gao
In this work, we proposed a high-resolution D-shaped photonic crystal fiber (PCF) surface plasmon resonance (SPR) sensor based on gold grating. Gold grating is introduced to modulate the resonance wavelength and enhance the refractive index (RI) sensitivity. Structure parameters of PCF and gold grating are analyzed by the finite element method for optimizing the SPR sensor. The simulation results indicate that air hole pitch, air hole diameter, and gold thickness and grating constant have little influence on the sensitivity of the refractive index, which reduces the requirement of precise processing...
July 1, 2018: Applied Optics
Nicola Coluccelli, Edoardo Vicentini, Alessio Gambetta, Christopher R Howle, Kenneth Mcewan, Paolo Laporta, Gianluca Galzerano
We demonstrate a Fourier transform (FT) coherent anti-Stokes Raman scattering (CARS) spectroscopy system based on fiber technology with ultra-broad spectral coverage and high-sensitivity. A femtosecond ytterbium fiber oscillator is amplified and spectrally broadened in a photonic crystal fiber to synthesize pulses with energy of 14 nJ at 1040 nm, that are compressed to durations below 20 fs. The resulting pulse train is coupled to a FT-CARS interferometer enabling measurement of high-quality CARS spectra with Raman shifts of ~3000 cm-1 and signal to noise ratio up to 240 and 690 with acetonitrile and polystyrene samples, respectively, for observation times of 160 µs; a detection limit of one part per thousand is demonstrated with a cyanide/water solution...
July 23, 2018: Optics Express
Sida Xing, Svyatoslav Kharitonov, Jianqi Hu, Camille-Sophie Brès
We demonstrate all-normal dispersion supercontinuum generation in chalcogenide photonic crystal fibers pumped at 2070-2080 nm with a femtosecond fiber laser. At 2.9 kW peak power, the generated supercontinuum has a 3 dB bandwidth of 27.6 THz and -20 dB bandwidth of 75.5 THz. We experimentally investigated the supercontinuum evolution inside our sample fiber at various peak powers and fiber lengths and study the impact of fiber water absorption on the generated supercontinuum spectrum. Multiple tests with fiber length- ranging from 0...
July 23, 2018: Optics Express
Yuya Furukado, Hiroshi Abe, Yosuke Hinakura, Toshihiko Baba
Time of flight light detection and ranging (LiDAR) has been tested and used as a key device for auto-driving of vehicles. Frequency-modulated continuous-wave (FMCW) LiDAR potentially achieves a high sensitivity. In this study, we fabricated and tested two components of FMCW LiDAR based on Si photonics. The ranging action was also experimentally simulated. A Si photonic crystal slow light Mach-Zehnder modulator was driven by linearly frequency-chirped signals to generate quasi-frequency-modulated signal light...
July 9, 2018: Optics Express
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