2012

• Record 349 of
  
  Title:Sideband-controllable mode-locking fiber laser based on chirped fiber Bragg gratings
  
  Author(s):Han, Dongdong(1); Liu, Xueming(1)
  Source: Optics Express  Volume: 20  Issue: 24  DOI: 10.1364/OE.20.027045  Published: November 19, 2012  
  Abstract:We have proposed a sideband-controllable fiber soliton laser by means of chirped fiber Bragg gratings (CFBGs). Each side of the spectral sidebands of laser could be removed by using a CFBG with proper dispersion. Numerical simulations have well reproduced the experimental observations. The numerical and experimental investigations show that the generation of the unilateral sidebands is attributed to the CFBG-induced spectral filtering effect. Our work provides an effective way to manage conventional solitons with spectral sidebands. © 2012 Optical Society of America.
  Accession Number: 20125015786481
• Record 350 of
  
  Title:Supercontinuum generation in standard single-mode fiber pumped by a nanosecond-pulse laser
  
  Author(s):Liu, X.M.(1); Wang, L.R.(1); Mao, D.(1); Duan, L.N.(1)
  Source: Laser Physics  Volume: 22  Issue: 1  DOI: 10.1134/S1054660X11230113  Published: January 2012  
  Abstract:We have experimentally investigated supercontinuum generation in a conventional single-mode fiber pumped with a nanosecond pulse source. The experimental results show that, when pump power increases, the spectral flatness is improved obviously and the spectral broadening only occurs in a red-shifted radiation rather than a blue-shifted radiation. A supercontinuum source is experimentally reported with a flatness of 4.7 dB over 180 nm (ranging from 1555 to >1735 nm) at pump power P R = 5 W and is predicted to have the flatness of less than 1 dB at P R > 8 W. The cascade of stimulated Raman scattering (SRS) together with soliton fission plays the key roles in supercontinuum generation. © 2012 Pleiades Publishing, Ltd.
  Accession Number: 20120614751367
• Record 351 of
  
  Title:Dispersion control in fiber-coupled THz-TDS
  
  Author(s):Liu, Jia(1); Fan, Wenhui(1); Xue, Bing(1)
  Source: Optik  Volume: 123  Issue: 24  DOI: 10.1016/j.ijleo.2011.11.002  Published: December 2012  
  Abstract:To construct a compact THz-TDS system equipped with movable emitter and receiver heads, a specific fiber-delivery system is developed to deliver ultra-short pulses from Ti: sapphire laser through a single-mode fiber. Hence, how to manage the dispersion in fiber-delivery system efficiently becomes one of the most important issues to be solved. In this paper, the theoretical calculation of dispersion in fiber-delivery system was discussed initially. And also, a pair of gratings, which can generate negative group velocity dispersion (GVD), was introduced to compensate the positive dispersion in fiber. A minimum temporal width of pulse about 60 fs was measured at the end of the fiber-delivery system by optimizing the relative position of gratings. The experimental result agreed well to the theoretical calculation and demonstrated the advantages of the fiber-delivery system. © 2011 Elsevier GmbH.
  Accession Number: 20124315603715
• Record 352 of
  
  Title:Improvement of beam quality in the far-field of annular core optical fibers by realizing single-mode operation
  
  Author(s):Hui, Xiangyun(1); Duan, Kailiang(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 8419  Issue:   DOI: 10.1117/12.975961  Published: 2012  
  Abstract:We have improved the beam quality by realizing single-mode operation in the annular core optical fibers (ACF), and discuss the relations between single-mode and its design parameters. Moreover the effect of the thickness of the guiding section on the energy distribution in the far-field is analyzed. With proper parameters design, more than 99% of the annular light emitted from ACF could be centralized at a bright spot in the far-field. These results may provide a theoretical guidance for the design and application of ACF. © 2012 SPIE.
  Accession Number: 20131416168424
• Record 353 of
  
  Title:Q-switched mode-locking and dissipative soliton operations in a large-anomalous-dispersion fiber laser
  
