Y.X. Xia

Shanghai Jiao Tong University, Shanghai, Shanghai Shi, China

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Publications (30)63.27 Total impact

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    ABSTRACT: We propose and experimentally demonstrate the propagation of slow/fast light in an erbium-doped fiber (EDF) using mutually modulated cross-gain modulation. The group velocity of the light signal can be manipulated by the effect of gain cross-saturation modulation by a saturating light at an arbitrary wavelength in the gain bandwidth of the EDF. The ultraslow propagation with a small group velocity of 5.6 × 10⁻³c (c is the light speed in free space) and superluminal propagation with a negative group velocity of -1.1 × 10⁻³c has been observed under different modulation phases.
    Optics Letters 06/2011; 36(12):2185-7. · 3.39 Impact Factor
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    ABSTRACT: The supercontinuum generation has been obtained in short conventional dispersion-shifted fiber using the femtosecond pulses from a passively mode-locked erbium-doped fiber laser. In the experiment, the supercontinuum spectrum of >300 nm has been observed by injecting 70-fs pulses into a several-meter dispersion-shifted fiber. The simulation of the evolution in the fiber shows that spectral broadening arises from soliton dynamics when pumping using femtosecond pulses in the anomalous group velocity dispersion regime of the fiber.
    Laser Physics 06/2010; 20(6):1459-1462. · 2.55 Impact Factor
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    ABSTRACT: A period-chirped long-period fiber grating (CLPFG), using ordinary multi-mode fiber (MMF), for broadband mode conversion (60 nm bandwidth of coupling efficiency >90%) has been proposed. Through using such a MMF-CLPFG, a broad-spectrum pulse can be converted into LP 02 for femtosecond pulse distortion-free delivery in MMF. The simulation shows that the pulse suffers less nonlinear distortion than that in a single-mode fiber. In addition, the negative pre-chirp introduced by MMF-CLPFG can offset the linear and positive SPM-induced frequency chirp and thus compress the pulse. Using this scheme, an initial 18 kW peak power 75 fs pulse distortion-free delivery in MMF has been numerically demonstrated.
    Journal of Modern Optics 03/2010; 57(6):485-491. · 1.16 Impact Factor
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    ABSTRACT: We experimentally demonstrate a simple-structure but efficient multiwavelength erbium-doped fiber laser based on nonlinear polarization rotation assisted by four-wave-mixing (FWM). Based on the com-bination of these two nonlinear mechanisms contributing to intensity-dependent loss to alleviate mode competition, the stable multiwavelength operation at room temperature can be realized in a length of dispersion-shifted fiber. We achieved up to 38-wavelength generation with a spacing of $0.4 nm in the laser. In addition, through tuning the birefringence fiber filter, the lasing wavelength can be accu-rately tuned in the free spectrum range.
    Optics Communications 01/2009; 282(14). · 1.44 Impact Factor
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    ABSTRACT: We propose and demonstrate a novel switchable multiwavelength erbium-doped fiber laser with a overlapping linear cavity, which is formed by a dual-section Lyot–Sagnac filter and three fiber Bragg gratings (FBGs). Taking advantage of the high extinction of the Lyot–Sagnac filter, independent controlling of the different wavelength losses and the spatial hole burning in the overlapping linear cavities, with this structure we realize stable switchable multiwavelength laser emission at room temperature. An output signal to background noise ratio of 43 dB and less than 3 dB fluctuation on output power were observed for all wavelength switching cases.
    Journal of Modern Optics 01/2009; 56:145-148. · 1.16 Impact Factor
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    ABSTRACT: We demonstrated a high-power single-longitudinal-mode (SLM) all-fiber laser. In the cavity, a fiber Bragg grating is used to select the appropriate wavelength at 1565 nm, and a fiber ring is incorporated to act as a Fabry-Perot resonator, which greatly reduces the longitudinal-mode density. Meanwhile, an unpumped erbium-doped fiber serves as a saturable absorber to ensure the SLM operation. Finally, a high-power SLM fiber laser producing as high as 867-mW output power has been experimentally demonstrated.
