J.H. Ji

Shanghai Jiao Tong University, Shanghai, Shanghai Shi, China

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Publications (7)13.48 Total impact

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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. DOI:10.1016/j.optcom.2007.09.046 · 1.54 Impact Factor
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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. DOI:10.1364/OE.14.010233 · 3.53 Impact Factor
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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
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    ABSTRACT: A new design of all-optical gain-clamped L-band double-pass (DP) erbium-doped fiber amplifier (EDFA) has been proposed and demonstrated, in which the input port and the odd-channel output port of an interleaver are connected with the DP configuration EDF through a circulator to form lasing ring cavity for clamping gain, and the even port is utilized to export the amplified signals. The low noise figure can be achieved because the lasing power copropagates with the signals, and it is exported separately from the amplified signal thanks to interleaver. Meanwhile, the fiber Bragg grating incorporated in DP configuration suppresses the backward amplified spontaneous emission generation, and therefore improves efficiently the gain and lowers the noise figure. In such a way, the clamped gain of 16.3 dB with a variation below 0.2 dB and noise figure below 5 dB are achieved in the new L-band all-optical gain-clamped EDFA.
    Journal of Lightwave Technology 04/2005; DOI:10.1109/JLT.2004.841441 · 2.86 Impact Factor
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    ABSTRACT: We propose and demonstrate a self-seeded multiwavelength Brillouin-erbium fiber laser with an internally self-excited Brillouin pump, which is achieved by incorporation of a length of single-mode fiber together with a Sagnac loop mirror into a fiber ring cavity. In this simple scheme the Brillouin pump is self-excited in the fiber ring cavity and then used to seed the Brillouin multiwavelength comb in the single-mode fiber. Stable generation of more than 120 Brillouin Stokes wavelengths with relatively uniform amplitudes is demonstrated with this scheme. It is also shown that such a self-seeded Brillouin laser has good stability and repeatability.
    Optics Letters 04/2005; 30(5):486-8. DOI:10.1364/OL.30.000486 · 3.18 Impact Factor
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    ABSTRACT: We have proposed and demonstrated a novel multiwavelength Brillouin-erbium fiber laser (BEFL) with a linear cavity, in which, the Brillouin pump is self-excited within the cavity, doesn't require the injection from the external cavity or direct generation within the intracavity. In this scheme, more than 115 Stokes lines with relatively uniform amplitudes have been generated. The experiment also demonstrates that such a self-seeded BEFL performs good repetition and stability for both the operating wavelengths and the output power of each Stokes line. Meanwhile, the effect of the 980nm pump on the performance of the laser is investigated.
    Proceedings of SPIE - The International Society for Optical Engineering 01/2005; DOI:10.1117/12.633276 · 0.20 Impact Factor
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    ABSTRACT: An obvious improvement on both the gain and noise figure (NF) is demonstrated in the new double-pass L-band erbium-doped fiber amplifier (EDFA) with incorporating a fiber Bragg grating (FBG). Compared with the conventional L-band EDFAs, the gain is improved by about 6 dB in the new configuration for a 1580-nm signal with an input power of -30 dBm at 60 mW of 980-nm pump power. It is important that the NF is greatly reduced in the new configuration, as the FBG greatly compresses the backward amplified spontaneous emission. For the economical utility of pump power and erbium-doped fiber length, such a configuration may be a very competitive candidate in the practical applications of L-band EDFAs.
    IEEE Photonics Technology Letters 05/2004; 16(4-16):1005 - 1007. DOI:10.1109/LPT.2004.823697 · 2.18 Impact Factor