  Author(s):Han, Dongdong(1); Yun, Ling(1)
  Source: Optical Engineering  Volume: 51  Issue: 4  DOI: 10.1117/1.OE.51.4.044201  Published: April 2012  
  Abstract:We have experimentally observed the Q-switched modelocking (QML) and dissipative soliton operations in the passively modelocked fiber laser operating in large-anomalous-dispersion regime. With the increase of pump power, the proposed fiber laser gradually evolves from continuous-wave to QML and finally to dissipative soliton operations. The transition state between QML and dissipative solitons has been observed. The experimental results suggest that the fiber laser based on the nonlinear polarization rotation technique exhibits Q-switching instabilities. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).
  Accession Number: 20140117165388
• Record 354 of
  
  Title:Plasmonic nanosensor based on Fano resonance in waveguide-coupled resonators
  
  Author(s):Lu, Hua(1); Liu, Xueming(1); Mao, Dong(1); Wang, Guoxi(1)
  Source: Optics Letters  Volume: 37  Issue: 18  DOI: 10.1364/OL.37.003780  Published: September 15, 2012  
  Abstract:We propose a plasmonic nanosensor based on Fano resonance in the strong-confinement metal-dielectric-metal waveguide side-coupled with a pair of nanoresonators. Due to the coherent interference of the splitting discrete and quasi-continuum modes, the reflection spectrum possesses a sharp asymmetric Fano resonance dip, which is dependent on the cavity-cavity phase and the refractive index change of the dielectric. The physical features contribute to a highly efficient plasmonic sensor for refractive index sensing. The nanosensor yields a sensitivity of ∼900 nm/ RIU and a figure of merit of ∼500, remarkable values compared with those of plasmonic sensors supported by perfect absorbers. © 2012 Optical Society of America.
  Accession Number: 20123815454165
• Record 355 of
  
  Title:Optimizing the phase-matching parameters of a BIBO crystal for ultrafast spontaneous parametric down conversion
  
  Author(s):Huo, Guang-Wen(1); Zhang, Tong-Yi(1); Wan, Ren-Gang(1); Zhang, Mei-Zhi(2); Cheng, Guang-Hua(1); Zhao, Wei(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 8333  Issue:   DOI: 10.1117/12.918955  Published: 2012  
  Abstract:We analyze and optimize the parameters of the Type I spontaneous parametric down-conversion (SPDC) process in BiB3O6 (BIBO) crystal directly from calculations. This can be used to construct a system to generate ultrafast entangled photon pairs, which play an important role in quantum communication, quantum positioning, and quantum clock synchronization. Our work on the problem makes it clear that the optimal phase matching orientation in the process of SPDC is a key mechanism in the BIBO crystal in a way that appears not to have been appreciated before. In the case of ω = 0.405 μm , the numerical results of the optimization parameters at room temperature ( 295 K ) are:θ = 152.00°,φ = 90°, and deff = 3.48 pm/V. Finally, we use a pair of 0.6 mm thick biaxial BIBO crystals to construct an ultrafast entangled photon source, where the crystals are stacked together perpendicularly and pumped by a 405 nm pulsed laser doubling from a Tsunami mode-locked Ti:sapphire laser. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).
  Accession Number: 20121014832676
• Record 356 of
  
  Title:Investigation on terahertz vibrational modes of crystalline benzoic acid
  
  Author(s):Yan, Hui(1); Fan, Wen-Hui(1); Zheng, Zhuan-Ping(1)
  Source: Optics Communications  Volume: 285  Issue: 6  DOI: 10.1016/j.optcom.2011.11.046  Published: March 15, 2012  
  Abstract:The characteristic absorption features of crystalline benzoic acid in 0.1-4.0 THz have been measured by terahertz time-domain spectroscopy experimentally. Three sharp and low-intensity peaks are observed in the lowest frequency range of 0.1-1.5 THz. In particular, the absorption peak at 0.63 THz is reported for the first time, to the best of our knowledge. Moreover, theoretical simulations have also been performed, and all measured terahertz absorption features are unambiguously assigned. Our calculations clearly show that the first three absorption features arise from translation motions of dimers held together by hydrogen bonds. © 2011 Elsevier B.V. All rights reserved.
  Accession Number: 20120314701898
• Record 357 of
  