    IEEE Photonics Technology Letters 07/2008; · 2.04 Impact Factor
  • X. X. Yang, L. Zhan, Y. X Xia
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    ABSTRACT: We have demonstrated a simple method to achieve a high-power single-longitudinal-mode all-fiber ring laser by employing two Sagnac loop filters. In the ring cavity, a high-birefringence Sagnac loop filter is incorporated to limit the affiliated longitudinal modes, and another Sagnac loop filter with unpumped erbium-doped fiber serves as a saturable absorber to ensure single-longitudinal-mode operation. Using such a simple configuration, a single-longitudinal-mode fiber laser with scalable output power of 360mW has been demonstrated.
    Optical Engineering 06/2008; 47(6):065001. · 0.88 Impact Factor
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    ABSTRACT: In this paper, we demonstrate a new architecture of a self-seeded multiwavelength Brillouin-erbium laser by using a nonlinear optical-loop mirror and a nonlinear amplifying-loop mirror (NOLM-NALM). A stable operation of 61 Brillouin-Stokes lines with a 0.08-nm spacing was obtained and the laser exhibited satisfied the flatness of the output spectrum with a low-threshold pump power. It is shown that the four-wave mixing (FWM) contributes to the generation of high-order Brillouin-Stokes and anti-Stokes and, consequently, results in the increase of the Stokes number and the reduction of its peak power.
    Laser Physics 04/2008; 18(4):442-445. · 2.55 Impact Factor
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    ABSTRACT: We have demonstrated a tunable multiwavelength self-seeded Brillouin-erbium fiber laser (BEFL) without externally Brillouin pumping. In this scheme, the stable multiwavelength comb can be produced within a ∼45-nm wavelength tuning range through adjusting the polarization controllers (PCs) in a high-birefringent Sagnac loop mirror. The generation of ∼200-line Stokes comb has been achieved by adjusting PCs under bidirectional pumping of two laser diodes, which is the largest wavelength number to the best of our knowledge. The effect of 980 nm pump power on the multiwavelength generation was also investigated.
    Optics Communications 02/2008; 281(3):452–456. · 1.44 Impact Factor
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    ABSTRACT: We have built a complete Raman detection system for multi-trace-gas diagnosis, which is suitable for analyzing the dissolved gases in electric power system. In the system, a high-sensitivity CCD device connected to a spectrometer is used as the detection unit of the Raman system. A near-confocal cavity is used for improving the detection sensitivity of the system. In the effective spectral range of about 570–710nm, Raman spectra of eight typical gases are achieved by using this Raman system. The detection limits for different gases have been obtained: 126ppm for CO2, 21ppm for CH4, 63ppm for C2H4, 42ppm for C2H2, 96.6ppm for H2. The detectability of the system satisfies the requirements of gas diagnosis in power transformer.
    Applied Physics B 01/2008; 93(2):665-669. · 1.78 Impact Factor
  • Z. Y. Fan, L. Zhan, X. Hu, Y. X. Xia
    Optics Communications 01/2008; 281:5467–5471. · 1.44 Impact Factor
  • N. Yu, L. Zhan, L. Xing, S.Y. Luo, Y.X. Xia
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    ABSTRACT: In this paper, we propose and demonstrate a new wavelength-switchable fiber laser with all-optical controlling. By adjusting the power of injected light in a cascaded fiber Bragg grating overlapping cavity erbium-doped fiber laser, we obtained the switching among dual wavelength, single wavelength and zero wavelength. Meanwhile, the effect of optical injection in erbium-doped fiber laser was investigated, and the optimized wavelength to control the lasing wavelength has been found. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    Laser Physics Letters 11/2007; 5(3):206 - 209. · 7.71 Impact Factor
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    ABSTRACT: A simple method to precisely measure fiber length has been experimentally demonstrated by using a mode-locked fiber laser configuration. Since the transit time in a cavity is exactly proportional to the cavity length, it is easy to obtain the fiber length from the generation of mode-locked pulses in the fiber laser with a long-range nonlinear optical loop mirror that includes the measured fiber. Our new method has a large measurement range, over hundreds of kilometers, and a high resolution, of the order of centimeters, as well as no measurement dead zone.
    Optics Letters 07/2007; 32(12):1605-7. · 3.39 Impact Factor
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    ABSTRACT: Passive harmonically mode-locked fiber ring laser with scalable repetition rate up to 1.2 GHz has been experimentally demonstrated. Two types of stabilization mechanisms for passive harmonic mode-locking are identified at different repetition rates. Through investigating the dynamics of pulse generation, it is found that a new operation mode, harmonic modelocking of multipulse bunching, favors higher order harmonic. The supermode suppression rates of harmonically mode-locked pulse trains at 439 MHz and 1.145 GHz are 40 dB and 30 dB, respectively.
    Laser Physics Letters 02/2007; 4(8):592 - 596. · 7.71 Impact Factor
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    ABSTRACT: We propose a sub-wavelength structured metal film with two sets of grooves with different periods. It can enhance the second harmonic generation (SHG) based on phase-matching. Meanwhile, we reduce the thickness of metal film to excite long-range surface plasma wave for improving the interaction length of SHG. The numerical study shows that this structure greatly improves the conversion efficiency of SHG for about 106 times, and that the SHG light is emitted in a direction perpendicular to the metal surface. This new type of structure could contribute to high conversion efficiency of SHG for the virtues of low loss and extremely compact structure.
    Optics Communications 01/2007; · 1.44 Impact Factor
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    L Zhan, J H Ji, J Xia, S Y Luo, Y X Xia
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    ABSTRACT: We have demonstrated a novel multiwavelength Brillouin-erbium fiber laser (BEFL), in which the Brillouin pump is self-excited within the linear cavity, instead of the injection from the external cavity or direct generation in the intracavity. By using this simple scheme, the generation of more than 160 Brillouin Stokes lines has been experimentally demonstrated, which is the largest one achieved in BEFLs to the best of our knowledge. Also, the single longitudinal mode operation and the low noise performance of output wavelength line have been confirmed. Meanwhile, the experiment demonstrates that the BEFL performs good stability on both the operating wavelengths and the output power of each wavelength.
    Optics Express 11/2006; 14(22):10233-8. · 3.55 Impact Factor
  • Z. X. Zhang, L. Zhan, Y. X. Xia
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    ABSTRACT: Multiwavelength comb generation in an all-fiber self-starting passively mode-locked figure-eight erbium-doped fiber laser is experimentally demonstrated. The nonlinear optical-loop mirror (NOLM) consisting of a symmetrical optical coupler and a length of single-mode fiber can act as the mode-locking element through nonlinear polarization rotation. The linear ring with a section of polarization-maintenance fiber and a polarization-dependent isolator can implement linear filtering. Such a self-starting passively mode-locked erbium-doped fiber laser can generate pulses with multiwavelength comb, which is characteristic of all-fiber and simple configuration. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1356–1358, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21659
    Microwave and Optical Technology Letters 04/2006; 48(7):1356 - 1358. · 0.59 Impact Factor
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    ABSTRACT: We proposed and demonstrated a new configuration of the low noise figure C+L- band erbium- doped fiber amplifier. In the configuration, a preamplifier is used to reduce the noise figure, and an improved double-pass configuration with a fiber Bragg grating was employed to enhance the L-band gain and while to reduce the noise figure. The experiment demonstrated that the noise figure in the new broad-band amplifier was improved by ~2 dB, and the gain was enhanced up to above 25dB over the region from 1525 to 1605nm.
    Proc SPIE 11/2005;
  • Z. X. Zhang, L. Zhan, Y. X. Xia
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    ABSTRACT: An all-fiber passively Q-switched erbium fiber ring laser with nonlinear polarization rotation is experimentally demonstrated. By incorporating a length of single mode fiber and polarization dependent isolator into the erbium fiber ring laser, intensity dependent transmission can be implemented due to nonlinear polarization rotation, which can act as an artificial saturable absorber for switching. Such a passively Q-switched erbium fiber ring laser has the simple and all-fiber configuration. In addition, passive harmonic mode-locking and chaotic pulses are also generated from the erbium fiber ring laser.
    Proc SPIE 11/2005;
  • Y.J. Song, L. Zhan, J.H. Ji, Y.X. Xia
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    ABSTRACT: We experimentally demonstrate an all-fiber passively Q-switched erbium fiber laser by the symmetrical nonlinear optical loop mirror with nonlinear polarization rotation. And this Q-switched laser has the all-fiber nature.
    Optical Communication, 2005. ECOC 2005. 31st European Conference on; 10/2005