  Title:Evolution of dual-wavelength fiber laser from continuous wave to soliton pulses
  
  Author(s):Yun, Ling(1); Han, Dongdong(1)
  Source: Optics Communications  Volume: 285  Issue: 24  DOI: 10.1016/j.optcom.2012.07.114  Published: November 1, 2012  
  Abstract:Evolution of dual-wavelength fiber laser from continuous wave to soliton pulses is investigated experimentally by using the nonlinear polarization rotation technique. With the increase of pump power, the proposed laser successively delivers the dual-wavelength continuous wave, the single-wavelength soliton pulses, and the dual-wavelength soliton pulses. The dual-wavelength laser operates at the central wavelengths of about 1533 and 1546 nm with the separation of ∼13 nm. The number of soliton pulses operating in the dual-wavelength state is much larger than that of the single-wavelength state, while the pulse intensity always keeps constant. Experimental results reveal that the dual-wavelength mode locking is determined by the combination of pump strength and the cavity filtering effect. © 2012 Elsevier B.V. All rights reserved.
  Accession Number: 20124315591115
• Record 358 of
  
  Title:Optimizing initial chirp for efficient femtosecond wavelength conversion in silicon waveguide by split-step Fourier method
  
  Author(s):Li, Xuefeng(1); Wang, Zhaolu(2); Liu, Hongjun(2)
  Source: Applied Mathematics and Computation  Volume: 218  Issue: 24  DOI: 10.1016/j.amc.2012.05.065  Published: August 15, 2012  
  Abstract:Based on solving numerically the generalized nonlinear Schrödinger (GNLS) equation by a split-step Fourier method, efficient femtosecond wavelength conversion in the telecommunication bands via four-wave mixing in silicon rib waveguide is numerically investigated by optimizing the initial chirp of the pump and signal pulses. It is shown that the relative narrower four-wave mixing spectra with the most of the energy remains in the central peak can be obtained by the use of appropriate negative chirp, and the conversion bandwidth greater than 500 nm and peak conversion efficiency of -1.6 dB can be obtained by using 200 fs pulses with a repetition rate of 40 GHz in a 3.2-mm-long silicon rib waveguide. © 2012 Elsevier Inc. All rights reserved.
  Accession Number: 20122915259147
• Record 359 of
  
  Title:Stability in a general coupled laser array
  
  Author(s):Zhou, Liang(1); Duan, Kailiang(1)
  Source: Optik  Volume: 123  Issue: 23  DOI: 10.1016/j.ijleo.2011.10.020  Published: December 2012  
  Abstract:For the first time we have presented a method to investigate the stability of quiescent state in a coupled laser array. By introducing tiny perturbation, stability of quiescent state can be known by investigating eigenvalues of coefficient matrix of the corresponding linear differential equations. Only when real parts of the eigenvalues were all negative or zero, the corresponding quiescent state is stable. Two tapes of coupled laser array with loop and linear topological structure were studied respectively. It was found that there were innumerable quiescent states and they could be divided into several types based on phase relation. Some types were stable and others were unstable. Topological structure affects the stability of quiescent state in a coupled laser array. © 2011 Elsevier GmbH.
  Accession Number: 20124215579875
• Record 360 of
  
  Title:Unidirectional excitation of surface plasmon polaritons in T-shaped waveguide with nanodisk resonator
  
  Author(s):Wang, Guoxi(1); Lu, Hua(1)
  Source: Optics Communications  Volume: 285  Issue: 21-22  DOI: 10.1016/j.optcom.2012.07.019  Published: October 1, 2012  
  Abstract:The unidirectional excitation of surface plasmon polaritons (SPPs) in a novel configuration is numerically investigated by the finite-difference time-domain method. It is found that the transmission varies periodically with the increase of distance between the nanodisk resonator and horizontal nanoslit, which can be interpreted by the interference theory. The operating wavelength of this structure can be tuned by altering the refractive index of the nanodisk resonator. This subwavelength-scale structure exhibits high transmission (∼58%) due to the constructive interference of the SPP modes, and thus can find important applications on the manipulation of SPP excitation in highly integrated optical circuits. © 2012 Elsevier B.V. All rights reserved.
  Accession Number: 20123615409678